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Ontario Division of Mines HONOURABLE LEO BERNIER, Minister of Natural Resources W. Q. MACNEE, Deputy Minister of Natural Resources G. A. Jewett, Executive Director, Division of Mines
E. G. Pye. Director, Geological Branch
MINERAL EXPLORATION TOPICS Ontario Geological Survey GEOSCIENCE DATA CENTRE
RECEDED By
S. A. Ferguson, E.B. Freeman, E.G. Blunden, D. S. Andrews, O. H. Bjarnason, J. A. McCance and E.G. Hamilton
MISCELLANEOUS PAPER 55 1973
MINISTRY OF NATURAL RESOURCES
'ODM 1973
Publications of the Ontario Division of Mines and price list are obtainable through the Mines Publications Office, Ontario Ministry of Natural Resources Parliament Buildings, Queen's Park, Toronto, Ontario and The Ontario Government Bookstore, 880 Bay Street, Toronto, Ontario. Orders for publications should be accompanied by cheque, or money order, payable to Treasurer of Ontario.
Parts of this publication may be quoted if credit is given to the Ontario Division of Mines. It is recommended that reference to this report be made in the following form: Ferguson, S.A., Freeman, E.B., Blunden, E.G., Andrews, D.S., Bjarnason, O.H., Mccance, J.A., and Hamilton, E.G. 1973: Mineral Exploration Topics; Ontario Div. Mines, MP55, 173p.
PREFACE
This book is intended to supplement existing publications that are used by people who are interested in mineral exploration and it is a revision of Lecture Notes to Mineral Exploration Classes published in 1969. Rocks and Minerals of Ontario by D.F. Hewitt has also been revised by D.F. Hewitt and E.B. Freeman and was published in 1972 by the Ontario Department of Mines and Northern Affairs. Two books on related subjects published by the Geological Survey of Canada are Prospecting in Canada, Economic Geology Report No.7, 4th edition/ 1970 by A.H. Lang and Geology and Economic Minerals of Canada, Economic Geology Report No.l, revised 1970, Scientific Editor R.J.W. Douglas. Classes for Prospectors given by the Ontario Bureau of Mines commenced in 1894. Responsibility for the classes has been assumed by the Geological Branch, but at most classes the lecture on claim staking and assessment work has been given by one of the Mining Recorders. Geological lecturers, from the Geological Branch, in recent years, who have left copies of their notes include L.D. Ayres, J.C. Davies, S.A. Ferguson, G.R. Guillet, S.B. Lumbers, V.G. Milne, and J.A. Robertson. These lectures have been revised and new lectures were written during 1968 and 1969 by E.G. Hamilton; at that time O.H. Bjarnason and F.W. Matthews each contributed one topic. Much of the text has been revised, updated, and new material added by the present authors. Art work on the drawings is by R. Balgalvis and his assistants of the Preliminary Map Unit of the Scientific Review Office. Acknowledgment is made to all these people for assembling or assisting in the assembly of these topics for publication. The author and source of certain figures used is given where the illustration occurs in the text.
Stewart A. Ferguson, Chief, Data Retrieval and Education Section, Geological Branch. Queen's Park, Toronto, Ontario. November 10, 1972.
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CONTENTS
Page
Topic
1:
Sources of Information, Revised by E.B. Freeman
Topic
2:
Claim Staking and Assessment Work Requirements, Revised by E.G. Blunden and D.S. Andrews . . . . . . . . . . ......
19
Topic
3:
Prospecting Methods, Revised by E.B. Freeman ............
33
Topic
4:
Tracing Float and Mineral Fragments, Revised by E.B. Freeman and S.A. Ferguson . . . . . . . . . . . . . . . . . . . . . . . . . .
43
Topic
5:
Geophysical Surveys, by E.G. Blunden and J.A. Mccance ...
61
Topic
6:
Geochemical Prospecting, Revised by E.G. Blunden ........
81
Topic
7:
Explosives, Drilling, and Blasting, by O.H. Bjarnason ...
93
Topic
8:
Showing Preparation, Initial Development, and Evaluation, Revised by E.G. Blunden ..................... 105
Topic
9:
Field Mapping and Report Writing, by E.G. Hamilton ...... 117
Topic 10:
Financing Mineral Exploration, Revised by E.B. Freeman .. 127
Topic 11:
The Future of Mining, by S.A. Ferguson .. . . . . . . . . . . . . . .. . 143
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TOPIC l
SOURCES OF INFORMATION
Revised by E.B. Freeman
- 2 CONTENTS
Sources of Information
Page
Introduction ......................................... .............. Ministry of Natural Resources . . . . . . . . . . . . . .. .. . . .. . . . . . . . . .. . . . . . . . Ontario Division of Mines .......... .. . . . . .. . .. . .. . . . . . . . . . . . . . . . Publication and Information Sources . . .. . . . . . .. . . . . . . .. . . . . . . . Publication Lists and Indexes ......... . ... . . . . . . . . . . . . . . . . . . . Ontario Index to Geoscience Data .. .. . .. . . . . . . . . . . . . . . . . . . . . . . Library Facilities ........................ ... .... ... .. .. .... . Geological Branch Services . . . . . . . . . . . .. . .. . . . . . . . . . .. . . . . . . . . Staff . . . . .. . . .. . . . . . . . . . .. . . . . .. . . . . . . . . . .. . . . . . . . .. . . .. . . Mineral Education Courses . . . . . .. . . . . . . . . . . . . .. . . . ... . . . . . .
3 3 3 3 3 5 5 5 5 5
Annual Reports . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . Field Parties and the Summary of Field Work . . . . . . . . . . . . . . . Preliminary Maps . . . . . . .. .. . . . .. . . . . . . . . .. . . . . . . . . . . . . . . . .. Open File Reports, Geological Reports, and Maps ........... Geological Circulars and Miscellaneous Papers . .. . . . . . . . . . . Mineral Resources Circulars . . . . . . . .. . . . . . . . . . . . . . . . . . . ... . Industrial Mineral Reports and Maps . . . .. . . . . . . . .. . . . . . .. . . Geophysical Publications .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Miscellaneous Publications .. . . . . . . . .. . . . . . . . . . .. . . . . . . . . . . Assessment Work Research Library . .. . . . . . . . .. . . . . . . . . . . . . . . Mineral Record Files . . . . . . .. . . . .. . . . . . . . .. . . . . . . . ... . . . . . . Mineral Resources Branch . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . Oil and Natural Gas Well Records . . . . . . . . . .. . . . . . . . . . . . . . . . Annual Reports . . . .. . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . Mineral Research Branch .......... . ........ . .. . .... . .. . . . . .. . . Evaluation and Assaying of Mineral, Rock, and Ore Samples .
7 7 7 7 7 8 8 8 9 9 9 9 9 10 10 10
Consultation Services ...... ............................... Ontario Division of Lands ....................................... Lands Administration Branch ............... .. ...... . . . ... . . ... Determination of Location and Ownership of Mining Lands ... Mining Recorders ... . .. . . . . .. .. . . . . . .. .. .. .. . . .. .. .. . . . . . . . Finance and Administration Division . . . . . . . ... . . . . .. . .. .. . .. . .. . . Information Branch (Mines) . . .. .. . . . . . . . .. . . .. . . . . . . .. . .. . . . . . Annual Review . . . .. . . . . . . .. . . .. . . . . .. .. .. .... .. . . . ......... Historical Booklets . .. . . .. . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . Other Ontario Government Services .............. ... ...... .......... . Aerial Photographs ... . .... . ............ ...................... Topographic, Surficial Geology, and Miscellaneous Maps ....... Large Scale Highway Maps, etc. . . . .. . . . . .. . . . . . . . . . . ... . . .. . . . Soil Survey Maps . . .. . . . . . . . . . .. . . . . . .. . . . . . . . . . . . ... . . . . . .. . . Water Well Records . .. . . .. . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . Travel and Tourist Information . . . . . . . . . . .. . . . . . . . . .. . . .. . . ... Federal Government Information ...... .......... ....... .......... .... Publications and Maps . . .. . . . . . .. . . . ... . . . . .. . . . .. .. .. .. . . . . . . Air Photographs ........................ ............ ..... ..... Other Publication Sources .................... ... ...... ........ .... . Papers, Magazines, Royal Ontario Museum, Universities, etc. .. Telex Communications, Northern Affairs Branch .......... ..... . Index of Services ... .. .. .. . ... . ... . . ... .. .. . . . .. .. .. . . . . . ... .. . . ...
11 11 11 11 11 12 12 12 12 12 12 12 13 13 13 13 13 13 14 14 14 15 15
FIGURE
l. Location of Regional and Resident Geologists ... ...... ...... .....
6
TABLE
l. Index of Geological Maps ........................................
4
SOURCES OF INFORMATION
Revised by E.B. Freeman' INTRODUCTION
Various units within the Ontario and Federal Governments are important sources of information for the mining industry. Additional sources are found in newspapers, magazines, and various miscellaneous reports of universities, museums, mining companies, and individuals. A reorganization is taking place within the Ontario Government which began to take effect in April 1972. At that time the Ministry of Natural Resources was formed to include the former Department of Lands and Forests, the Department of Mines and Northern Affairs, and the Conservation Authorities Branch of the Department of the Environment. Also included in the Ministry are the St. Lawrence Parks Commission and Historical Parks, which were trans ferred from the Department of Tourism and Information and the Niagara Parks Commission, transferred from the Prime Minister's Department. An index of Mining and Related Services is provided at the end of this topic in the hope that it will help the public find the services that they require without being concerned with the organizational structure. MINISTRY OF NATURAL RESOURCES
Ontario Division of Mines Publication and Information Sources Each year much information is published that is of great interest to the mineral exploration industry in Ontario. These maps, geological reports, and other publications may be examined at the Mines Library, Room 1603, Whitney Block, Parliament Buildings, Toronto; at university libraries, at many public libraries, or at the offices of the Regional and Resident Geologists (see Figures l and 2) throughout Ontario. Publications in print may be purchased in person or by mail from the Mines Publications Office, Ministry of Natural Resources, Room 1509, Whitney Block, Queen's Park, Toronto M7A 1W4. Publication Lists and Indexes Bulletin 25 ^1.00) lists the publications of the Ontario Division of Mines from 1891 to 1965 inclusive, and a yearly supplemental list has been issued for the years since 1965. In addition, at various times throughout
^Geological Lecturer,Geoscience Information Office, Geoservices Section (formerly Data Retrieval and Education Section), Geological Branch, Ontario Division of Mines, Ministry of Natural Resources.
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each year, advance notice of forthcoming publications is released. These supplemental and advance notification lists are free, and are recommended to anyone interested in mineral exploration. Persons wishing to be placed on the Division's Notification (mailing) List should send their name and address to the Mines Publications Office, at the address listed above, and request this service. Most areas of Ontario covered by airborne radioactivity and l inch to l mile aeromagnetic surveys are shown on Map 2229, Aeromagnetic Index of Ontario (available free of charge). Specific reports and maps for any particular area of Ontario can be selected by using the previously mentioned publication lists in conjunction with the following geological Index Maps (which are updated at regular intervals), available without charge from the Mines Publications Office.
Table l
Index of Geological Maps
Part of Ontario Covered
Northwestern Ontario West Central Ontario East Central Ontario Northeastern Ontario Southern Ontario
For Preliminary Maps 2088 2082 2079 2085 2091
For Maps in Print 2089 2083 2080 2086 2092
For Out of Print and Miscellaneous Maps 2090 2084 2081 2087 2093
A large amount of printed material is provided free to teachers and students within Ontario. This information is mailed upon request to people interested in or working on, a project related to mines, geology, minerals, or the mineral industry. A most helpful source of information is 'Rocks and Minerals Information 1 , a free booklet revised yearly, which gives selected references to maps and reports of general interest, industrial mineral reports, books on rock and mineral collecting, certain publications of the Geological Survey of Canada and the Mineral Resources Division of the Department of Energy, Mines and Resources, company brochures, and names and addresses of rock and mineral dealers, and of lapidary and mineral clubs in Ontario.
Requests for this type of information should be addressed to the Mines Publications Office, Ministry of Natural Resources. There are seven General Index Volumes published which sell for $1.00 each. These indexes list references by subject and report number to all reports of the former Ontario Department of Mines. Usually in a library search where a 'start from scratch 1 is required, these indexes will provide the first specific map and report references covering the area or subject being investigated. For example, looking up the names such as Vermilion River, Dog Lake, drag folds, uranium, or copper, all of which are listed alphabetically as in a telephone book, will provide specific references to the maps and reports in which these subjects are mentioned.
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Once known, those references that appear to be of interest can be ordered from the Mines Publications Office, or the references may be studied by a visit to the nearest library that contains Division of Mines publications, or at the office of a Regional or Resident Geologist. Ontario Index to Geoscience Data Microfiche copies of the Ontario Index to Geoscience Data 1971 may be examined at the Mines Library, Room 1603, Whitney Block, Queen's Park, and at the offices of the Regional or Resident Geolotists. This computer-based index is produced cooperatively by the Geological Branch, Ministry of Natural Resources, and the Canadian Centre for Geoscience Data, 601 Booth Street, Ottawa K1A OE8. Key words or concepts used in the index are contained in a Thesaurus. Documents covered in the present index are all current publica tions of the Geological Branch to the end of 1971, the Annual Reports for the years 1950 to 1969, Assessment Work Reports 1960 to 1967, Geological Survey of Canada publications up to March 1969, and records of mineral occurrences compiled by the Mineral Resources Branch, Ottawa. Arrangements can be made to purchase duplicate copies of the microfiche cards through the Geoscience Data Centre of the Geological Branch. Library Facilities The Mines Library, located on the main floor, Room 1603 of the Whitney Block, at the southeast corner of Queen's Park Crescent and Wellesley Street, Toronto, provides facilities for consultation and study in the Library of most maps, reports, and publications pertaining to the mining industry of Ontario. Facilities are available for copying material of interest at a modest cost. Information concerning the availability of texts, maps, reports, etc., can best be acquired by first telephoning the Library (416) 965-1352. Greater use of the Library services by the mineral exploration industry is desired. Geological Branch Services Staff; With more than 50 staff geologists, the Division of Mines can provide much fundamental information concerning the mining industry of Ontario. Use should also be made of the facilities provided exploration personnel for geological library search and assessment record search. Consultation with District Mining Recorders and Regional and Resident Geologists is highly recommended. Mineral Education Courses: A number of Mineral Exploration Courses are offered throughout Ontario each year to aid persons interested in prospecting and rock and mineral identification. A Special Topics Course dealing with specific aspects of mineral exploration is offered each year at Toronto. Other Special Topics Courses are offered from time to time elsewhere in the province when sufficient demand is shown. Both of these courses are open to anyone interested and there is no registration charge.
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V Trout L PA T R l Cl Winisk
O
Miles 50 100
ISO
h-M
80 160 Kilometres
COCH RANE
240
Regional Geologist's Office Resident Geologist's Office Boundary of Resident Geologist's District in 1972 Boundary of Territorial District
RED LAKE
ONTARIO GOVT. BLD6.
KENORA
808 ROBERTSON ST.
468-9085
THUNDER BAY
179 S. ALGOMA ST.
345-8603
SAULT STE MARIE
370 LAKE ST.
254-1791
SUDBURY
1540 B LA SALLE BLVD.
566-2580
TIMMINS
60 WILSON AVE.
264-4262
KIRKLAND LAKE
4 GOVERNMENT RD. E.
567-5242
LONDON
458 CENTRAL AVE.
433-8431
RICHMOND HILL Revised to March, 1973
80"
965-1182
Figure 1 LOCATION OF REGIONAL AND RESIDENT GEOLOGISTS ONTARIO DIVISION OF MINES MINISTRY OF NATURAL RESOURCES
(for information)
ODM, MP55
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A practical Field work Course is offered each year near Madoc, Ontario. The emphasis in this course is upon 'learning by doing 1 . A laboratory exercise in the evening is followed by field work on the same subject the next day. Subjects covered are drilling, handling explosives, blasting, claim staking, geological mapping, and some geophysical and geochemical methods. Registration is $20.00 and is restricted to 20 participants per course. Annual Reports; An Annual Report was first issued in 1891 by the former Ontario Bureau of Mines. Until 1959, the Annual Report was divided into separate books or parts each year and contained most final geological reports. From 1961 to 1970, the Annual Report was restricted to the report of the Mines Inspection Branch containing statistics on Ontario's mines and their production. Beginning with Volume 81, 1971, the Annual Report has been produced by the Mineral Resources Branch. Field Parties and the Summary of Field Work; Each summer season, the Geological Branch sends out about 30 field parties to perform basic geological mapping. After the field season a brief summary of each of these surveys, usually including at least one paragraph on economic possibilities, is issued in November or December of that year. Any new information of economic importance such as the location of new showings or structural and geologic conditions favourable for new showings is published in this report. Occasion ally important new exploration targets are first published in this report. Each spring the Division of Mines releases information on field personnel and field party locations. Company and individual exploration personnel are welcome to visit these field crews during the field season. Preliminary Maps; Uncoloured preliminary maps are released as soon as they are completed after the summer field season at a cost of 50C each. These very useful maps, with their marginal notes, provide prospectors and mining companies with new easily located information soon after field work is completed. Occasionally new showings are located on these maps. Open File Reports, Geological Reports, and Maps; A final report contain ing more detailed descriptions of the geology and mineral occurrences is published after completion of field mapping and any necessary laboratory work. This is first issued as an 'Open File Report 1 (OFR) in order to make the report and maps available without the delay required by editing and map preparation for final publication. Open File Reports can be consulted by a visit to the Mines Library in Toronto or by visiting the particular Regional or Resident Geologist's office in whose area the field work was carried out. Arrangements can be made for photocopying all or part of these reports. After final editing, the report and coloured maps are printed and issued as a Geological Report (GR). Coloured geological maps without reports are issued from time to time of parts of Ontario. These coloured maps are usually published one or two years after the preliminary maps of the area are issued. Geological Circulars and Miscellaneous Papers; Geological Circulars (GCs) were published from approximately 1955 to 1966 and contain reports on various specific topics. Information of interest to the rock and mineral collector can be found in several of these circulars. At present, the Miscellaneous Paper (MP) has assumed the function of the Geological Circular.
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Miscellaneous Papers contain the annual Summary of Field Work report, the Annual Report of the Resident Geologists, and special topics of interest to mining exploration in Ontario. Mineral Resources Circulars: A Mineral Resources Circular (MRC) contains useful compilations of a particular type of mineral showing in Ontario. For example, if the price and interest in copper is high and a study and evaluation of all the copper showings in a selected area is to be performed, Mineral Resources Circular 12, which lists, locates, and describes most of the copper deposits in Ontario, provides an excellent start. This manual lists both developed showings, which are usually staked, and many miscellaneous small showings. A search of the present mineral title status covering showings of interest may be done through the Lands Administration Branch, Ministry of Natural Resources, Whitney Block, Parliament Buildings, Toronto, or the district Mining Recorder. Copper showings of merit that are 'open 1 may be acquired by staking, and exploration programs near these favourable environ ments started. The following deposits have been summarized to date: copper-nickel-leadzinc, pyrite, iron, uranium and thorium, phosphate, molybdenum, phlogopite mica, gold, columbium (niobium), and silver-cobalt-calcite vein deposits. Industrial Mineral Reports and Maps: These reports consist of studies of industrial minerals or Pleistocene (Quaternary) geology of selected areas and of the following reviews: asbestos, barite, building stones, clay products, feldspar, fluorspar, graphite, gypsum, kyanite and sillimanite, limestone, marl, pegmatites, salt, sand and gravel, silica,talc, and vermicu lite and perlite. Many of these products are relatively easy to identify in the field and should be known to any prospector. Geophysical Publications; Included in this category are a few reported investigations of geophysical surveys and anomalies in Ontario plus many airborne magnetic and radioactivity maps. The former Ontario Department of Mines participated in producing 116 maps at a scale of 4 inches to l mile from surveys taken from 1952 to 1958. Aeromagnetic maps at a scale of l inch to l mile, covering about three-quarters of Ontario, were prepared by the former Ontario Department of Mines in conjunction with the Geological Survey of Canada. These maps are very useful in mineral exploration and can be acquired from either the Publications Office, Geological Survey of Canada, 601 Booth Street, Ottawa KlA OE8, Ontario; or Mines Publications Office, Ministry of Natural Resources, Whitney Block, Queen's Park, Toronto M7A 1W4, Ontario. A free index map to the l inch to l mile surveys in which the Division of Mines participated is available from Toronto as Map 2229, Aeromagnetic Index of Ontario. Geophysical compilation maps at a scale of l inch to 16 miles are also available as follows for all of Ontario: Northwestern Ontario, Map P.575, Sachigo River Sheet and Map P.577, Ogoki River Sheet; Northeastern Ontario, Map P.576, Ekwan River Sheet, and Map P.578, Albany River Sheet; Southern Ontario, Map P.800, Great Lakes-Ottawa River Sheet. A set of files containing information on various geophysical instruments and installations is available for reference in the Mines Library in Toronto. Starting in 1973, a series entitled Geophysical Reports will be initiated.
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Miscellaneous Publications; These publications consist mainly of outof-print Bulletins dealing with the geology/ mining, mineral production, accident statistics, and mining legislation of Ontario. All of these publi cations can be consulted in the Mines Library in Toronto. It should be noted that not all of these publications are out of print. A new publication series of Geochemical Reports is planned to begin during 1973. Assessment Work Research Library; The assessment record files available for free consultation consist of all the geological, geophysical, geochemical, airborne, and radiometric surveys that have been filed for assessment work credits since 1941. In addition, all diamond drill logs submitted for assessment work credit since April l, 1969 and thousands of logs filed earlier are available for inspection. A complete set of available data for Ontario is filed in Room 1606, Whitney Block, Queen's Park, Toronto. Each Regional and Resident Geologist also has a complete assessment work file for his own area. A thorough target area search would require consultation with both the Toronto and Regional or Resident Geologist's assessment work data. Much important information is available from the local Mining Recorder or the Regional or Resident Geologist, such as names and addresses of prospectors, bushmen, and geologists who may have worked in previous surveys in the proposed target area under investigation. Mineral Record Files; Source Mineral Deposit Records are a system of files that summarize the known data on location, development, ownership, geology, ore minerals, reserves, production, references, etc. for each known occurrence of a mineral. Files are complete for uranium deposits and partially complete for copper, nickel, lead, and zinc deposits. The files are located in the Geoscience Data Centre, Geoservices Section, Whitney Block, Queen's Park, and any file that has been completed is available for the cost of making a photocopy. Computer mineral records for uranium deposits are complete and are installed on the Univac 1106 computer at Queen's Park, and work is in progress to expand the system to include copper, nickel, lead, and zinc deposits. Access to the computer file is made by making a request through the Mines Publications Office, Room 1509, Whitney Block, Queen's Park, Toronto. Mineral Resources Branch Oil and Natural Gas Well Records; The Petroleum Resources Section of the Mineral Resources Branch has up-to-date information submitted by petroleum exploration companies from the Phanerozoic rocks of Ontario. Various technical publications and some maps from a variety of sources dealing with the geology and stratigraphy of southwestern Ontario are also available here. Mail orders or a visit should be made to the Petroleum Resources Section, Mineral Resources Branch, Ontario Division of Mines, Ministry of Natural Resources, Whitney Block, Queen's Park, Toronto M7A 1X3. All the well chip samples and rock cores collected from drill tests, including the base metal tests on the Bruce Peninsula are stored at the Petroleum Resources Section offices at 458 Central Avenue, London, N6B 2E5, Ontario, where they may be examined.
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Annual Reports; The Annual Reports produced by this Branch (formerly produced by the Mines Inspection Branch) give statistics of the mineral industry and mining operations in Ontario for the previous calendar year. These reports contain much information on operating mines and quarries; the prices of metals, nonmetallic minerals, and structural products; and the dividends paid by mining companies. The statistical files of this Branch contain the records of mineral production and operating statistics of indivi dual mining properties for each year. Mineral Research Branch Evaluation and Assaying of Mineral, Rock, and Ore Samples; The Mineral Research Branch provides free mineral and rock sample evaluation by visual inspection and radioactivity testing only. Parcels containing samples should be forwarded by prepaid mail or express to the Mineral Research Branch, Division of Mines, Ministry of Natural Resources, 77 Grenville Street, Toronto M7A 1X3. Specific instructions should be forwarded with the rock or mineral samples as charges are made if any special work or analysis is required to comply with a client's request. All mining license holders in Ontario are eligible for two free assay coupons for each claim recorded up to a total of 18 coupons per license year. For example, a 9-claim group is eligible for 18 free gold, silver, or copper assays within two years after the claims have been staked and recorded. Two further free assay coupons per claim are provided for each 40 days assessment work recorded thereon. The current schedule of free coupon assay determinations follows:
l Assay Coupon Gold *Silver *Copper *Lead Iron Insoluble (silica)
2 Assay Coupons Aluminum *Antimony *Arsenic Barium *Bismuth Calcium Carbon *Chromium *Cobalt Ferrous iron Magnesium *Manganese
*Mercury *Molybdenum *Nickel Phosphorous Silica Strontium Sulphur *Tin *Titanium *Tungsten *Vanadium *Zinc
3 Assay Coupons Platinum Palladium *Cadmium Calcium and magnesium Cesium Fluorine *Lithium *Niobium (columbium) Potassium Sodium
4 Assay Coupons Platinum and palladium *Beryllium *Cerium Gadolinium *Germanium Lanthanum Selenium Sodium and potassium *Tantalum *Tellurium * Thorium *Uranium *Yttrium *Zirconium
* In addition to the above, a real bargain exists where for two of these coupons the 29 asterisked elements are determined semi-quantitatively within a sample.
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Consultation Services; The staff of the Mineral Research Branch are available for consultation with mineral exploration companies and individuals to assist in solving special problems involving: a) mineral dressing tests; b) reference analysis of samples to check results of other laboratories; c) analysis of difficult samples for elements not usually determined by private industry; and d) new processes or mines that require special assay and mineral dressing services or research not usually provided by commercial laboratories. Ontario Division of Lands Lands Administration Branch Determination of Location and Ownership of Mining Lands; The Lands Administration Branch possesses the facilities, records, and information for the determination of the location and ownership of mining properties and can provide copies of maps and records at cost as follows: a) Claim maps showing patented, leased, license of occupation, and unpatented mining claims; b) The name and address of the taxpayer on patented claims who generally is the owner; c) The name and address of the staker or holder of unpatented mining claims; d) Records and results of previous exploration surveys and drilling filed as assessment work. It should be stressed that much of this information and search into the status of mineral rights in target areas is provided free. In fact, this search into previous exploration history and present claim title status is probably the most important part of general mine finding research procedure. The members of the Lands Administration Branch, Whitney Block, Queen's Park, Toronto, and the Mining Recorders of the various mining divisions welcome the exploration industries' participation in this search and information service by telephone or visit. Personal visits are usually the more valuable. The information on claim maps and assessment work reports may be studied and copied at Toronto or the various Regional and Resident Geologist's and Mining Recorder's offices throughout Ontario. A holder of an individual miner's license is entitled to five free claim maps per license year, with any further claim maps costing the usual 50C each. There are about 3,300 claim maps covering a large part of Ontario, each providing a reference and base map over 36 to 100 square miles. These maps show the current claims and mineral holdings of staked and open ground. Since each claim is numbered on the claim map with the corresponding number on the claim posts in the field, new showings or general field data can be plotted on the map and located by reference to these posts. Mining Recorders; The Mining Recorder has duties related to unpatented mining lands. Therefore, the Mining Recorder is able to supply information on miner's licenses, claim staking, claim recording, and claim assessment work required to maintain a claim. Information concerning the method of claim staking and recording is provided in the office consolidation of the Ontario Mining Act, and a summary pamphlet, both of which are supplied free by any Mining Recorder's office. It is usually wise to see or telephone the Mining Recorder before going to the field thus preventing costly mistakes. The
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regulations concerning assessment work in order to retain claims for more than one year after staking are also provided in the free Mining Act consolidation as well as in a summary pamphlet. Knowledge of assessment requirements before planning an exploration program is usually essential. Finance and Administration Division Information Branch (Mines) This section releases information to newspapers, prepares displays and exhibits for showing at various localities around the Province, and distri butes various articles of interest to the general public. Annual Review; The free Annual Review of the Division of Mines is an excellent source of current information about mining activity and production in Ontario. Historical Booklets: A series of non-technical booklets have been written dealing with the development of the mining industry, a part of the mining industry, or a particular mining area. These publications are distri buted free of charge and include the following subjects: Ontario Mining The Early Years; Ontario's Mineral Heritage; Iron Mining; Oil and Gas in Ontario (written by Petroleum Resources Section); Cobalt, Elliot Lake, Porcupine, Manitouwadge, Red Lake, and Kirkland Lake. OTHER ONTARIO GOVERNMENT SERVICES Aerial Photographs
Ontario government aerial photographs are available from the Ontario Division of Forests, Ministry of Natural Resources, Room 3501, Whitney Block, Queen's Park, Toronto. Vertical aerial photographs (contact prints) at a scale of l inch to h mile for Ontario, south of Latitude 53ON and covering an area of about 5 square miles are available for $1.31 per copy. Enlargement of parts of these air photos are also available at various scales and prices. Photo mosaics may be acquired for parts of Ontario (primarily southern Ontario) at scales of l inch to l mile at $2.10, l inch to \ mile at $5.78, and l inch to \ mile at $6.30 each. Topographic, Surficial Geology, and Miscellaneous Maps Most topographic maps of Ontario are available at a nominal charge of about 50C each, including the very useful 1:25,000, 1:50,000, and 1:125,000 National Topographic Series. Smaller scale topographic maps and maps of the Provincial Series (1:126,720) showing cultural features and lands alienated from the Crown may also be obtained at 50C each from the Division of Lands, Map Distribution Office, Whitney Block, Queen's Park, Toronto. Maps showing surficial geology on a scale of l inch to 8 miles over large sections of Ontario are available for a cost of about $2.00 per map from this office, and some other maps at various scales and prices are also available.
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Large scale base maps at a scale of l inch to h mile are available for about $2.00 each showing topographic features in areas that generally have no other suitable map coverage. This scale is well suited to exploration work and these maps make very satisfactory field base maps for plotting data. Large Scale Highway Maps, etc. Highway information and yearly revised road maps are available free by writing the Map Office, Ministry of Transportation and Communications/ East Building, Downsview, Ontario. In addition, some of the various county and district highway maps, which may be purchased from the above office, make excellent reconnaissance base maps for plotting field data. In particular 'white prints' of various Districts and Counties in Ontario usually on a scale of l inch to 2 miles are useful. Soil Survey Maps Soil Survey Reports and maps which contain some geological information and might be used as a base map may be seen by visiting the local Agricultural Representative or ordered from the Information Branch, Ministry of Agriculture and Food, Parliament Buildings, Toronto. If soil investigation reports of bore hole investigations by the Ministry of Transportation and Communications are of interest, they may be obtained from that Ministry. Water Well Records The Water Resources Division, Ministry of the Environment, has compiled and published about nine Ground Water Bulletins. Each Bulletin contains information and brief descriptions of the geology and rock chips encountered in thousands of water well holes drilled in Ontario. These Bulletins containing the water well drill log data can be studied at some public libraries and at the Water Quality Management Branch, Ministry of the Environment, 7th floor, 40 St. Clair Avenue West, Toronto. Since thousands of water wells are drilled each year, this drill hole data could provide a very substantial source of new exploration leads each year. Travel and Tourist Information The Ministry of Industry and Tourism provides literature, maps, and information as to locations of Provincial and tourist parks, campsites, and historical features in Ontario. Copies of the general highway maps (obtainable free) of northern Ontario or of the entire province are also available from this Ministry, at Hearst Block, 900 Bay Street, Toronto. FEDERAL GOVERNMENT INFORMATION Publications and Maps
Information Canada bookshops are located at 221 Yonge Street, Toronto, and in Ottawa at the corner of Mackenzie and Rideau Streets. These bookshops contain most of the publications in print of the Geological Survey of Canada, but they do not carry maps that are not included with a report. Geological maps of the Geological Survey are obtainable from the Publications Office,
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Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario. Topographic maps are available from the Surveys and Mapping Branch, Department of Energy, Mines and Resources, 615 Booth Street, Ottawa, Ontario, from the Information Canada Bookshop in Toronto, or from the Ministry of Natural Resources, Map Distribution Office in Toronto. Two publications of special interest to the prospector are 'Geology and Economic Minerals of Canada 1 (1970) price $20.00, and'Prospecting in Canada 1 (1970) price $10.00. Air Photographs The National Air Photo Library is in the Surveys and Mapping Branch of the Department of Energy, Mines and Resources, 615 Booth Street, Ottawa. Aerial photographs for any area in Canada and at any scale can be examined at this library and orders placed here for the photographs desired. The l inch to l mile photo-mosaic maps used as the base for aeromagnetic plotting west of Hudson Bay may also be obtained here. Photographs may be ordered by mail if the exact area for which photographic coverage is required is indicated on a map. Indicate as well whether you wish a matte or glossy finish and if stereoscopic coverage is required. OTHER PUBLICATION SOURCES Papers, Magazines, Royal Ontario Museum, Universities, etc. The Northern Miner, a weekly newspaper specializing in mining news, is published in Toronto and can be obtained by subscription. The Canadian Mines Handbook, published each year, providing information on active or recently active mining companies in Canada, and the book Mining Explained, which explains geology and rock structures, the financing of mining companies, and mine exploration and operation, are both available as well from the Northern Miner Press Limited, 77 River Street, Toronto. Other newspapers besides The Northern Miner frequently carrying news about Ontario's mining industry are The Globe and Mail and The Financial Post. This latter newspaper produces the annual reports Survey of Mines and Survey of Oils. Magazines containing articles of interest about mining and geology in Canada particularly are the Canadian Mining Journal, and the Canadian Mining and Metallurgical Bulletin. The Canadian Mining Journal reports recent developments in mining across Canada, publishes each February a yearly review of Canadian and Provincial mineral production, summarizes many papers presented at the yearly Prospectors and Developers Convention held in Toronto, and publishes much technical information about mining. The Canadian Mining and Metallurgical Bulletin primarily contains technical papers dealing with mines and mining in Canada. The Royal Ontario Museum publishes a number of pamphlets, etc., which are of general interest and may be obtained from the Royal Ontario Museum, Sales Desk, 100 Queen's Park, Toronto, Ontario.
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Most geology or geography departments of universities have some information of interest to the field mineral collector or prospector. With regard to maps/ the collection at the University of Toronto Library, is excellent. A comprehensive collection of topographic maps from all parts of the world in addition to many geological maps from Canada, the United States, and Alaska is available in Room 617, Sidney Smith flail at the university. This map library, complete with light tables and xerox facilities, is open from 9 am to 5 pm each weekday and,during the school year, is also open most nights until 9 pm. Telex Communications, Northern Affairs Branch For communication with the Toronto offices and other parts of the Ontario Government, the Northern Affairs Branch of the Ministry of Natural Resources maintains telex service at the following locations: Atikoken,Clinic Bldg., 123 Marks St. South, P.O. Box 788 Blind River, 13 Lawton St., P.O. Box 760 Cochrane, 161 Sixth Ave. Dryden, 7 King St. Elliot Lake, 114 Ontario Ave. Espanola, 100 Tudhope St., P.O. Box 1718 Fort Francis, Court House, P.O. Box 717 Geraldton, 103 Main St., P.O. Box 69 Kapuskasing, 42 McPherson Ave. Kenora, Court House Bldg., P.O. Box 139 Kirkland Lake, 32A Prospect Ave, P.O. Box 635 Marathon, Peninsula Blvd., P.O. Box 280 Moosonee, Provincial Government Bldg., P.O. Box 307 New Liskeard, 49 Armstrong St., P.O. Box 68 North Bay, 267 Main St. West Red Lake, 242 Howey St., P.O. Box 950 Sault Ste. Marie, 370 Lake St. Sioux Lookout, Provincial Court House, P.O. Box 147 Sturgeon Falls, 191 Main St., P.O. Box 1178 Sudbury, 15 Frood Rd. Thunder Bay, 140 South May St. Timmins, 60 Wilson Ave. Wawa, 37 Broadway St., P.O. Box 1370
(operator) (705) (705) (807) (705) (705) (807) (807) (705) (807) (705) (807) (705) (705) (705) (807) (705) (807) (705) (705) (807) (705) (705)
333-2701 356-2226 272-4274 223-5231 848-7133 869-1532 274-5329 854-0266 335-6008 468-5548 567-3291 229-1153 336-2991 647-7391 472-3911 727-2870 254-6623 737-1318 753-2900 675-1176 623-5518 267-1463 856-2354
INDEX OF SERVICES Ontario Division of Mines and Related Parts of the Ministry of Natural Resources Accidents, mining (investigation, reports), Whitney Block Accounts payable, Mines, Whitney Block Administrative Services, Whitney Block Aeromagnetic Maps, Whitney Block Assessment Work Submissions, Whitney Block Assessment Work Research Office, Whitney Block
965-1328 965-2461 965-2711 965-1348 965-6918 965-6139
Base Metal Deposits, Whitney Block
965-4641
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Cable and Rope Testing Laboratory, Whitney Block Cartography Section, Whitney Block Chemical Analyses, 77 Grenville Street Claim Maps, Whitney Block Claim Staking, Whitney Block Complaints, investigation re mining operations, quarries, gravel pits, Whitney Block Computer File, Mineral Deposits, Whitney Block
965-1327 965-1198 965-1337 965-1349 965-1323
Data Retrieval, Whitney Block Deputy Minister, Ministry of Natural Resources, Whitney Block Diamond Drill Logs, Whitney Block Disputes, Mining Land, 5th floor, Mowat Block
965-4641 965-2704 965-6139 965-1826
Education, Geological, Whitney Block Electrical Inspection, Whitney Block Employment, Ministry of Natural Resources, Whitney Block Energy Board, Energy Studies, 790 Bay Street Executive Assistant to Minister, Ministry of Natural Resources, Whitney Block Executive Director, Division of Mines, Whitney Block Exhibits, Mining, Whitney Block Exploration Classes, Whitney Block
965-4641 965-1328 965-2707 965-2851 965-6451 965-4271 965-1345 965-4641
Fatalities, Mines, Whitney Block Files, Assessment Work, Whitney Block Files, Mineral Records, Whitney Block Film Library, Whitney Block Fire Assaying, 77 Grenville Street Forest Resources Inventory Maps, Whitney Block
965-1328 965-6139 965-4641 965-2758 965-1337 965-6914
Gas and Oil Drilling, 880 Bay Street Geochemical Analyses, 77 Grenville Street Geochemical Surveys, Whitney Block Geological Branch, Director, Whitney Block Geological Field Parties, Whitney Block Geological Lecturer, Whitney Block Geological Surveys, Whitney Block Geologist, Chief, Whitney Block Geology, Environmental, Whitney Block Geology, Equipment, Whitney Block Geology, Guidebooks, Whitney Block Geology, Map Preparation, Whitney Block Geology, Maps and Reports, Whitney Block Geophysical Surveys, Whitney Block Geoscience Data Centre, Whitney Block Granted Lands, tax and rentals, Whitney Block Gravel and Sand Pits, Whitney Block
965-1981 965-1337 965-7046 965-1283 965-1321 965-4641 965-1321 965-1321 965-1182 965-1466 965-1349 965-1198 965-1349 965-7047 965-4641 965-1319 965-1182
Hoisting Ropes and Cable Testing, Whitney Block
965-1327
Indexing, Ontario Index to Geoscience Data, Whitney Block Industrial Minerals, Whitney Block Information Mines, General, Whitney Block Information Ministry, General, Whitney Block
965-4641 965-1182 965-1345 965-3315
965-1328 965-4641
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Information, Northern Affairs, 26 Breadalbane Street Inquests on Mine Fatalities, Whitney Block Inspections, Electrical, Whitney Block Inspections, Mechanical, Whitney Block Inspections, Mines, Whitney Block Inspections, Mining Claims, Whitney Block Inspection, Pits and Quarries, Whitney Block
965-7577 965-1328 965-1328 965-1328 965-1328 965-1380 965-1328
Laboratory Work, 77 Grenville Street Leasing and Acquisition, Mining Lands, Whitney Block Library, Mines, Whitney Block License, Miner's, Whitney Block
965-1337 965-1380 965-1352 965-1323
Map Making, Cartography, Whitney Block Map Distribution, Mines, Whitney Block Map Office, Topographic Maps, Whitney Block Mechanical Inspection, Whitney Block Metallurgical Inspection, Whitney Block Mine Assessor, Whitney Block Mine Rescue Training, Whitney Block Miner's License, Whitney Block Mines Engineering, Director, Whitney Block Mineral Economics, Whitney Block Mineral Education Classes, Whitney Block Mineral Identification, 77 Grenville Street Mineral Resource Records, Whitney Block Mineral Sets Purchase, Whitney Block Mineral Research Branch, 77 Grenville Street Mineral Resources Branch, Whitney Block Mineralogical Work, 77 Grenville Street Minerals and Rocks Identification, 77 Grenville Street Mining Claims Inspection, Whitney Block Mining Claims Surveys, Whitney Block Mining Lands Acquisition and Leasing, Whitney Block Mining Regulations Underground, Open Pits, Quarries, Whitney Block Minister, Ministry of Natural Resources, Whitney Block
965-1198 965-1349 965-6511 965-1328 965-1328 965-1311 965-1328 965-1323 965-1328 965-1016 965-4641 965-1337 965-4641 965-1349 965-1337 965-1675 965-1337 965-1337 965-1380 965-1187 965-1187
Northern Affairs, 26 Breadalbane Street
965-7577
Oil and Gas Drilling, 880 Bay Street
965-1981
Personnel Inquiry, Whitney Block Petrological Services, 77 Grenville Street Photographs, Air, Whitney Block Pits and Quarries Inspection, Whitney Block Prospector's License, Whitney Block Public Relations and Mines Information, Whitney Block Publications Distribution, Mines, Whitney Block Purchasing, Whitney Block
965-2707 965-1337 965-6914 965-1328 965-1323 965-1345 965-1349 965-1601
Radiometric Analyses, 77 Grenville Street Rock Testing, 77 Grenville Street Rope and Cable Testing, Whitney Block
965-1337 965-1337 965-1327
965-1328 965-1301
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Sand and Gravel Deposits, Whitney Block Sand and Gravel Pit Regulations, Whitney Block Sand Testing, 77 Grenville Street Spectrographic Analyses, 77 Grenville Street Staking Claims, Whitney Block Statistics, Mineral, Whitney Block Stone Testing, 77 Grenville Street Student Employment, Geological, Whitney Block Surveys, Geological, Whitney Block Surveys, Mining Claims, Whitney Block Systems and Proceedures, Whitney Block
965-1182 965-1328 965-1337 965-1337 965-1323 965-1016 965-1337 965-1321 965-1321 965-1187 965-5671
Tax Payments for Mining Lands, Whitney Block Tax and Rental of Granted Lands, whitney Block Tax and Rental Rolls, Whitney Block Taxation Information, Mining, Whitney Block Thin Section of Minerals, 77 Grenville Street
965-1319 965-1319 965-1319 965-1319 965-1337
Underground Workings, Plans, Whitney Block Uranium Deposits, Whitney Block
965-1328 965-4641
White Prints, Claim Maps, Whitney Block
965-1187
X-ray Analyses, 77 Grenville Street
965-1337
Renewable Resources (Forests, Lands, Parks, Waters) Air Photographs, Whitney Block
965-6914
Conservation Information, Whitney Block
965-2756
Films and Exhibits, Whitney Block Forest Resources Inventory Maps, Whitney Block
965-2758 965-6914
Library, Ministry of Natural Resources, Whitney Block
965-6310
Map Office, (purchase of maps and publications) Whitney Block
965-6511
Photos and Slides, Purchase (lands, waters, wildlife, trees, forest activities), Whitney Block
965-2756
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TOPIC 2
CLAIM STAKING AND ASSESSMENT WORK REQUIREMENTS
Revised by E.G. Blunden and D.S. Andrews
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CONTENTS Claim Staking and Assessment Work Requirements Page Introduction .. ... ........................... ... .... ... .. . .. . .. .. . . . . Prospectors' Licenses .. ...... .. .... ... .. ... ... .. .. .. . . .. .. .......... Rights of Licensee .................................. ..... . ...... . Lands Open for Staking ............ .... .. . ... .. .... ... ... .. .. . . . . .... Lands Not Open for Staking .......................................... Size and Form of Claims ........................ .... ... .. ... .. . . . .. .. Staking Procedure ......... .. ..... ... ... .. ... .. .. . . . .... . . .. . . . .. . .. . Recording of Claims ........................................... . .. ... Pre-tagged Claims ................................................ Transfers . ...... ... .... .. . . ..... . ................................ Assessment Work . . ... . . .. .. . .. .... .. . ... ... ... .. ... . .. . .... . . ........ Grouping of Work ................................................. Survey ... ........................................................... Automatic Forfeitures ... .. . .. . ... ...... .... .. . .. .... . . .. . . . . .. ... .. . Extensions ... ... . .. ... . .. ... . ... ... . .. ... ... ... .................. Death of Licensee ................................................... Compensation for Surface Rights .. .. ... .. .. . .. .. . . ... . . . .. . . .. ... ... . Certificates of Record and Work . .. ..... ...... ....................... Issue of Lease ......................................................
23 23 24 24 24 25 26 26 28 28 28 29 29 29 30 30 30 30 31
FIGURE 2.
Location of Mining Recorders' Offices .. .. ... ... .... . ... . . . . . .. . .
22
TABLE 2.
Type of Assessment Work and Credits . ... ... ... .... .. .. ... .. . .. . ..
27
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96*
75'
K'-
-55'
LOCATION OF MINING RECORDERS' OFFICES MINING LANDS BRANCH ONTARIO DIVISION OF LANDS MINING DIVISION RED LAKE
MINING RECORDER V. TUKKANEN
KENORA
H. L. BELL
PATRICIA
W. A. BUCHAN
THUNDER BAY
R. POUTANEN
SAULT STE. MARIE PORCUPINE
D. A. JODOUIN R. DENOMMEE
SUDBURY LARDER LAKE
P. LOGEE
EASTERN ONTARIO
D.S.ANDREWS
to More* 1,1973
ADDRESS ONTARIO GOVERNMENT BUILDING. RED LAKE 808 ROBERTSON ST. KENORA COURT HOUSE SIOUX LOOKOUT 179 SOUTH ALGOMA ST. PORT ARTHUR 75 ELGIN ST. SAULT STE. MARIE 60 WILSON AVE. TIMMINS 11 8 CEDAR ST. SUDBURY 4 GOVERNMENT RD. E. KIRKLAND LAKE ROOM 1506, WHITNEY BLOC QUEEN'S PARK. TORONTO.
85'
Figure 2
OOM, HP 55
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CLAIM STAKING AND ASSESSMENT WORK REQUIREMENTS
Revised by E.G. Blunden 1 and D.S. Andrews 2 INTRODUCTION
The Province of Ontario owns and administers all public lands within its boundaries except Indian Reserves and National Parks, these being under the jurisdiction of the Federal Government. The principal statute concerning mines and the mineral industry of Ontario is the Mining Act, R.S.O. 1970, Chapter 274, with amendments. Mineral rights to such public lands are allowed under a system of lease from the Crown upon completion of acceptable assessment work and certain other prerequisites. If production of minerals in quantity is achieved, a freehold may be acquired. Where the surface rights are available the appli cant may elect to have them included in the lease but they may be used only in connection with mining operations. Where the surface rights are not available through the Crown, the prospector and miner must compensate the surface owner for any injury or damage caused to the surface rights. To provide optimum service and convenience, nine Mining Divisions have been established, each with a resident Mining Recorder and Mining Claims Inspector. Up to the time of grant of a lease, all applications and documents affecting available mining claims are filed in the office of the Mining Recorder in whose district the claims are situated. Leased and freehold lands are registered under a land titles system or registry system, all relevant documents being filed in the appropriate local Land Title Registry Office. Questions and disputes arising out of the application of the Mining Act are first adjudicated by the local Mining Recorder and are subject to appeal to the Mining Commissioner. Judgments or orders of the Commissioner may be appealed to the Court of Appeal for Ontario and thence to the Supreme Court of Canada if necessary.
PROSPECTORS' LICENSES
Before one may prospect for minerals and stake out mining claims on Crown Lands or lands of which the mining rights are reserved to the Crown in Ontario, it is necessary to acquire a Prospector's License, formerly called a Miner's License. Any individual over the age of 18 years may, on proper application, obtain a Prospector's License from any Mining Recorder's office. Licenses to companies are issued only by the Minister or Deputy
'-Geological Lecturer, Geoscience Information Office, Geoservices Section (formerly Data Retrieval and Education Section), Geological Branch, Ontario Division of Mines, Ministry of Natural Resources. o
Mining Recorder for Southern Ontario, Mining Lands Branch, Ontario Division of Lands, Ministry of Natural Resources.
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Minister of the Ministry of Natural Resources and may be used to acquire mining claims by transfer but not by staking directly. The fee for an individual license, either new or renewal, is presently $5; for a company license the fee is presently $25, $50, or $100 depending on the authorized capitilization of the company. If a license is lost or destroyed a substitute license may be supplied on payment of the fee of $l. All licenses, regardless of the date of issue, expire on March 31 of each year and must be renewed on or before that date to maintain in good standing any rights acquired thereunder. Failure to renew the license by March 31 automatically entails the loss of any rights acquired. Rights of Licensee A licensee is entitled to prospect for minerals on Crown Lands or lands of which the mining rights are reserved to the Crown, and may stake out and record as many mining claims as desired in each license year (April l to March 31 following) provided the lands are open for staking. Proxy staking is not permitted. A licensee may have assistance in staking but must be person ally present on the ground at the time of planting or erecting the posts and must mark such posts with the required data. The licensee may acquire title to the claims after filing proof of completion of acceptable assessment work and certain other requirements or he may at any time transfer claims to another licensee. For each claim staked out and recorded the licensee may obtain from the Mining Recorder of the appropriate District, two free assay coupons, and for each 40 days work recorded an additional two assay coupons may be obtained up to a maximum of 18 coupons in each license year. Such coupons are valid for two years and entitle the licensee to have samples from the claims assayed at the laboratories of the Mineral Research Branch without charge, on a coupon tariff basis. LANDS OPEN FOR STAKING
Generally speaking, all Crown Lands and all lands of which the minerals are reserved to the Crown are open to prospecting and staking if not already taken up. These include lands sold, patented, or leased after May 6, 1913 for which there was the provision that the mines, minerals, or mining rights are reserved to the Crown. Also included are lands where the mines, minerals, or mining rights have been forfeited to the Crown for non-payment of mining taxes, and subsequently have been declared open for staking. Where forfeiture or loss of rights for any valid reason has occurred, the land, mining rights, or mining claims become open for staking the day following the forfeiture but not before 7 am Eastern Standard Time. LANDS NOT OPEN FOR STAKING
Lands to which the mineral rights are already held or to which the mineral rights have already been staked and are held in good standing, are not open for staking. Lands transferred to or vested in the Ontario Northland Transportation Commission may not be staked except with the consent of the Minister of Natural Resources and of the Commission. Lands reserved or set
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apart as a town site by the Crown, lands laid out into town or village lots on a registered plan by the owner, lands forming a railway property or right of way, or lands forming a road or road allowance may not be staked except with the consent of the Minister of Natural Resources. Lands set apart for summer resort or similar purposes by the Ministry of Natural Resources, or lands required for the development of water power or for highways or other purposes in the public interest, may not be staked except where the Minister certifies in writing that in his opinion discovery of valuable mineral in place has been made. Lands set apart for Provincial Parks may not be staked except as provided for in 'The Provincial Parks Act 1 . Lands set apart as Indian Reserves are under the jurisdiction of the Federal Government and enquiries should be directed to Head, Mining Lands Unit, Department of Indian Affairs and Northern Development, Ottawa, Ontario. Certain areas are patented lands under the jurisdiction of the Algoma Central Railway. The company officer dealing with these lands and to whom enquiries about staking should be directed is The Superintendent of Lands and Forests, Algoma Central Railway, 289 Bay Street, Sault Ste. Marie, Ontario, Telephone (705) 254-4331.
SIZE AND FORM OF CLAIMS
Part of the Province has been partitioned into townships and many of these townships have been subdivided into lots and concessions. However there are large tracts, mainly in the north, which have not been so subdivided The various areas are referred to as surveyed or unsurveyed territory, or as subdivided townships and unsubdivided townships. The Ministry of Natural Resources makes available for 505 each, white prints of individual townships or areas on which is shown the status of the mining lands. The holder of an individual Prospector's License is entitled to five such free claim maps per year. In unsurveyed territory, a mining claim is a square area of 40 acres, each side having a length of 1,320 feet (20 chains or h mile), running astro nomically north, south, east, and west. In a subdivided township, claims must conform to the surveyed lines, and will be as follows: Area of Lot (acres)
Aliquot Claim Portion
Area of Claim (acres)
640
NE-, NW-, SE-, or SW-3* of a quarter Section of 160 acres
40
320
NE-, NW-, SE-, or SW-3* of the N half Section or S half Section
40
200
NE-, NW-, SE-, or SW-1* of the lot
50
150
NE-, NW-, SE-, or SW-3* of the lot
37^
100
N-, S-, E-, or W-Js of the lot
50
Irregular areas may be staked as claims where local conditions dictate, either in surveyed or unsurveyed territory, but the boundaries must conform
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as nearly as possible to the prescribed form, and the claim must not exceed the prescribed acreage. STAKING PROCEDURE
Mining claims are staked out by the following procedure: (a) planting or erecting a post at each of the four corners of the claim, beginning with and marking that at the northeast corner "No.l", that at the southeast corner "No.2", that at the southwest corner "No.3", and that at the northwest corner "No.4", so that the number is on the side of the post toward the post next following it in the order named; (b) Writing or otherwise inscribing on No.l post his name, the letter and number of his license, the date and hour of the commencement of staking out, and, if the claim is situated in a township surveyed into lots, quarter-sections or subdividions of a section, the part thereof comprised in the claim, mentioning the lot and concession or the section by number; (c) writing or otherwise inscribing his name and the letter and number of his license on No.2, No.3, and No.4 posts; (d) plainly blazing the trees on two sides only along the direction of travel where there are standing trees, and cutting the underbrush along the boundary lines of the claim, or where there are not standing trees clearly indicating the outlines of the claim by planting thereon durable pickets not less than 5 feet in height at intervals of not more than 2 chains (132 feet) or by erecting at such intervals monuments of earth or rock not less than 2 feet in diameter at the base and at least 2 feet high so that the lines may be distinctly seen. (Section 56(1)). Where at a corner of the claim the nature or conformation of the ground renders the planting or erecting of a post impracticable, the corner may be indicated by planting or erecting at the nearest practicable point a witness post bearing the same marking as that prescribed for the corner post at that corner together with the letters "W.P." and an indication of the direction and distance of the site of the true corner from the witness post. (Section 56(2)) Every post shall stand not less than four feet above the ground, and shall be squared or faced on four sides for at least one foot from the top, and each side shall measure at least four inches across where squared or faced, but a standing stump or tree may be used as a post if cut off and squared and faced to such height and size, and when the survey is made the centre of the tree or stump where it enters the ground shall be taken as the point to or from which the measurement shall be made. (Section 56(3)). Every post shall be a post, standing stump, or tree not before used as a post for a mining claim. (Section 56(4)).
RECORDING OF CLAIMS
A licensee who has staked out a mining claim must, within 31 days from the date of staking, furnish the local mining recorder with the following documents, etc: (a) an Application to Record setting forth a description of the area staked
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Table 2
Types of Assessment Work and Credits
TYPES OF ASSESSMENT WORK MANUAL LABOUR - by pick shovel or hand-steel
Section 86 (17) Using PLUGGER or approved MECHANICAL EQUIPMENT Section 86 (8)
CREDITS
l day for each 6 hours each man is employed, limited to NOT more than 12 working hours per day. l day for each 3 hours each man is employed, limited to NOT more than 12 hours work per day, and not more than two operators at one time .
DIAMOND DRILLING (a) Core under 7/8" (x-ray) (b) Hole is 100' or less and 7/8" core or over (c) Core is 7/8" or over and hole is over 100' Holes must exceed 25 feet depth or length to count. Location sketch and core logs required in duplicate. Credit may also be given on submission of drill core specimens. Section 86 (6) For deep drilling
Section 85 (12)
l day for each 4 feet drilled l day for each 4 feet drilled l day for each l foot drilled Section 86 (5)
l day for each 3" specimen of bore hole, the maximum credit not to exceed the hole depth divided by 25. Section 86 (6)
Section 86 (7)
l day per two feet drilled. On application to the Minister for a permit. Permit if granted, to be filed in the record ing office before commencement of work.
Section 86 (18)
l day for each $15 expended. (Proof of expenditure required). Where free assay coupons are used, equivalent rate is allowed based on schedule of charges of the Mineral Research Branch of the Ontario Division of Mines.
BORING other than core drilling to a depth greater than 200 feet.
ASSAYS AND CHEMICAL ANALYSES
GEOPHYSICAL, GEOLOGICAL, GEOCHEMICAL, AND RADIOMETRIC SURVEYS Credits of up to 40 days per claim can be obtained for geological or geochemical surveys and up to 80 days per claim for geophysical surveys (ground and airborne). STRIPPING by Mechanical Equipment bulldozer, air or water equipment. (Receipts for expenditures are required and are to be approved by the Mining Recorder).
Ask for separate booklet explaining the requirements respecting the submission of geological, geophysical, geochemical, and radiometric surveys for assessment work credits. Section 86 (9) (10) (11) (12) (13) l day for each $10 spent but NOT exceeding 100 days per claim.
Section 86 (14) SHAFT-SINKING OR LATERAL WORK Size of opening to be not less than 5' x 7' and at least 10' below the surface.
4 days for each man for each six hours of employment, limited to not more than 12 working hours per day.
Section 86 (16) LAND SURVEYS May be done at any time where required.
40 days per claim. The survey must be done by an Ontario Land Surveyor.
Section 86 (1) OTHER TYPES OF WORK such as Beneficiation Studies, Analyses, Assays, Microscopic Studies, or Exploration and Development not otherwise provided. Section 86 (18) NOTE:
Prospecting, staking, or the construc tion of roads or buildings is not considered as assessment work. Section 85 (13)
The Minister may direct that certain other types of technical work be counted at the rate of not more than one day's work for each $15 expended. Enquiries concerning this should be made directly to the Mining Lands Branch, Ontario Division of Lands, at Toronto.
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(lot, concession numbers, township, etc.)f the date and hour when the claim was staked; (b) a sketch or plan of the mining claim showing the corner posts and witness posts if any, the distance between the posts in feet, lakes, rivers, roads, or other topographical features, lot and concession lines, and adjacent mining claim numbers; (c) the fee of $10.00 per claim; (d) his prospector's license. If the claim is accepted, it will be assigned a number by the mining recorder and the recorded claim holder will be given a set of four metal tags bearing the claim number which he must then affix to the claim posts within a period of six months from the date the claim was recorded. Pre-tagged Claims There is an alternative method of tagging mining claims whereby tags may be purchased in advance of staking on payment of the fee of $1.00 per claim number. Tags so purchased may only be used by the licensee who purchased them and must be affixed to the claim posts at the time of staking. The tag fee is deducted from the recording fee at the time of recording. Tags not used in staking out claims during the license year in which they were purchased are not valid and there is no refund of the tag fee for unused tags. When metal tags are purchased in advance and subsequently used in staking out mining claims and the licensee stakes out a group of two or more contiguous claims as part of a continuous action, and presents the claims to the recorder for recording at the same time, he may plant or erect and use common posts at common corners. The metal tag and the writing pertaining to each claim are placed on that side of the common post facing the next post in a clockwise manner. Transfers The recorded holder may at any time transfer all or part of his interest in his claim to another licensee. A transfer document in the prescribed form must be registered with the local recorder at a cost of $5.00 per claim.
ASSESSMENT WORK
The recorder holder of a mining claim must, within five years immediately following the recording thereof, perform or cause to be performed thereon, assessment work to the total of 200 days. The work is required to be performed at a rate of not less than 20 days in the first year,. 40 days in each of the three succeeding years, and 60 days in the fifth year. The work may be accumulated in less than the five year period, and the excess for any one year is credited to the requirements of the succeeding year or years. Reports of work performed must be made in the prescribed form to the Mining Recorder within ten days of each of the periods specified. Payment in lieu of assessment work is not permitted.
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Grouping of Work It is not mandatory that the total required assessment work for each of the claims of a contiguous group be actually performed on each of the individual claims. A licensee who holds a group of unpatented claims, or of which he is a recorded optionee, may perform the work on any one or more of these claims and register the work performed against any or all others of the group. However, no more than 4,000 days work done on any one claim may be used to apply on others of the group. If a claim is transferred, the new holder or optionee of record is entitled to the amount of assessment work credits filed on the claim (Section 85(6)). However, regardless of what may have been done by the former holder or optionee, he may proceed to perform a further maximum of 4,000 days assessment work on the claim and have it registered against any one or all of the contiguous claims of which he is the recorder holder or optionee of record. Further, he may rearrange the group as he desires provided that the claims are still contiguous. The provision for grouping does not apply where geological, geochemical, or geophysical surveys have been performed. Credits for these types of work are recorded equally over only those claims actually covered by the survey.
SURVEY
Each mining claim located in unsurveyed territory must be surveyed by an Ontario Land Surveyor at the expense of the recorded holder. The survey may be made at any time prior to application for a lease provided permission to survey is first obtained from the local Recorder. Each surveyed claim is entitled to an assessment work credit of 40 days when the survey data is approved by the Surveyor General. When two or more contiguous claims are recorded in the same name in unsurveyed territory, the Minister of Natural Resources may, in special circumstances consent to a perimeter survey of the circumference in lieu of a survey of each claim. In such cases, special instructions are given concerning prior inspections and the manner of performance of the survey. Mining claims located in surveyed townships are normally not required to be surveyed. In areas, however, where the original township surveys have deteriorated almost to the point of nonexistence or because of unusual topographic features, highways, summer resort parcels, etc., the Minister of Natural Resources may at any time prior to the issue of title, require that the claim be surveyed.
AUTOMATIC FORFEITURES
If the recorded holder of a claim fails to maintain his Prospector's Licence in good standing, moves or defaces the claim posts without prior consent, fails to perform the assessment work, or fails to report the performance of the work and fails to apply and pay for a lease within the prescribed time, the claim is automatically forfeited without notice to the holder by the Recorder.
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Where forfeiture or loss of rights has occurred, the land, mining rights, or mining claims come open for staking the next day following forfeiture, but not before 7 am, Eastern Standard Time.
Extensions If application is made within thirty days before the time forfeiture or loss of rights would occur, the Mining Commissioner may allow an extension of time in respect of affixing metal tags to the posts, performing assessment work, and paying for a lease. When application is made after the claim has lapsed, the Commissioner may make an order relieving the claim from forfeiture and allowing an extension of time. If the holder of a claim has been prevented from doing his work, affixing the tags, or applying for the lease because of illness, verified by a doctor's certificate, the Mining Recorder may grant a free extension for a period not exceeding six months. Orders of the Mining Commissioner do not come into effect until they are filed in the office of the local Recorder and the prescribed fees are paid. Both the Commissioner and a Recorder may make an order authorizing the rein statement of a Miner's License on payment of twice the normal renewal fee.
DEATH OF LICENSEE
If the holder of an unpatented claim dies prior to the issue of a lease, no other person except by consent of the Commissioner may stake out or record a claim on the same lands, or acquire any interest therein for a period of twelve months. During this period, the Commissioner may at any time vest the interest of the claim to the heir or representative of the deceased holder.
COMPENSATION FOR SURFACE RIGHTS
Where the surface rights have been granted, sold, leased, or located, and the mining rights have been reserved to the Crown or where land is occupied and the occupant has made improvements such as, in the Minister's opinion, entitle him to compensation, a licensee who prospects for mineral or stakes out a mining claim or carries on mining operations upon such land must compensate the occupant for any damage caused, and in default of agreement the Mining Commissioner may determine the amount and condition of such compensation.
CERTIFICATES OF RECORD AND WORK
When a claim has been on record for 60 days or more and where no dispute is in question, the surface rights compensation, if any, has been paid, and the survey has been approved, the Recorder, if satisfied that all prescribed conditions have been complied with, may issue a Certificate of Record.
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Similarly the Recorder, when satisfied that the prescribed work has been duly performed, may issue a Certificate of Work. On the issue of these certificates, the claim is not thereafter, in the absence of mistake or fraud, liable to impeachment or forfeiture except as expressly provided in the Act. ISSUE OF LEASE
The application and payment for a leasehold patent must be made to the Recorder within one year from the date upon which all work on a mining claim is required to be performed.
The term of a leasehold comprising both surface and mining rights is 21 years at a rental payable in advance of $1.00 an acre for the first year and 25 cents an acre for each subsequent year. If the lease is limited to the mining rights only, the subsequent annual rate is reduced from 25 cents to 10 cents an acre. These leases may be renewed for further terms of 21 years at the discretion of the Minister. Where a holder of a lease satisfies the Minister that he is producing mineral in substantial quantities and production has been continuous for more than one year, he may surrender the lease and obtain instead, a freehold patent. This does not apply to navigable waters which are only leased. Patents or leases of Crown Lands contain a reservation to the Crown of all timber and trees standing, but the owner or lessee may cut such trees on the lands as may be necessary for the development or working of the minerals on the property, subject to terms and conditions imposed by the Minister. Every patent or lease contains a reservation for road purposes of 10 percent of the surface rights as well as a reservation of all sand and gravel. The surface rights of 400 feet in width from the high water mark along the shores of navigable bodies of water are also reserved to the Crown. All ores or minerals, raised or removed from lands, claims, or mining rights leased, patented, or otherwise disposed under the Mining Act must be treated and refined in Canada. (Section 113(1)).
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TOPIC 3
PROSPECTING METHODS Revised by E.B. Freeman
- 34 -
CONTENTS Prospecting Methods Page Introduction and Mineral Requirements . . . . . . ... . .. . . . . .. . . . . ........ What to Prospect For ..... ...... ......... .................... ....... Guidelines to Prospecting . . .. . . . .. .. .. . . . .. . . . . . .. . .. . .. . . . .. .. . . .. Visual Prospecting . . . . .. . .. . .. . ... . . .. . . .. . ... . .. .. . . . . . . . . . .. . . . . . Careful Rock Inspection . .. . .. .. . . . . . . . . . .. . . . . . . . . . . . . .. . . . . .... Use of a Hand Lens and Binocular Microscope . . .. . . . . .. . . .. . . . . . . . Colour Change in Rocks . . . ... .. . .. .. . . .. .. . . . ... .. ... . . .. . . . . .. . . Ore Mineral Stains .. . . .. . . . . . . . . . . . .. . .. . .. .. . ... .. . . .. . . . . . . . . . Boulder Tracing . . .. . .. . . . . . . . ... .. . .. . . . . . . . . .. .. . .. . . . . . . . . . .. . Sluice Boxes . . . .. . . . . . .. . . . . . . .. . . . . .. .. . . .. .. . .. . . . .. . . . . . ..... Panning . .......... . .. .. ......................................... Assaying ...................... .......... ........................... Geochemical Prospecting ..... ... ... ... ..... ... .... ....... ........... Instrumental Methods . .. . . . . . .. . .. . .. . .. . . . .. .. . . . . .. .. . .. . . . . . . . . . . Fluorescence . . . . . . . . . . .. . . . . . . .. .. . . ............................ Radioactivity . .. . .. . . . . . . . . . . . . . . . . .. ... . . . . . . . . . . . . . ........... Magnetism .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . ........................ Electrical Properties ............................ .. .. . . . .. . . .... Summary ...... ............. .. ... .... ...... ...... ......... ... ........
35 36 37 38 38 38 38 39 39 39 40 40 40 41 41 41 41 42 42
TABLES
3. 4.
Canadian Mines Starting Production or Re-Opening 1950-1967 ..... Specific Gravity of Some Minerals Heavier than Quartz ..........
36 40
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PROSPECTING METHODS
Revised by E.B. Freeman^ "The wizards, who also make use of rings, mirrors, and crystals, seek for veins with a divining rod shaped like a fork; but its shape makes no difference - for it is not the form of the twig that matters, but the wizard's incantations which it would not become me to repeat..." Georgius Agricula, 1556 INTRODUCTION AND MINERAL REQUIREMENTS
Today's prospector,bedeviled by mosquitos and black flies in his search for mineral wealth, still has his special brand of incantation. However, the prospector has made a tremendous contribution to the development of mineral resources in Ontario. Possibly two-thirds of the mineral finds discovered before 1970 were first observed by a prospector. And although geology, geophysics, and geochemistry are important aids in locating promising mineral localities, the actual discovery is still made by either finding ore naturally outcropping or by exposing ore by means of trenching, drilling, etc. So the prospector carefully examining each outcrop and boulder, especially if they are iron stained or altered-looking (gossans), has been responsible for finding ores worth many billions of dollars. Some examples of these past discoveries in Ontario are the gold deposits of the Timmins and Kirkland Lake areas, the silver of Gowganda, the iron of Steep Rock Lake, the copper of Manitouwadge, the uranium of the Blind River area, and the nickel of Shebandowan. The first observation of the presence of ore minerals in all the above mining areas has been credited to the prospector. Sudbury and Cobalt are two other areas where visual observations led to the discovery of many mines. Duncan R. Derry analyzed the discovery methods of 150 mines that started production, re-opened, or were making plans for production between 1950 and 1967. He then made some predictions for the future as seen in the table below summarized from the Northern Miner, January l, 1970, p.14. His conclusion as seen in the table is that the conventiona visual prospector faces greater difficulty in finding new mines as companies search, by use of instruments, beneath the forests, moss, muskeg, and soils to discover new mineral wealth. However, even with this sophisticated method of mineral search only an average of 2.7 new mines per year were found from 1964 to 1971 whereas an average of 5.3 new mines per year were found in the 13 years prior to 1964.
Geological Lecturer, Geoscience Information Office, Geoservices Section (formerly Data Retrieval and Education Section), Geological Branch, Ontario Division of Mines, Ministry of Natural Resources.
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Table 3
Canadian Mines Starting Production or Re-Opening 1950-1967
Discovered prior to 1950 More than 50 percent of all mines. ^20 percent dis covered before 1920, 85 percent found by conventional prospecting.
Discovered 1950-1967
Prediction 1970-1980
33 percent by conventional prospecting.
60-70 percent to be found by geophysics and(or) geochemistry.
28 percent by drilling based on geology. 38 percent by drilling based on geophysics.
Prediction post-1980 Geological studies will lead to most orebodies as dis coveries will be too far below surface or too disseminated to be detected by geochemistry or geophysics.
l percent by geochemistry.
Thus, need for new sources of mineral wealth is great. If we wish our present industries to continue, new sources must be found now for more than 80 elements, many in large quantities, in order to maintain industrial services in step with 'normal 1 population growth. The United States Bureau of Mines has predicted that non-fuel world mineral requirements will increase fivefold (500 percent) between 1968 and 2000. Today's various mineral demand forecasts all imply the need for an accelerated mineral discovery rate in Canada and Ontario in order to supply the larger export market of the future. Further, Canada, with a stable political base and a life style similar to the United States, is favourably situated for exploration and mineral supply to the United States compared to countries with political unrest.
WHAT TO PROSPECT FOR
Analysis of reports concerning metal markets, new inventions, and our future way of life can give clues as to what minerals are going to be in demand, for example, articles, as already mentioned, published by the United States Bureau of Mines. Information of this nature is found in the Northern Miner and Metals Week, also occasional articles appear in Fortune, Saturday Review, Financial Post, Financial Times, etc. The astute prospector will attempt to chart out either in his mind, or on paper, the past and future developments concerning various mineral products. Those minerals that will be in demand should be placed high on any prospector's search list.
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GUIDELINES TO PROSPECTING
Most easily observable ore deposits have already been found in Ontario. Since even the more remote areas of the Province have been fairly well prospected and travelled in the past, new discoveries will be more difficult to achieve. A different approach and new techniques of mineral finding will be required. For example, most past discoveries have been made by visual prospecting of rock outcrops and 'float 1 (the gravel and boulders of the regolith^-). Whereas this approach is still very useful, the prospector will neet to examine rock samples in greater detail using a hand lens and possibly a microscope in the search for fine-grained ore minerals. It should be remembered when inspecting fresh granite, sandstone, shale, or carbonate rocks that only one to three grains of a copper mineral out of every 100 grains may be enough to make a valuable ore deposit. Some examples of economic grades for large open pit deposits are: 0.02 percent 0303, 0.17 percent nickel, 0.12 percent tin, and 0.1 ounce gold per ton. Most of the exposed bedrock surface has been prospected, but unfortunately more than 90 percent of the bedrock surface is buried beneath glacial till or soil. Thus, closer examination of the mineral content of glacial tills and of the soil cover appears to be needed. Many old-time prospecting methods such as panning and the use of sluice boxes to collect heavy minerals, tracing ore minerals found in float back to their source, and the visual search, are still important today. However, the use of sulphide-sniffing dogs (used in Sweden, Finland, British Columbia, and recently in the Timmins area, Ontario), some geochemical tests, and some geophysical methods should also be known to the prospector. A mineral exploration search will include one or more ore minerals. For example, when panning for heavy minerals, the prospector may encounter magnetite, scheelite, galena, gold, or uraninite. These are only a few of the ore minerals that may be found with the 'heavies' collected in the pan. The ability to recognize as many ore minerals as possible is of major importance, because the mineral considered to be of second or third importance, or a newly discovered mineral in an exploration target area, may ultimately prove to be the most valuable. All rocks encountered should be inspected in detail. Prospectors should outfit themselves in accordance with the nature of the search area and the minerals to be discovered. Individuals financing themselves should have an adequate separate source of income sufficient to cover all costs, including the staking and sale of claims. Prospecting is an outdoor activity but the library search and selection of targets and explora tion methods is generally performed in the winter months. Weekend and part time summer prospecting trips provide an enjoyable challenge to the search and the possibility of both fame and financial reward. When discovery of ore minerals is made, usually the prospector immedia tely acquires the mineral rights by staking claims. Before proceeding with much expensive development work, however, some prospectors submit their showing to a mining company or geologist for appraisal. Many experienced Regolith, a general term for the loose unconsolidated soil and weathered rock debris above the solid bedrock of the earth's crust.
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Ore Mineral Stains Chemical weathering of some ore minerals causes a change to brightly coloured secondary minerals, thus drawing attention to the precise locality where they exist. 'Gossans' are rusty to yellow-brown zones that are rich in hydrated iron oxides. Some uranium minerals alter to secondary minerals that are yellow (uranophane, carnotite, etc.). Molybdenite also alters to yellow secondary minerals. Pink cobalt bloom (erythrite) is found on cobalt minerals in many places, and an apple-green alteration product (annabergite) is found on some nickel minerals. Lead, zinc, and iron minerals weather in some places giving a whitish stain, whereas copper minerals usually alter to hydrated copper carbonates that are a bright green (malachite) or a bright blue colour (azurite). Boulder Tracing Tracing boulders of float, containing ore minerals, either up slope, or toward a glacial source, to the mineralized outcrop is an age old method of prospecting. This method of prospecting is still practical today. In the Precambrian of Ontario many more mines will be found by detailed grid sampling of glacial till deposits (see Lee, H.A. (1963), GSC Paper 63-45, p.5-6). Plotting the locations of ore minerals found assists in the selection of target areas for more detailed surveys. Sluice Boxes Many types of sluice boxes, rockers, and suction devices have been used to concentrate heavy minerals by a water washing and gravity sorting process. This heavier equipment is less portable than the prospector's pan. Therefore, valuable gravels are usually located by panning and sluice boxes may then be installed for economic recovery of the valuable heavy minerals or to obtain a bulk sample for analysis. Various models of a commercially sold portable dredge and sluice box are available or a low cost portable sluice box may be made from three pieces of 1/8-inch thick aluminum each 3 feet long and about 18 inches wide. Each piece of metal is shaped into flat bottomed troughs about l foot wide with sides 3 inches high, and then bolted together to form a 9-foot long sluice box. Next, a burlap bag or wooden riffle sticks are placed along the bottom of the box to collect the heavy minerals. The gravel or sand is then placed at the upstream end of the metal trough and slowly washed downslope. The heavier minerals sink to the bottom and are concentrated in the burlap bag or along the riffles. Occasionally, as required, the heavy concentrate is collected by washing the burlap bag and sweeping out the riffles, An excellent reference to a practical combined sieving and sluice box concentration process suitable for glacial overburden is found in Geological Survey of Canada, Paper 63-45 by H.A. Lee, entitled 'Glacial Fans in Till from the Kirkland Lake Fault: A Method of Gold Exploration 1 . This paper describes a field method of heavy mineral concentration, and laboratory identification, of relatively low cost that can be performed by the prospector.
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Panning Panning for heavy minerals when investigating river sands, glacial deposits, or soils remains an important method of search today. An experienced panner can recover about 80 percent of the minerals that are heavier than quartz. The valuable 'heavies' are most easily recognized after washing and concentration. Some of these heavy minerals are listed below: Table 4
Specific Gravity of Some Minerals Heavier than Quartz
Mineral
Specific Gravity (the weight of a substance compared with the weight of an equal volume of water)
Quartz
2.65
Mica Hornblende Epidote Diamond Garnet Rutile Pyrochlore Barite Zircon Pyrite Magnetite Niotite-Tantalite Scheelite Cassiterite Galena Cinnabar Uraninite Gold
2.8-3.2 3.2 3.4-3.5 3.5 3.5-4.3 4.2-4.3 4.2-4.4 4.5 4.7 5.0 5.2 5.2-7.9 5.9-6.1 6.8-7.1 7.4-7.6 8.1 9.0-9.7 15.0-19.3
ASSAYING
Field identification of minerals by visual means can be very difficult. Assaying of rock, therefore, is now an important method of searching out new exploration target areas. Some of the very low grade ores being mined today contain ore minerals of such fine grain size that only analysis can identify their presence.
GEOCHEMICAL PROSPECTING
Geochemical prospecting is based on systematically measuring one or more of the chemical properties in samples of rock, soil, glacial debris, stream sediment, or plants. These trace-element measurements in parts per million
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(ppm) usually are plotted on a map to show areas of high or low metal concentrations. Then the areas of anomalously high metal concentrations can be investigated by trenching to bedrock or by geophysical methods. Various field kits are available from suppliers for the determination of total heavy metals (combined copper, lead, zinc), or of a single metal. These simple, relatively low cost tests, can be easily performed. Usually these tests measure the concentrations of metal ions present by the degree of colour change of dithizone reagent. For example, in the copper test, a measured amount of soil or sediment is placed in a test tube and dissolved in an ammonium citrate buffer solution at room temperature or by heating. Dithizone powder or solution is then added and after shaking and allowing time for settling, any copper taken into solution from the sample will cause the colour of the solution to change to red. The intensity of the red colour is propor tional to the amount of copper present. Kits can be obtained for about $65.00 to test for copper and total heavy metals. Replacement chemicals for these kits are available for as little as 8C per test.
INSTRUMENTAL METHODS Fluorescence
Ultraviolet lamps emit ultraviolet rays that excite the atoms of certain minerals, causing them to vibrate and glow (fluoresce) in the dark. Short wave ultraviolet lamps are better for mineral fluorescence than longwave lamps, Scheelite, an ore mineral of tungsten, and many secondary uranium minerals may be identified using a shortwave ultraviolet lamp. Portable lamps weighing only about 1*5 pounds can be purchased for $30.00 to $100.00. Other minerals usually showing fluorescence are: calcite, fluorite, willemite, scapolite, diamond, hackmanite, and autunite. This property is unpredictable and not all samples of a given mineral will display fluorescence. Radioactivity The discharge due to radioactive decay of potassium, uranium, and (or) thorium in rocks can be measured by a geiger counter (low efficiency) or scintillometer (high efficiency). Geiger counters and some scintillometers measure the total radioactive discharge from these three elements. However, some scintillometers have three channel settings that allow the total field to be read on one setting, an intermediate setting recording only uranium and thorium, and a high energy setting recording only thorium. A few inches of barren rock, soil, or water will drastically reduce the amount of radio active discharge and when prospecting with these instruments one should keep the instrument as close to the outcrop or rock sample as possible. Radiation detection instruments can be purchased at prices ranging from $100.00 to more than $2,000.00. Magnetism Magnetite is a strongly magnetic mineral and most samples of pyrrhotite are fairly magnetic. Many instruments are available for surveying the magnetism of rocks depending upon the speed and accuracy required. The dip
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TOPIC 4
TRACING FLOAT AND MINERAL FRAGMENTS
Revised by E.B. Freeman and S.A. Ferguson
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CONTENTS Tracing Float and Mineral Fragments Page Introduction . . .. . . . . .. . .. . . .. . . . . .. . . . . . ............................ Mines Discovered by Boulder Tracing . . . . .. ... . . . . .. . . . . . . . . .. . .. .. ... Steep Rock Iron Mines Limited ............................... . .. . . Canadian Charleson Limited ....................................... Josephine Mine . . .. . . . . . . . . ... . .. . . .. . . .. . . .. . .................... Gaspe Copper Mines Limited ....................................... Vendome Mine . . . .. . . . .. . . . .. . . . .. . . . . .. .... . ...................... Lamaque Mine .................. . . . .. .. . . .. . . . . . .. . . .. .. . . . . . . . ... . Malartic Gold Fields Mine ........................................ Newfoundland Zinc Mines .......................................... Jade Queen Mines .. .. . .. . . .. .. . . .. . . . . . . . . . . . ..................... Techniques of Tracing Float and Mineral Fragments ................... Tills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Eskers ...... . ..... . .............. ......... .... .... . . . . . .. . . . . .. .. Glacial Trains . . . . . . . . . . . . . . . . . . . . .. .. .. . . . .. .. . . . . .. . . . .. . .. . .. . Summary . . . .. . . . . . . .. . . . . . . . . . . . ... . ... . . . . .. ... . . . ... . . . . . . . . .. .. Ore Boulders of Unknown Source In or From Ontario . . . . . . . . . . . . . . . . . . . Bornite Float, Chambers Township, District of Nipissing .......... Native Copper, near London . . . . . . . . . . . .. . . . . . . . .. . . . . . . . . . . . . . . . .. Copper Float, Isle St. Ignace, District of Thunder Bay ........... Gold Float, Long Lake Vicinity . . . . . . . . .. . . .. . . .. . . . . . . . .. . . . . ... . Gold Float, Robb Township . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . .. . . . . Gold Float, Lee Township . . . . . . . . . .. . . . . .. . . . . .. . . . . . . . .. ... . . . . . . Gold Float, Lebel and McGarry Townships . . . . . . .. . . . . .. . . ... .. . . .. . Gold Float, Elliot Township . . . . .. . . . . . . . . . . .. . . . . . . . .. . . . . . . . .. . . Nickel Float, Loveland Township . . . . .. . . . . . . . . . ... . . . .. . . . . .. .. .. . Sulphide Float, Muskeg Lake Area, District of Thunder Bay ........ Zinc Float, Auden Township . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. Placer Gold . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. . Ontario Localities . . . . . . . . . . . . . . . . . .. . . . .. . . .. . . . . . .. .. . .. .. .. .. . Gold Particles in Till .. .. .... ... ............... ...... .. .... ... .. Buried Valley at Kirkland Lake . .. . . . . . .. . . . . . . . . . .. . ... . . . . . .. .. . Munro Esker . . . .. .... . . . . . . . .. . .. .. . . . . . . . . .. .. . . .. . . . . . .. . .. . .... Indicator Minerals for Kimberlite . . . .. . . . . . . . . . . . ... . . . . . . . . .... . .. . References .. . . . . .. . . .. . .. . . . . . . .. . . .. . . . . . .. . . . . .. . . . . .. . ...........
45 47 47 47 49 49 49 50 50 50 50 50 51 51 52 52 52 52 52 52 53 53 53 53 53 53 53 53 54 54 54 54 58 58 58
FIGURES
3. 4. 5. 6. 7.
Indicator Trains, Steep Rock Lake Vicinity ....... ...... .. . ...... Indicator Trains, Piedmont Township, Quebec .. .... ........ ..... .. Glacial Trains in Till and Buried Valley ........................ Munro Esker Sampling Points and Pyrope Garnet Occurrences ....... Sketch Map of Great Lakes-James Bay Area ........................
46 48 55 56 57
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TRACING FLOAT AND MINERAL FRAGMENTS
Revised by E.B. Freeman j1 and S.A. Ferguson^p INTRODUCTION
Canada has been almost completely covered four times by major advances of glacial ice in relatively recent times. The last main glacial surge is believed to have ended about 18,000 years ago when the glaciers started to melt more or less continually northwards. By 12,000 years ago, Lake Ontario was in existence, and most of Canada as we know it today was clear of ice 5,000 years ago. When ore deposits were glacially eroded, boulder to clay-sized fragments from these mineral deposits were pushed into a linear pattern known as a 'boulder train 1 (see Figure 3). By discovering fragments of ore minerals in glacial debris and knowing the general direction of ice movement, the source of these ore minerals can usually be found. Loose pieces of rock, fossils, or vein materials that have been separated from bedrock by weathering and erosion are called 'float 1 , and if this loose material has been deposited by glacial action it is called 'glacial drift' or 'till'. The tracing of pebbles and boulders in till has been directly responsible for the discovery of some of the largest mines in the glaciated areas of many northern countries such as Finland, Sweden, the USSR, Ireland, and Canada. Tracing mineralized float to its source is an age-old method of pros pecting. For 200 years or more in Canada, valuable ore has been found by this visual prospecting method. Many other discoveries, such as the large zinc-copper orebody of Mattagami Lake Mines in northwestern Quebec, may be partly credited to the knowledge of ore grade boulders, which helped to select this exploration target area. Two principle sources of as yet undiscovered large mines in Ontario include: 1) outcrops with very fine-grained ore minerals; and 2) disseminated fine-grained or massive ore deposits covered by glacial drift. In the past, the attention of prospectors has been primarily concentrated on the larger cobble- and boulder-sized float containing coarse-grained ore minerals. Future discovery chances will be helped by paying more attention to locating and tracing fine-grained mineralized float and mineral fragments. The concept of boulder tracing in till includes tracing mineralized float of all grain sizes from silt to boulder. This implies that, besides visual prospecting of boulders, cobbles, and pebbles, the panning, sieving, and
-'-Geological Lecturer, Geoscience Information Office, Geoservices Section (formerly Data Retrieval and Education Section), Geological Branch, Ontario Division of Mines, Ministry of Natural Resources. 2special Projects Geologist (formerly Chief, Data Retrieval and Education Section), Geological Branch, Ontario Division of Mines, Ministry of Natural Resources.
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ODM (Modified after Dreimanis. 1958. C.l.M.M. Bull.. Vol. 51, No.550, p.74)
Figure 3 INDICATOR STEEP ROCK
TRAINS
LAKE
VICINITY
ONTARIO
Outside boundary of ore pebble boulder train
SYMBOLS More than 2 percent iron ore pebbles. Less than 2 percent iron ore pebbles No iron ore pebbles observed. Canadian Charleson Mine 6,700,000 tons of gravel contained 12 percent goethite and hematite.
ODM. HP 55
Glacial striae, y is the latest direction of ice movement.
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geochemical surveys of basal tills should also be included in a well co ordinated boulder tracing program. A good general reference is Erland Grip (1953), 'Tracing of Glacial Boulders as an Aid to Ore Prospecting in Sweden 1 ; Econ. Geology, Vol.48, p.715-725. A review of previous boulder tracing discovery case histories follows.
In past times, mines were almost exclusively found by visual prospecting in a manner such as described in the Second Report of the Ontario Bureau of Mines, 1892, p.237. "A gold property was located in the fall of 1891 about 20 miles east of Sudbury ... near lake Kookogaming .... The discovery was made in a swale, where in drift boulders free gold was found in the form of small nuggets.... Mr. McKellar traced the boulders to their place of origin, a distance of only 200 feet, where several segregated veins were found...." Briefly described below are some eastern Canadian mines discovered by means of tracing mineralized float to its source; most of these are summarized from the ones listed by A. Dreimanis in the Canadian Mining and Metallurgical Bulletin, Vol.51, No.550, 1958, p.73-80. Steep Rock Iron Mines Limited Iron-rich float was first reported by Wm. Mclnnis in the 1897 report of the Geological Survey of Canada where he wrote: "The beds from which the blocks of rich float were derived seem to be largely covered by the waters of the lake [Steep Rock], and were not discovered ..." This premise was proven correct when subsequent exploration located these beds, and production of iron ore has been continuous here since 1944. A well-defined train of float 20 miles long and 3 miles wide extends southward from the source area (see Figure 3). Normally float occurs only within 2 to 3 miles of its source, thus float found 20 to 25 miles southwest of Steep Rock Lake led to the detailed mapping of iron ore float as shown in Figure 3, in the hopes of finding another Steep Rock mine farther south. One interesting conclusion from this survey, and proven by other surveys since, is that the smaller size pebbles and mineral grains are more accurate indica tors of source area location than cobbles or boulders. For example, iron ore boulders were as abundant at 21 to 24 miles distant from their source as at l to 4 miles, whereas the percentage of iron ore pebbles was 0.05 percent and 8 to 10 percent respectively at these locations. Canadian Charleson Limited The potential of the Steep Rock gravel deposits as a source of iron ore was recognized after Steep Rock Iron Mines opened up some pits for sand and gravel. Exploration work, from 1954 to 1956, showed that a higher percentage
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Figure 4 INDICATOR TRAINS
Vendome zone of sphalerit and galena
PIEDMONT TOWNSHIP ft,
QUEBEC
Feet 2000 l 1
I 500
4000 1000
Metres
SYMBOLS Sphalerite and galena in boulders or cobbles Pyrite in boulders or cobbles Esker Glacial striae
Most of area covered by glacial lake sediments
ODM ( Generalized after Dreimanis 1958 C l.M.M. Bull. Vol.51,No.550,p.76 ) OOM.MPSS
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of iron ore was present in the gravel and sand sizes than in silt. Mining was selective with only the higher grade portions of the deposit being worked and the average weight recovery was 12 percent iron ore. The goethite-hematite concentrate produced was in the size range from minus l inch to plus 65 mesh and in addition a sized gravel and sand product was obtained. Production occured from 1958 to 1965 and was 784,000 tons of concentrate valued at $6,401,000 from 6,700,000 tons of mill feed. Details of the operation are given by Shklanka (1972, p.59-64). Josephine Mine This iron deposit in the District of Algoma, Ontario, was located by Alois Goetz in 1899. Boulders of hematite and brown iron oxides were found beside Parks Lake and indicated that there might be an orebody underneath the lake, which was subsequently proven to be the case. Gaspe Copper Mines Limited In 1909, while Alfred Miller was helping some timber cruisers, he noticed float containing copper mineralization along the York River in the Gaspe. Later, in 1921, he and some of his brothers traced this float several miles upstream to what is now called 'Copper Mountain'. These deposits produce some 31,000 tons of smelted copper per year at present. Vendome Mine This lead and zinc mine near Barraute, Quebec, was .located by P. R. Geoffroy about 1938 by persistent tracing of sulphide boulders to their source. Dreimanis describes the history of this discovery, shown in Figure 4, as follows: "...This discovery is in the clay belt, in an area not very suitable for boulder tracing. Most of the ground is covered by glaciolacustrine deposits, clays, silts, or sand. As a consequence, boulders are found only in washed till remains on higher bedrock outcrops, end-moraines, or eskers which protrude through the mantle of the lake clays, or deep in the valleys eroded through these clays. It is difficult here to trace a boulder train. Nevertheless, by combining boulder tracing with geophysical surveys and test-drilling, Geoffroy succeeded in locating the source of the float, which had a very low ratio of lead to zinc. The search is still continuing for the other source of boulders with a relatively higher content of lead..." Geochemical methods were also tried in the area south of Vendome where boulders were found more than 3,500 feet from their source, but with negative results. The abundance of sulphide boulders was only l to 5 per 1,000 other
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boulders at this distance, with boulders containing massive or disseminated pyrite outnumbering 5 to 10 times the boulders containing sphalerite. Lamaque Mine This gold occurrence at Val d'Or, Quebec, was found by R. Clark in 1923. Clark observed a quartz boulder with visible gold and tourmaline about 250 feet south of the main gold vein, which was subsequently located by trenching. Malartic Gold Fields Mine Gold-bearing float was found near Malartic, Quebec, along the inferred extension of a fault associated with gold ore. Drilling through the glacial drift began in 1935 and led to the discovery of the gold ore zone in 1938. Newfoundland Zinc Mines The mine is at Daniel's Harbour, Newfoundland, and the discovery of zinc mineralization in 1964 was based on the following sequence: 1) geochemical soil sampling locating the target area; 2) discovery of boulders containing zinc sulphide; and 3) discovery of the zinc ore in place. Jade Queen Mines In western Canada jade boulders had been known for years to occur at various places along the Fraser River. Mrs. Winnifred Robertson spent her free time over a 10-year span tracing these boulders upstream to their source, which she located in 1968. This deposit of nephrite jade contains 8 million pounds of solid jade making it one of the world's largest jade mines.
TECHNIQUES OF TRACING FLOAT AND MINERAL FRAGMENTS
Ore float has generally been traced to its source over a distance of 3 miles or less. Usually, ore float when plotted on a map forms an indicator train narrowing toward its source in bedrock (see Figures 3 and 4). Boulder counts in till frequently show an increase toward their source in bedrock. Use of pebble counts and indicator trains as tracers to ore zones is usually more relaible when observations are restricted to basal till, till plains, end moraines, and eskers, or slightly sorted till outwash plains. The source is more difficult to trace for some samples, such as some surface erratics may travel hundreds of miles, and lake bottom clay beds or other well-sorted deposits may contain anomalously high mineral concentrations. Ice movement may have been in different directions at various times in the past. For example, in the Big Trout Lake area, Kenora District, four directions of ice movement are suspected and two are recorded by glacial striae on the rocks. The last ice movement in an area usually leaves the forms of the present surface topography. The last ice advance may have
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overridden earlier clay and till deposits, depositing younger till on top. When this ice melted and receded, the esker s, drumlins, outwash and glacial lake plains, kames, kettles, meltwater channels, and end moraines that form much of our present landscape remained. Tills Probably most large accumulations of massive ore boulders have already been discovered in Ontario. However, there is no doubt that massive ore cobbles, pebbles, and ore mineral grains are still to be found in glacial drift (till), particularly where the ore is of a friable nature. Also, finely disseminated ore minerals remain to be discovered in many pieces of float within till. An example of a suitable environment for prospecting in till would be down ice from a glacially covered sheared peridotite or gabbro. The till should be investigated for copper and nickel by concentrating heavy minerals, using sieves and a gold pan or portable sluice. The standard indicator train tracing technique of visual prospecting with hammer mattock, mineral glass, and gold pan remains an effective, low cost reconnaissance technique. In the Soviet Union, panning has led to the discovery of many kimberlite pipes in Siberia (Satterly 1971). The modern prospector, in order to increase his chances of success, should plot on a base map information observed, including 1) ice movement directions, 2) locations and size of ore float, and 3) ore boulder, pebble, and mineral grain counts in till. It should be remembered that an isolated erratic ore boulder may have been ice-rafted more than 100 miles. It is necessary, therefore, to trace an indicator train in till. Geochemical sampling in basal till in the Precambrian Shield of Ontario is a workable reconnaissance exploration method. Low grade anomalies 2 or 3 times background may be significant. Several Open File Reports of the Geological Survey of Canada contain material relating to geochemical programs, in particular: Open File 89, Lake Geochemistry - A Low Sample Density Technique for Reconnaissance Geochemical Exploration and Mapping of the Canadian Shield. Open File 112, Regional Geochemical Lake Bottom Sediment and Till Sampling in the Timmins-Val D'Or Region of Ontario and Quebec. Open File 116, Drift Prospecting in the Abitibi Clay Belt Overburden Drilling Program Methods and Costs. Open File 127, contains anomaly maps for 8 elements in the lake bottom sediments described in Open File 112. Eskers Systematic sampling, sieving, sorting, counting, and plotting of ore mineral or diagnostic rock fragments by weight percent should result in locating anomalously high percentage concentrations and positions of peak abundance along eskers.
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Esker research by H.A. Lee (1965) indicates that the dunite source in bedrock is generally 8 miles up-ice movement from the position of peak abundance of 3.3 mm to 8 mm dunite particles in the esker. Similarly, trachyte was found in outcrop 3 miles up-ice movement from the position of peak abundance of 8 mm to 16 mm trachyte particles in the esker. The systematic sampling of eskers, therefore, may delineate favourable target areas up-ice where geochemical or geophysical surveys or visual prospecting may be applied to locate the ore in bedrock. Glacial Trains Grid sampling across poorly sorted till in a glacial outwash, using the method described for eskers may result in delineation of boulder, cobble, or sand size ore mineral indicator trains. This method is recorded in Geological Survey of Canada Paper 63-45 (Lee 1963) (see Topic 3, Boulder Tracing, where grid sampling of glacial trains south of the Kirkland Lake Fault gold camp produced enough chlorite and visible gold fragments to locate the Kirkland Lake fault zone, even though drift covered. Summary Boulder and fine-grain indicator train tracing remains, as ever, an effective prospecting method. More precise sampling and mineral identifica tion methods as described above and in 'Ontario Occurrences of Float, Placer Gold, and Other Heavy Minerals' (Ferguson ejt a^, in preparation) are necessary to locate and identify fine-grained ore minerals in glacial drift. The modern boulder train prospector must have a sound knowledge of Pleistocene geology so that the most useful basal till samples can be identified and sampled. ORE BOULDERS OF UNKNOWN SOURCE IN OR FROM ONTARIO Bornite Float, Chambers Township, District of Nipissing A first-sized piece of bornite float was found in the west-central part of claim 317861 (Assessment Work Research Library, Toronto, File 2.725, p3; Graham 1971). Native Copper, near London Native copper in an egneous rock boulder is present in the Ingersol moraine, south of London, Ontario. This appears to be an erratic boulder from the District of Algoma (Dreimanis 1958). Copper Float, Isle St. Ignace, District of Thunder Bay Native copper float occurs 1-7/8 miles south of McEachan Lake in pieces of prehnite (Giguere 1969).
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Gold Float, Long Lake Vicinity Gold float has been reported west of Making Ground River, Long Lake Area (Fairbairn 1937). Gold Float, Robb Township Quartz float, originally weighing several tons, with visible gold and assaying 0.28 ounce per ton has been broken up by prospectors. This float was found 330 feet northwest of the 17-mile post located on the south boundary, l mile east of the southwestern corner of Robb Township (Burrows 1915). Gold Float, Lee Township A speck of gold was found in a narrow dike cutting a granite boulder thought to have been moved only a short distance from its original position. Location is just west of S^-mile post on the southern boundary of Lee Township (Wright 1922). Assays of quartz float discovered on the property of Lee Gold Mines Limited, northeastern Lee Township, were $2.70 and $6.00 of gold per ton (gold at $35.00 an ounce) (Lovell 1971). Gold Float, Lebel and McGarry Townships Gold values were encountered by H.A. Lee in a sampling program south of Kirkland Lake on claim 2396 of Lebel Township and on claim 31119 of McGarry Township (Lee 1963) . Gold Float, Elliot Township Well-mineralized and gold-bearing float were found on claims 7400 and 7399 near the northern boundary of Elliot Township (Gledhill 1925). Nickel Float, Loveland Township A group of boulders, with the largest 25 feet in diameter, are located in the southwestern quarter of Loveland Township (ODM 1957, 1964; Berry 1944). Sulphide Float, Muskeg Lake Area, District of Thunder Bay Large angular pieces of float containing pyrrhotite, pyrite, and minor chalcopyrite occur near an anomaly cutting claims TB276035, TB276036, TB276039, and TB276049 (Assessment Work Research Library, Toronto, File 2.451, and claim map M1699; Oja 1970). Zinc Float, Auden Township On claim SSM31945 some first-sized cobbles were found on the Nagagami River about 14 miles north of Palmquist. The cobbles of Paleozoic limestone contained sphalerite and were observed by S.A. Ferguson (personal communication)
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- 56 -
Munro esker and outwash deposits
O
Pyrope occurrences
Direction of glacial movement
Figure 6
Munro esker sampling points and pyrope garnet occurrences (modified after Lee GSC 1965 Paper 65-14 and Ontario Dept. of Lands and Forests Map S 465, and ODMNA, MP 7, Figure 7, p.28 )
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^LJ^ 1*1*1* *^t r^-^v 4
Conjectural path of diamond travel Direction of glacial movement Pyrope occurrence Kimberlitic rock or kimberlite occurrence Carbonatite-alkalic complex Major fault Horst block
Figure 7 Sketch map of Great Lakes-James Bay area showing diamond and pyrope garnet occurrences, carbonatite-alkalic complexes, kimberlitic dikes, and direction of glacial movement. After ODM, MP 7, Figure 1
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Munro Esker This esker, shown on Figure 6, was sampled at intervals over a length of 70 miles from the western shore of Lake Abitibi to southeast of Kirkland Lake. The esker consists of mineral and rock fragments with the greatest concentration for a particular mineral or rock about 2 miles downstream from the source. Two of the concentrations of gold in the esker are correlated with the Upper Canada Mine and Cathroy Larder Mine but other concentrations of gold in the townships of Munro, Michaud, Clifford, and Arnold, are not related to any bedrock source. The presence of indicator minerals for diamonds in the esker in Gauthier Township led to the discovery of kimberlite in the Upper Canada Mine (Lee 1968).
INDICATOR MINERALS FOR KIMBERLITE
Since 1863, at least 82 discoveries of diamonds in till have been made adjacent to the Great Lakes; one is in Ontario near Peterborough. Many of the diamonds were recovered in sluicing for gold. As the gold undoubtedly came from the Precambrian Shield, the diamonds have probably also come from the Precambrian Shield. Alluvial indicator minerals for kimberlite are pyrope, magnesian ilmenite, olivine, and chrome diopside. In the USSR, studies made on pyrope and ilmenite showed that over the distance of l mile the quantity of these minerals decreases little but the grain size decreases to a fraction of a millimeter. These indicator minerals have been found in the Moose River Basin and in 1960, Selco Exploration Company collected 94 samples from the Mattagami, Abitibi, Little Abitibi, North French, and Moose Rivers. Further work was done in 1962 and 1963 by Canadian Rock Company Limited, a subsidiary of Anglo American Corporation of South Africa and DeBeers. Because all of the kimberlite minerals are abraded, very few occur at any one locality and the average grain size is about l mm, it was concluded that the kimberlite source was not in the immediate vicinity (Brown et al 1967; Edwards and Bellow 1969; Satterly 1971).
REFERENCES
Berry, L.G. 1944: Geology of the Robb-Jamieson Area; Ontario Dept. Mines, Vol.53, pt.4, p.1-16. Brown, D.D., Bennett, G., and George, P.T. 1967: The Source of Alluvial Kimberlite Indicator Minerals in the James Bay Lowland; Ontario Dept. Mines, MP7, 35p. Burrows, A.G. 1915: The Porcupine Gold Area; Ontario Bur. Mines, Vol.24, pt.3, 73p. Dreimanis, A. 1958: Tracing Ore Boulders as a Prospecting Method in Canada; CIM Bull. Vol.51, No.550, p.73-80.
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Edwards, N., and Bellow, P. Gratton 1969: Unpublished Report on the Coral Rapids (Canada) Investigation, Selection Trust Ltd., Section Diamonds; on file with ODM Assessment Work Research Library, Toronto, File 83.1-30. Fairbairn, H.W. 1937: Geology of the Northern Long Lake Area; Ontario Dept. Mines, Vol.46, pt.3, p.1-22. Ferguson, S.A., Wahl, W.G., and Freeman, E.B. in preparation: Ontario Occurrences of Float, Placer Gold, and Other Heavy Minerals; Ontario Div. Mines. Giguere, J.F. 1969: No.10 St. Ignace Island and Vicinity, District of Thunder Bay; p.28-30 in Summary of Field Work, 1969, by the Geological Branch, edited by E.G. Pye, Ontario Dept. Mines, MP32, 79p. Gledhill, T.L.
1925:
Lightning River Gold Area, District of Cochrane; Ontario Dept. Mines, Vol.34, pt.6, p.86-98.
Graham, R.J. 1971: Unpublished Report on the Geological and Geophysical Surveys for Copperfields Mining Corporation Limited by Geophysical Engineering and Surveys Limited of North Bay, Ontario; on file with ODM Assessment Work Research Library, Toronto, File 2.726. Grip, Erland 1953: Tracing of Glacial Boulders as an Aid to Ore Prospecting in Sweden; Econ. Geol., Vol.48, p.715-725. Hobson, G.D., and Grant, A.C. 1964: Tracing Buried River Valleys in the Kirkland Lake Area of Ontario with a Hammer Seismograph; Canadian Mining Journal, April 1964, p.79-83. Lee, Hulbert A. 1963: Glacial Fans in Till from the Kirkland Lake Fault: A Method of Gold Exploration; Geol. Surv. Canada, Paper 63-45, 36p. 1965:
1. Investigation of Eskers for Mineral Exploration; 2. Buried Valleys Near Kirkland Lake, Ontario; Geol. Surv. Canada, Paper 65-14, 20p.
1967:
Thickness of Drift: Lebel, Gauthier, Boston, and McElroy Townships, Ontario; Geol. Surv. Canada, Map 11-67.
1968:
Glaciofocus and the Munro Esker of Northern Ontario; Geol. Surv. Canada, Paper 68-lA, p.173.
Lovell, H.L.
1971:
Geology of the Bourkes Area, District of Timiskaming; Ontario Dept. Mines and Northern Affairs, GR92, 37p.
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Meyn, H.D. 1970: Geology of Hutton and Parkin Townships, District of Sudbury; Ontario Dept. Mines, GR80, 78p. Accompanied by Map 2180, scale l inch to h mile. Mcinnes, William 1897: Report on the Geology of the Area covered by the Seine River and Lake Shebandowan Map Sheets; Geol. Surv. Canada, Annual Report, Vol.10, 54p. OEM 1892:
Second Report of the Ontario Bureau of Mines, 1892, 264p.
1957:
Loveland Township; Ontario Dept. Mines, Prelim. Map P.25, scale l inch to h mile.
1964:
Timmins-Kirkland Lake Sheet, Cochrane, Sudbury, and Timiskaming Districts; Ontario Dept. Mines, Map 2046, Geol. Comp. Ser., scale l inch to 200 miles.
ODM
Oja, R.V. 1970:
Unpublished Report on the Properties of Meridian Mining and Exploration Co. Limited, District of Thunder Bay; on file with ODM Assessment Work Research Library, Toronto, File 2.451.
Prest, V.K. 1949: The Pleistocene Geology of the Vermilion River System near Capreol, District of Sudbury, Ontario; Ontario Dept. Mines, PR 1949-2, 8p. Satterly, J. 1971: Diamond, USSR and North America: A Target for Exploration in Ontario; Ontario Dept. Mines and Northern Affairs, MP48, 43p. Shklanka, R. 1972: Geology of the Steep Rock Lake Area, District of Rainy River; Ontario Dept. Mines and Northern Affairs, GR93, 114p. Tremblay, Mousseau 1963: Unpublished Report of Operations within the Licence Area, Canadian Rock Co. Limited, Exploratory Licence of Occupation 13304; on file with ODM Assessment Work Research Library, Toronto, File 83.1-30. Wright, Douglas G.H. 1922: Geology of the Watabeag Area; Ontario Dept. Mines, Vol.31, pt.7, 33p.
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TOPIC 5
GEOPHYSICAL SURVEYS
By E.G. Blunden and J.A. McCance
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CONTENTS Geophysical Surveys Page Introduction . ... . . . . . . . . . . . . .. .. . .. . . . . . . .. ......................... Gravity Methods . . . . . . . . . . . . . . . . . . . . . . . . . . ........................... Magnetic Methods . .. . . .. . .. . .. . . . ... . .. .. . .. . . . . . . . . . ................ Compass Surveys . .. . .. .. . . .. .. . . . .. . . . . .. . . . ...................... Dip Needle Surveys . . . . . . . . .. . . . .. . . . . . . .. . . . . . . . .. . . . .. . ... . ..... Magnetometer Surveys .. . . .. .. . .. . . . . . .. . .. . .. .. . ... ... . . . ... . .. .. . Electrical Methods . . . . . . . . . .. . . . ... . .. ... .. .. .. . . . .. . .. . ... . .. ...... Electromagnetic Surveys .......................................... Self-Potential (or Spontaneous Polarization) Surveys ... . . .. . . . . . . Resistivity Surveys . . . . .. .... . . . . . . . .. .. . .. ..... . . . . . . . . .. . . . .. . . Induced Polarization Surveys ..................................... Radiometric Methods ................................................. Principles of Radioactivity . .. . . .. . . . .. . . . .. .. . . . .. . . . . . . . .. . . . . . Detecting Instruments ............................................ Significant Indications . . . . . . .. .. . . . . .. . . . .... ... . . . . . . . . . . .. . . . . Seismic Methods ....... .............................................. The Reflection Method ............................... . .. . ...... . . . The Refraction Method ............................................ References . .. .. . . . . . .. . .. ... . . . . . . . . .. .. . .. .........................
63 63 65 67 67 68 68 70 71 72 72 73 73 74 75 76 76 76 78
FIGURES
8. 9. 10.
Iron Formation Detected by Compass Survey ...... ... ....... .. ... . Dip Needle Survey .............................................. Examples of Electromagnetic Method Dip Angle Profiles ..........
66 66 69
TABLE 5.
Mining Geophysical Equipment Manufactured in Canada ............
77
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GEOPHYSICAL SURVEYS
By E.G. Blunden 1 and J.A. McCance 2 INTRODUCTION
Geophysics is the branch of science concerned with relationships between the earth phenomena and the forces producing them (Geo - the earth, Physika the natural things). In the minerals exploration industry the word carries the connotation of procedures whereby various instruments can be used to detect or to quantify physical criteria related to earth materials so that the data may be translated into terms of Geology, Mineralogy, or Petrology; especially towards economic ends. As the demand for minerals has expanded and the more easily discovered deposits have been exploited, the search for new sources has created a challenge to mankind's ingenuity. Rapid advances in instrumental technology have created the need for specialists in the field of geophysics, not only to design and construct more sophisticated instruments, but also to interpret instrument data into geological terms. Fortunately many of the instruments and procedures presently employed, especially the ground-operated ones, can be used by the ordinary or amateur prospector who is willing to take the time and trouble to understand the principles involved and apply them to his already extensive knowledge and understanding of nature. Airborne techniques for both fixed-wing aircraft and helicopters operate on the same principles as ground instruments but are considerably more expensive and complex than their ground-based counterparts; the ordinary prospector generally does not become involved in their operation. The main application of airborne surveys is in covering large areas in a short time so as to outline 'targets' which then may be followed up with ground surveys. Helicopters have the additional advantages of being operable at near tree-top level thus eliminating the need for linecutting, and they are particularly useful for surveys in water-covered or boggy terrain. Geophysical methods may be conveniently grouped according to the phenomenon upon which they depend, as follows: Gravity Methods, Magnetic Methods, Electrical Methods, Radiometric Methods, and Seismic Methods.
GRAVITY METHODS
In the year 1687, Sir Isaac Newton enunciated the laws of universal gravitation that formalize the observation that any mass is attracted towards any other mass. He showed that this force of attraction varies directly as
Geological Lecturer, Geoscience Information Office, Geoservices Section (formerly Data Retrieval and Education Section), Geological Branch, Ontario Division of Mines, Ministry of Natural Resources, p Geophysicist, Geophysics-Geochemistry Section, Geological Branch, Ontario Division of Mines, Ministry of Natural Resources.
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the product of the masses (the greater the masses, the stronger the force of attraction between them) and that the force varies inversely as the square of the distance between the masses (the farther apart the masses, the smaller the force of attraction between them). These facts are expressed in the mathem atical statement: F^ mlm 2 g oc —— d2
or
F,,g oc ml x m 2 d d
'Weight 1 is simply a measure of the force of gravitational attraction between an object (a mass) and the earth (a huge mass); in metric units its value is of the order 980 dynes of force on each gramme of mass, a quantity which, for gravity survey purposes, would be equivalent to 980 'gal 1 ( a unit named in honour of Galileo). Common gravity survey instruments are so sensitive that the basic unit of measurement used is the 'milligal 1 which is one-thousandth of a gal, and measurements to an accuracy of one-thousandth of a milligal are feasible. Gravity surveying requires systematic measuring of the different forces of gravitational attraction between the sensor mass of the instrument and subsurface rock or mineral masses of differing densities; for example there would be a greater pull, or gravitational force of attraction, between the instrument's sensor mass and an underlying high-density sulphide concentration than between the sensor mass and an underlying lower-density body of graphite, both of which, incidentally, might have shown up similarly as 'anomalies' with electrical surveys. Similarly, there would be a lesser pull between the sensor mass and an underlying granite than between the sensor mass and an underlying gabbro or peridotite. In general, large bodies of lesser or greater densities than their surroundings may be indicated as gravity anomalies when the corrected instrument readings are plotted. A common type of gravity meter comprises a counterbalance system whereby the sensor mass, suspended by a spring mechanism, is displaced towards sub surface rock or mineral masses; the displacements, which are proportional to the gravitational forces causing them, are measured and recorded systematic ally at known locations on grid lines. Normally these locations are at 100foot intervals along parallel crosslines spaced at intervals of 400 feet or more. However, the apparent simplicity of this procedure is complicated by the necessity to adjust all readings as follows: 1) Latitude corrections because the value of the gravitational force of attraction ('g') increases from the Equator towards the Poles; 2) Tidal gravity corrections because of the effect of 'tidal bulge' due to relative changes in sun and moon positions throughout the day; 3) Instrument drift corrections because of the effect of minor shocks during handling, and of imperfect thermal and barometric compensation devices incorporated in the instrument; (Factors 2 and 3 above may be compensated for by establishing a Base Station in the survey area and taking readings at that station every hour during the time of the survey). 4) Elevation corrections because the higher (or lower), topographically, the instrument is when readings are taken, the greater (or lesser) the distance between it and the earth's centre of mass, therefore, the lesser (or greater) the gravitational force of attraction;
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5) 'Bouguer 1 corrections because allowance must be made for the effect of differences in the types of earth material between the different elevations where readings are taken; 6) Terrain corrections because of the plus or minus gravitational effect of surrounding hills or valleys. In addition to these complications, there are the disadvantages to the ordinary prospector that gravity meters are very delicate instruments and are very expensive. The major applications of this type of survey are towards detection of rock structures, of large masses of minerals whose densities are in marked contrast to their surrounding host rocks, and for regional geological survey data. Used in conjunction with magnetic surveys, gravity surveys provide a better resolution of sources causing anomalies; for example, distinction between a structural high in mafic volcanic units and a concentration of massive sulphide minerals having similar magnetic response.
MAGNETIC METHODS
The phenomenon of magnetism as an inherent force in the earth has long been known; the Chinese are believed to have used a form of compass as long ago as 2000 B.C., but not until the 12th century do we have any comprehensive written record of the compass instrument. Then, in 1600, Sir William Gilbert published his paper on magnetism and included the concept of the earth itself being a dipole magnet that determined the orientation of the compass needle. Nowadays we envisage the earth's magnetic field, the 'geomagnetic field 1 , as a series of lines of force passing along great circle routes through the North and South Magnetic Poles. The force field at any point can be con veniently considered as comprising a horizontal component (H) and a vertical component (Z). The H and Z components, as well as the total magnetic field (F) at that point, can be measured directly by modern instruments; the unit of measurement is the 'gamma' (7). The geomagnetic field is not uniform; it is distorted by differences in the earth's composition at different locations. Also, the field at any one location changes throughout the day due to solar activity (diurnal variation), which, when intense enough, creates atmospheric magnetic effects called magnetic 'storms'. Furthermore, the relative position of the magnetic North Pole is slowly changing. Two kinds of magnetism are recognized: 1) Induced; The geomagnetic field has a greater effect on rocks or minerals that are more susceptible than others to magnetic realignment; this is the property known as 'magnetic susceptibility 1 and is simply the affinity of a mineral or rock to magnetization at any time, past or present. 2) Remanent or Permanent: This may have either a positive or negative effect and is dependent on the state of the earth's magnetic field during and since the time the particular rocks were formed, as well as on their composition, attitude, etc., during geological history. The total magnetism of rock formations is the sum of the Induced and the Permanent magnetism.
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Figure 8
Diagram illustrating how a band of iron formation may be detected by a compass survey (from Lang 1970, prospecting in Canada, p.137 )
O
20
40
60
Metres
Contour interval 5 degrees of dip GSC
Figure 9
An example of a dip needle survey ( from Lang 1970, Prospecting in Canada, p.138 )
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Minerals and natural concentrations of minerals show varying magnetic susceptibilities; for example, among the 'ore minerals' we have: High Susceptibility
Low Susceptibility
Magnetite Ilmenite Pyrrhotite Manganese minerals Chromite (some)
Pyrite Hematite Sphalerite Galena
Magnetic surveys are conducted along lines of known geographic position. The aim is to find 'anomalies', that is, deviations from the normal back ground, in the survey area as a consequence of any local magnetic character istics. In making a survey, the operator should take the following precautions: 1) Remove all metal objects from his person, e.g., penknives, lighters, belt buckles, watches, rings, etc.; 2) Select Base Control Stations (usually along a base line) so that geomag netic variations due to solar effects may readily be taken every hour during the survey; 3) Make corrections to all readings, based on natural changes in the magnetic field throughout the day and from day to day; 4) Take base station readings at hourly intervals and make appropriate corrections to survey readings. Three procedures that may be followed are known as Field Time slope method, Looping method, and Leap-frog method. Compass Surveys The compass comprises a magnetized needle that aligns itself in the direction of the HORIZONTAL component of the earth's magnetic field. Since this field is affected by local magnetic phenomena, the compass will indicate variations from the normal which constitute an anomaly. By taking compass readings at regular spacing along known lines or directions, usually cut at right angles to the 'strike' (horizontal direction) of the local structure, it may be possible to delineate anomalies where there are rocks of widely differing magnetic character. It is important to realize that the lines or traverses for compass surveys must be laid out by other than compass methods. Dip Needle Surveys Whereas the compass is designed to indicate the direction of the local HORIZONTAL component (H), the Dip Needle, somewhat like a compass used on its side, has its pointer mounted on a horizontal axis or pivot and so is designed to indicate the direction of the local VERTICAL component (Z) of the earth's magnetic field. If a counterweight device is incorporated, which can be used to balance out the pull of the vertical component, some quantitative value for that vertical component may be obtained. Groups of such readings above or below the normal in the area indicate magnetic anomalies. Use of this
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instrument for magnetic surveys at the present time is very limited, other methods and instruments for recording quantitative data more precisely having been developed.
Magnetometer Surveys Magnetometers are sensitive instruments for measuring local variations in the earth's magnetic field, and surveys made with these instruments are very useful for determining geomagnetic data. Interpretation of such data can be of considerable use in extending or detecting geological features beneath areas of overburden. Both ground-operated and airborne types of instruments are available. The 'Schmidt 1 and 'Askania' magnetometers, seldom used nowadays, were early quantitative instruments using mechanical and torsion-wire principles; their successors are simpler to use and more compact. The 'Conimag 1 recently made its debut as a modern 'Schmidt-type' instrument; the 'Fluxgate' and 'Nuclear Precession' are electronic instruments. Compact 'pocket magnetometers' that measure the vertical component (Z) are available for general prospecting, two such instruments being the Finnishmade "ARVELA" and the Norwegian 'MINIMAG'. They are simple, easy to operate, and relatively inexpensive; but of course, they do not have the range of degree of accuracy of the more expensive instruments. Although these magnetometers do not need to be oriented it is advisable that the prospector take each reading while facing the same general direction. Both instruments may be hand-held or tripod-mounted if desired. Most Fluxgate instruments measure the vertical component (Z) and those models adapted for mobile vehicle operation may incorporate devices for continuous recording of magnetometric data. The ground-operated models are held by the operator, usually by means of a shoulder strap and are selflevelling, self-orienting, and thermally insulated, making them quick and easy to use. Recently numerical readout models have become available. Nuclear precession type instruments measure the total magnetic field (F), do not require orientation and again, are quick and easy to use. However, the operating principles on which they function are more sophisticated and presently these units are heavier and more expensive. They also incorporate numerical readout capabilities.
ELECTRICAL METHODS
The interrelationship between earth materials and the several phenomena of electricity has many applications in mineral exploration. In some circum stances, a mineral body itself may initiate electric currents that can be detected and measured using highly sensitive instruments. Otherwise, geo physical techniques use equipment that generates artificial electrical fields within rocks by transmitting electric currents through a variety of wire coils and loops. A similar variety of receiving devices is used to record the response of the rock or mineral bodies to these electrical fields.
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East
West 500 E
Ground Surface
Cross section of the theoretical magnetic field surrounding an energised electrical conductor; with search coils in the null position, the arrow on the instrument points toward the conductor.
Example 1 Station No.
1 2 3 4 5 6
Dip and Direction O0 20 N 16 0 N 10 0 N 20 0 S
50 S O0
7
Geological Section
Example 2 Station No. 1 2 3 4 5 6 7
Note:
Dip and Direction O0 20 E 16 0 E 100 E 20 0 W 60 W O0
An arrow on the VLF instrument points toward the conductor. A reverse crossover is present when on adjacent readings the arrow directions are away from each other.
Figure 10 - Examples of Electromagnetic Method Dip Angle Profiles
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As always, interpretation of results calls for an understanding of the ways of nature, knowledge of the techniques used, and considerable field experience. Electromagnetic Surveys Several methods and types of equipment are available both for ground and for airborne EM (electromagnetic) surveys; they seem to be best suited, in Canada, to the detection of massive sulphide minerals in vein or shearzone (tabular-type) deposits having a high conductivity. Modern instrumen tation, measuring several parameters, has allowed the prospector to discri minate between useful mineral concentrations and barren fault, fracture, or fissure zones that contain conductive groundwater solutions. The physical principle employed in EM surveying results from the effect created when a strong alternating current is fed into a wire coil or loop held in a definite direction. This alternating current produces a fluctuating magnetic field, called the PRIMARY field, which induces a complementary alternating electric current in any conveniently local conductive mass. The induced alternating electric current in turn creates its own fluctuating magnetic field, called the SECONDARY field. Depending on the particular characteristics of the conductor mass, the secondary field causes both directional and time-lag (phase-shift) distortion of the primary. The resultant TOTAL field, the overall combination of primary plus secondary, is detected and measured through a receiver coil (or search coil). The results are then interpreted using the mathematical principles of 'vectors', which are symbols representing both quantity and direction. The combination of variables inherent in the local geology, and alter natives available in method and procedures that can be used, presents no small challenge to the knowledge and experience of the geophysicist and prospector. A typical portable vertical-loop EM instrument has a battery-powered transmitting coil of specific diameter carried by one man, and a similar receiver or search coil with integral clinometer and earphones carried by a second man. These two men traverse parallel cross-lines, usually 100 to 400 feet apart, on a pre-cut grid, stopping at each station to take a reading. For example, the transmitter operator stops at picket 34+OON on line 3+OOE, holds the transmitter loop vertical and pointed towards the receiver operator who is at picket 34+OON on line 5+OOE; the transmitter operator pushes a button to transmit the signal and at the same time the receiver, or search operator, rotates his coil on a horizontal axis until he hears the minimum noise signal in his earphones. The receiver operator then notes the direction and amount of 'dip angle' of his coil, in degrees, as indicated by the clinometer; a zero dip angle (i.e. a horizontal receiver coil) indicates no conductor. Clinometer (dip angle) readings and directions, when plotted on a map or grid plan, indicate any local conductors. Some reconnaissance EM instruments are light in weight and have two combination transmitter-receiver coils, each carried by an operator; these are well suited to bush traverses without pre-cut grid lines.
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A more recent innovation is an EM receiver unit that responds to local distortions of VLF (very low frequency) signals in the 12 to 24 KHz range generated by communications stations established at strategic locations around the world. These stations are intended primarily for submarine navigation. The EM receiver is 'tuned in 1 to a particular transmitting station, lying approximately along the line of strike of the local geological structures/ the approximately oriented to obtain measurements of dip angle, out-of-phase field strength, or resultant field strength as required. Readings are taken systematically at picket locations on a pre-cut grid or known series of lines. The results are plotted and interpreted as for other EM surveys. Self-Potential (or Spontaneous Polarization) Surveys In certain circumstances, some types of rock or mineral bodies will behave like natural 'batteries' capable of generating small natural electric currents; in these circumstances, the mineral body becomes 'polarized 1 , that is, one part gains a higher electric potential relative to another, and where there is such a difference of potential (voltage), an electric current will flow. This difference in potential, being small, is measured in MILLIVOLTS (thousandths of a volt) by an instrument known as a millivoltmeter-potentiometer. The actual cause of the potential difference is not known; earlier observations that the effect was most noticeable in conductive sulphide bodies such as pyrite, pyrrhotite, and chalcopyrite that were undergoing oxi dation ('weathering') in the surface zone, led to the idea that oxidation was a major factor. Groundwater solutions in the oxidation zone are weakly acid, due to humus and atmospheric carbon dioxide, whereas at depth they are weakly alkaline, due to chemical reactions with the primary rock minerals. However, the method has been very effective where permafrost conditions pertain and where oxidation is minimal. Unfortunately for the prospector, bodies high in graphite, but with virtually no sulphide minerals and unaffected by oxidation, can also generate these currents. In simple practice, two porous pots filled with saturated copper sulphate solution are used as non-polarizing electrodes to be placed in contact with fresh earth. Into each pot (electrode) is placed a copper bar that is connected by waterproof insulated copper wire to the millivoltmeterpotentiometer. One of these pots may be kept at a fixed location or Base Station, while the other is moved systematically from point to point on known grid lines. Readings are taken and recorded for each point. An alternative procedure may be used whereby both pots are kept at a fixed distance apart, usually 25 to 100 feet, and both moved along the grid lines from point to point in 'leap-frog 1 fashion. Again, readings are taken and recorded for each point. In taking readings, the operators read both the magnitude and the sign (* or -) of the potential difference. Results, plotted on maps or profiles, are interpreted in relation to other known data and may indicate conductive bodies worthy of further investigation. Presently, modifications of the technique are being investigated using copper plate electrodes and copper nail electrodes in trees, rather than the above-mentioned pots.
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Some general factors to bear in mind if considering the SP method are: 1) It is relatively easy, simple, and cheap; 2) It is effective for massive sulphide minerals or similar bodies (sulpharsenides, sulphantimonides, arsenides, etc.) under a variety of geographical conditions, provided appropriate precautions are taken; 3) Non-conductive sulphide bodies, such as sphalerite, are not likely to show the phenomenon; 4) Areas of thick overburden (300 feet or more) may mask the effect; 5) Differences of potential due to other natural phenomena (storms, topography, etc.) may contribute to false results; corrections must be made to allow for these; 6) The method has been successful where other methods have failed to give indications of mineral bodies. Resistivity Surveys Frequently used in conjunction with SP surveys, the Resistivity method requires that an artificial electric current, DC or low-frequency AC from a portable generator, be fed into the ground through widely-spaced metal stakes (current electrodes). The resulting potential differences created in the general area are measured by a voltmeter connected to a pair of properly spaced measuring electrodes that are moved systematically along picket lines covering the survey area. As with natural currents, these artificaillygenerated currents will pass through rock or mineral formations under certain conditions. Here again, graphite masses and highly porous rocks filled with mineral-bearing groundwater could produce the same indications as sulphide minerals or some oxide bodies, therefore the results from this method can be inconclusive. By measuring the potential differences (voltages) between the measuring electrodes, which are placed in the ground at selected locations along the picketted lines, and knowing the current and the distance between the current electrodes, it is possible to calculate the 'apparent resistivity 1 for each set-up. Various relative arrangements of the current- and measuring-electrodes ('arrays') are claimed to have particular advantages in particular situations. The calculations of apparent resistivity are given in 'ohm-metre' or in 'ohm-feet 1 units and are plotted on plans or profiles in the usual way. On the basis of interpretation of the results, targets for closer investigation by diamond drilling or other means are delineated. At present, resistivity values can more easily be obtained as a by-product of the data collected in Induced Polarization surveys. Induced Polarization Surveys The Induced Polarization (IP) method, like the Resistivity method, requires that an artificial electric current be fed into the ground, but the objective is to polarize discrete conductive mineral grains that may occur in the area between the current electrodes. When the artificial electric current is interrupted, the potential that has built up does not immediately fall to zero
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but 'decays' over a period of time, much the same as happens with capacitors. The rate of discharge, or decay, of the potential depends on the character of the mineral grains and the interstitial groundwater in the rock pores between the electrodes. As with the resistivity method, measuring electrodes connected to a voltmeter are placed in contact with the ground at known points along picketted lines; at each set-up several readings are taken of the voltage at the instant the current is interrupted, and of the voltage remaining after a given number of seconds. Polarity is reversed for successive readings so as to minimize 'residual 1 effects and other natural interferences. Average values for each set-up are plotted on profiles for each surveyed line, and the results are interpreted drawing on all accumulated knowledge and experience. The method has been successful in the detection of disseminated deposits which, lacking the continuity of the conductive mineral, are considerably more difficult to locate by EM or Resistivity surveys. The principal dis advantages of IP are that the method is complicated, costly, and slow.
RADIOMETRIC METHODS Principles of Radioactivity
"The uranium atom is the heaviest in nature and is constantly trying to 'reduce' by giving off matter and energy in a process known as 'radioactive decay' or 'radioactive disintegration 1 . In doing this, uranium changes to elements of lower atomic weights until the stable element lead is finally reached, whereupon no further disintegration takes place. "Some of the matter and energy emitted by uranium (and, unfortunately for the uranium prospector, thorium also - the parent member of another radio active series) are capable of penetrating considerable thicknesses of air or solid material and it is this property of the rays that makes possible the use of detecting devices. "Three types of rays are emitted by uranium, and have been named 'alpha', 'beta 1 , and 'gamma 1 rays. Alpha rays are relatively large particles of matter emitted at low speeds. These are so easily absorbed that they travel only from one inch to four inches in air and are stopped by a sheet of paper, and are therefore not detected by prospecting instruments. Beta rays are electrons, small particles negatively charged with electricity that are emitted at speeds approaching the speed of light; beta rays have considerably more penetrating power than alpha rays, but are stopped by less than one-tenth of an inch of brass or aluminum; they are not detected by all prospecting instruments but can be detected by specially adapted 'beta counters', which are useful under certain conditions. Gamma rays are the armour-piercing bullets in uranium's arsenal. They are bursts of energy very similar to the familiar x-rays, which, as is well known, will penetrate considerable thicknesses of solid material. Gamma rays are even more penetrating than x-rays and will pierce up to 1\ inches of iron and up to one foot of solid rock. This is the type of ray that is normally registered by radioactivity detectors and it is therefore the most important of the three kinds in prospecting for uranium. The special beta counters detect gamma rays also.
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"Alpha, beta, and gamma rays are emitted directly by radioactive minerals. In prospecting for uranium, however, it should be remembered that one of the decay products of uranium is radon, a radioactive gas derived from radium, small quantities of which are present in uranium ores. This gas may migrate considerable distances from its source in a uranium occurrence through fracture zones, loose overburden, or water. The presence of uranium in the vicinity may therefore be indicated by the radioactive effects of this gas when the detecting instrument is actually far outside the range of the gamma rays directly emitted by the uranium mineral.
Detecting Instruments
"The heart of any type of Geiger counter is the Geiger-Muller tube. This is a glass tube containing two electrodes, one of which is in the form of a thin wire running the length of the tube (the anode or positive electrode); the other is a cylinder, frequently of copper, lying next to the glass wall (the cathode or negative electrode). The interior of the tube contains an inert gas, commonly argon, at low pressure, with a small amount of ether or alcohol vapour. A high voltage is supplied to the tube but one not sufficiently high to overcome the resistance of the gas to the passage of current. If a gamma ray strikes the cathode, electrons are emitted by the copper, and the gas within the tube becomes ionized so that a pulse of current flows between the electrodes. This action might be compared to the passage of electricity through water; pure water resists the passage of electricity, but if a pinch of salt is added the salt solution will pass current readily owing to the presence of ions. The pulse of current thus produced in the tube may be amplified and made audible in the earphones of the instrument, or the pulses may be registered by a meter that shows on a numbered dial the number of pulses per minute. "Although the Geiger counter is an effective instrument for detection of gamma rays, it actually has a low operating efficiency, since only about onetenth of one per cent, or one in a thousand, of the gamma rays that strike the cathode cause a 'count 1 , that is, an electrical discharge in the tube. This apparent disadvantage becomes an advantage in some phases of exploration, such as logging diamond drill core or examining underground exposures in a mine, when it is desirable to detect beta radiation within a very small area and to exclude gamma radiation from beyond that area. For this purpose a beta counter is used. The beta counter is simply a Geiger counter in which the tube either has a very thin cathode and glass wall or an 'end-window 1 , sometimes of mica, in a lead-shielded probe. The beta rays can therefore penetrate directly into the tube and cause a discharge. Of course, a beta counter tube also admits gamma rays, but beta rays are ten times as effective in causing flow of current in the tube, therefore of every ten counts recorded nine will be due to beta rays and only one to gamma. The beta counter has also been found useful in testing samples of low-grade uranium ores. Owing to the greater ionizing properties of the beta rays, radioactivity can be detected readily by the beta counter at very close range. "The scintillation counter has become a popular detecting device in recent years. It operates on an entirely different principle from the Geiger counter, taking advantage of the fact that certain crystals emit light when
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struck by a radioactive ray, each ray generating a tiny spark in the crystal. To record this effect a section of a crystal is fitted very exactly to the end of a photomultiplier tube. This is a very sensitive 'electric eye 1 that converts light impulses into electric impulses, as do the simpler ones used in light meters and door closers, but multiplies the original voltage and delivers an amplified pulse of electricity for each flash of light. These pulses after further amplification can be recorded by a meter or made audible in earphones. "An interesting feature of scintillation counters is that certain sub stances used for the scintillating crystal respond only to gamma rays, and others only to alpha rays; scintillation counters may therefore be made selective for either type of ray. The alpha scintillation counter is employed much like the beta Geiger counter, for studying localized radiation. The gamma scintillation counter is a very efficient detector of radiation and is several times as sensitive as the Geiger counter. It should be remembered, however, in comparing the relative sensitivities of Geiger and scintillation counters, that the efficiency of each instrument also depends on the effective area of the crystal scintillator as compared to the cathode area in the Geiger-Muller tube or tubes which, in portable models, is much greater. The greater sensitivity of the gamma scintillation counter, to gether with the fact that it has a greater speed of response, makes it the best detector yet devised for use in airplane or helicopter. On the ground, the scintillation counter can detect radioactive material beneath a greater depth of cover than the Geiger counter, making it an instrument well adapted for tracing a known radioactive zone beneath drift or for detailed surveys of areas that include drift-covered sections. The sensitivity should not be over-estimated, however, since radiation drops very rapidly as the distance from the source increases, so that eventually the normal surface and cosmic radiation will mask the indication. When this point is reached, no matter how sensitive the instrument may be, it will be unable to detect the radio active material beneath the overburden. Generally speaking, about four feet of water or two feet of overburden, or six feet of snow will successfully mask the radiation from a pitchblende source when a scintillation counter is used. These distances are about 30 per cent smaller when a Geiger counter is used. "For general prospecting, the Geiger counter is still preferred by many experienced operators because of its lower cost, lightness, and simplicity of operation. It has been found that Geiger counters are sufficiently sensitive to pick up all the significantly mineralized occurrences, as well as many that are relatively unimportant. Greater sensitivity might only serve to increase the number of unimportant occurrences detected. Scintillation counters are desirable for detecting slight radioactivity and for making detailed surveys. Significant Indications "One of the most frequent queries about radioactive prospecting is 'What is a significant indication?', by which is usually meant 'Will a certain countrate indicate a certain grade of ore?' There is no simple answer to this question, as may be gathered from the preceding paragraphs. Generally speaking, count-rates double the normal background are considered worth
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investigating further, but even this rule of thumb should not be interpreted too literally. The background count is derived from the slight radioactivity of rocks plus the effects due to cosmic rays. Therefore background may differ with the rock type. In the Beaverlodge area, for instance, it is not uncommon for the count to rise to double or more in proceeding from sediments or amphibolite into granite. The higher radioactivity of granite, especially pink or red granite, may be due to the presence of radioactive potassium in the feldspars and such an 'anomaly 1 is often of no significance, as the prospector quickly learns. On the other hand, within an area of one rock type a double background count may indicate that radioactive minerals are in the vicinity and that the indication simply has been diminished by distance from the source or by overburden. Therefore the vicinity of such an indication should be further investigated until it is established that no significant source of radiation is present. If a seemingly significant count is obtained, particularly over more than an isolated spot, the next step is to take some samples and to hold them close to the counter, at a place where the background is normal; this will eliminate the all-too-common mass effect. If the samples do cause a count of twice background or more, the next step is to send them for laboratory tests. "Anyone planning to work in a certain area should visit any known occurrences of radioactive minerals there and make observations with his own particular instrument, if at all possible. There is no more effective way of learning to recognize a significant indication." The preceding description of Radioactivity is mainly excerpted from Lang (1956, p.192-196).
SEISMIC METHODS
Seismic methods are not in general use as mineral exploration tools; their major applications are in acquiring structural data related to regional geological surveys, to civil and engineering problems, and to the search for oil and natural gas. Shock waves, whether natural or man-made, are propagated through different types and densities of rock masses at different velocities. They are subject to the general physical laws of reflection and refraction at 'interfaces' and it is these phenomena that are used in the two common seismic methods, the Reflection Method and the Refraction Method. The Reflection Method is extensively used in North American oil explora tion practise, being well suited to contouring of deep structures. The Refraction Method is used for shallow investigations and has a useful application in mineral exploration for determining depth to bedrock. For this purpose a portable seismic detecting-recording device is set up at a selected site, then at successive equally-spaced points along a known line, shock waves are created by detonating a small charge of blasting powder or by striking a steel plate, set on the ground, with a sledge hammer. Wave travel through unconsolidated overburden is at a much lower velocity than that through underlying consolidated bedrock, and these velocities may be
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deduced from a graph on which the operator plots distances of wave travel against times of wave travel (as indicated by the recording instrument) for each one of the above points. The distance at which the graph indicates change in velocity (a change of 'slope 1 of the graph) is called the 'critical distance 1 (Xc ) and this figure, together with the wave velocity in overburden (Vi) and the wave velocity in bedrock (V2) t is used to derive the depth to overburden from the following formula: d ^ 2
y V2+V],
REFERENCES CIM
1957:
Methods and Case Histories in Mining Geophysics; Sixth Commonwealth Mining and Metallurgical Congress, Montreal, Mercury Press Co., 359p., 12 figures.
Dobrin, M. B. 1960: Introduction to Geophysical Prospecting; McGraw-Hill Book Company, Inc., New York, London, Toronto, 446p. Griffiths, D. H., and King, R. F. 1965: Applied Geophysics for Engineers and Geologists; Pergamon Press Ltd . , Oxford , England . Heiland, C. A. 1963: Geophysical Exploration; Hafner Publishing Co., New York, N.Y., 1013p. Heiner, L. E., and Wulf, S. A. 1968: Handbook of Geophysical Prospecting Methods for the Alaskan Prospector; Mineral Industry Research Laboratory, Report No. 19, University of Alaska, College, Alaska 99701, 61p. Lang , A . H . 1956: Prospecting in Canada; Geol. Surv. Canada, Econ. Geol. Ser.7, Third Edition, 401p. 1970:
Prospecting in Canada; p. 134-167 iri Geol. Surv. Canada, Econ. Geol. Rept. No. 7, Fourth Edition, 308p.
Morley, L. W. (ed.) 1967: Mining and Groundwater Geophysics; Geol. Surv. Canada, Econ. Geol. Rept. No. 26, 722p. Nettleton, L. L. 1971: Elementary Gravity and Magnetics for Geologists and Seismologists; Society of Exploration Geophysicist s, Monograph Series No. l, Tulsa, Oklahoma, 121p.
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Parasnis, D.S. 1966: Mining Geophysics; Elsevier Publishing Co., Amsterdam, 356p. Society of Exploration Geophysicists 1966: Mining Geophysics, Volume I, Case Histories; The Society of Exploration Geophysicists, Tulsa, Oklahoma, 492p. 1967:
Mining Geophysics, Volume II, Theory; The Society of Exploration Geophysicists, Tulsa, Oklahoma, 708p.
Wahl, W.G. 1973: W.G. Wahl Ltd., Consultants, Geology-Geophysics, Toronto. Many personal communications on this subject.
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TOPIC 6
GEOCHEMICAL PROSPECTING Revised by E.C. Blunden
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CONTENTS Geochemical Prospecting Page Introduction ...... . . . . .. .. .. .. . . . .. . .. . .. . .. .. . . .. . . .. .. . .. . . . . . . . . . Geochemical Anomalies .. .. . .. . . . . . .. . . . . ... ... . . . .. . . . . . ... . . .. . . .. .. Primary Anomalies ...... ............ ............. ...... .. ........ . Secondary Anomalies . .... ...... ............ ..... ............. ..... Types of Samples .................................................... Bedrock Samples . . . . . . . . .. . . . .. .. . . ... . . .. . . . . . .. ................. Soil Samples . .. .. . .. . . . .. ... . .. . .. . . .. .. . .. . . . . . . . .. . . . . . .. . . . ... Stream Sediment Samples . . .. . . . . . ... . . . . . .. . . ... . . . . . . . . . . . . . . . .. . Vegetation Samples .. . .. . . .. . . . . . . .. . ... . .. .. ... . .. . . . . . . . ... . ... . Water Samples . ......................... ... . .... .................. Survey Methods . . . .. . .. . . . . . . .. . .. . . . .. . ... .. . . . .. . .. .. . . ... ... . . .. .. Variable Factors ............... .... ............ .................. Selection of Procedures . ............ ............ ................. Detailed Survey Procedures .. .. .... ...... ...... ... ........ ... ... .. Analytical Methods ... . . . . . .. . .. ... . .. . . . . . . .. .. . . . . .. . . . . .. . . .. .. . .. Field Kits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ................... Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .. References . ... .. . .. ... . .. . .. . .. .. .. . . ... . ...........................
83 83 84 84 84 84 85 87 87 89 89 89 89 90 90 91 91 91
FIGURES
11. 12.
A Mature Podzol . . . ... .. . .. . ... . .. . .. . . . . . . . .. . .. ... . .. . . . . ..... Basic Conditions Allowing Geochemical Exploration ..............
86 88
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GEOCHEMICAL PROSPECTING
Revised by E.C. Blunden 1 INTRODUCTION
Geochemistry involves application of the fundamental principles of chemistry to studies of naturally occurring earth materials and the geologi cal environment in which they occur. Applied to prospecting, it is a tool that can be used in the search for economic deposits of minerals, especially the metallics. As the more easily detected deposits have been found and developed, the prospector has been obliged to use more sophisticated techniques to guide him to areas where mineral wealth is hidden. Indeed, it is now commonplace to use a variety of techniques in each prospecting endeavour rather than to depend mainly on one. So then, geochemical prospecting should not be regarded as an entity but as one tool to be used in conjunction with visual and geophysical techniques where conditions permit. A quantitative list of chemical elements comprising the earth's crust shows very small proportions of useful metals to be present, but fortunately these are not uniformly distributed. Through various geological processes many of them have been concentrated into mineral deposits some of which, under special conditions, may be mined and processed economically.
GEOCHEMICAL ANOMALIES
Mineral deposits are abnormal, or anomalous, concentrations of useful elements in contrast with the general background count of those elements in a particular geological environment. Relatively, they occupy very small amounts of space, are usually concealed by surficial features, and so are difficult to detect. However, continuing and various geological processes during and since the formation of such deposits have caused physical and chemical disin tegration products to disperse away from the deposits, creating 'dispersion haloes'. These haloes provide wider targets for the prospector or geochemist in his search for hidden mineral wealth. Geochemical methods employ simple, relatively cheap, but effective chemical techniques to detect the small amounts of metallic ions dispersed from deposits through surrounding naturally occurring substances such as bedrock, sediment, soil, vegetation, surface and underground waters, and even the atmosphere. But a vitally important part of the process of geochemical prospecting is integration of the results of systematic chemical testing with knowledge and understanding of the geological and geographical criteria that pertain, so that the disseminations may be traced back to source.
Geological Lecturer, Geoscience Information Office, Geoservices Section (formerly Data Retrieval and Education Section), Geological Branch, Ontario Division of Mines, Ministry of Natural Resources.
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and pressure conditions. The primary dispersion haloes, as with primary mineral deposits, may be considered as of two types: Syngenetic: formed at the same time as the host rock; Epigenetic: formed later than the host rock. As well as the more obvious chip or channel sampling of bedrock outcrops, geochemical sampling of drill cores from surface or underground drilling may prove indicative of the proximity of mineral bodies. Soil Samples Soil develops through the physical and chemical weathering of a parent material. It is important to distinguish between areas where the parent material is the underlying bedrock, and areas where the material is extraneous rock debris that has been transported by water, wind, or ice. Depending on such factors as the parent material and the extent to which the soil forming process has progressed, a soil may develop a characteristic profile consisting of fairly distinct layers. Percolating waters tend to dissolve and carry down soluble and very fine-grained material, this process of soil leaching being called 'podzolization' and the fully developed profile being called a 'podzol'. Most Canadian soils are podzols although in poorly drained areas such as in the Shield, soil profiles have not fully developed. As shown on the accompanying figure the main soil zones are called A, B, and C. The upper, or A zone, is principally a zone of leaching and part of this zone is usually light coloured. The B zone is the zone of accumulation where much of the material removed from the A zone is deposited or precipita ted, generally giving a rusty colour due to an abundance of iron oxides. The C zone consists partly of rock fragments of parent material and partly of soil formed from weathering of these fragments. In a mature soil profile, or where a layer of organic material is present at the surface, the main zones may be further divided into subzones which show marked variations of colour. Of principal concern to us in the application of geochemical techniques is that metals leached from the A zone are deposited mainly in the B zone, which is thus enriched in these metals. In residual soils then, the B zone is generally an excellent source of material for sampling as it gives a good indication of conditions in the underlying bedrock. The soil forming process also accelerated lateral dispersion and gives rise to secondary haloes that present good target areas. Transported soils, such as soils formed by glacial action, may contain indicators from a near or a distant bedrock source, depending on the type and time of transportation. Clays usually are not good sample material as they are impervious to the movement of ground water downward from the surface or drawn upward by capillary action. The presence of large areas of clay in northern Ontario has acted as a deterrent to wider use of geochemical prospecting in that region. Drilling through clay to the underlying till or soil may provide significant information but greatly increases the cost of sampling. Although sampling the B or C zone is usually recommended, Boyle's work at Cobalt (Lang 1970, p.174) indicated that the A zone developed generally on clayey overburden yielded the best results because it was enriched in
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Organic debris largely undecomposed Decomposing organic debris ( humus )
Partly bleached
SOLUM OR 'TRUE SOIL 1
Leaching of iron and aluminium oxides, clay and humus
y \ Maximum of leaching : well bleached
Top level of accumulation
Very dark
PARENT MATERIAL
Maximum accumulation: often cemented in places (iron - pan)
Top of parent material, partly weathered
Figure 11 -A Mature Podzol (modified after W.E.Nevill 1963, Geology and Ireland, published by Allen Figgis, Dublin p.123)
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metals from leaves of trees that apparently had tapped deeper soil zones. Normally carbonaceous, black humic, and organic material are avoided where possible because they can yield misleading results and special precautions are necessary in the chemical procedures for analysis. Soil sampling generally is the most direct method of locating a secondary geochemical anomaly, either by reconnaissance or detailed survey, particularly where the overburden is shallow and clays are not present. Stream Sediment Samples Along creeks, streams, rivers, and lakes, fine, silt-size material is selected for geochemical analyses. Often where groundwaters with metals in solution enter a surface drainage system, the change in chemical environment results in precipitation of metallic ions. Therefore the silt samples taken may contain both physical and chemical weathering products from any mineral deposits lying within the drainage basin. Silt samples scooped up should be drained of as much excess water as possible and placed into special plastic bags, marked, and then put into the regular sample bags. After drying, each sample is screened through an 80mesh sieve and only the material that passes through the sieve is used for analysis. This type of sampling is widely used for reconnaissance or regional surveys, which then may be followed by detailed surveys of any areas where anomalously high 'values' are indicated. Vegetation Samples Weathering and soil-forming processes provide concentrations of ions dissolved in soil moisture, absorbed on to the surface of clay particles, or precipitated as salts that are readily available in the soil for plant nourishment. To the prospector, plant roots might be regarded as selective sampling agents that probe deep into the ground and spread out over a wide area. Different kinds of plant life absorb different material from the soils and generally reflect visible signs of the presence or absence of particular elements. This phenomenon of 'indicator plants' has been known by astute observers for many generations and is called 'geobotannical prospecting". 'Biogeochemical prospecting 1 , on the other hand, requires sampling of the tips of branches, twigs, leaves, etc., reducing the samples to white ash, under laboratory conditions, in order to determine the content of the desired elements. As with other kinds of samples, vegetation samples must be taken systematically and uniformly in order to provide reliable results. In any one survey it must be the same plant species that is sampled and the same part of each plant. Some organic material gives results that are higher than the background and it is necessary to investigate the results carefully.
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