INVENTORY FILE NO.
NAME OF PROPERTY
1983 – Inco Limited
Thompson, MB R8N
77 & 78
(Note Picture on original)
“The nickel sulphide mineralization at
Thompson Mine forms a thin, fairly continuos sheet that is confined to
the pelitic member of the (Precambrian) metasedimentary sequence. This sheet has
been traced over more than 7 km, but economic sulphide concentrations are
present only where the sheet has been deformed. The sulphides define very tight
dragfolds where the host pelitic schist is highly deformed (Fig. 10). Large
concentrations of sulphide occur in the hinges of these dragfolds, and lesser
concentrations occur on the limbs. Where ultramafic lenses are present within
the dragfolds, large concentrations of massive sulphides occur in direct contact
with the ultramafic rocks, or laterally away from them, but in the same
stratigraphic position. Disseminated nickel sulphides commonly occurs in the
ultramafic rocks and constitute part of the ore.
The sulphides at the
Thompson Mine consists mainly of pyrrhotite, pentlandite and chalcopyrite
with minor pyrite, violarite and mackinawite as secondary minerals. Arsenides
are present in trace quantities and include niccolite, gersdorffite and
The ore is classified into “massive, inclusion, stringers and
disseminated sulphide type.
“Ultramafic rocks at the Thompson Mine,
although closely associated with the ore, are not volumetrically abundant. They
occur as small scattered lenses in the pelite and as blocks inclusions in the
ore. Roughly estimated, the ratio of total sulphide mineralization to total
ultramafics in the pelitic layer is about one to one.
The Cu/Ni ratio for the
bulk of the ore at Thompson Mine is about 1/5, although on a local scale
it is quite variable. The Ni/(Ni+CU) ratio is close to 0.93, and illustrates the
Ni-rich or Cu-poor character of the Thompson Mine ore.
Cu/Ni Ni/(Ni +
Thompson Mine 1/5 0.93”
MINERALS OR PRODUCTS OF VALUE
Copper, cobalt, gold, silver, platinum, sulphur, selenium,
EXPLORATION AND DEVELOPMENT
The Thompson Mine is 1.6 km southeast of the city of
Thompson and approximately 2 m east of Provincial Road 391.
International Nickel Company of Canada (hereafter INCO) found two linear,
north-trending anomalies during routine geophysical surveys. The stronger
magnetic anomaly, west of Thompson was investigated first because
geophysical theories at that time assumed magnetic highs indicated nickel, and
strong electromagnetic responses did not. When the western anomaly was found to
be barren, INCO turned its attention to the eastern anomaly. This later anomaly
had a weak magnetic response but a strong electromagnetic response (INCO
Thompson Exploration staff, Sept. 24, 1975).
The deposit extends
south-southwest from approximately PIP 613 to Pip 460, then swings
north-northwest to about Pip 462 before turning southwest to Pip 459. It covers
many Pip claims and Bel fractional claims. The claims on which the shaft were
sunk are assumed to be representative, so their histories are given
Pip No. 456 (P21401) and 476) P21421) were staked by employees of
Canadian Nickel company Limited and assigned to that company in 1954. Detailed
ground and geophysical surveys outlined a conductor in this area. A diamond dill
hole was put down on an anomaly about 0.8 km southwest of Thompson
(formerly Cook) Lake in 1956. The anomaly was drilled because it was on the
drill road between two other planned drill sights, but it probably would have
been drilled eventually. This “discovery hole”, possibly on Pip 460, intersected
high-grade ore by cutting both flanks of the major fold at Thompson (INCO
staff, op. Cit.).
By 1956, when the claims were assigned to INCO, diamond
drilling in the area had indicated enough ore to justify a mine (Zurbrigg, 1963,
p. 227). Construction of a surface plant and the sinking of two shafts started
in 1957. A 3-compartment development shaft (T-2 on Bel 7) was completed to a
depth of 1,057 ft. “this shaft was sunk for the express purpose of expediting
development on the 400-, 600-, 800’ and 1000 foot levels. It is of interest to
note that, prior to the completion of the sinking of No. 1 shaft, 38,000 ft. of
drilling was carried out from the development shaft” (Boucher et al., 1964). The
5-compartment production shaft, T-1 on Pip 456, was sunk to 2,106 ft. Levels in
T-1 were established below the 400 ft. level at 200 foot intervals. Over 155,000
ft. of diamond drilling was done at the Thompson Mine in 1958 (INCO
Annual Report, 1958). Pip 456 and 476 were leased as M04987 and M-5007,
respectively, in 1969.
A refinery using direct electrolysis was begun in
1959. Proven reserves of 25,000,000 short tons of ore containing 742,000 short
tons of nickel-copper metal were reported in the company’s annual report for
1960. One-year later full scale production commenced at a rate of more than
75,000,000 pounds per year. Grade was estimated at 3% nickel plus copper, “but
this is practically all nickel since the copper content is only about 1/5th that
of nickel. That suggests an approximate grade of 2.8% nickel and 0.2% copper”,
(Northern Miner, March 30, 1961). Processing and capacity changes brought
production to 90, 000 000 pounds of nickel per year. Resource potential of 0.5
billion tons ore more; including very low grade material is reported by the
Northern Miner (august 17, 1961, p. 94). Zurbrigg (1963) reported the
grade to be 2.97% nickel-copper.
In 1963, a winze was driven between 1,600
and 2,310 levels in T-1 to maintain production while shaft deepening was taking
place. The sinking of the T-3 shaft on Pip 476 started in March 1965 and
completed 15 months later to a depth of 2,607 feet. It was put into operation in
Amax Exploration, Inc. made an airborne geophysical survey over the
area in 1967 under Airborne Permit 66. A small anomaly was found south of
As of December 31, 1967 proven ore reserves of
Thompson and possibly Birchtree., Pipe and Soab were 67 314 000 tons with
a nickel content of 1,270,000 tons and a copper content of 90 000 tons (INCO
prospectus for 1968).
Deepening of the T-1 shaft, began in 1965, was
completed to 4,427 ft. by 1969. Below the 2 400 foot level, levels were
developed at 400-ft. intervals.
Expansion of the mill, smelter and refinery
increased production to 100 000 000 pounds per year. Production included
electrolytic nickel and copper, sulphur, selenium and cobalt oxide concentrates.
Copper concentrate was shipped to Copper Cliff, Ontario for smelting and
refining. The ore did not come from the Thompson Mine, which produced at
a rate of 8 000 short tons per day (INCO Annual Report for 1969).
December 31, 1969 proven ore reserves of Thompson, Birchtree, and
possibly Pipe and Soab were 71 472 000 tons with a nickel content of 1 335 000
tons and a copper content of 104 000 tons (INCO Prospectus for 1970).
in 1971 it was expected that the production rate of the mine would research 12
000 tons per day and by the end of the year 16 000 tons per day.
December 31, 1970 proven ore reserves of Thompson, Birchtree, and
possibly Pipe and Soab were 71 550 000 tons with a nickel content of 1,400,000
tons and a copper content of 100 000 tons (INCO Prospectus for 1971).
1972, the T-1 shaft became operational and in 1973 ore was produced between the
400 and 2,000 foot levels. Ore was also produced between the 400 and 1 600 foot
levels of T-3 (INCO staff, Op. Cit.). Extensive lateral development was underway
between the 1 600 and 4 000 foot levels of T-1 and between 2 000 and 2 400 feet
in T-3. Exploration took place from the 4 000 foot level of T-1 and 2 000 foot
level of T-3 (Northern Miner, August 2, 1972). The T-1 and T-2 shafts are
connected on several levels. Coats, et al., (1972) state that the reserve figure
of 25 000 000 tons has been “essentially maintained”. This figure and a grade of
2.97% nickel-copper continued to be maintained in 1976 (Financial Post, June 19,
In 1980 INCO was considering an open pit to mine the crown pillar area
of the Thompson Mine as one option to replace the Pipe Open Pit operation
(see: 63 O/8 NI 3), which was expected to reach optimum depth by 1983. The crown
pillar area, largely underlying Thompson Lake between the T-1 and T-3
shafts consists of ore deliberately left between the uppermost workings of the
underground mine and the bedrock elevation. Thompson Lake would have to
be drained and clay overburden removed to safely and efficiently remove the ore
(Northern Mines, May 29, 1980).
On October 23, 1981 INCO announced an $87
million project to develop the open pit mine. The first phase to be completed by
1984 involve the dredging of 21 666 000 cubic metres of overburden (Winnipeg
Free Press, October 24, 1981). When complete, this phase will permit open pit
mining of a portion of the orebody to a depth of 130 m. The second phase will
require the dredging to a further 20 million cubic metes of overburden to
provide access to the remainder of the orebody. This phase, expected to begin I
1988 with production by 1991, will cost approximately $64 million (Northern
Miner, November 5, 1981).
Plans for a second, somewhat smaller, open pit
adjacent to the first Thompson open pit, were on the drawing boards for
1988”. The cost of this pit is estimated at $77 million. Both projects would
have a life span of 17 years (Wpg. Free Press, April 19, 1982).
In 1979 INCO
resumed deep drilling program, below the 4 000 foot level of the Thompson
Mine. This program, suspended in 1975 was designed to locate ore-bearing zones
below the zones presently being mined and thus to ensure continued productions
from the mid-eighties onward (Wpg. Tribune, Jan. 5, 1979). Additional mineral
reserves were identified by the deep drilling program (INCO Annual Report,
On July 22, 1982 INCO postponed construction of Thompson open
pit for at least one year. For the past eight months about 100 workers were
employed building a road and pipeline, and to set up equipment (Wpg. Free Press,
July 23, 1982).
The $167 million project was reactivated on May 2, 1983, with
the first phase to be completed and production to commence in January 1986.
Chief contractor on the project is Kesmark Marine Ltd. (Wpg. Free Press, May 3,
1983). Dredging began in August 1983 and the excavation rate is expedited to be
1.1 million cubic metres per month (Northern Miner, August 18, 1983).
Rate of Production:
mid-1961 75 000 000 lbs.
1962? <90 000 000 lbs. Nickel/year
1969 100 000 000 lbs.
or 8 000 short tons/day, expected to reach 12 000 tons/day in
early 1971 (Northern
Miner, October 8, 1970). Not all this ore was mined at
Thompson, but it was all processed there.
Year Tonnage % Ni % Cu
1967 1,976,000 2.77 0.18
Production from Thompson and Birchtree
Year Tonnage % Ni % Cu
3 198 000 2.25 0.15
1970 3 867 000 2.18 0.14
(INCO Prospectus for 1968,
INCO Estimated Metal Production for
Cobalt Copper Gold Nickel Platinums
(lbs.) (lbs.) (lbs.) (lbs.) (lbs.) (lbs.)
1970 664.5 10,164 3.7
142 250 29.0 70.1
1971 454.9 9,670 2.6 135 428 27.1 60.8
1972 447.8 7,987
2.7 111 852 22.4 55.6
Report of the Task Force on Manitoba Mineral Policy
Airborne Permit 66; Non-confidential Assessment File; Manitoba
Recording, Manitoba Mineral Resources Division.
Allen, C.C., 1960: The
Platinum Metals; Mineral Resources Division, Ottawa, Mineral Report No. 3, p. 7,
Bell, C.K., 1971: Boundary Geology, Upper Nelson River Area,
Manitoba and Northwestern Ontario; in Geoscience Studies in Manitoba; Geological
Association of Canada, Special Paper 9, p. 11-40.
Boucher, H.P. and
Armstrong, W.G., 1964: The Thompson Mine; Canadian Mining and Metallurgy,
v. 7, n. 631, p. 1157-66.
Canadian Mines Handbook; 1971-72, p. 200.
C.J.A., Quirke, T.T., Bell, C.K., Cranstone, D.A., and Campbell, F.H.A., 1972:
Geology and Mineral Deposits of the Flin Flon, Lynn Lake and Thompson
Areas, Manitoba, and the Churchill-Superior Front of the Western Precambrian
Shield; International Geological Congress, 24th Session, p. 63-71.
G.E., 1957: Mystery-Moak Lakes Project; Western Miner & Oil Review, v. 30,
n. 1 (January), p. 44-57.
Davies, J.F., 1962: Mineral Deposits in the
Churchill Geologic Province, Manitoba; Canadian Mining Journal, v. 81, n. 4, p.
1960: Geology of the Thompson-Moak Lake District, Manitoba;
C.I.M.M. Bull., v. 81, no. 4, p. 101-4.
Davies, J.F., Bannatyne, B.B., Barry,
G.S. and McCabe, H.R., 1962: Geology and Mineral Resources of Manitoba; Manitoba
Mines Branch, p. 103-8.
Dawson, A.S., 1952: Geology of the Partridge Crop
Lake Area; Manitoba Mines Branch, Publication. 41-1.
Douglas, R.J.W. (Ed.),
1970: Geology and Economic Minerals of Canada; Geological Survey of Canada ,
Economic Report 1, p. 180, 1.
Frohlinger, T.G., 1968: The Thompson Ore
Suite; Unpublished Assay.
Gale, G.H., Somerville, R.C., Chornoby, J.,
Haystead, B., Provins, N. Braun, D., Mundy, D. and Walker, A., 1982: Geological
setting of the Mineral Deposits at Ruttan, Thompson, Snow Lake and Flin
Flon; C.A.C.-M.A.C. Annual Meeting, Winnipeg, May 17-19, 1982, Trip 14, p.
Inco Metals Company, Staff, 1982: More Than Just A Hole in the Ground;
in Manitoba, v. 12, n. 1, p. 3-5.
Kilburn, L.C., Wilson, H.D.B., Graham,
A.R., Ogura, Y., Coats, C.J.A., and Scoates, R.F.J., 1969: Nickel Sulphide Ores
Related to Ultrabasic Intrusions in Canada; Economic Geology, Monograph 4, p.
MacKenzie, B.W., 1968: Nickel-Canada and the World; Mineral Resources
Division, Ottawa, Mining Report 16, p. 69, 75.
Manitoba Mineral Resources
Division; Corporation File: INCO Limited.
Mineral Policy Sector; Ottawa;
Corporation File: INCO Limited.
Patterson, J.M., 1963: Geology of the
Thompson-Moak Lake Area; Manitoba Mines Branch, Publication.
Phillips, K.A., 1974: Untitled, Unpublished Report, Manitoba General,
Unpublished Information Files, Manitoba Mineral Resources Division.
Force on Manitoba Minerals Policy, 1974: Report of the Task Force; Department of
Mines, Resources and Environmental Management, p. 65-70.
Cranstone, D.A., Bell, C.K. and Coats, C.J.A., 1970: Geology of the Moak-Setting
Lakes Area, Manitoba; GAC-MAC Annual Meeting, Winnipeg August 28-30, 1970, Trip
1, p. 10-21.
Wilson, H.D.B., and Brisbin, W.D., 1961: Regional
Structure of the Thompson-Moak Lake Nickel Belt; C.M. & M. Trans., v.
LXIV, 1961, p. XXX and Bull., v. 54, no. 595 (November, 1961), p.
Zurbrigg, H.F., 1963: Thompson Mine Geology; C.I.M.M.
Bulletin, Vol. 56, No. 614, p. 451-60 (same article).
Map 63P/12W, Thompson (Topographic), Scale 1:50 000; Surveys
& Mapping Branch, Ottawa.
Map 2601 G, Thompson (Aeromagnetic),
Scale 1:63 360; Manitoba Mines Branch and Geological Survey of Canada.
51-3, Sipiwesk (Geology), Scale 1:253 440; accompanied Marginal Notes by
Harrison (1951), Geological Survey of Canada.
Map 41-1, Partridge Crop Lake
Area (Geology), Scale 1:126 720; accompanied Publication by Dawson (1952);
Manitoba Mines Branch.
Map 60-4, Thompson-Moak Map-Area (Geology),
Scale 1:63 360; accompanied Publication by Patterson (1963); Manitoba Mines
The T-2 shaft on Bel 7 was used in development before the T-1 shaft
was brought into production. The T-2 shaft is now user only for ventilation.
None of the shafts were intended to overlie the deposit. T-3 shaft is collared
in the mineralized zone because at the desired location the zone was the highest
point in basement.
SMH JDB JDB
2-73 11-75 09-83