NI 2
1983 – Inco Limited
Manitoba Division
Thompson, MB R8N 1P3
The Pas
Uncertainty (m)
150 m
UTM Zone
L.S./Quarter Section
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 maucherite.
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 + Cu)
Thompson Mine 1/5 0.93”
Copper, cobalt, gold, silver, platinum, sulphur, selenium, palladium
The Thompson Mine is 1.6 km southeast of the city of Thompson and approximately 2 m east of Provincial Road 391.
The 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 below.
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 1967.
Amax Exploration, Inc. made an airborne geophysical survey over the area in 1967 under Airborne Permit 66. A small anomaly was found south of Thompson Lake.
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).
As of 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).
Early 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.

As of 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).
In 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, 1976).
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, 1980).
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. Nickel/year
1962? <90 000 000 lbs. Nickel/year
1969 100 000 000 lbs. nickel/year
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.

Production from Thomson
Year Tonnage % Ni % Cu

1967 1,976,000 2.77 0.18

Total Production from Thompson and Birchtree
Year Tonnage % Ni % Cu
1969 3 198 000 2.25 0.15
1970 3 867 000 2.18 0.14
(INCO Prospectus for 1968, 1970, 1971)

INCO Estimated Metal Production for Manitoba
Year Metals
Cobalt Copper Gold Nickel Platinums Silver
(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 (Table 3.3)
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, 9-11, 55.
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.
Coats, 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.
Cole, 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. 60-2.
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. 17.29.
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. 276, 7.
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. 60-4.
Phillips, K.A., 1974: Untitled, Unpublished Report, Manitoba General, Unpublished Information Files, Manitoba Mineral Resources Division.
Task Force on Manitoba Minerals Policy, 1974: Report of the Task Force; Department of Mines, Resources and Environmental Management, p. 65-70.
Quirke, T.T., 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. 815-23.
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.
Map 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 Branch.
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.
Compiled/Revised by:
2-73 11-75 09-83