MINERAL INVENTORY FILE NO.
187
______________________________________________________________________________________________________
PRODUCT
CESIUM
NTS AREA
52L6NW
REF.
CS 1
______________________________________________________________________________________________________
NAME OF PROPERTY
Tanco Pegmatite
(Lith No. 12)
OWNER OF OPERATOR ADDRESS
1988-Tantalum Mining Corporation of Canada Limited
Bernic Lake, MB R0E 0G0
37.5% interest – Hudson Bay Mining & Smelting Co.,Limited
37.5% interest – Kawecki Berylco Industries
25% interest – Province of Manitoba
OBJECT LOCATED
Shaft
MINING DIVISION
Winnipeg
Latitude
5025.71’
Longitude
9527.15’
Uncertainty (m)
50m
UTM Zone
_____
Easting
_______
Northing
_______
L.S./Quarter Section
___
Section
___
Township
___
Range
_________
DESCRIPTION OF DEPOSIT
The Tanco pegmatite, which is host to the deposit, occurs in the Archean Bird River greenstone belt which is comprised of metavolcanic, related and derived metasedimentary rocks of the Rice Lake Group. The areas north, east and southwest of the belt are occupied, respectively, by the Maskwa Lake, Marijane Lake and Lac du Bonnet batholiths (Crouse et al., 1979).
The Tanco pegmatite was emplaced, cogenetic with the Lac du Bonnet intrusion, as a bi-lobate shallow north-dipping doubly plunging feature, into the core of a synclinorium. The core is composed of interlayered polymictic metaconglomerate, metavolcanic rocks and iron formation; synvolcanically intruded by large stocks of composite nature of gabbro, diorite, quartz-feldspar porphyry and granodiorite (Crouse et al., 1979).
The pegmatite occupies an almost horizontal cross-cutting fracture in near vertical dipping amphibolites, forming a flat, tabular body almost 1l300 m long, up to 300 m wide and 20-90 m thick (Tanco, 198l). According to Cerny (1982a) and Bannatyne (1985, p. 46), the pegmatite is 1440 m x 820 m, and just over 100 m thick.
From a large-scale viewpoint, the internal structure of the pegmatite exhibits nine zones of different mineral composition, texture and location plus a zone of contact exomorphism in the wallrock. Some of the outer zones appear to be concentric envelopes, but the inner zones occur as more or less discontinuous layers (confined to the upper central parts of the pegmatite). In detail the structure, however, shows a complex array of mineral assemblages and thus the nine zones are an over-simplification (Crouse et al., 1979).
Cesium occurs in the "pollucite zone" in three sheet-like bodies, the largest of which is l67 m (550 ft) in length, an average of 6l m (200 ft) in width and up to l4 m (45 ft) in thickness; its dimensions have also been reported as l80 x 75 x 12 m (Cerny, 1982a, p. 533; Bannatyne, 1985, p. 48).
"The zone consists almost entirely of pollucite, finely veined by very subordinate amounts of spodumene, albite, lithian muscovite, microcline, and quartz. Large crystals of manganoan apatite and amblygonite-montebrasite are found in the lower parts of the pollucite bodies and masses of petalite and quartz occur sparingly within them. Most of the pollucite shows a peculiar 'augen'-structure, consisting of clear glassy eyelets embedded in a braided white matrix" (Crouse and Cerny, 1972). Cestibtantite, and cesian analcime has been reported in the Tanco pegmatite (Cerny, 1982b).
According to Penner and Clark (197l), the Tanco pegmatite is approximately 2.6 billion years old.
Pollucite has been reported in another pegmatite body (370 m x 900 m, and up to 47 m thick), the lower Tanco pegmatite, which occurs below the main Tanco pegmatite (Ferreira, 1984). (See 52 L/6 TA l). The discovery of Rb-Cs-rich zinnwaldite in the lower Tanco pegmatite is the first of its kind in Manitoba (Olson and Cerny, 1982).
ASSOCIATED MINERALS OR PRODUCTS OF VALUE
Beryllium, lithium, tantalum, gallium, rubidium, tin, quartz, feldspar, niobium, apatite, .
HISTORY OF EXPLORATION AND DEVELOPMENT
The deposit is situated beneath Bernic Lake, approximately 180 m south-southeast of the Jack Nutt shaft (See: 52L/6 SN 2). The deposit is accessible by road from the west, a branch off of Provincial Road No. 315.
The early history of this deposit is shared with that of Akmen M.C. and Lith No. 5 (see: 52L/6 SN 2 and LI 8, respectively). However, because of its stratigraphic position it was not known to exist until The American Metal Company of Canada (later, America Metal Climax, Inc.) found massive pollucite containing up to 35.43% Cs2O in five separate holes drilled on Lith No. 12 (W21671), optioned from Montgary Explorations Limited in 1957.
In 1959, drifting to the pollucite deposit began. In 1960, a 213 m (700 ft) cross-cut on the 87 m (285 ft) horizon from the shaft towards the south, and a raise driven up into the pollucite were completed. Two lots of cesium-bearing samples were sent to large American chemical firms.
Analysis of the composite of 49 channel samples representing a drift length of 64 m (2ll ft) from the beryl-tantalite zone gave:

0.l5% tin
0.42% tantalum pentoxide
0.15% beryllium oxide
0.01% columbium pentoxide
with pollucite and lithium minerals.

It was reported that the Chemalloy deposit "is not only the largest deposit known in the world (125 000 - 150 000 tons (113 430 - 136 120 tonnes) grading between 25%-30% Cs20 and 1.0% Rb20) but also the only known sizable deposit in North America" (Northern Miner, April 28, 1960). By June 1960, a stockpile of 2058 tonnes (2268 tons) of cesium ore averaging close to 27% Cs20 was accumulated. Eighteen additional diamond drill holes, totalling 1577 m (5173 ft) were drilled from the ice of Bernic Lake to map the extent of the cesium and rubidium mineralization. At the end of September 1960, a total of 884 m (2900 ft) of drifting, cross-cutting and raising had been completed and underground drilling of 50 holes totalling 2134 m (7000 ft) carried out. "The shaft was deepened to 103 m, 1840 m of drifting was completed, and 149 underground holes were drilled by Chemalloy" (Bannatyne, 1985, p. 44).
During 1961 most operations appeared to have ceased except that 544 tonnes (600 tons) of quartz were removed from the underground workings by Nick Soroka. A 21-year Lease M-7542 was issued to Chemalloy Minerals Limited about the same time. Later in 1961, Chemalloy acquired the Noble Group adjoining the main property to the west from The Lithium Corporation of Canada, Limited, for stock (see remarks).
Early in 1962, 91 tonnes (100 tons) of pollucite were mined for Chemalloy by Mr. Soroka. Shortly afterward the underground pump was taken out and the mine was allowed to flood. During the next five years underground work ceased, but Chemalloy continued to sell ore from its stockpile (see History of Production).
Early in 1967, Chemalloy obtained backing for exploratory tests on the tantalum content of the Bernic Lake deposit. In 1959, Chemalloy commenced investigations to establish tantalum values (see Mineral Inventory Card 52L/6 LI 8), but the project was abandoned because of depressed markets at that time for the material. For a continuation of the history, see: 52L/6 TA l.
Cesium reserves occur in three sheet-like bodies. The largest, in the southeast quadrant of the pegmatite, up to 14 m (45 ft) thick, is estimated to contain 272 230 tonnes (300 000 tons) 23% Cs2O (as of December 31, 1972). In addition, there are 145 190 tonnes (160 000 tons) averaging 5% Cs2O in the lower grade zones (Northern Miner, June 14, 1973).
Indications are that future markets for cesium are in magnetohydrodynamic (MHD) power generation and space propulsion.
George (1978) reported 372 000 tonnes of ore reserves. As of December 31, 1978, reserves were reported as "270 000 tonnes of pollucite averaging almost 23.9% Cs2O in the main zone, 47 000 tonnes averaging almost 23.9% Cs2O in one westerly zone and 55 000 tonnes of somewhat lower grade in the second westerly zone"; no allowances were made for dilution or pillars. Reserves don't include: "large areas of the pegmatite body containing quantities of pollucite averaging 500 to 1500 g of Cs2O per tonne" (George, 1978). In addition, drilling below the main pegmatite body has indicated a second sill, approximately 30 m below the main body, that contains pollucite, tantalite and spodumene mineralization" (George, 1978). (See 52L/6 TA 1).
Ore reserves as of January 1, 1980 were estimated at pollucite (cesium oxide) - 270 000 tonnes grading 23.0% Cs2O (Zahalan, 1980).

Reserves as of December 31, 1982:
...........................................................................Tonnes........................................... Grade
a) Main pollucite zone................................... 317 520.............................................23.89% Cs2O
b) Additional "drill indicated"........................ 54 430..................................... 'slightly lower grade'
c)....................................................................... 145 150.............................................5% Cs2O

(Source: Bannatyne 1985, p. 44)

Bannatyne (1985, p. 49) reported reserves of 320 000 tonnes grading 23.3% Cs2O while the Canadian Minerals Yearbook (1985) reported reserves of 300 000 tonnes of pollucite grading 24% Cs2O.
HISTORY OF PRODUCTION
In 1965 it was reported that the U.S. space program had been using around 2270 kg (5000 lbs) of cesium annually from the Chemalloy deposit and in 1964 was closer to 9070 kg (20 000 lbs) (Northern Miner, March 18, 1965). On April 18, 1965, the Northern Miner published that "Cesium metal refined from the 300 000 ton (272 230 tonne) pollucite ore deposit of Chemalloy's Bernic Lake property is propelling the first U.S. cesium ion engine rocket on a 90-day orbit through space at speeds as high as 100 000 miles (160 930 km) per hour".
From late 1969 to the end of 1975, a total of 1400 tonnes of pollucite averaging 27% Cs20 was produced. Of the total, 86% went to the U.S.S.R., 8% went to the U.S.A., and the remainder to England, West Germany and Japan (Canadian Minerals Yearbook, 1975).
In 1976, the Canadian government banned shipments of cesium to communist countries (Canadian Minerals Yearbook, 1976). The deposit is the only source of Canadian cesium production (Canadian Minerals Yearbook, 1985).
Bannatyne (1985, p. 5) reported the following production history of pollucite:

.......................................Pollucite: contained Cs2O (kg solid)

..............................1960...............2 268....................1970...........36 288?
..............................196l................2 268....................1971...........90 720
..............................1962...............2 268....................1972...........19 6l8
..............................1963...............2 268....................1973...........68 040
..............................1964...............9 072....................1974...........7l 887?
..............................1965-1968...................................1975......... .78 640?
..............................1969...............9 072

No shipments of ore were made in 1976, and a minor amount was shipped in 1977. In 1978, about 254 tonnes were shipped to the U.S. (George, 1978).


.....................................Table 1. Canadian cesium production*, 1978-85
............................(Source: Canadian Minerals Yearbook, 1985, p. l7.4-l7.5).

...........................................................Pollucite....................Cesium....................Contained....................Contained
Year.......... Country...........................Shipped...............Oxide Grade..............Cesium Oxide...................Cesium
.............................................................(tonnes).....................(%).........................(tonnes).........................(tonnes)

1978............U.S.A...................................254..........................27.2.............................69...................................65
1979............F.R.G.**................................53..........................25................................13...................................12
1980 - - - - -
1981............F.R.G....................................300.........................24................................72...................................68
1982 - - - - -
1983............F.R.G...................................200..........................24................................48...................................45
1984............F.R.G...................................300..........................24................................72...................................68
1985***.....F.R.G./U.S.A(1).................525..........................24...............................126.................................119

*In addition, there have been small orders from time to time
**Federal Republic of Germany
***Estimated; - Nil
(1)F.R.G. 500 tonnes/U.S.A. 25 tonnes.

In January, 1988, Regulation 59/88 regarding the shipment of cesium ore was passed: Production lease No. 7, 8, and 9 were to be exempted from subsection 9 (1) of the Mines Act with respect to cesium ore shipments not exceeding 1000 tonnes annually, and rubidium ore not exceeding 500 tonnes annually for a five year period starting June 1, 1987 (Manitoba Gazette, February 6, 1988) (see 52 L/6 TA l, remarks).
REFERENCES
Bannatyne, B.B., 1985: Industrial minerals in rare-element pegmatites of Manitoba; Manitoba Energy and Mines, Geological Services, Economic Geology Report ER84-1, p. 5, 43-49.
Brinsmead, R.E., 1960: Manitoba mine yields rare metals (Chemalloy Minerals Ltd.); Precambrian, v. 33, No. 8 (August), p. 18-39.
Canadian Minerals Yearbook, 1985: Review and Outlook; Energy, Mines and Resources Canada, Mineral Report 34, p. 17.1 -17.5.
Cerny, P., 1972: Secondary minerals from the spodumene-rich zones; in The Tanco Pegmatite at Bernic Lake, Manitoba, ed. L.G. Berry; The Canadian Mineralogist, v. 11, Part 3, p. 714-726.
Cerny, P., 1982a: The Tanco pegmatite at Bernic Lake, southeastern Manitoba; in Granitic Pegmatites in Science and Industry, ed. P. Cerny; Mineralogical Association of Canada, Short Course Handbook 8, p. 527-543.
Cerny, P., 1982b, Mineralogy of rubidium and cesium; in Granitic Pegmatites in Science and Industry, ed. P. Cerny; Mineralogical Association of Canada, Short Course Handbook 8, p. 152-153.
Cerny, P., Trueman, D.L., Ziehlke, D.V., Goad, B.E. and Paul, B.J., 1981: The Cat Lake-Winnipeg River and the Wekusko Lake pegmatite fields, Manitoba; Manitoba Department of Energy and Mines, Mineral Resources Division, Economic Geology Report ER80-1, p. 87-93, 152-153.
Crouse, R.A. and Cerny, P., 1972: Geology and paragenesis; in The Tanco Pegmatite at Bernic Lake, Manitoba, ed. L.G. Berry; The Canadian Mineralogist, v. 11, Part 3, p. 591-608.
Crouse, R.A., Cerny, P., Trueman, D.L. and Burt, R.O., 1979: The Tanco pegmatite, southeastern Manitoba; The Canadian Mining and Metallurgical Bulletin (CIM Bulletin), v. 72, No. 802 (February), p. 142-150.
Davies, J.F., 1955: Geology and mineral deposits of the Bird Lake area; Manitoba Mines Branch, Publication 54-1, 44p.
Davies, J.F., 1958: The lithium and beryllium pegmatites of southeastern Manitoba; The Canadian Mining and Metallurgical Bulletin (CIMM), Transactions, v. 61, No. 4 (April), p. 230-236.
Dawson, K.R., 1974: Niobium (columbium) and tantalum in Canada; Geological Survey of Canada, Economic Geology Report No. 29, p. 39-41, 81.
Ferreira, K.J., 1984: The mineralogy and geochemistry of the lower Tanco pegmatite, Bernic Lake, Manitoba, Canada; M.Sc Thesis, University of Manitoba,
Gamvrelis, A.G., 1984: An evaluation of the potential for Manitoba's cesium; Master of Natural Resource Management Thesis, University of Manitoba, 164p.
George, J.G., 1978: Cesium; in Canadian Minerals Yearbook 1978; Energy, Mines and Resources Canada, Mineral Report 28, p. 99-100.
Howe, A.C.A. and Rowntree, J.C., 1966: Geology and economic significance of the Bernic Lake pegmatite, Manitoba; The Canadian Institute of Mining and Metallurgy, CIM Annual Meeting (April, 1966), Quebec City; abstract in The Canadian Mining and Metallurgical Bulletin (CIM Bulletin), v. 59, No. 647 (March), p. 273.
Manitoba Gazette, The 1988: (February 2), Regulation 59/88; v. 117, No. 6.
Manitoba Mines Branch:
a Corporation Files; Lithium Corporation of Canada, Limited, The; Chemalloy Minerals Limited
Mineral Policy Sector, Corporation File: "Chemalloy Minerals Limited".
Nickel, E.H., 1961: The mineralogy of the Bernic Lake pegmatite, southeastern Manitoba; Mines Branch, Ottawa, Geological Survey of Canada, Technical Bulletin TB 20, 38p.
Penner, A.P. and Clarke, G.S., 1971: Rubidium-strontium age determination from the Bird River area, southeastern Manitoba; in Geoscience Studies in Manitoba, ed. A.C. Turnock; Geological Association of Canada, Special Paper No. 9, p. 105-110.
Rinaldi, R., Cerny, P. and Ferguson, R.B., 1972: Lithium-rubidium-cesium micas; in The Tanco Pegmatite at Bernic Lake, Manitoba, ed. L.G. Berry; The Canadian Mineralogist, v. 11, Part 3, p. 690-707.
Simpson, F., 1974: The mineralogy of pollucite and beryl from the Tanco pegmatite at Bernic Lake, Manitoba; M.Sc Thesis, University of Manitoba (copy in GSC library MR 8255.S 61).
Springer, G.D., 1950: Mineral deposits of the Cat Lake-Winnipeg River area; Manitoba Mines Branch, Publication 49-7, 14p.
Trueman, D.L. and Turnock, A.C., 1982: Bird River greenstone belt, southeast Manitoba: geology and mineral deposits; Geological Association of Canada - Mineralogical Association of Canada, Joint Annual Meeting (Winnipeg, Manitoba), Field Trip Guidebook, Trip No. 9, p. 1-16.
Zahalan, R.G., 1980: Mining in Manitoba; Manitoba Department of Energy and Mines, Mineral Resources Division, Educational Series ES80-3, p. 30-33.
MAP REFERENCES
#Map 52L/6, West, Ryerson Lake (Topographic) Scale 1:50 000, Mines & Technical Surveys, Canada.
Map 1194 G, Ryerson Lake (Aeromagnetic), Scale 1:63 360, Manitoba Mines Branch and Geological Survey of Canada.
Map 49-7, Cat Lake-Winnipeg River area (Geology), Scale 1:63 360 - Accompanying Report by Springer (1950), Manitoba Mines Branch.
Map 54-1, Bird Lake area (Geology), Scale 1:12 000 - Accompanying Report by Davies (1955), Manitoba Mines Branch.
Preliminary Map 1975 F-9, Bird River area East (Geology), Scale 1:31 680, by D.L. Trueman, Manitoba Mines Branch.
Map ER80-1-1, Cat Lake-Winnipeg River pegmatite field (Geology), Scale 1:100 000 - Accompanying Report by Cerny et al.(1981), Manitoba Mineral Resources Division.
Map ER80-1-3, Winnipeg River pegmatite district (structural geology), Scale 1:50 000 - Accompanying Report by Cerny et al.(1981), Manitoba Mineral Resources Division.
Claim Map Series NW 6, 52L, Scale 1:31 680, Mining Recording, Manitoba Mines Branch.
URL
N/A
REMARKS
1. In 1956, Lithium Corporation had carried out surface diamond drilling (656 m (2l52 ft) in four holes) here, and succeeded in extending the Chemalloy pegmatite westward. Also, a second body, about 38 m (125 ft) beneath the upper, was intersected. It contains lithia-bearing material and beryl. Gallium was found in the lithia mica sections. Chemalloy, in 1961, drilled four holes totalling 734 m (2407 ft), on the Noble claims. Only one of these intersected pegmatite.
2. Mineral Inventory Cards 52 L/6 SN 2, LI 8, CS 1 and TA l form a continuous series.
NOTES
N/A
Compiled/Revised by:
JDB AJ CFL HRW HDB PA
Date
11/73 07/75 11/78 02/82 04/82 04/88