Modern-day LAC Minerals rests on four pillars — the Doyon mine (featured in the Fall Issue of The Northern Miner Magazine), the Bousquet complex, Bullfrog in Nevada and the El Indio complex in the windswept Chilean Andes. Smaller, but no less important supports include Golden Patricia and Macassa in Ontario and Colloseum and Richmond Hill in the western U.S. In sum, these gold mines make LAC a million-ounce-per-year, top-tier gold miner. (LAC also has the Toqui zinc mine in Chile.) You’ll read about the mines and the people who run them in the following pages.
The Quebec Sector
In the Cadillac area of northwestern Quebec stands two of LAC’s key operations — the Doyon mine (for details see the Fall Issue) and the Bousquet complex. Bousquet No. 1 was discovered in the late 1970s and has been a consistent LAC producer for more than a decade. Bousquet No. 2 was discovered in 1986, when a deep hole from an adjacent property, now owned by Agnico Eagle Mines, intersected ore 2,800 ft. below the surface.
The Bousquet No. 1 orebody trends roughly east-west and dips steeply at 85d to the south. Six major mineralized zones are known. Mineralization is found in disseminated and vein-type pyritic rock. This operation hoists 1,000 tons per day. The two mining methods used are open stoping, which accounts for 82% of the tonnage, and Avoca, yielding the remaining 18%.
Bousquet No. 2 occurs in a pyritic horizon within a series of volcanic rocks striking east-west and dipping steeply south. The horizon extends from the eastern boundary of the property some 1,050 ft. to the west and is open at depth. Gold mineralization is associated with the pyritic horizon and shows a strong relationship with copper content. The host rock is andalusite and kyanite schist. The shaft accommodates 1,350 tons of ore per day and has capacity for 3,000. The shaft is 4,084 ft. deep and has compartments for a cage-skip combination, two skips and an escapeway and services. It was completed in February, 1990.
The Ontario Producers
The Macassa mine is the sole Kirkland Lake survivor (apart from Lakeshore tailings Project). It has been producing gold continuously since 1933. The workings extend 9,000 ft. horizontally and 7,050 ft. below the surface. The orebody sits in an east-west trending belt of volcanic and sedimentary rocks intruded by an elongated syenite stock parallel to the trend of the belt. Gold mineralization is found in quartz veins associated with the Main break, an east-west fault that was also the structural control for such namemines as the Lake Shore and Wright Hargreaves.
Apart from the main 04 Break, Macassa’s geologists have uncovered the 05 Break running parallel to 04 about 1,300 ft. to the north. They are also probing the westerly extension of the orebody at depth. The predominant mining methods are overhand and underhand cut-and-fill and some longhole. The Macassa shaft is the deepest single-lift shaft in North America, bottoming at 7,239 ft.
Golden Patricia in the Pickle Lake area of northwestern Ontario came with LACs acquisition of Bond International Gold. This fly-in/fly-out operation is mining a deposit in the Meen-Dempster Archean greenstone belt. Gold is found in a narrow steeply-dipping quartz vein, which has been outlined by drilling for an astounding strike length of 2 1/2 miles. Geophysical techniques have traced favorable stratigraphy up to eight miles. The average width is 5 ft. and has been intersected up to 2,200 ft. below surface.
LAC’s U.S. beachhead
The Bullfrog mine is an open pit producer near Beatty, Nev., that rests on the southwestern edge of a volcanic centre. Proven and probable reserves exceed 15 million tons at 0.10 oz. and recent developments have established a high-grade extension that will be worked from the pit and underground. The mine is a high-volume, open-pit operation and, despite its low grade of 0.06 oz. per ton (1990), uses a conventional crush-grind-CIP circuit for gold recovery: 220,000 oz. in 1990, more than a fifth of LAC’s production.
The Colosseum mine in San Bernardino, Calif., is a 3,400-ton-per-day carbon-in-pulp operation. Gold mineralization is associated with two igneous breccia pipes that have intruded the Precambrian basement rocks. The South Pipe was the primary production area, but now the North Pipe has that distinction.
Richmond Hill in the Black Hills of South Dakota, a heap leach gold mine, is facing depleting reserves. However, there is hope that two other areas offer mine-potential. The orebody being worked now is hosted in an elongated breccia pipe with an associated zone of stockwork fracturing intruding into the older surrounding rock.
The Latin Quarter
The El Indio gold-copper complex is LAC’s biggest South American producer. For details on that operation see accompanying mine-visit story.
The Toqui mine is in mountainous terrain in the southern part of Chile. It is a zinc operation with access to the orebody via adits into the mountainside. Room-and-pillar mining produces 1,300 tons of ore per day. The tabular Toqui orebodies lie within and partially replace a fossiliferous limestone unit ranging from 20 to 50 ft. in thickness. The limestone unit is found in a sequence of volcanic and sedimentary rocks that are faulted and cut by intrusions separating the ore into different zones. The deposits are known as manto type and one of them, in the Dona Rosa zone, has gold mineralization.
LACs Consolidated Gold Production Statistics
US$ Per Ounce RESERVES
(Proven/probable)
Gold Millhead Cash Non-Cash Tons Grade
Prod. Grade Charges Charges Total (000’s)
Doyon
1990 128,421 0.207 $220 $51 $271 5,634 0.19
1991(E) 125,000
Macassa
1990 103,389 0.545 $260 $41 $301 1,672 0.53
1991(E) 100,000
Lake Shore Tailings
1990 13,885 0.088 $245 $106 $351 3.1m
1991(E) 13,000
Bousquet No. 1
1990 83,224 0.156 $311 $42 $353 3,545 0.17
1991(E) 63,000
Bousquet No. 2
1990 67,163 0.401 $256 $40 $296 3,909 0.25
1991(E) 170,000
Francoeur
1990 5,877 0.180 $466 $145 $611 521 0.20
1991(E) 4,000
Bullfrog
1990 220,192 0.080 $276 $154 $430 15,551 0.10
1991(E) 175,000
El Indio
1990 215,767 0.210 $160 $143 $303 12,203 0.14
1991(E) 215,000
Golden Pat.
1990 80,846 0.611 $257 $124 $381 560 0.55
1991(E) 76,000
Colosseum
1990 73,157 0.071 $333 $39 $372 3,958 0.04
1991(E) 53,000
Richmond Hill
1990 38,897 0.033 $256 $213 $469 2,310 0.05
1991(E) 42,000
TOTAL
1990 1,030,818 $246 $104 $350 49,863 0.15
1991(E) 1,036,000
1. The table above includes the percentage production credited to LAC’s account from mines in which it has a partial interest. For example, it owns a 50% interest in the Doyon mine, which produces double the production figure noted above.
2. The table does not take into account any by-product copper, which in some mines is significant.
3. Production from the Toqui zinc mine in Chile is not included.
4. LAC has an 83% interest in El Indios ore reserves (not 100%).
5. All reserves have been audited by independent consultants.
6.1991 estimates of gold production come from the 1990 annual report.
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