RESERVING A FUTURE: LAC has instituted a systematic, three-pronged

LAC’s exploration efforts are divided into three informal components. Two are already functioning and a third only recently was initiated. The first such component has a worldwide mandate for “pure exploration” and is headed by Craig Nelsen, senior vice-president of exploration. Pure exploration is LAC’s designation for exploration beyond the boundaries of an operating mine. The second component involves exploration in and around existing mines. This is done by the various minesite geology departments. (On a day-day-basis, the definitions are not so rigid that crossovers between pure and mine-site exploration cannot occur.) This second section is headed by Phillip Walford, vice-president and chief geologist, who is responsible for reserve development. This involves working with minesite geologists on definition of reserves and on mine-directed exploration in and near the mines. The last segment of the exploration triad is Business Development. Neil Westoll was appointed to this new post only recently. It is concerned with property acquisition. (Westoll’s appointment came too late for our coverage.) All three work out of LAC’s Toronto office.

LAC’s pure exploration presence reaches to Australia, and preliminary examinations have been carried out in Uruguay and Argentina. But most of the interest is closer to home. It centres on Red Mountain, near Stewart B.C.; the Rosebud property, Nevada; and the Ortiz Mine Grant, New Mexico.

At Red Mountain, a 3,000-m diamond drill program this year yielded “mixed results,” Nelsen said. “We were exploring extensions of the resource to verify our interpretations.” Working against this property is its Alpine setting and isolation — there is no road to the property yet. “We’re assessing the next phase now,” Nelsen said.

The Rosebud, meanwhile, is another priority project. Earlier work on the gold project was oriented to its open pit potential. However, LAC has ruled out that option and is now refining the tonnage and grade model. That will probably require underground access, Nelsen said. “We’re keen on the project, we think it has a lot of potential, but we’re striving to further refine the resource.” High-grade intersections of an ounce and more have been pleasant surprises on the project.

Rosebud is indicating a geological “resource” of 5.2 million tons at 0.12 oz. per ton using a cutoff grade of 0.02 (recently announced results include a drill intercept of 0.85 oz. over 30 ft.). Using a cutoff of 0.05 oz. per ton, the geological resource is 2.3 million tons grading 0.231 oz. per ton. The resource figure for the underground scenario is dependent on the higher cutoff grade. The 0.05 cutoff could change as LAC further defines the resource and the underground model.

On the Ortiz property, Pegasus Gold Corp. is earning a 50% interest and should complete a feasibilty study by mid-1992. A decline will probably driven to access the deposit.

In an interview, Nelsen also mentioned the Niblack prospect in Alaska. This property has been explored in joint venture with Noranda since 1984 and has all the hallmarks of a major polymetallic deposit, with copper and zinc its principal components.

While Nelsen is occupied with finding reserves for LAC’s future mines, Walford focuses on the reserves of existing mines — a formidable task with 11 operations across two sub-continents and ranging in size from Golden Patricia’s 375 tons per day to Bullfrog’s 8,400.

Bullfrog is located at Beatty, Nevada about 50 miles northeast of Death Valley. Proven and probable reserves exceed 15 million tons at 0.10 oz. Recent drill holes have returned 12-ft. to 30-ft. widths, with grades from 0.23 oz. to 0.47 oz. The ore picture is still being defined, but expectations are that 1,000-1,500 tons per day will be mined from underground by 1994, or perhaps as early as 1993. Underground production is to begin on a trial basis in 1992 from an adit and ramp. Both entries are collared in the pit wall.

In Latin America, mine-group exploration at the El Indio complex will total up to $1.6 million next year, Walford said. The main focus will be depth exploration via the extension of an existing drift at El Indio and a search for the northerly extensions of both the El Indio vein and the Viento vein. In addition, surface showings at El Indio will be probed, as will structures at the nearby Tambo.

In Canada, Golden Patricia will also receive attention. This rich, fly-in/fly-out operation maintained a head grade of 0.69 oz. per ton in 1990. It produced 81,000 oz. in 1990 and is currently the scene of a shaft sinking program. The mine works a single vein that has been defined by drilling for 2.5 miles along strike. Favorable geology continues for eight miles and the vein has been proved to depths of 2,200 ft. This is a most unusual occurrence by virtue of its persistence and also because it appears to be the only vein in the area. Veins almost always run in clusters; solitary veins are anomalies. It averages 5 ft. in width and is mined by trackless shrinkage methods. Until now, entry has been by two ramps collared on surface. The new shaft is half completed at the time of writing, and will be taken to 1,100 ft. It will serve as an ore hoisting and service opening. Clearly, LAC has great faith in this mine — as well as committing itself to the major expense of shaft sinking, it will also have spent $1.5 million on diamond drilling by the time the year comes to an end.

At Doyon, in the Cadillac area of northwestern Quebec, the mine geology group is shifting gears on the Warrenmac/Westwood property 5,400 ft. east of the big producer. “We’re going to start rock geochemical studies to determine alteration and mineralization patterns,” Walford told The Northern Miner Magazine. LAC intersected 20 ft. of sulphide mineralization grading 0.12 oz. gold and 2.25 oz. silver per ton and 6.7% zinc, 6.0% lead and 0.4% copper at a depth of 2,300 ft. A second wedged hole intersected similar mineralization 200 vertical ft. above the first hole. Followup holes were less encouraging and that is why LAC is conducting the geochemical work.

Within Doyon proper, LAC will drill below the eighth, or bottom, level to test the downdip extensions of the West and Main zones. This work should set the groundwork for a future shaft deepening decision.

At Bousquet No. 2, LAC is testing the down-dip and down-plunge extension of the orebody. An exploration drift for diamond drill stations is being driven west on the ninth level towards Bousquet No. 1.