LAC likes potential of narrow structure at Kirkland Lake

The geology department at LAC Minerals’ (TSE) Macassa mine is excited about a vein system that runs parallel to the Kirkland Lake Main Break, the gold-rich structure upon which Macassa has feasted for 57 years. The parallel system found by Macassa has been dubbed the 05 Break. (Macassa terms the depth expression of the Kirkland Main Break the 04 Break.) The 05 has been traced by drifting for roughly 400 ft. horizontally on at least two levels 500 ft. apart. For example, along the 6100 level (6,100 ft. below surface), the 05 Break ran 0.36 oz. per ton gold across a width of 5.9 ft. for a length of 160 ft. Another 166-ft. length ran 0.48 oz. across 6.8 ft.

At the 6600 level, drifting has revealed similar results — high grade, narrow widths. Already, LAC has calculated a proven reserve of about 70,000 tons grading 0.44 oz. gold in the 05 Break.

The significance is that the structure remains open vertically and horizontally.

“This is not just a little localized thing. It’s got a structure with it,” George Nemcsok, chief area geologist, told The Northern Miner during a visit to the region. Nemcsok and mine geologist Terry Lackey have proposed a series of six widely spaced diamond drill holes be spotted from the 04 Break.

Down holes will be drilled from the 5875 level in the 04 Break to intersect 05 at about the 6300 to 7000 levels. “We’re just going to try to identify the zone. If we can show the structure is there, it means we’re chasing something big,” said Nemcsok.

Gerry Gauthier, LAC’s senior vice-president of operations, expressed delight over the find and its potential, but warned, “What the implications are I couldn’t tell you.” He added that the diamond drill “hit ratio” in Macassa customarily runs 20%-25%. “We can have gaps that run 200 to 500 ft. (horizontally) where it’s uneconomic to mine.”

The depth of the structure will also dictate the advance rate of exploration and development. Gauthier guessed that up to four years might be required to define the structure within the mine.

The known 05 mineralization lies east of the No. 3 production shaft. The proposed program will test continuity farther to the east toward Macassa’s old No. 2 shaft.

More easterly yet (only 50 ft. inside Macassa’s eastern boundary), a diamond drill hole collared at the 3,000-ft. level in 1987 intersected 0.30 oz. across 6 ft. The gold intersection, again to the north of the 04 Break, actually occurred on ground adjacent to LAC’s claims being worked by Newfields Minerals. Apparently, the drill hole had wandered on to Newfields’ ground.

At the time, Nemcsok was looking for what was known as the Narrows Break zone, an extension of a vein identified in the famous Lakeshore mine to the east which Newfields had been testing from underground.

“What we intersected was not the Narrows Break zone. We don’t want confusion here. This is a different zone,” said Lackey. Nemcsok was assured by a Newfields consultant that the intersection was too northerly to have cut the Narrows Break.

Macassa probably will be mining the known portion of the 05 structure this year.