Things keep o9n looking up for Westmin’s Silbak bet

The news just keeps getting better from Westmin Resources’ British Silbak property near Stewart, one of only a few exploration programs currently under way in B.C. Westmin Resources’ British Silbak property near Stewart, one of only a few exploration programs currently under way in B.C.

Several spectacular gold-silver intersections were encountered during phase 2 of a fill-in drill program. The holes are being drilled on 20-m centres and the grades are improving over the original ones, says Westmin.

The company has been drilling the “glory hole” area which is actually a subsistance crater. Hangingwall material has caved into old stopes and enlarged the once- smaller glory hole opening. Much of this caved material has been very high grade, something that is sure to improve the reserve grade significantly, The Northern Miner gathers.

Things are not looking too bad either at the nearby Big Missouri property where some dandy shallow intersections have been reported from four proposed open pit zones. But more on that later.

The surface program at Silbak, which involved 5,297 ft of drilling in 20 holes, now has been completed as well as about half of the planned 17,000 ft of underground drilling. The underground holes, which are being drilled from the No 2 level of the former producer, are designed to test the lower portion of the proposed open pit and also beneath it for additional reserves.

According to Arthur E. Soregaroli, vice-president exploration, the highest grade intersection obtained to date was in Hole 86-122 which cut 5 ft grading 22.7 oz gold per ton and 18.4 oz silver, followed by 10 ft averaging 0.39 oz gold and 2.15 oz silver. Those intersections are about 85% of true thickness and occurred approximately 60 ft from an earlier high grade intersection which returned 1.9 oz gold and 20.9 oz silver over 15 ft.

Bonanza grade mineralization was also found 230 ft further east along strike in the underground drill program. Hole 86-U-148 returned 31.5 ft of 2.1 oz gold and 3 oz silver and there was 3.5 ft of unrecovered core that could have carried precious metals values. Both those impressive drill intersections were located in the previously stoped west portion of the glory hole area.

Harlan Meade, Westmin’s exploration manager (western region), suggests the material might have been left by previous operators because of extensive cross-faulting. These faults also made for poor ground conditions and caving often drove them out of working areas. Mother Nature continued the process during the dormant years at Silbak, filling in the stopes with good grade material for open pit mining. Reserve grade increased

What is really exciting about the high grade results is their impact on reserve grade. As an example, Mr Meade states that 10,000 oz of material in one of these high grade sections would increase the reserve grade (and production economics) by 2.6%. And the probability of finding more such material is excellent.

Much of this material was considered to be waste before, so the stripping ratio also stands to drop, another economic consideration. “We have certainly increased the grade and the tonnage will go up with it,” says Mr Sorengaroli.

Because the underground potential is starting to look better and better, Westmin is considering a drill program from the No 6 level, the lowest working horizon in the mine. In the past, the company has stated its intention to draw feed from the Silbak and Big Missouri (four miles to the north) but the latest results have added a new dimension to the project — the possibility of developing an underground producer. In any event, this would follow an open pit production decision.

The Northern Miner looked at a longitudinal section of the old Silbak mine workings which simply terminate at the bottom level and the potential seems to be definitely there. “The underground potential is untouched and wide open,” says Mr. Sorengaroli, adding, “there has to be some ore there.”

Westmin also says a reverse circulation drilling program on the No 4 level dump will begin this month. “Earlier sampling indicated this material to be ore grade,” says Westmin, noting that there are 500,000 tons of it available. The grade could average 0.1 oz or better and would be a nice source of mill feed for startup. Metallurgical, geotechnical and environmental studies are in progress and a re-estimation of reserves is expected in January. Modest tonnage increase

The most impressive intersection to date at the Big Missouri was 96 ft of 0.32 oz gold and 0.57 oz silver and that was from a shallow hole where mineralization was encountered 10 ft below the collar. “Along with other intersections, this increases the high grade core of the S-1 zone and indicates increased tonnage and grade,” says Westmin.

A modest increase in tonnage is expected in the Dago zone and large diameter core drilling in the Province West zone returned good grade material in holes 86-51 and 86-52. The first hole returned 22 ft of 0.23 oz gold and 0.31 oz silver and the second 35 ft of 0.19 oz gold and 0.15 oz silver. These diamond drill hole grades are higher than percussion drill samples taken earlier and should increase the grade of the zone.

The Martha Ellen zone is the largest open pit zone at Big Missouri and a significant increase in size is estimated, says Westmin. Two stepout holes returned ore grade mineralization some 500 ft west of the previously indicated boundary. Significant base metals were also encountered in several holes. A few years back it was thought the Big Missouri would be phased in at a later date but Westmin now confirms it now is in their initial mining plans.

In 1986, a total of 7,255 ft of diamond drilling was completed on the property in 61 holes. Westmin has earned a 70% interest in the property while Tournigan Mining Explorations retains a 30% carried interest. Westmin can pick up another 7.5% by paying Tournigan $1 million within 90 days of making a production decision. Exploration on the Silbak and Big Missouri properties is being funded by Canacord Resources for an interest in the project. British Silbak Premier Mines is Westmin’s major partner in the Silbak.