Grade improving at depth on Astoria gold project

Impressive gold grades are being confirmed by recent underground exploration work on Belmoral Mines (TSE) and Yorbeau Resources’ (TSE) Astoria gold project, three miles south of here. The companies have been hitting high-grade gold values while drifting into the property’s AW zone at depths of around 1,000-1,500 ft. below surface, The Northern Miner learned during a recent visit to the site.

The companies are especially encouraged by the fact that both grade and width have been improving with depth.

For example, on the 10th level, the deepest level so far at 1,500 ft. below surface, recent chip sampling has yielded grades of up to 0.33 oz. gold per ton across average widths of 9.6 ft. for an impressive drift length of 571 ft.

The AW zone dips at roughly 75 degrees to the north and exhibits exceptionally uniform grades along remarkably straight drifts, The Northern Miner observed on the underground level plans.

Chip sampling on the 9th level (about 1,340-ft. depth) yielded 0.30 oz. gold across 8.5 ft. for a drift length of 476 ft., and chip sampling on the 7th level returned 0.21 oz. across 7.6 ft. for a length of 423 ft.

Chip sample plans for the 7th level (1,000-ft. depth) examined by The Northern Miner showed extremely consistent and uniform high-grade gold values at each 8-ft. sampling interval along the drift.

Recently completed work has included deepening the shaft to 1,683 ft. from 490 ft., and drifting on three levels in a sulphide-rich, gold-bearing horizon known as the AW zone. The zone, with average grades better than 0.30 oz. gold per ton, is hosted by talc-chlorite schists and is the focus of the current underground exploration work and drilling program.

A “bankable” feasibility study is being prepared by the company’s consultant for a future production decision, and about 10,000 tons of bulk sample material have been extracted for metallurgical testing.

The partners are contemplating a number of options at present, including production at a rate of 500 tons per day. Also being considered are deepening the shaft for more exploration work on the AW zone, or a combination of both production and more exploration.

When The Northern Miner visited the site, five drills were busy working underground to confirm and expand on previous results in the AW zone where preliminary reserves are currently estimated at around 400,000 tons grading 0.26 oz. gold, with significant potential for increases above that figure.

Lying at depths of 500-1,500 ft. below surface, the AW zone is essentially a tabular-shaped sulphide horizon containing fine gold associated with substantial amounts of arsenopyrite mineralization along with minor amounts of pyrite and chalcopyrite.

Operator Belmoral owns 40.5% of Yorbeau, as well as a 50% interest in the 546-acre Astoria property which saddles the Cadillac Fault. That major structure extends in a roughly east-west direction for more than 100 miles from Kirkland Lake, Ont., to Val d’Or, Que.

The Cadillac Fault is a well- known geological feature since it hosts several other significant gold deposits in the area.

Yorbeau spent about $16 million in flow-through funds exploring the Astoria deposit before Belmoral became involved in 1988. The latter company has invested $10 million in the project so far to earn its 50% interest in the property.

The availability of flow-through share funding has been a key factor in the success of the project. “Had it not been for flow-through share financing, the Astoria gold project would not exist,” Yorbeau President Karl Glackmeyer told The Northern Miner. “We are now in the fortunate position that we have some reserves outlined, and our project still has considerable exploration potential.”

Since the AW zone is still open to the west and at depth, ongoing exploration is expected to expand the reserves substantially.

Total reserves from all zones, including three smaller carbonate zones closer to surface, were estimated previously at 1.4 million tons averaging 0.18 oz. gold, but that figure is expected to increase as the latest exploration results are tallied.

According to senior project geologist Daniel Kelly, the AW zone does not contain much visible gold. He said microscopic free gold occurs in microfractures along the sulphide grains as well as on the outside of the arsenopyrite crystals.

He said the Astoria deposit is similar geologically to the altered ore zones of the Kerr Addison mine, 30 miles to the west in Ontario. “What really made the Kerr mine was the sulphide ore,” explained Glackmeyer. He said the two deposits share similar alteration patterns and mineralization types. “What got the Kerr mine going were the sulphide zones and what will get us going is the AW zone,” he added.

Bulk-sampling and metallurgical test results are expected next month, according to Glackmeyer, and about 3,000 tons of material are being processed at Belmoral’s mill in Val d’Or, about 70 miles to the east.

The milling tests are designed to confirm the grades encountered in underground chip sampling. Once the deposit enters production, possibly later this year depending on results of the feasibility study, ore will be milled at the Belmoral facility in Val d’Or. Yorbeau previously signed an agreement with Belmoral to mill ore from the Astoria during the life of the mine.

A feasibility study, currently under way, is expected to reach completion by April, and then a production decision could be taken, the companies said.

“The grades are good and the widths are improving with depth,” Glackmeyer told The Northern Miner. “My personal feeling is that we’ve got the goods to go into production.”

Belmoral’s Val d’Or manager Enrico Boiocchi said a number of options are available to the companies in light of the new encouraging results from the AW gold zone. He said the partners could decide to deepen the shaft and continue exploration at depth in an effort to double the current reserve figure. Alternatively, a combination of limited production from the deposit and ongoing exploration work in the AW zone could also be feasible, said Boiocchi.

A rock mechanics study is also under way to determine the appropriate mining methods, and Boiocchi is encouraged by the fact that the AW zone might be amenable to longhole mining methods, which would reduce production costs significantly. “The ground here is very competent and dilution shouldn’t be much of a problem if longhole mining is used.” he said.

He said the current feasibility study will incorporate recent results in a calculation of minable reserves, as well as data for the rock mechanics studies and metallurgical testing.

“With grades above 0.30 oz. gold, this is one of the highest grade gold projects in the Rouyn-Noranda camp,” he said. “We expect to continue exploring the AW zone at depth and the area to the west is also looking encouraging.”

The AW gold zone, which does not outcrop at surface, starts at about the 500-ft. horizon and is still open at depth and along strike to the west. More results from ongoing exploration are expected in the months ahead, and the companies anticipate both tonnage and grade will be revised upwards.