The tiny Redstone mine is making so much money, and the reserve potential at depth is so promising, that operators are starting to think in terms of a production shaft and mill. One might well ask whether this is Timmins or Sudbury.
“We could be going to tender on a production shaft by fall, and contemplating our own 1,000-ton-per-day (910-tonne-per-day) mill is not out of the question,” Mine Manager William Hedderson told The Northern Miner Magazine on a visit in mid- August. That’s startling news for a mine that didn’t exist 12 months ago.
Earlier this year joint-venture partners BHP-Utah Mines (49%) and Timmins Nickel (51%) decided to build a low-cost, ramp-access mine on the Redstone property. The project was based on probable mineable reserves of just 350,000 tons (320,000 tonnes) to a depth of 1,000 ft (300 m). Grades were high enough (about 2.91% nickel), the partners figured, that a small operation could turn a healthy profit at contemporary nickel prices. Giant Yellowknife Mines was winding down its gold operations in Timmins at the time, and their Schumacher mill and attached Government of Ontario mill (gomill) were available for custom milling. This fortunate set of circumstances led to a fast production decision. No time was wasted developing the mine.
While contract miners began driving a 12×15-ft (3.6×4.5-m) ramp, exploration work continued, showing good tonnage potential below the 1,000-ft (300-m) level. If this pans out, however, there would exist the potential to increase mineable reserves significantly at a depth where haulage up a ramp would be impractical; a production shaft would then be justified. Providing optimism is a single drill hole which intersected 19.6 ft (5.9 m) of sulphides 1,400 ft (420 m) below the known reserves. The mineralized section averaged 2.76% nickel. To give weight to the argument that this is the extension of the known orebody, a down-hole geophysical survey was conducted by Jonathan Mivenifumbo of the Geological Survey of Canada. That survey measured the electrical conductivity between the deep drill hole and a hole in the known orebody. “The results indicate continuity between the known ore zone and the deep hole,” Mivenifumbo said.
Timmins Nickel has since completed an initial $6-million underwriting, which will finance a 3-month drilling program. That will fill in the information gap between the known orebody and the deep intersection. If the results surpass a target value of total reserves set by the mine partners, then a new mill would be justified. The company is not disclosing that target figure.
In January, contract miners from Dynatec Mining began working three shifts per day, seven days a week, in order to construct a ramp as quickly as possible. (Dynatec President Robert Dengler is also a director of Timmins Nickel.) It was driven at an average grade of 15%, down to a depth of about 320 ft (96 m). Drifts measuring 5×7 ft (1.5×2 m) were then driven in ore on the 100-, 150- and 200-ft levels (30, 45 and 60 m). When we toured the underground workings in mid- August, three open stopes were in production. Dynatec was winding down its development contract and had 16 miners on site. Timmins Nickel was hiring its own production miners and about 50 (of a total requirement of 75) had been hired. A new mine superintendent, Donald McKinnon, formerly in charge of Westminer’s Forest Hill gold mine in Nova Scotia, had been hired.
“We see no problem meeting the 270-tonne-per-day target for the rest of 1989 from three or four stopes,” said mine geologist and exploration manager Kenneth Lapierre. “We’re aiming for 20 tons (18 tonnes) per manshift. We’re not sure yet if we have good stope-miners because they mostly come from contracting companies, which stress footage, not grade. But some guys are getting 80 tons (72 tonnes) per manshift.”
The company has only one piece of new equipment underground — a JDT-426 truck; the remainder is used equipment. That includes three Wagner load-haul-dump machines, a custom-built 5-cu-yd scoop, one 15-ton truck and a service tractor. “We’re looking for two 1.5-cu-yd scoops,” Hedderson said.
Production drilling in the narrow stopes is by jackleg. Ore is stockpiled on surface, then loaded into 50-ton (45-tonne) trucks and hauled about 22 km to the GOMILL in Timmins. Most of that haul is over an all-weather passage, known as the Tisdale Road, from South Porcupine. A shorter, 5-km stretch snakes its way into the mine site; this is an old timber road that presents some rather tough going in the spring. Timmins Nickel was upgrading that road during our visit and a power line was being brought into the mine site to replace diesel generators. Also, a Bailey bridge was being erected across the Redstone River at the time of our visit. The previous timber structure was deemed unsafe by the Ontario Ministry of Transportation and Communications.
Talc is by far the biggest challenge in treating the Redstone ore, Mill Superintendent Tony Lipiec explained. First it has to be suppressed in the first stage of flotation, then the pentlandite is floated off. The reagents necessary to suppress the talc adds to the cost of milling the ore.
Sherritt Gordon’s nickel smelter in Fort Saskatchewan would like to have a concentrate grading 8% nickel, but Timmins Nickel has shipped 82 lots, so far averaging about 15%.
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