Fort Knox's Steve Lang talks progress.

• Author: Jones, Patricia
• Position: Interview

Steve Lang came to Alaska a year ago to take over as general manager of Fort Knox, the large-scale hard-rock gold mine and mill about 20 miles northeast of Fairbanks.

During his first year at the helm, Fort Knox miners produced the first 1,000-ounce gold bars, equal to a day's worth of work at the mammoth-sized mine.

In a recent interview, Lang talks about the mine's progress, its affect on the state's gold mining industry and the project's future plans.

Steve Lang, general manager of Fort Knox Mine, points to areas of improved efficiency since the first gold dore was poured in December, 1996.

ABM: You're six months into commercial production here at Fort Knox. Basically, how are operations going?

LANG: The first part here is to get the design capacity, out of the mill and we've been above the design capacity, since the first of May. Not significantly above, but we weren't expecting to reach that rate of 36,000 tons (of ore processed) per day until the first of December. We've been there since the first of May.

At the same time we recognize a couple of bottlenecks that are holding us back. We expect to have the major one corrected by this week. And then we'll have an opportunity to see what additional tonnage we can run through the plant.

For our part, we're very confident in the 36,000 tons a day, and hopeful in getting something in excess of that....above the original design rate.

The other part has not just been the capacity, but the ability to bring it in at the expected costs. There are two parts to that. One is the capital, which has been a problem for the project. About a year ago, the expected cost was up to $396 million and we haven't finished everything, but it's more likely to be about $23 million less than that.

To bring on this capacity it took a little bit more cost than what we were expecting a year ago.

The third part is looking at the operating costs, which, for this year, were expected to be about $215 an ounce. Since we've been commercial, our costs have been a little bit less than $170 per ounce. That's very good news.

ABM: How have you been able to do that, bring those operating costs down?

LANG: The biggest savings have been in the mill, in the reagent use. As we've fine-tuned that...ammonium bisulfate, the cyanide, the lime, these costs have come down significantly in all areas.

Reagents and consumables amount to about $14 to $15 million a year in operating costs. At the first of the year, we were running about two and one-half pounds of ammonium bisulfate for every ton of ore. Right now, we've been running closer to .6 of a pound.

The cyanide use was expected to be about .27 pounds per ton, and it's running less than half of that rate right now.

We've gone to a little bit coarser grind, which has saved us the grinding media and grinding balls - and it's also lowered our power costs a bit. So instead of using 20 kilowatt-hours a ton, we're down around 18.

At the same time, since we're running more tons, we're able to get some efficiencies just on our power demand.

A year ago we were looking at tire usage in the mine. They typically lasted 3,800 to 4,000 hours. This year, we've been able to improve operations to where we're getting about 4,800 hours. Tires are one of the biggest single controllable costs in a mine.

ABM: Going back to the chemical agents - are you able to use less of...