TURNAROUND Renabie

When he took over in 1987, McCalllum saw that the back end of the mill presented serious restrictions. It could handle only between 600 and 630 tons per day. About $700,000 was spent on new equipment, including a filter press, a clarifier tank, a Merrill- Crowe vacuum tank and new vacuum pumps. Other equipment, such as three drum filters and the No. 1 conveyor, was completely rebuilt or revamped.

The most pressing problems involved labor relations. For example, in a single month in mid-1987, seven mill workers packed their bags for what they felt were greener pastures at a mine nearby. At Renabie, it was discovered that mill workers objected to the existing bonus system. Specifically, they wanted bonuses based on gold production, recovery rates and tons milled, not on gold production, recoveries and reagent costs (they believed reagent costs were largely beyond their control). So the bonus system was changed. And, on a community-wide scale, the company arranged for several television and radio signals to reach local sets.

To direct all the changes in the mill, mine superintendent Bruce McDonald was appointed mill superintendent. It seems unorthodox, but putting the mining man, after a successful stint underground, into the mill was “just the right move,” McCallum said. Chief Engineer Martin Wafform was put in charge of the mine as well as the engineering department. McCallum says those two, along with plant superintendent Nick Frenks and mine manager Brian Eyres, have maintained the momentum that came with the initial rehabilitation program.

In the mill, improvements are stark. For January, 1989, 21,120 tons were milled, for a recovery of 93.5% and gold production of 4,000-plus oz. In the month of October, 1987, total throughput was 14,500 tons with recoveries of 87% and production of 3,000 oz. (the October figures were slightly lower than monthly averages in 1987.) Today, the mill operates at 725 tons per day (sometimes averaging 750 to 760 tons). On Jan 29, a record 886 tons were milled. Mill availability is 93% to 94%.

In the mine and mill, productivity has risen 61%, to 6.1 tons per man- shift in January, 1989, from 3.8 tons per man-shift in October, 1987. “What we’re concentrating on now are the direct operating costs,” McCallum said. “Our targets are to get costs down to less than $70 per ton and less than $300 (us) per oz.” In January, the comparative figures were $71.48 per ton and $285 (us) per oz.

Mining, in the form of sub-level caving, is in progress almost 3,600 ft below surface. Ore and waste are dumped down passes to the 4245 level, where skips in a winze carry material to 3105. Rail cars transport muck along 3105 to the shaft. Even at current mining depths, ground control has not been a problem, according to McCallum. The back is screened throughout the mine and walls are rockbolted on a 4×4-ft pattern.

The 18 zone has been providing millfeed until now, but operators are testing a new area called the 19 zone. It is situated to the east and west of a dyke that cuts vertically through 19 and acts as the westerly boundary of the 18 zone. The 19 zone is below the 18.

If the 19 zone to the west of the dyke is distant enough from current workings, that area can be mined simultaneously with stopes in 18. And that will be a big plus because having production confined to one area, as it is now, causes bottlenecks in the production cycle.

“We won’t have all our eggs in one basket, but everything hinges on the proximity to 18,” McCallum said.

On the exploration front, a decline is being driven to probe for an extension of the orebody at depth. The decline starts at the 4245 level and will go down to the 4365 level (4,365 ft below surface). The operators plan to drive crosscuts into the hangingwall of the orebody and, from there, establish stations to drill as deep as 4,600 to 4,700 ft below surface. Diamond drilling should be under way by early next year.

The orebody has demonstrated consistency in both grade and structure since mining began in the late 1940s. “It has been continuous all the way down to 4,000 ft,” said McCallum. “There’s no reason why it shouldn’t be continuous down to 6,000 ft.” The current reserve figure is one million tons of proven and probable ore grading 0.215 oz gold per ton the figure includes a 7% dilution factor and the cut-off grade is 0.1 oz per ton.

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