TORONTO (miningweekly.com) – Canadian miner Wesdome Gold Mines on Monday said it had temporary suspended contract mining at the Mishi openpit mine, located near Wawa, northern Ontario, as a considerable stockpile of ore grew at the nearby Eagle River mill.

The company said it was fast-tracking a multi-pronged upgrade to its Eagle River milling facility, targeting a 66% increase over current rates to 1 000 t/d to deal with the growing supply of ore from the Mishi mine.

The focus of the upgrades was to streamline dry-stack tailings handling; increase the throughput and efficiency through the filtration conversion to a carbon-in-leach process; and to permit a new long-term tailings management solution.

The mill upgrade was being done in consultation with global milling specialist Kappes, Cassiday & Associates of Reno, Nevada.

"The Mishi openpit has been a great success from a mining standpoint, with recovered grades at or above resource grade for the past five quarters. However, we have been constrained by our milling operations and have generated a substantial stockpile of Mishi ore,” Wesdome president and CEO Donovan Pollitt said.

The combined Eagle River and Mishi ore stockpiles at the mill currently totalled about 100 000 t, and the Mishi stockpile had about 85 000 t of ore at estimated grades of about 2.5 g/t of gold and that from the Eagle River mine comprised about 15 000 t of ore grading 7 g/t. Additional Mishi broken ore still in the pit currently totalled about 15 000 t.

To date, Mishi had produced 2 100 oz of gold from 20 000 t milled at a recovered grade of 3.2 g/t.

Wesdome noted that deferring mining at Mishi would reduce operating costs by about $3.5-million until year-end and that contract mining activities would restart in the spring of 2014.

The company affirmed that the mining suspension would not impact its output guidance of 55 000 oz of gold for the year, and that as milling rates increased, it would have the flexibility to restart mining activities sooner.

“We see considerable potential for expansion given Mishi's increasing reserves as well as positive deep-drilling results and better grades at Eagle River. We are confident in our ability to optimise these assets over the long term through an affordable and phased incremental capital investment programme,” Wesdome said.