Mt. Milligan operations temporarily suspended

Lack of water has halted mill processing operations for a month

  • Jan. 10, 2018 12:00 a.m.

On Dec. 27, 2017 Centerra Gold Inc. reported that, due to a lack of sufficient water resources, mill processing operations at the Mount Milligan mine in Fort St. James B.C. have been temporarily suspended. Mill processing operations are expected to recommence at partial capacity by the end of January 2018 and at full capacity after the spring melt.

As disclosed in Centerra Gold’s news release of Oct. 31, 2017, Mount Milligan experienced a drier than normal spring and summer during 2017 with a limited amount of spring snow melt. This resulted in lower than expected reclaim water volumes in the tailings storage Facility (TSF) at Mount Milligan which is used for mill processing operations. The water shortage has been exacerbated by unanticipated extremely cold temperatures at Mount Milligan, which has resulted in a greater than expected loss of water volumes in the TSF due to ice formation.

In the fourth quarter of 2017, Centerra sought to mitigate the water shortfall by drilling additional water wells to draw water from nearby aquifers located on the property. While such wells were partially successful, the additional water obtained was not sufficient to offset the loss of water volumes noted above. In addition, as a further, longer-term mitigation measure, Centerra is pursuing an amendment to Mount Milligan’s Environmental Assessment (EA) to allow pumping of water from a nearby lake (Phillips Lake) and is applying for the additional related permits.

It is expected that by the end of January 2018 there will be adequate fresh water available to restart mill processing operations utilizing just one of the ball mills (38,000 tpd to minimize water requirements). Centerra expects that additional fresh water will become available after the spring melt, typically in April, at which time it expects to re-start the second ball mill returning mill processing operations to full capacity. However, as noted, above, the availability of water is subject to, among other things, natural forces that can be unpredictable.

During this downtime, mill maintenance crews will continue to carry out outstanding preventative maintenance activities and will look to bring forward other maintenance work that had been planned for later in the year. The Mount Milligan mine continues to operate according to its mine plan and will continue to expose, mine and stockpile additional ores for future processing.

Year-to-date the Mount Milligan mine has produced approximately 225,000 ounces of payable gold and approximately 54 million pounds of payable copper.

Centerra expects to issue its 2018 full year production guidance in mid-January 2018 and will be providing additional information regarding Mount Milligan as it becomes available, including updates on and additional steps to mitigate Mount Milligan’s water shortfall.

– files from press release

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