By Guy Archibald
August 21, 2012
As reported on KRBD, Niblack CEO Patrick Smith said if Niblack starts mining ore, the company would prefer to process it locally, rather than ship it south.
No operating mine in Southeast Alaska ships unprocessed ore south. Greens Creek and Kensington both process ore on site into a concentrate that is then shipped to smelters in Asia. It seems clear that Heatherdale is proposing to build a concentrate facility on Gravina, not a smelter.
Such a facility within KGB, will require three things in abundance; power, water and room for a toxic waste dump. The future citizens of KGB may bear the responsibility for maintaining a hazardous waste dump for centuries in order to protect Ketchikan’s clean water resources. It is very important that tough questions be answered first.
The proposed Niblack Mine has been compared to both the Kensington Mine near Juneau and the Greens Creek Mine on Admiralty Island. The Kensington mine near Juneau currently processes about 1,400 tons of ore per day. Kensington operates six 1.2 MW generators for a total production capacity of 7.2 MW. “Is that much renewable power available on Gravina?”
The water required to operate a flotation plant is harder to estimate because it relies on the amount of water recycled from the tailings. Greens Creek and Kensington both utilize water pumped out of mine tunnels to mill ore, but that will not be possible if the mine is on Prince of Wales and the mill is on Gravina.
As a rule of thumb, 2.5 tons of water is needed to concentrate each ton of copper ore. (Estimated Water Requirements for the Conventional Flotation of Copper Ores, 2012 at: http://pubs.usgs.gov/of/2012/1089/pdf/ofr2012-1089.pdf ) A ton of water is about 240 gallons. If the Niblack processes the same amount of ore as Greens Creek, 2,200 tons per day, and assuming 87% recovery and recycling rate of used water, 168,000 gallons of water will be needed per day. “Where will this amount of fresh water come from? Where will the contaminated water be treated or disposed?”
Then there are the leftovers from processing the ore, commonly referred to as “spoils” or tailings.
Based on the waste produced during the exploration of the Niblack mine, it is known that significant quantities of acid generating rock are present and will be part of the waste. Where will these be stored?
Acid generating wastes will require long term treatment to protect surface and ground water from contamination. Active treatment and management of the tailings dump could be necessary for hundreds of years and maybe forever. This is the scenario the City and Borough of Juneau is facing with the Greens Creek Mine. How does one create a financial assurance that will last forever to protect the community in the event that the company walks away when the waste dump becomes a financial burden? This happened recently up the Taku River when the Chieftain Mining Company announced its intent to stop operation of its water treatment plant at the Tulsequah Chief Mine.
Forever is a long time. Two states, New Mexico and Michigan, have recognized the lunacy of planning for “forever” and passed laws prohibiting the issuing of a permit for any mine plan that calls for perpetual water treatment.
KGB’s decision makers need to look past the glitter of short-term gains and take a hard look at the long term consequences. Is this the best use for our power, water and clean environment?
Received August 21, 2012 - Published August 21, 2012
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