Kensington Gold Mine
The Kensington Gold Mine project is an underground gold mine located about 45 miles northwest of Juneau. Operation is expected to being in 2010 and tailings will be deposited directly into Lower Slate Lake.
The Kensington Gold Mine project is located 45 miles northwest of Juneau, in the Tongass National Forest near Berners Bay (click here for map). The mine is owned by Coeur Alaska, Inc., a subsidiary of Coeur d’Alene Mines, Inc. Two prospects comprise the mine site: the Kensington prospect (over 6000 acres of federal patented and unpatented claims and state claims) and the Jualin prospect (9000 acres of federal patented and unpatented claims and state claims). The gold reserves are located on the Kensington prospect and production is projected to begin by mid-2010. The mine is expected to produce 120,000 ounces of gold per year for 12 years.
Mining operations will include an underground mine, an ore storage facility, and a development rock storage facility. Milling will include a flotation and gravity circuit, followed by regrinding and a second flotation circuit to produce concentrate, which will be shipped off-site for additional processing. Some tailings will be used to back-fill the mined out areas underground, but about 60% of the tailing will be deposited into the Lower Slate Lake behind a tailings impoundment. During 2009, no mining operations took place. A little underground development was carried out, but no gold or tailings were produced. By late 2010, the mill is expected to be completely operational . In 2009, cash operating costs for the mine were estimated at US$475/ounce.
Several conservation groups opposed depositing the tailings directly into Lower Slate Lake. Depositing tailings directly into the lake would kill the fish population and alter the aquatic ecosystem forever. However, the U.S. Supreme Court ruled that the tailings constituted “fill” under the Clean Water Act, and thus could be deposited directly into the lake with an U.S. Army Corps of Engineers permit. By allowing the deposition of tailings into existing lakes instead of requiring the mine operator to construct a tailings storage facility, the Court’s decision has major implications for future mine proposals and the impact of mining on wildlands and aquatic habitats.
last modified Mar 26, 2010 05:14 PM