The Kensington Gold Mine, consisting of the Kensington and adjacent Jualin properties, is located on the east side of the Lynn Canal about 45 miles north-northwest of Juneau, Alaska. Access to the mine is presently by helicopter, float plane or boat from Juneau.
The Kensington property, which contains the mine's reserves, consists of over 6,100 acres of patented and unpatented federal mining claims and state claims. The adjacent Jualin property to the south consists of 9,236 acres of patented and unpatented federal mining claims and state claims.
The Kensington mine is located within the Berners Bay Mining District at the northern end of the Juneau Gold Belt; a north-northwest trending, 120-mile long, 10-mile wide structural zone consisting of deformed and metamorphosed sedimentary and volcanic rocks intruded by large felsic- to intermediate-composition igneous bodies. Numerous gold occurrences are documented in the belt in a variety of host rock and structural settings. Regional deformation, starting in the Cretaceous and ending in the Tertiary, controlled emplacement of gold-bearing veins at Kensington and within the Juneau Gold Belt.
At Kensington, gold is hosted in multiple mesothermal, quartz-carbonate-pyrite vein swarms and discrete quartz-pyrite veins within the Cretaceous-aged Jualin Diorite. Veins and vein swarms define several north-south trending zones that dip steeply to the east. Mineralization has been defined over a very large vertical extent that exceeds 2,500 feet. Gold occurs predominantly as gold-telluride minerals, such as calaverite, in visible native form, and as inclusions in pyrite.
Kensington is currently expected to have a mine life of approximately 10 years, based on proven and probable gold mineral reserves of approximately 1.35 million ounces. The reserves have a grade of 0.31 ounces per ton.
Mining will be conducted underground via ramp access. The primary mining method will be longhole open stoping with drift and fill mining used in the flat-lying, higher grade zone. In some areas, stopes will consist of initial sill development followed by uphole drilling and blasting to recover localized high grade ores.
The mine is currently expected to produce as much as 150,000 ounces of annual production in early years of operation. Over the life of the mine, Kensington is expected to produce more than 1 million total ounces of gold.
Kensington will use an on-site flotation mill to produce concentrate that will be shipped elsewhere for processing. The mill will not use harsh chemicals such as cyanide.
The processing facilities are located at an elevation of 980 feet above sea level. Ore will be received from the underground mine by 40-ton trucks. Power is supplied by on-site diesel generators. Gold recovery is by a combination of flotation and gravity concentration, followed by concentrate regrind and cleaner flotation.
Tailings produced by Kensington will be inert sandy material similar in composition to the sand at nearby Comet Beach. Approximately 40% of the tailings will be recycled back into the mine as fill. The remaining tailings will be placed in a nearby impoundment (see Tailings Fact section in Environment).
At the conclusion of mining, the processing facility and related infrastructure will be removed and the surface area reclaimed. Similarly, the company will reclaim Lower Slate Lake such that the resulting body of water will be larger and provide improved aquatic habitat for the native fish that will be restocked into the lake. Coeur has posted a reclamation bond to ensure that this work is completed.
