Kitsault Molybdenum Mine, British Columbia, Canada
Kitsault molybdenum mine is a high grade resource located 140km from Prince Rupert in British Columbia, Canada. Owned and operated by Avanti Mining, the mine is considered to be one of the top five molybdenum projects in the world.
Kitsault mine was discovered in 1911 and the first diamond drilling programme at the mine was carried out by Kennco Exploration in 1959. The mine produced 9.3Mt of ore between January 1968 and April 1972.
In 1976, a feasibility study was conducted to explore options for re-opening the mine. Production resumed between 1981 and 1982. Avanti acquired the Kitsault property in October 2008. All necessary permissions for the mine's development are in place. A new environmental assessment was only needed for tailings disposal.
A feasibility study of the mine, undertaken by AMEC, was completed in late 2010. Avanti entered into an agreement with five lenders in April 2012 to provide up to $640m of financing for the mine's development.
In May 2012, the Environmental Impact Statement for the mine was accepted for review by the Canadian Environmental Assessment Agency.
Geology and reserves at British Columbia's mine
Kitsault mine consists of three deposits - Kitsault, Bell Moly and Roundy Creek. The deposits are part of the Bowser Lake Group in the Intermountain tectonic belt of the Coast Plutonic Complex.
Proven and probable reserves of the mine are estimated at 232.5 million tons (Mt) grading at 0.081% molybdenum. Indicated reserves are estimated at 158Mt grading at 0.10% molybdenum and inferred reserves are estimated at 133Mt grading at 0.08% of molybdenum.
Mineralisation of the Kitsault, Bell Moly and Roundy Creek deposits
Mineralisation at the Kitsault, Bell Moly and Roundy Creek deposits occurs in metamorphosed interbedded argillite and greywacke of the upper Jurassic to lower Cretaceous Bowser Lake Group.
The mineralisation zones are annular in plan. Intrusives of molybdenum mineralisation include diorite, quartz monzonite and felsic units.
Mineralisation at the Kitsault deposit occurs in a hollow, steeply dipping annular shape in the central Lime Creek Intrusive Complex. Bell Moly consists of molybdenum mineralisation in the form of a south-west zone intrusive and the Clary Creek stock.
Molybdenum mineralisation at the Roundy Creek deposit includes composite quartz monzonite stock disrupted by faulting.
Mining methods used at the Canadian molybdenum mine
Molybdenum from the mine is planned to be recovered through open-pit operations. Shovels, loaders and haul trucks are expected to be used for the mining activities. Benches will be drilled in an eight metre by eight metre pattern for recovering the ore.
The mine will be equipped with a processing plant consisting of a 40,000t/d concentrator to process the recovered ore. The plant will use conventional processing technology. The project is located near existing infrastructure, with road and sea access enabling easy transport of product.
Ore processing at Avanti Mining's Kitsault mine
Run-of-mine ore will be crushed and sent to the stockpile. From the stockpile, the ore will be sent to a semi-autogenous grind (SAG) mill. Crushed ore from the SAG mill will be passed over a vibrating screen, which will separate out larger ore pieces. These pieces will be sent to the pebble crusher for further crushing.
A discharge screen is used to separate any coarse material which is sent to a cyclone pack where it is crushed in a ball mill. From the cyclone pack, the crushed ore is sent to the rougher-scavenger bulk flotation circuit where molybdenite and some pyrite is recovered.
The concentrate from the rougher circuit passes through a series of cleaning steps and the final concentrate is sent to the thickener.
After thickening, the concentrate is sent to the leaching circuit where it is treated with hydrochloric acid. Leached material is filtered, washed and dried before being shipped.
Tailings from the rougher circuit are sent to the de-pyritisation flotation and will either be used for dam construction or discharged into the tailings management facility. The facility is designed to enable secure disposal of 233Mt of tailings, which can be expanded up to 300Mt