Mining and exploration review north of the 60th parallel

Digging Deep – One billion tonnes of ore at Western Copper and Gold Corporation’s Casino project

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The Yukon’s Casino gold-copper project is the focus of Western Copper and Gold Corporation. With a feasibility study completed in 2013, and an environmental assessment application submitted in 2014, Western Copper and Gold is confident it will be construction-ready in 2016, with initial heap production in 2017 and mill operations commencing in 2019.

 

Western has now been trading for eight years, having acquired Lumina Resources Corporation and, in consequence, Casino, which is 100-per-cent-owned by Western. Casino is situated 380 kilometres northwest of Whitehorse, Yukon, and 560 kilometres from the year-round port at Skagway, Alaska. Its characteristic terrain comprises rounded, rolling topography with moderate to deeply incised valleys, the Yukon River flowing to the west about 16 kilometres north. It is the Yukon River that will provide Casino’s fresh water.

Within Casino there are significant resources and reserves of not only copper and gold but also molybdenum and silver. Overall mill ore at reserve grade runs to 92 Mt proven and 885 Mt probable. The percentages for the four metals are:

– copper percentage 0.2 per cent overall (0.34 per cent proven, 0.19 per cent probable);

– gold g/t 0.24 overall (0.44 proven, 0.22 probable);

– molybdenum percentage 0.023 overall (0.028 proven, 0.023 probable); and

– silver g/t 1.73 overall (2.23 g/t proven, 1.68 probable).

Adding heap leach ore into the equation, Casino offers 4.4 billion pounds of copper, 8.9 Moz of gold, 494 million pounds of molybdenum, and 65 Moz of silver (source is the feasibility study by M3 Engineering & Technology Corporation).

The mine is open pit and expected to enjoy a 22-year life-span. At the height of construction employment is likely to be 1,000 people and 600 at peak production.

One real challenge to Casino is its lack of accessibility. Year-round access is currently attainable only by air. After consideration of the options, the choice is a new 130 kilometres unpaved road extending from the current Freegold Road, which meets the Klondike highway at Carmacks.

18 - image005Geology

As a result of supergene alteration, Casino is weathered to 70 metres in depth; the consequent leached cap contains a certain amount of gold enrichment but also erratic grades of copper depletion. The copper at Casino descends from a 10 metre upper copper oxide zone to a 60 metre lower copper sulphide zone.

Development plan

Casino will progress as a conventional truck-shovel, open-pit mine, initially processing the gold-bearing oxide cap as a heap leach operation. Sulphide ore processing will start approximately two years later at 120,000 t/d in a concentrator, in order to produce copper and molybdenum concentrates. Higher ore grades and greater concentrate production during the initial four years of operation will simultaneously provide faster cash flow, resulting in a capital payback in three years at long-term commodity prices.

Western is stressing that Casino’s strip ratio for the first four years has been calculated at 0.49:1, with 0.59:1 for the following years. In other words, the amount of ore produced (notably for gold, copper, silver and molybdenum) will outweigh unwanted material.

After drilling and blasting, the rock will be loaded onto rigid-frame haul trucks by electric shovels. The oxide ore will be transported to the run-of-mine heap leaching facility by off-highway haulage trucks.

Copper will be recovered, as a precipitate, by the SART process to control the quality of the leach solution; this precipitate will be shipped to smelters.

Any ore to be milled will be transported from the mine to the primary crusher, again by off-highway haulage trucks. Mineral concentrates of copper and molybdenum will be produced by conventional flotation.

The gold and silver will report in the copper concentrate and will be recovered in the smelting process resulting in credits to the Casino Mine. Gold bullion produced from the oxide gold ore will be shipped by truck to metal refiners.

The project includes a power island consisting of two gas turbine generators complete with heat-recovery boilers and a single-steam driven generator, and internal combustion engine driven generators for a total installed generation capacity of 150 MW. Liquefied natural gas will be imported to the site and gasified to provide natural gas to fuel the power generation plant.

Western announced its appointment of the Engineering, Procurement and Construction Management (EPCM) contract at Casino to M3 Engineering & Technology Corporation of Tucson, Arizona. M3 is very familiar with Casino, having worked on the project from an early stage, preparing two pre-feasibility studies as well as the feasibility study issued in early 2013.

First Nations

Casino is located on Crown land administered by the Yukon Government and is within the Selkirk First Nation (SFN) traditional territory; the Tr’ondek Hwechin First Nation traditional territory lies to the north. Based just 40 kilometres from the project, SFN comprises around 480 members and signed its land claim and self-government agreements in July 1997. As a self-governing First Nation, SFN can make laws on behalf of its membership and deliver an array of programmes and services to its citizens.

Early in June 2014, Western Copper And Gold and the Little Salmon/Carmacks First Nation (LSCFN) signed a settlement agreement and a consultation work plan. The parties will in general review, evaluate and discuss Casino and, more specifically, promote and capture positive impacts of Casino that could benefit LSCFN members.

Casino’s particularly favourable strip ratio, its poly-metallic structure and the successful negotiations with the local First Nations all contribute towards a successful formula.

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