Conference program
November 22, 2011 |
Grade control at the Detour Lake gold deposit, Ontario |
The Detour Lake gold project is located in northeastern Ontario, approximately 300 km northeast of Timmins, within the Abitibi greenstone belt in the northwestern portion of the Archean Superior Province. Discovered in the mid-70s, Detour Lake was in operation from 1983 to 1999, producing approximately 1.8 million ounces of gold mainly from underground methods. After acquiring the project in January 2007, Detour Gold Corporation initiated a comprehensive drilling program to define the potential for a large, open pitable, low-grade gold deposit. The gold mineralization is found within a 200 to 350 metres wide corridor over a strike length of >3 kilometres within a mafic metavolcanic assemblage, from surface to at least 1,000 metres depth. In 2007, the drilling focused on the eastern portion of the deposit on a 80m x 80m grid pattern. From 2008 to now, the drilling was completed on a 40m x 40m grid to categorize the mineral resources to the measured and indicated resources categories and to estimate mineral reserves. To date, Detour Gold has completed over 500,000 metres of diamond drilling and has defined an open pit mineral reserve of 14.9 million ounces of gold, which is Canada’s largest pure gold reserve. As a grade control exercise to confirm that the 40m x 40m drilling spacing is adequate for mineral reserve estimation, Detour Gold completed a 20m x 20m drilling program in the eastern portion of the deposit. The successful results confirmed that drilling the deposit on a 40m x 40m drill spacing is sufficient for reserve estimates. In 2010, Detour Gold started a drilling program to establish the appropriate grade control procedures for production. This diamond drilling program consisted of short holes testing the first four benches (approximately 40 metres) of a selected portion of the deposit on a 10m x 10m spacing. The results did confirm the grades and tonnes that were outlined on both the 20m x 20m and the 40m x 40m spacing. This exercise provided the confidence that a closed-spaced drilling program will allow Detour Gold to manage the gold grade of the deposit during the mine life. The tightly spaced drilling pattern proposed is an accepted grade control practice world-wide for gold deposits of this type. In the fall of 2011, Detour Gold has started the production grade control program at Detour Lake. Approximately 9,000 metres of reverse circulation (RC) drilling will be completed on a 10m x 10m spacing. The Detour Lake project is currently under construction. Gold production is expected to commence in the first quarter of 2013. |
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