The Victor Diamond Mine, Northern Ontario, Canada: Successful Mining of a Reliable Resource

Abstract

The Victor Diamond Mine opened in 2008. Different phases of evaluation were used from 1997 to 2003 to systematically build a resource. The Mineral Resource Model suggested an extremely variable and overall relatively low grade for Victor, but that the diamonds would be of superior value. The development of a robust geological model and understanding the emplacement processes were critical to the design and implementation of sampling programs and to the establishment of a reliable resource for mine planning. Victor comprises two kimberlite pipes; the larger pipe, Victor North, includes the highest predicted grades and is the focus of current open pit mining and this paper. The variability in grade reflects the complex geology of Victor North which comprises two cross-cutting volcanic craters. The later crater was infilled by the products of two separate eruptions; a central high grade pyroclastic kimberlite nested within previous unlithified low grade pyroclastic infill. Extensive mixing produced a wide, gradational, inhomogeneous internal contact zone with variable, but overall intermediate grades. Apart from macrodiamond bulk sampling, the contrasting grade zones can only be differentiated using micropetrography and groundmass mineral compositions which creates a practical mining issue in separating ore from kimberlite waste. Ore versus waste is identified during mining by routine bulk sampling of newly exposed kimberlite which is treated in a separate processing plant. The mining bulk sample data and mined mineral resource performance data show that the Victor North Mineral Resource is accurate, significantly contributing to the success and reliability of commissioning and operating the mine