In nature, diamonds occur in volcanic pipes called kimberlites and lamproites. These pipes contain diamond-bearing rock brought close to the earth's surface through volcanic eruptions. Erosion may cause these diamonds to be distributed over large areas, creating alluvial (river or marine) deposits. While diamonds are not scarce in geological terms, it remains difficult to identify deposits of sufficient quantity close enough to the earth's surface to allow economic extraction. Kimberlite diamonds are most concentrated, which makes them attractive for large-scale surface and underground mining. We also mine marine diamonds and large-scale alluvial deposits in Namibia and South Africa. Alluvial diamonds are usually gem quality and higher value.
	Bringing a diamond mine into production requires significant effort, skill and investment. The capital cost of De Beers Canada's Victor project is in excess of C$980 million (US$814 million). This includes costs for permits, sampling and studies. Mine construction costs alone amount to C$842 million (US$698 million). A significant amount of this cost is returned to local economies through the employment of construction firms and associated businesses. (See Preferential procurement) Taking a diamond deposit from discovery to production may take 10 years. This makes it imperative to determine the economic viability of any deposit before progressing beyond exploration. The concentration and quality of diamonds, as well as the size of the mine, are key factors. Specifically, viability depends on the potential capital and operating costs and the expected economic returns. In accordance with our Principles, and to be monitored by our Assurance Programme, we conduct extensive social and environmental impact assessments. These complement our economic feasibility studies.