Diamond Exploration

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Primary (as opposed to secondary or alluvial) diamond deposits are mined from either kimberlite or lamproite rock-types which originate deep beneath the earth’s crust. Diamonds exist at more than 100km depth within the earth’s mantle and are transported to the earth’s surface by extremely rapid volcanic eruptions (“diatremes”), which form these rare kimberlite and lamproite pipes.

Kimberlites host the most common type of commercial diamond deposits. Approximately 12% of all known kimberlites contain diamonds, while only 2% contain economic quantities. Lamproites are extremely rare: of the 25 known lamproites in the world, about 25% contain diamonds. The most famous lamproite is the Argyle Pipe in Western Australia, which produces about 30% of the world’s diamonds.

Although very rare, the risk-versus-reward profile for exploration success in the diamond exploration business can be spectacular. For example, the Jwaneng kimberlite diamond deposit in Botswana contains diamonds with a gross value of around $75 billion. At Ekati in the Lac de Gras region of the Northwest Territories of Canada, the deposits have a gross mineable resource worth over $15 billion and produce over 10% of the world’s diamonds.

Delta Mining's Micro Diamond.  Click picture to enlarge.