De Beers stopped its 30-year open pit mining operations at Venetia last year to transition it to underground extraction.

The miner is confident about the positive effects that supply curbs by major producers and India's two-month import moratorium will have on the market.

Superdeep diamonds likely migrated to the surface together with different parts of the former supercontinent Gondwana following violent volcanic eruptions.

Amid a wider slump, MINING.COM’s ranking was lit up by newcomer Amman Minerals, which now sits just outside the top 10 after minting at least six new billionaires since its July IPO.