1990s: Diamond Mines in Argyles Will End Up If Not Recovered
The 1997 annual report for the Rio Tinto, the majority partner in the Argyle Diamond Mines Joint Venture in the Kimberly region of Western Australia shows that diamond reserves there will be exhausted in several years time, unless a deep shaft mine is developed at the site. Rio Tinto has a 59.7% stake in the Argyle Diamond Mines Joint Venture (Argyle) Ashton Mining has a 40.1% interest in Argyle. Production from Argyle’s major resource, the AK1 kimberlite pipe began in 1985. According to the annual report, output from the AK1 pipe in 1997 was 38.6 million carats recovered from 10.4 million tons of ore.
Total “proved and probable ore reserves from the AK1 pipe as at December 31, 1997,” notes the report, were 51.1 million tons of ore at an average grade of 2.6 carats per ton, containing 135 million carats of recoverable and saleable diamonds. The report adds that “The AK1 ore grade will decline as Argyle mines deeper into the deposit.” Alluvial production in 1997 was 1.6 million carats recovered from 5.9 million tons of ore for a total AJV production of 40.2 million carats, slightly less than 1996 production.
According to these figures, and the pattern of past production, the total reserves will only add up to a little more than the amount mined in the last three years. The moral of this story: perhaps those who worry about the oversupply of small goods can breathe a little easier when viewing the situation from the perspective of the Argyle mine’s reduced output.