BHP Billiton today posted record results for the year ended June 30, showing full-year profit before exceptional items of $21.7 billion, a 74% increase on last year, mainly boosted by iron ore and coal.

For diamonds, BHP Billiton said: “Strong demand and a shortage of rough diamonds resulted in higher prices, which increased underlying EBIT (earnings before net finance costs and taxation and exceptional items) by $254 million.”

Diamond production at the Ekati mine in Canada for the 2011 financial year was 2.5 million carats, an 18% decrease from the prior period.

BHP Billiton said it expects lower average ore grades to impact Ekati production in the medium term, consistent with the mine plan.