The figures are presented in the Canada-based miner's preliminary mine plan for 2016. The firm also reported processing volumes in the fourth calendar quarter of 2015 were 9% lower than the same quarter of the year before due mostly to three weeks of maintenance shutdowns in the processing plant. Diamonds recovered in the fourth calendar quarter were 3% lower than the same quarter of the previous year, reflecting lower processing volumes which was partially offset by a higher recovered grade.
Meanwhile, diamonds recovered in calendar 2015 of 6.4 million carats were 9% lower than the original calendar 2015 plan of 7.0 million carats due to a combination of ore availability issues resulting from lower mining rates from A-154N and lower grades from A-418 earlier in the year, and availability of the process plant in the fourth calendar quarter. The miner operates the Ekati diamond mine through its 88.9% ownership, and also owns 40% of the Diavik diamond mine with Rio Tinto Diamonds owning the rest.