PERTH (miningweekly.com) – Gold miner Northern Star Resources has reported a slight fall in production during the December quarter, as weather events impacted on its Australian operations.

Gold production during the three months to December reached 193 252 oz, compared with the 207 600 oz produced in the previous quarter, while ounces sold declined slightly from 212 682 oz to 210 561 oz in the same period.

The Jundee operations delivered 63 650 oz during the quarter, while the Kalgoorlie gold operations produced 79 469 oz. The newly acquired Pogo gold miner, in Alaska, produced 50 106 oz during the quarter.

Northern Star executive chairperson Bill Beament told shareholders that the operations had performed well, given the combination of lower-grade mine sequences and the extensive reform programme under way at Pogo.

Some 57 534 oz of gold were sold from the Pogo operation during the quarter, with Northern Star reporting that the average mined grade fell to 8.2 g/t during the quarter from 11.2 g/t in the previous quarter, reflecting the company’s gradual transition to a more bulk mining approach and the mine sequence during the quarter.

Strong productivity gains were reported at Pogo in the quarter, with mined tonnage up 22% and mill throughput up 33% to date. These efforts have lowered the cost per tonne by some 23%.

The miner was still in the process of implementing its operational changes at Pogo, with further increases in tonnage and cost reductions expected in the current half-year.

As a result of this, Northern Star has increased its upfront investment in mine development, diamond drilling, mobile fleet and other measures aimed at taking full advantage of the opportunities at Pogo.

This accelerated expenditure has prompted Northern Star to increase its all-in sustaining cost guidance from between A$1 050/oz and A$1 150/oz, to between A$1 125/oz and A$1 225/oz.

“These lower grades reflect two factors. The higher gold price in the December quarter allowed us to extract lower-grade ore, which reduced production and in turn increased our per-unit costs without damaging our margins.

"This is entirely consistent with Northern Star’s long-standing policy of mining to a margin.

“Second, the lower grades also stemmed in part from the mine sequence encountered during the quarter. Our mine plans show that grades will be higher at each of our three operating centers in the current half.”

Northern Star has maintained its 2019 financial year production guidance of between 850 000 oz and 900 000 oz.