Adjusted net profit for the quarter was 10% higher than a year ago at US$223 million, while revenue edged up 1% to $743 million.

Its adjusted EBITDA was also 1% higher on the year at $387 million, with the adjusted EBITDA margin steady at 63%.

Group total cash costs for the three-month period were 1% higher at $383 per ounce, while all-in sustaining costs jumped 17% on the year to $684/oz due to lower gold sales volumes.

Polyus noted that it produced the first volumes of antimony concentrate from its newly-launched high-grade antimony-rich ore processing at Mill-1 during the March quarter, although no shipments to foreign offtakers were made before May, and the total cash costs did not reflect any by-product credit.

Net cash inflow from operations dropped 7.4% on the year to $261 million, while capital expenditure rose 39% to $182 million due to higher spending at Natalka, Verninskoye and Kuranakh.

It ended the March quarter with $1.1 billion, compared to $1.5 billion a year ago and $1.2 billion at the end of December due to an early repayment of certain credit facilities.

Net debt on March 31 was $3.1 billion, relatively steady from the end of the March 2017 and December 2017 quarters.

As previously reported, total gold output for the quarter from all operations rose 13% year-on-year to 506,500 ounces.

Polyus CEO Pavel Grachev said the company remained on track with all its initiatives. Natalka continued to ramp up ahead of expectations, with its operations at 80% of the design processing capacity.

"We are progressing with the drilling campaign and engineering works at Sukhoi Log, and are also working on efficiency improvements across our existing operating assets," he said.

He kept the company's full-year gold production guidance at 2.375—2.425 million ounces.