PERTH (miningweekly.com) – Mining giant BHP has reduced its full-year production expectations for its Pilbara iron-ore operations, as well as the Olympic Dam mine, in South Australia.

The miner on Thursday reported a 6% drop in iron-ore production during the three months to March, compared with the previous quarter, reflecting the impact from Cyclone Joyce and unplanned car dumper maintenance.

Total iron-ore production for the nine months ended March increased by 2%, to a record 175-million tonnes, BHP told shareholders.

However, the miner has reduced its iron-ore production guidance for the full year from the previous estimate of between 239-million tonnes and 243-million tonnes, to between 236-million tonnes and 238-million tonnes.

BHP on Thursday reported that petroleum production for the three months to March was also down 8% on the previous quarter, to 45-million barrels of oil equivalent, as operations were impacted by severe weather and natural field decline.

Petroleum production for the nine months ended March was also down 8%, to 143-million barrels of oil equivalent, with BHP maintaining its full-year guidance for the petroleum assets of between 180-million and 190-million barrels of oil equivalent.

The miner told shareholders that the exit process for its onshore US assets was progressing to plan, with the data rooms for all field and mid-stream assets now open.

BHP was expecting to receive bids for these assets by June, and would proceed with negotiations to potentially announce one or several transactions in the first half of 2019. In parallel, the company was also continuing to explore potential asset swap opportunities, as well as an exit through a demerger or initial public offering.

Meanwhile, copper production for the three months to March was up 6% on the December quarter, to 457 000 t, with year-to-date production reaching 1.29-million tonnes, up 37% on the previous corresponding period.

Copper production from the Escondida mine, in Chile, increased by 64% during the nine months under review, supported by the start-up of the Los Colorados extension project.

However, at the Olympic Dam mine, in South Australia, copper production decreased by 18% over the same period as a result of a planned major smelter maintenance campaign in the first half of the financial year.

BHP has also reduced the production guidance for the Olympic Dam operation from 150 000 t to around 135 000 t, owing to a slower-than-planned ramp-up during the March quarter. A return to full capacity is expected over the course of the June quarter.

For 2018, BHP expected copper production to be between 1.65-million and 1.79-million tonnes.

Meanwhile, metallurgical coal production during the March quarter was up by 7% to 10-million tonnes, and down by 2% in the nine months-to-date, to 31-million tonnes, while energy coal production was down 16% on the previous quarter, to six-million tonnes, and down 4% in the year-to-date, to 20-million tonnes.

BHP noted that its Queensland coal operations were affected by challenging roof conditions at the Broadmeadow operation and geotechnical issues triggered by wet weather at the Blackwater mine.

The New South Wales coal production was affected by severe weather conditions, as well as a significant build in raw coal inventory late in the quarter.

Full-year coal production has remained unchanged at between 41-million and 43-million tonnes.