BHP Group, the world’s biggest mining company, reported quarterly iron ore shipments fell 8% from the previous three months as production was affected by coronavirus-related manpower issues and planned maintenance. 

Total iron ore sales from its Western Australia operations were 67.1 million tons in the three months to March 31, BHP said Thursday in a statement, meeting a median forecast of 67.2 million tons among five analysts. Full-year guidance for attributable output was held at a range of 249 million tons to 259 million tons, although the company cut forecasts for copper and nickel production.

BHP said the lower volumes from its Western Australian iron ore operations reflected “temporary labor constraints due to Covid-19, train driver shortages and planned maintenance activities.” Compared with the year before, quarterly iron ore shipments were little changed from 66 million tons.

Like some other miners, BHP faces headwinds from growing cost pressures and increased investor scrutiny of its management of environmental, social and governance issues. Still, the surge in commodity prices, exacerbated by Russia’s war in Ukraine and supply chain issues, could help cushion some of the impact. 

“Market volatility and inflationary pressures have increased further as a result of the Russian invasion of Ukraine,” Mike Henry, BHP’s chief executive officer, said in the statement. “While we expect conditions to improve during the course of the 2023 calendar year, we anticipate the skills shortages and overall labor market tightness in Australia and Chile to continue.” 

BHP’s report comes after rivals Rio Tinto Group and Vale SA announced a drop in shipments and production in the year’s first quarter. Rio said the current inflationary environment was unlike anything the global economy had witnessed in almost half a century, creating growth risks for the steel-making ingredient’s key consumers.

While BHP’s full-year guidance remains unchanged, it said iron ore production in the June quarter was expected to be impacted by “continued Covid-19 related absenteeism as Western Australia approaches anticipated peak case numbers, and planned car dumper maintenance.”

Output across BHP’s copper mines was 1% higher than the previous three months, but the financial year-to-date total was down 10%, partly due to a “challenging” operating environment in Chile as Covid-19 cases increased.

The company in August agreed to merge its oil and gas business with Woodside Petroleum Ltd. and said earlier this month that completion of the deal is on track and targeted for June 1.

BHP’s Sydney-traded shares have climbed 26% this year, compared with a 18% advance for top rival Rio Tinto. BHP’s production report was published before Thursday trading began in Australia.