Newmont Corp. shares fell the most in four months as the world’s biggest gold miner grapples with operational challenges and accelerating cost gains.

The Denver-based company churned out less bullion and profit than expected last quarter. In a report Thursday, it also lowered annual output guidance while raising its projection for costs.

Mining companies are navigating lingering operational restrictions in the pandemic. At the same time, tight labor markets and pricier freight, energy and other inputs are pushing up costs as supply-chain snarls continue to impact shipping of everything from bulldozers to iron ore. Those headwinds are hitting bullion producers harder than base metal miners given gold prices are down from a year ago.

Newmont cut its full-year guidance to 6 million ounces from 6.5 million ounces, citing difficulties at its mines in Boddington, Western Australia, and Nevada, as well as the continued impact from the pandemic in Canada and Australia.

That’s after third-quarter output slipped to 1.45 million ounces versus the 1.6 million-ounce average estimate. Heavy rain at Boddington disrupted a switch to autonomous trucking.

Production is expected to increase about 5% next year, with costs likely to be in line with 2021 levels, Chief Executive Officer Tom Palmer said on a call with analysts.

The company’s all-in sustaining cost jumped to $1,120 an ounce versus consensus of $1,024. It now projects $1,050 for the year from $970 previously.

Newmont reported adjusted earnings of 60 cents a share for the quarter, down from 86 cents a year ago and missing the 74-cent average estimate among analysts.

The company’s shares fell as much as 5.3%, the steepest intraday decline since mid-June.