Yamana said the exact cause of the accident, that involved two employees of a local contracting company on an access road to the Las Vacas exploration site, was not yet known.
The Buenos Aires-based heavy equipment rental company had worked with Yamana at Gualcamayo for more than five years and Yamana COO and executive vice president Daniel Racine said the pair were well-known at the operation.
"On behalf of everyone at Yamana, our deepest sympathies and thoughts are with the families and friends of those involved in this tragic accident," he said.
The company is working with local authorities and the contractor to investigate the cause.
Gualcamayo produced 154,000 ounces of the company's total gold production for 2017 of 977,000oz, and the company last month announced it had beat guidance for its gold, copper and silver production.