A grassfire at the proposed Ajax mine site was started by workers surveying mineralization as part of a geological investigation needed for the permit process, community relations spokeswoman Robin Bartlett said Tuesday.
"The exact cause is not yet determined. We're investigating further to pinpoint the cause and to prevent it from happening it again."
She was not able to say what the workers might have been doing Monday morning that could have caused a fire.
The fire was at first reported to be two hectares but grew to 4.4 hectares before it was extinguished by an Ajax crew.
Kamloops Fire Rescue was called, but the blaze was under control by the time they arrived. Three firefighters from the Kamloops Fire Centre's initial attack crew also drove to the scene.
The fire was not near any buildings and there were no injuries.