A wildfire that started about 6 p.m. on Sunday kept Black Hills fire crews busy near Keystone.

The State Wildland Fire Office says authorities think slash pile burns got out of control and caused the wildfire just off Playhouse Road between Keystone and Hermosa.

More than 3 acres burned but no structures were damaged as of Sunday night.

Fire officials say no homes or businesses were evacuated and that firefighters had the flames mostly under control late Sunday.