SUPERIOR — Crews battling the West Mullan Fire have made good progress in keeping it from burning into Superior, but some structures still remain threatened on the northwestern part of the blaze.

Fire information officers say the fire, which started Sunday, had burned an estimated 4,550 acres, or just over seven square miles, by Friday morning.

Fire information officer Greg DeNitto says he thinks the residents of Superior are resting a little easier now that crews have about 6 or 7 miles of fire line along the southwestern edge of the fire, parallel to the Clark Fork River.

Work Friday will include efforts to prevent the northwestern edge of the fire from burning across Keystone Creek and getting the southeastern edge of the fire to burn fuels down to a fire line near Flat Creek.