NSW Rural Fire Service (RFS) crews responded to four fires caused by lightning strikes on Friday.
A number of units are currently at Bowmans Creek Road, east of Muswellbrook, which is estimated to cover 100 hectares.
At this stage, the fire is under control, according to the NSW RFS website.
Mount Pleasant Public School is not under threat.
Meanwhile, a grass fire at Ravensworth mine, Hebden Road, has reached six hectares.
Mine staff and two NSW RFS trucks have attended the scene.
Another fire, at Hebden Road, Hebden, is also under control.
Earlier on Friday, the RFS sent one unit to a fire at Dartbrook mine, who extinguished the blaze in a short time.
To keep up to date, go to www.rfs.nsw.gov.au/fire-information/fires-near-me