An unplanned sulfur fire occurred on the 4450 level of the C4 south wall at 6:30 am. No equipment, no structures and no miners were put in harm. There was an existing sprinkler system in the area cooling hot spots. MSHA issued a 103(j) order at 7:40 am to prevent destruction of evidence. Sprinkler system extinguished fire at 8:25 am.