Very large smoke plume on Fielder Mountain

A very large plume of smoke, presumably from a large fire, shot up from the slopes of Fielder Mountain above I-5 near the small city of Rogue River, Or. today shortly after 3:00 pm. The smoke appeared to originate from the vicinity of a quarry operation known to use explosives in its mining process. The column of smoke was approximately twice the size of that caused by a burning three bedroom house. The cause of the fire could not be ascertained from this location but the color of the smoke was alternately white to dark, dirty gray with only hints of petroleum black. Most such mining operation use ammonium nitrate/fuel explosives which are also highly combustible in open air. Speculation is running in that direction as to the cause.