'Coal dust is very explosive, so mines are sprayed with "dust" from this common calcium-rich sedimentary rock'
limestone
COAL RIDGE: Coal dust is very explosive, so mines are sprayed with dust from this common calcium-rich sedimentary rock
Coal dust is very explosive, so mines are sprayed with "dust" from this common calcium-rich sedimentary rock
Coal dust is very explosive, so mines are sprayed with "dust" from this common calcium-rich sedimentary rock
COAL RIDGE
limestone
COAL RIDGE