veine de grès

CONT: Il ont évalué diverses solutions au problème d'inflammation par frottement associé aux veines de grès et à d'autres structures favorisant les incendies dans le filon de charbon, le plancher et le plafond immédiats.

CONT: Frictional Ignition Control. Frictional ignition continues to be a major problem when sandstone channels are encountered. Water jet assisted road headers, diamond insert pick trials, and thru-flush pick trials are attempts to reduce or control frictional ignition problems associated with drag-style bit cutting.
CONT: [Researchers] evaluated options available to deal with frictional ignition problems caused by sandstone channels and other incendive structures within the coal seam, immediate roof, and floor.