CONTROLLING SHIELD DUST
Over the last several years, advances in longwall mining technology have resulted in more powerful and faster shearers capable of mining at cutting speeds exceeding 100 fpm. This also requires shields to advance at a faster rate. As shield supports are lowered and advanced, crushed coal and/or rock fall from the top of the shield canopy directly into the airstream ventilating the longwall face. Shield advance has become automated and is now initiated by the shearer position. Shields are typically being advanced within two or three shields of the trailing shearer drum. As a result, shield movement can be a significant source of dust exposure for shearer operators when shields are advanced upwind of the shearer during head-to-tail passes. Following is a discussion of observed spray systems that offer potential solutions for shield dust control.