Evaluationg the Ventilation of a 40-Foot Two-Pass Extended Cut

摘要

About one-half of all mechanized mining units in the United States use extended211u001ecutting, advancing more than 20 ft past the last row of bolts. Little is known 211u001eabout what happens to the ventilation of the 40-ft box cut when the continuous 211u001eminer backs out of the box cut to begin the slab cut. To gain some understanding 211u001eof the ventilation of the box cut on a two-pass 40-ft extended cut, researchers 211u001eat the National Institute for Occupational Safety and Health's Pittsburgh 211u001eResearch Laboratory (PRL) undertook a full-scale study. Tests were conducted to 211u001edetermine how the location of the mining machine and other operating conditions 211u001eaffect the quantity of fresh intake air reaching the box-cut face during a 40-ft 211u001etwo-pass extended-cut mining sequence. Two series of tests were conducted in the 211u001ePRL methane test gallery to determine---How much fresh intake air reaches the box-211u001ecut face during various phases of the extended-cut mining sequence; How the 211u001eamount of fresh intake air reaching the box-cut face is affected by operation 211u001econditions; and How airflow to the box-cut face can be increased.