PDF United States Department of Labor Mine Safety and Health Administration
angle, pillar geology, coal cleat and longwall panel orientation, and inadequate rib control. The depth of cover over much of the G longwall panels is some of the deepest cover (over 1,000 feet) that has historically been encountered in the Pittsburgh seam. The depth of cover was 1,040 at the scene of the accident and the mining height was 8½ ...