Target Drilling's long boreholes maximize longwall dimensions

摘要

To address increasing ventilation and methane emission issues underground horizontal long boreholes (longholes) are utilized in the mine plan at a large Pittsburgh coal bed longwall mine. Considerations in designing the placement of long boreholes included existing mine ventilation design, reserve recovery, ventilation limitations of three entry development, belt air direction, federal ventilation criteria, longwall panel dimensions, and estimated methane liberations. Evolution to the current in-mine longhole drilling pattern, shielding gate road development is reviewed. Utilizing this technology has allowed the mine operator to successfully and profitably mine the largest longwall panels (416 acres) in the Pittsburgh Coal Seam, extending both length and width of the panels. Target Drilling Inc. employed their directional drilling technology and an experienced staff, to successfully drill all longholes utilizing two drills simultaneously. Target has directionally drilled one hundred sixteen in-mine longholes greater than 1,219 m (4,000'), in the Pittsburgh coal seam primarily shielding gate road development.