For an adequate design of the shortwall face support, it is necessary to understand fully the support-roof interaction. A series of studies has been carried out at a shortwall panel to develop the methods of monitoring support resistance and determining load density of the chocks. Various aspects of applications, for improvement of chock design and understanding of roof conditions, are discussed.
Shortwall mining method is a relatively new technique in the United States coal mining industry. In comparison with longwall mining method, its development and application are not encouraging ¹, ². One o f the major causes of unsuccessful operation comes from ground control problems. The lack of understanding of the support- roof interaction resulted in improper chock design. A series of studies has been carried out at the shortwall panel in Valley Camp No. 3 Coal Mine near Triadelphia, WV. The methods of monitoring support resistance and determining load density of the chocks were developed, and their applications are discussed in this paper. Shortwall Minimum at Valley Camp No. 3 Mine Valley Camp No. 3 Mine is located in the northern panhandle of West Virginia. The thickness of the coal seam (Pittsburgh Seam) ranges from 5 to 6 feet. The shortwall panel, located under rugged and hilly topography, has an overburden whose thickness ranges from 800 to 950 feet. 2he typical stratigraphic columns are shown in Fig. 1. The shortwall panel was 150 feet wide by 2,655 feet long. The panel employed retreating shortwall mining method with advancing tail entry (Fig. 2). In the head entry side there were 6 rows of chain pillars, while the tail entry was constructed by setting cribs in a regular interval as the face advanced. As shown in Fig. 2, roof falls occurred frequently at the cross- cut areas.
