Determination of In situ Horizontal Rock Stress on Both a Mine-Wide and District-Wide Basis

摘要

Several underground coal mines currently operating in the Beckley district of West Virginia are experiencing serious roof and floor problems. A significant portion of the estimated 2 billion tons of coal resources may be lost as a result of these ground control problems. Preliminary studies by the Bureau of Mines indicated that these are due in part to a high horizontal stress field. Using the Bureau's strain-relief overcoring technique, 14 overcoring sites in five mines were drilled producing 53 data sets. Analysis of the data was done to provide in situ horizontal stresses for each of the five mines and for the district as a whole. Stress data indicate horizontal stresses far in excess of that predicted by theory and in some cases, up to six times the estimated vertical stress.