M. S.

The Appalachian coal fields contain many contiguously placed seams of coal. Mining in these seams has been active over such an extended period of time that considerable knowledge has been gained in the area of multiple seam mining. It is commonly accepted that the preferred sequence of extracting contiguous seams is in descending order. However, in the past, selection of the mining sequence has been based primarily on seam ownership, availability and economics, not on ground control considerations. One of the major ground control mechanisms that must be considered in mine design, when contiguous seams have not been extracted in descending order, is subsidence. This investigation examines the affects of subsidence not on the surface but on mineable seams of coal lying above the seam that has been extracted. Case studies were collected from the Appalachian region. These studies were analyzed to determine which factors could be correlated with damage. An empirical model was then developed to predict when interaction problems caused by subsidence will noticeably effect mining in an upper seam. / M.S.