
strip mining, removal of soil and rock (overburden) above a layer or seam (particularly coal), followed by the removal of the exposed mineral. the common strip-mining techniques are classified as area mining or contour mining on the basis of the deposit geometry and type. the cycle of operations for both techniques consists of vegetation clearing, soil removal, drilling,pa mining history,coal mining in pennsylvania pa mining history. room-and-pillar mines have been active in pennsylvanias bituminous coalfields since the late-1700s. bituminous coal was first mined in pennsylvania at coal hill (mount washington), just across the monongahela river from the