ABSTRACT
This chapter is the result of a Bureau of Mines program to characterize roof conditions near outcrop in drift coal mines of eastern Kentucky. It was centered in MSHA District 6 in eastern Kentucky. While collecting data for information on roof instability near outcrop in drift mines, the origin of weathered joints that decreased in both degree of weathering and frequency of occurrence as the distance from outcrop increased became a puzzle. Stress relief joints in eastern Kentucky are nearly vertical and perpendicular to the bedding planes, allowing groundwater to percolate downward from the surface. The occurrence of stress relief joints and weathering near outcrop are crucial drift mine ground control factors in the region. In addition to contributing to roof falls in underground coal mines, strip mine highwall stability can also be adversely affected.
