EVALUATING THE RELATIONSHIP BETWEEN MOISTURE INDUCED EXPANSION AND HORIZONTAL STRESS ORIENTATION IN SAMPLES FROM THE NONESUCH SHALE FORMATION

High horizontal stresses can cause numerous ground control problems in mines and other underground structures ultimately impacting worker safety, productivity and the economics of an underground operation. Mine layout and design can be optimized when the presence and orientation of these stresses are recognized and their impact minimized. A simple technique for correlating the principal horizontal stress direction in a rock mass with the preferential orientation of moisture induced expansion in a sample of the same rock was introduced in the 1970s in the White Pine Mine, in White Pine, Michigan and has since gone un-reported and unused. This procedure was reexamined at a locality near the original test site at White Pine, Michigan in the Nonesuch Shale formation in conjunction with the proposed opening of a new copper mine in the area. This was done in order to validate the original research and consider its usefulness in mining and civil engineering applications in high horizontal stress conditions. This procedure may also be useful as an economical means for characterizing regional stress fields for comparison with World Stress Map data.