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APPENDIX A <br /> Height of collapse-chimney equation (Whittaker and Reddish,1989) <br /> z = (k_ 1)(n)(d2) (2(w)(hz) cot(0) + h(w2)) <br /> k = bulking factor <br /> z = height of collapse-chimney <br /> d = diameter of collapse-chimney <br /> w = width of mined roadway <br /> h = height of mined roadway <br /> 0 = angle of repose of caved rock <br /> Variables for an 18 feet wide roadway: <br /> k = 1.33 <br /> z = variable solved for <br /> d = 7.8m <br /> w = 5.5m <br /> h = 3.35m <br /> 0 = 35' <br /> Variables for a 34 feet diagonal intersection: <br /> k = 1.33 <br /> z = variable solved for <br /> d = 10.3m <br /> w = 7.3m <br /> h = 3.35m <br /> 0 = 35' <br />