A tabular ore body 4.6 m thick is mined full-seam height at a depth of 700 m by repeated slices 6 m wide and 1,520 m long, so the first drive is simply a 6 m ft wide tunnel from the rock mechanics view. Rock properties are E = 39.3GPa, v = 0.25, Co = 174.4 MPa, To = 17.9 MPa. The premining stress field is due to gravity alone. If safety factors of 2.2 in compression and 4.4 in tension are required, how many slices side by side can be safely taken?