A 3.7 × 7.4 m rectangular shaft is sunk to a depth of 914 m in ground where the premining stress field is given by formulas, Sv = 27.2h, Sh = 828 + 11.3h, SH = 22, 345 + 6.8h, where h is depth in m and the stresses are in kPa. Show by sketch, the best orientation of the shaft relative to the directions of h and H. Is this the best orientation at all depths to 914 m? If mine expansion plans call for two additional shafts of the same size, show by sketch the position and orientation of these additional shafts. Explain.