A rectangular shaft 10 ft by 20 ft with the long axis parallel to the N–S line exists at a depth of 950 ft. The mining plan calls for deepening the shaft to 1,800 ft. The premining stress state relative to compass coordinates is: SE = 350 + 0.2h, SN = 420 + 0.35h, SV = 1.12h where stresses are in psi, h=depth in ft, E, N, V refer to compass coordinates (x = east, y = north, z = up) and compression is positive. Premining shear stresses are nil relative to compass coordinates. Rock properties are: Co = 23,700 psi, To = 1,480 psi, E = 5.29(106 psi), ν = 0.27, γ = 162pcf. A second shaft of identical shape is also planned to the new depth of 1,800 ft. Show a location and orientation (plan view) of the two shafts that is most favorable with respect to stress concentration and explains the basis of your choice.