Question 41. For a shrinkage stope the following data values are givenInsitu tonnage                   9000 tonneInsitu grade                       5.2 g/tonneAverage grade of waste  1.4 g/tonneLoss of ore in the stope  10%Dilution                              20%The grade at the mill-head in g/tonne is ________

Question 42. The boundary of a mine is plotted on a scale of 1:2000. If a planimeter measures the plotted area as
58 cm2, the actual mine area in m2 is

Question 43. In an experiment to determine specific gravity of a soil sample, the following data is obtained:Mass of empty pycnometer                                                   20.4 gMass of pycnometer with soil sample                                 51.6 gMass of pycnometer with soil sample filled with water   88.6 gMass of pycnometer filled with water                                 70.4 gThe specific gravity of the sample is __________

Question 44. A cylindrical rock specimen of diameter 54 mm has Young's modulus of 68.97 GPa and Poisson's
ratio of 0.35. The rock specimen fails in uniaxial compression at a lateral strain of 0.01%. The axial
load at failure in kN is __________

Question 45. A surface miner with 2.0 m cutting drum width excavates coal in windrowing mode from a bench
with effective face length 200 m. The cutting speed of the surface miner is 10 m/min and the
cutting depth 25 cm. The density of coal is 1.4 tonne/m3. If the average turning time of the machine
at the face end is 5 min, the rate of production in tonne/hour becomes ____________

Question 46. Given the following differential equation d2y/dx2 + 7 dy/dx + 12y = 0 the general solution is

Question 47. Given the following,Excavating/loading machine     Transportation schemeP Bucket Wheel Excavator        1 Mine tubQ Continuous Miner                  2 Armoured flexible chain conveyorR Shearer                                     3 Shiftable ConveyorS Load Haul Dumper                 4 Shuttle carthe correct match is

Question 48. The uniaxial compressive strength of a limestone sample is 80 MPa. The sample is confined at a
pressure of 20 MPa in a triaxial compressive strength test. Based on Hoek-Brown failure criteria
the maximum principal stress at failure in MPa is (consider rock constants as m = 7.88, s = 1.0 and a = 0.5)

Question 49. Given the following,Mining method                              TechniqueP Thick seam extraction             1 Double unit faceQ Bord and pillar extraction      2 Jet cuttingR Longwall face development   3 Inclined slicingS Hydraulic mining                      4 Half moon methodthe correct match is