Mining Engineering Gate 2018 Questions with Answer

Ques 53 GATE 2018

Air enters a bord and pillar panel at 10 ppm CO and 20.78% O₂. The air at the panel return has 80 ppm CO and 20.52% O₂. The 'Graham's ratio' for the status of fire in the panel in % is _______.

Ques 54 GATE 2018

In a sublevel stope, 20 m high excavation is made with ring drilling in a 6 m wide orebody. In an effective shift time of 6 hrs, three rings are blasted resulting in 9 m extraction length. LHDs of 5.0 m³ bucket capacity and cycle time of 5 minutes are used for ore transportation. The number of LHDs required for this operation is __________.

Ques 55 GATE 2018

A coal seam lying at a depth of 200 m is developed by bord and pillar method. Pillars are 30 m centre to centre with a gallery width of 4 m. Unit weight of the overlying strata is 28 kN/m³ If the pillar strength is 9.32 MPa, the factor of safety of pillar is ___________.

Ques 56 GATE 2018

Following information about a longwall retreating panel is given.
Panel length =1800 m
Face length =150 m
Depth of web=0.6 m
Shearer travels at a speed of 1.5 m/min along the face. Each cutting cycle requires a non-operational time of 2 h 20 min. The panel is fully extractable. The number of working days required to extract the panel is ________.

Ques 57 GATE 2018

In a direct rope haulage operating along a 1500 m long incline, 180 tonne of coal is hauled in 7 hours. The average rope speed is 7.5 km/h. The set changing time for the tubs is 2 minutes each at the top and bottom of the incline. If the tub capacity is 1.0 tonne, the number of tubs in the set is __________.

Ques 58 GATE 2018

An SDL of 1.0 tonne capacity operates with a cycle time of 6 minutes. The dimension of the face is 4 1 m×3 m. Five blasts are conducted per shift with an average pull of 1.2 m. If the density of blasted coal is 0.8 tonne/m³, the time required by the SDL in the shift to lift all the prepared coal in hours is __________.

Ques 59 GATE 2018

The experiment to determine permeability of a soil sample is illustrated below. The cross-sectional area of the sample is 20.0 cm². The permeability of the soil sample in cm/s is _________.

Ques 60 GATE 2018

In underground face blasting, the pull is found to be 10% less than the drillhole length. The headings of 3.6 m width are supported by prop density of 1.44/m². The hole length is 1.5 m, and 6 rounds of blasting are done in the panel per shift. The number of props to be erected in a shift is ____________.

Ques 61 GATE 2018

The immediate roof of a mine is supported by bolts of length 1.5 m, arranged in 1.2 m×1.2 m grid pattern. If the unit weight of roof rock is 2.25 tonne/m³ and load carrying capacity of each bolt is 7.5 tonne, the factor of safety of the support system is ___________.

Ques 62 GATE 2018

In a level terrain, a vertical orebody of 20 m uniform width is worked by surface mining method. The density of the ore is 2.5 tonne/m³. The ultimate pit has a depth of 60 m, width of 20 m at pit bottom, and a pit slope of 45° The overall stripping ratio for this condition in m³/tonne is _____________.

Ques 63 GATE 2018

A 20 m long steel tape used for survey is found to be short by 10 cm. If the area measured with the steel tape is 5000 m² the actual area in m² is ___________.

Ques 64 GATE 2018

The following figure shows the designed blast pattern of a bench. The explosive column is charged at 18 kg/m. If the unit weight of the blasted material is 2.5 tonne/m³, the powder factor for the blast in tonne/kg is _____________.

Ques 65 GATE 2018

Two points on the equator have longitudes 55°E and 25°W. Considering radius of earth as 6400 km, the distance between the two points in km is ___________.