Underground Coal Mining Technology Mid - I, September - 2014

1.The minimum thickness of the coal seam for adopting Bord and pillar method of mining?
  • 1.0 m
  • 1.5 m
  • 2.0 m
  • 2.5 m
Answer: B
2.The stowing efficiency in hydraulic sand stowing?
  • 50%
  • 73%
  • 60%
  • 70%
Answer: B
3.The line of extraction is best suited for hydraulic sand stowing is?
  • Step diagonal
  • diagonal 45°
  • parallel
  • diagonal 60°
Answer: A
4.The max width of the gallery in Indian coal mines is....?
  • 3m
  • 4m
  • 4.8m
  • 5.5m
Answer: C
5.The minimum pillar distance from center to center; if the depth of seam is 450m and gallery width is 4.8m?
  • 39m
  • 45m
  • 48m
  • 52m
Answer: C
6.The method suitable for workings seam under the surface containing valuable property water bodies for whose protection some coal is left unworked is?
  • Longwall retreat
  • Bord and pillar
  • Hydraulic mining
  • Longwall advancing
Answer: B
7.In deciding the size of the panel the important factor to be considered is?
  • thickness of the seam
  • output required
  • depth of the seam
  • incubation period
Answer: D
8.The daily advance in development of galleries by continuous miner?
  • 20m
  • 30m
  • 40m
  • 50m
Answer: C
9.The minimum life of the mine should be more than.....years for adopting horizon mining?
  • 10
  • 20
  • 30
  • 40
Answer: C
10.The holes in BG method are inclined....deg from the vertival towards the goaf?
  • 20
  • 35
  • 45
  • 60
Answer: B
11.Taylor’s mine life rule, Life (years) = _______________________________.
Answer: 0.2 × (expected ore tonnage)1/4 or (1±0.2)×6.5×(tonnage in millions)1/4
12.In BG method the supports are installed up to __________________m from the face
Answer: 40m
13.SDls are used in the coal seams having gradient ______________.
Answer: 1 in 3
14.Split means __________________________________________________.
Answer: Support for making small pillars (Big pillar into two pillars)
15.The precautionary measure against air blast is ________________________.
Answer: Constructing stoppings
16.Stowing means ___________________________________.
Answer: Filling up voids with sand
17.As per Indian standards thick seam means having seam thickness _____________ to _______________.
Answer: 4.5 to 9m
18.The shape of the pillar in steep seams for haulage and loading and in flat and inclined seam for adoption of high capacity machinery like shuttle cars and locomotive is ___________________.
Answer: Rhombus
19.Dividing the coal seams in to no of Pillars by driving road ways at right angle up to the boundaries is called _________________.
Answer: Bord and pillar
20.The panel shall be such that, it is extracted within __________________.
Answer: Incubation period