51,The travelling road height should not be less than ...?,
1m,1.8m,2.5m,3m,
52,The minimum piller to piller distance if the depth of seam is 250m and gallery width is 4.2m?,
34.5m,30m,39m,45m,
53,The minimum piller to piller distance if the depth of seam is 150m and gallery width is 3.6m?,
16.5m,19.5m,25.5m,13.5m,
54,The min pillar distance from center to center;if the depth of seam is 450m and gallery width is 4.8m?,
39m,45m,48m,52m,
55,The % of extraction if the depth of seam is 300m and gallery width is 4.2m?,
11,15,17,20,
Ans: 2, 3, 2, 3, 4
No comments:
Post a Comment