Mine Supports And Strata Control - Study Mode

Show All Answers

[#171] It is a good practice to keep . . . . . . . . m of coal intact near a shaly roof during development

(A) 0.2

(B) 0.3

(C) 0.6

(D) 0.8

Correct Answer

(C) 0.6

[#172] The value of the threshold convergence in long wall mining is . . . . . . . . mm/m.

(A) 30

(B) 40

(C) 50

(D) 60

Correct Answer

(B) 40

[#173] Method of estimation in which shape and size of ore can be estimated called

(A) Boring

(B) Propspecting

(C) Exploitation

(D) Exploration

Correct Answer

(B) Propspecting

[#174] The hydraulic oil used in hydraulic prop may be water with . . . . . . . .% of suitable oil.

(A) 5%

(B) 10%

(C) 20%

(D) 40%

Correct Answer

(B) 10%

[#175] Which kind of roof weathers quickly when exposed to atmospheric action and spalls off.

(A) shale

(B) sand stone

(C) clay

(D) coal

Correct Answer

(A) shale