(4) The angle of inclination that is virtually universally adopted for major access
openings to ensure minimum length is
(a) 14°
(b) 16°
(c) 18°
(d) 20°
(7) The use of which cutting method is seen as more environmentally preferable
in terms of dust control on a longwall face?
(a) Bi-directional cutting
(b) Uni-directional cutting
(c) Half web high seam variant
(d) Half web Kaiser cut
(8) Which of the following cutting method is more likely to cause creep on a
longwall face?
(a) Bi-directional cutting
(b) Uni-directional cutting
(c) Half web high seam variant
(d) Half web Kaiser cut
(11) Which of the following statements is incorrect?
(a) A shield support with lower set to yield ratio will allow more roof closure
before yield load is achieved.
(b) The desired effect of support stiffness is to create the minimum buffer in
terms of roof closure and time between the 'set' condition and the immediate
roof becoming stable.
(c) Support stiffness is controlled by the closure of the leg between set and yield
and the subsequent closure characteristic once yield is reached.
(d) The roof area resisted by the powered supports is minimised if the roof
support system can be kept close to the coal face and the immediate roof
allowed to cave as soon as possible.
(12) If the strata is predicted more likely to cave prematurely at the canopy rear,
which of the following supports will provide better roof stability
(a) 2-leg supports
(b) 4-leg supports
(c) 6-leg supports
(d) None of above
(13) The magnitude of the horizontal (lateral) stress has a major impact on
roadway stobility and support requirements. Which of the following
roadway alignment to lateral stress would give roadway the best stability?
(a) Parallel or at angles less than 15°
(b) At angles 30 to 60°
(c) At angles 60 to 80°
(d) Perpendicular to lateral stress
(14) For a longwall face using conventional system with the use of forepoling, the
correct right mining sequence is:
(a) Shearer passes to cut a web of coal → extend extension bar to support newly
exposed roof → advance AFC→ Advance chock and retract extension bar→
Shearer passes to cut a web of coal
(b) Shearer passes to cut a web of coal → extend extension bar to support newly
exposed roof → Advance chock and retract extension bar → advance AFC Shearer passes to cut a web of coal
(c) Shearer passes to cut a web of coal → advance AFC → Advance chock and
retract extension bar → extend extension bar to support newly exposed roof
→ Shearer passes to cut a web of coal
(d) Shearer passes to cut a web of coal → Advance chock and retract extension
bar → extend extension bar to support newly exposed roof → advance AFC
→ Shearer passes to cut a web of coal