Explosives, Accessories and Blasting Practice – 2

1. In hard rocks the spacing and burden vary from ......times the height of the bench?

2. The rate at which the detonation wave passes through the column of explosive is called?

3. Which explosive is blasted by safety fuse?

4. The permitted explosive used in u/g in BOS of all gas mines?

5. To get lumpy coal or to minimize the coal dust the blasting technique adopted is?

6. The main element in Fuse head of detonator is..?

7. The explosive charge per hole in BG method?

8. To control the fly rock the blasting technique adopted is?

9. To avoid freezing of NG explosive which agent is mixed?

10. Hazard performance initiation propagation are related to one of the characteristics of an explosive?

11. The VOD of LOX?

12. The pattern of cut mostly preferred for laminated strata is?

13. The PETN booster occupies only ....% of the total explosive charge?

14. The current required for the ignition of the fuse head is?

15. The amount of energy released by an explosive during blasting is called..?

16. Which is the low density explosive?

17. The delay period between 2 consecutive shots with different delay numbers will not exceed?

18. The important characteristic of an explosive which will give an idea about heat and humid condition and time of exposure?

19. The pattern of cut mostly preferred in tunnels and drifts of small area is?

20. In general each shot hole in round u/g covers an area of (sq.m)?

21. The composition of Gunpowder is (charcoal:sulphur nitrate in %)?

22. The process of conversion of chemical energy into heat and mechanical energy is called...?

23. For irregular ore bodies the preferred drilling pattern is?

24. The elements in the delay element of short delay detonator?

25. The peak particle velocity should not increase ...mm/sec?

26. Safety tests are carried out for?

27. Shuttering effect is obtained with the explosive having?

28. While using non-incentive delay detonators in BOS the max delay period (milliseconds) between 1st and last shot in deg 1 and 2 is 'X' and deg 3 is 'Y'. Then X is?

29. Relieving hole should be drilled at least ....m away from the misfired hole in u/g?

30. The powder factor with solid blasting is (te of coal/kg of explosive)?

31. In controlled blasting the fly rock should not go height more than?