Category: Drilling and Blasting

• Critical diameter
• Optimal diameter
• Rapid burning but not an explosion
• Change in the inclination of drill hole

• Rapid explosion
• Burning and explosion
• Rapid burning but not an explosion
• Change in the inclination of drill hole

• Two blast holes in same row
• Distance between two holes blasted at same delay
• Distance between first row of blast holes and bench crest
• Distance between two holes blasted in consecutive delay

• As a primer with the bulk SME explosives
• As a primer in underground coal mine
• As a primer in blasting-of the solid
• None of the above

• (a) Velocity of Detonation (mm/s)
• Density (gm/cc)
• Compressive strength (MPa)
• Weight strength (Jule/g)

Chemical                                    Purpose
P- Calcium nitrate               1- Cross linking agent
Q- Potassium dichromate 2- Gelling agent
R- Diesel oil                          3- Oxidizer
S- Starch                               4- Fuel

• P-1, Q-2, R-3, S-4
• P-2, Q-4, R-3, S-1
• P-3, Q-1, R-4, S-2
• P-4, Q-3, R-2, S-1

• Detonating fuse Nonel Electronic detonator
• Electric detonator Nonel Detonating fuse
• Electric detonator Detonating fuse Nonel
• Electronic detonato Detonating fuse Nonel

Blasting Elements                            Initiator
P- Electric detonator                     1- Match stick
Q- Safety fuse                                 2- Booster
R- Detonating fuse                        3- Exploder
S- Non cap-sensitive explosive   4- Ordinary detonator

• P-2, Q-3, R-4, S-1
• P-3, Q-1, R-4, S-2
• P-3, Q-1, R-2, S-4
• P-1, Q-4, R-2, S-3

• It has greater shock to the surrounding
• It is noiseless in character
• It deflagrates explosive column
• It cannot be used in a place where there is a chance of stray current

• Ammonium nitrate, TNT, NG
• Ammonium nitrate, TNT, guar gum
• Ammonium nitrate, NG, water
• Ammonium nitrate, water, hollow micro-balloons.