Mumbai University > Civil Engineering > Sem 8 > Construction Engineering

Marks: 5Marks

Sometimes blasting is to be performed to loosen rock in order that it may be excavated or removed from its existing position. Blasting is accomplished by discharging an explosive that has been placed in a hole specially provided for this purpose.

After a hole is filled with an explosive to the required depth, the remaining portion of the hole should be filled with stemming. Stemming, which may consist of rock cuttings or other suitable inert material, confines the energy and increases the effectiveness of the explosion.If a continuous charge of explosion is not required from the bottom to the top of the charge, stemming may be placed between charges at predetermined intervals.When charges are separated with stemming, a separate primer should be provided for each charge. The following figure illustrates several methods of loading boreholes for firing the electric blasting caps.