What are the common blasting methods used in open pit mines?

Commonly used blasting methods in open pit mines include deep hole blasting, shallow hole blasting, chamber blasting, pot blasting, and overburden blasting.

Shallow hole blasting is mainly used for blasting operations of small open pit mines and auxiliary blasting operations for large and medium-sized mines. The shallow hole has a depth of 3 to 5 m and a pore diameter of 25 to 75 mm.

Deep hole blasting is the main blasting method commonly used in medium and large open pit mines, and some small open pit mines are also used. The depth of the deep hole is generally 10 to 15 m and the hole diameter is 75 to 300 mm.

Chamber blasting is mainly used for open pit mine infrastructure and some special circumstances. A few quarries with small piercing capacity also use chamber blasting as the main means of production blasting.

The medicinal pot blasting is used under the difficult conditions of perforation to reduce the drilling workload and overcome the large resistance line. It is generally used in combination with shallow hole blasting to reduce the bulk rate.

Overlay blasting (also known as paste gun) is a method of blasting a certain amount of explosive on the surface of the rock, mainly used for secondary crushing and root treatment.