A new technical and economic model to calculate specific charge and specific drilling using hole diameter, height bench, uniaxial compressive strength, and joint set orientation

Calculation of the specific charge and specific drilling before blasting operation play a significant role in blasting pattern design and reduction of the final extraction cost of minerals. Information from Sungun, Miduk and Chah-Firouzeh copper mines in Iran was assessed, and found that there is a significant relationship between specific charge and specific drilling with hole diameter, bench height, uniaxial compressive strength and joint set orientation and tested this model in Sungun copper mine. Due to insufficient consideration during the design of the blast pattern and because of the high hardness in the rock in some parts of the mine, lots of destructive events such as boulders, back break, bench toe, high specific charge and high specific drilling, fly rock and ground vibration in the blast operation were observed. The specific charge and specific drilling are the most important technical and economic parameters in designing the blasting pattern and play an important role in reducing the cost of blasting. The blasting cost could be largely controlled by the accurate examination and computation of these parameters. Based on this model, an increase in the rock strength and the angle between the bench face and the main joint set will increase the specific charge and specific drilling. On the other hand, the specific charge and specific drilling will decrease when the hole diameter increases in every range of uniaxial compressive strength.