The influence of geology on blast damage
The geological features of a rock mass have a direct influence on its blasting characteristics.
It has been observed that perimeter control techniques provide excellent results in massive crystalline formations but may give poor results in weak and or highly jointed formations.
A field study was conducted with the objective of understanding the role played by the geological features of a rock mass in producing and controlling blast damage. The field work involved the assessment of blast damage at several operating mines and the blasting of drift rounds in a geologically dominant rock mass.
The effect of rock strength, rock quality designation (RQD), joint parameters and hydrogeological
conditions on blast damage is described below. The influence of number and thickness of weak layers on blast damage is also discussed below on the basis of quantitative data. In addition, critical particle velocity ranges for damage to different rock types have also been outlined in this paper.
KEYWORDS: Rock mass, Blast damage, Half cast factor, Blast vibration.