Effects of some blast design parameters on ground vibrations at short scaled distances

Blast design components: primer location, collar stemming, charge weight and hole diameter, were varied during three independent investigations to study their effects on the generation of ground motion, air blast and fly rock over small scaled distances.

The location of the primer in the explosive column, charge weight and charge diameter, were found to have the greatest effect. Furthermore these studies also indicated that:

• (1)

  borehole pressure is the major source of induced ground motion;

• (2)

  as long as the air blast is controlled, it is quite likely that ground vibrations will remain at minimum levels;

• (3)

  air blast and fly rock effects resulting from the collar priming are expected to be greater than those resulting from bottom priming of the explosives.