Features of Rock Blasting and Control

Flyrock is the rock that is launched into the air and travels further than was intended by the blast design. Flyrock can cause considerable damage.

Blasting Mats are used to help control flyrock (Figures 7 and 8). These are very heavy mats usually made from rubber tires, conveyor belts, steel cables, or other similar materials. Blasting mats are of particular use where flyrock may damage buildings or other structures.

Heave (also called Throw) is the distance the rock displaces from the in-situ condition due to blasting.

Powder Factor is the ratio between the weight of explosives that have been detonated and the total volume of rock that was blasted. For construction practice, this volume is measures in cubic yards or cubic meters. The powder factor of the blast includes the total weight of explosives and the total volume of rock above grade level. The powder factor should always be reported on construction monitoring documents. The units of powder factor are pounds per cubic yard or kilograms per cubic meter.