How is the powder factor defined?

• A. Divide the pounds of explosives into the amount of fly rock produced
• B. Divide the fly rock by the pounds of explosives
• C. Multiply pounds of explosives by fly rock
• D. Sum of pounds of explosives and fly rock

Answer: (A)

Powder factor is a measure of how much rock is produced for each unit of explosive used. It is calculated by dividing the amount of fly rock produced by the pounds of explosives. This gives a ratio of rock per pound of explosive (often expressed in cubic yards per pound or cubic meters per kilogram). It helps you judge blast efficiency and predict fragmentation: a higher powder factor means more rock per pound of explosive (rougher fragmentation, and potentially different movement), while a lower factor uses more explosive per volume to achieve finer fragmentation. The idea is about the output per unit input, not about multiplying or adding amounts, or using the inverse ratio.