Powder Factor is generally the kg of explosives loaded divided by the cubic metres or tonnes of rock broken.

PF = Explosives (kg) / Rock Volume (m³)

Powder factor can be calculated for a range of scenarios as follows:

Powder Factor		Explosives Mass	Volume of material (yield)
Concept PF Average parameter inputs to drill pattern and charge pattern		kg in a single hole =pi() * diameter ^2/4000 *explosives density	in-situ material broken by a single hole burden * spacing * bench height
Design PF		kg in blast from load sheet summary	m3 in blast from drill pattern design lines
As-built (actual) powder factor		kg loaded from explosives delivery records	m3 blasted from survey volumes

 

There is also a Target Powder Factor defined. This is generally derived from the planning process based on budget constraints.

Note that some sites use kg/tonne instead of kg/m³.