How charges and volumes are calculated

The terms used in the calculations shown in this topic are defined in the table below.

Terms:
TD	Total drill depth
Inclination	Hole inclination (-90 = vertically down)
SD	Subdrill
H	Bench height (a vertical height)
B	Burden
S	Spacing
D	Hole diameter
CD	Charge density (grams per cubic centimetre)
PF	Powder factor
SL	Stemming length
CL	Charge length

TD = SL + CL

H = Cos(Inclination) x TD – SD

Volume of rock per hole = B x S x H (cubic metres)

Charge (weight) per hole = PF x B x S x H (Kg)

Charge per hole = (PF x B x S x H) / (1000 x CD) (cubic metres)

Hole volume (per metre) = (3.14159 x D x D) / 4000000 (cubic metres)

CL = (PF x B x S x H x 4000) / (3.14159 x D x D x CD)