Langefors’ Formula

Langefors’ Formula

Langefors suggested that the burden determination was based on more factors,

including diameter of hole, weight strength of explosives, degree of packing, a rock constant, and the degree of fracture.

Langefors’ formula for burden determination is

where

]V = burden, m                                                                                                                                                                                     db = diameter of drill bit, mm
P   = the degree of packing 1.0 to 1.6 kg/dm3
s    = weight strength of explosive (1.3 for gelatin)
c    = rock constant, generally 0.45
f     = 1 degree of fraction, for straight hole 1
E   = spacing
E/V = ratio of spacing to burden