PDF Chapter 8 BLAST DESIGN National Park Service
BURDENSPACING CALCULATION From Powder Factor of 1 lb./ Determine borehole size. Determine stemming: 24 x borehole diameter; Divide by 12 to get the number of feet. Determine subdrilling: 1/3 x stemming. Determine amount of hole to be loaded. Use bench height plus subdrilling minus stemming.