3
deviation (i.e., inclination and orientation) mea-
surements and interviews with drilling operators to
evaluate the potential impact of pre-split drilling
quality on trim-blasting operations. The results are
shown in Table 1.
The results showed that the spectrum of pre-split
hole deviation could interfere directly with the design and
execution of trim blasts in front of them. Especially for
the bottom, second 45ft (13.7m) pass, where the devia-
tion (i.e., walk of the pre-split holes) was more accentuated
(see Figure 4 for visual reference and Figure 5 for a detailed
schematics of the issue).
On one hand, the pre-split holes can intersect trim
row holes, if drilled later than the trim blast holes in front
of them. On the other hand, if drilled and blasted earlier,
Figure 3. Plan and cross-section views of the traditional trim-blast designs used at Capstone
Copper Pinto Valley mine for 90ft (27.4m) final bench heights
deviation (i.e., inclination and orientation) mea-
surements and interviews with drilling operators to
evaluate the potential impact of pre-split drilling
quality on trim-blasting operations. The results are
shown in Table 1.
The results showed that the spectrum of pre-split
hole deviation could interfere directly with the design and
execution of trim blasts in front of them. Especially for
the bottom, second 45ft (13.7m) pass, where the devia-
tion (i.e., walk of the pre-split holes) was more accentuated
(see Figure 4 for visual reference and Figure 5 for a detailed
schematics of the issue).
On one hand, the pre-split holes can intersect trim
row holes, if drilled later than the trim blast holes in front
of them. On the other hand, if drilled and blasted earlier,
Figure 3. Plan and cross-section views of the traditional trim-blast designs used at Capstone
Copper Pinto Valley mine for 90ft (27.4m) final bench heights