During blasting operation, three explosives were
considered, i.e., Explus, Nitram 9 and ANFO. Batch
weights (EB-BWR102) are used to measure the
amount of each of the explosives before loading into
the blast hole. In charging operations, each of the two
explosives (Explus and Nitram 9) was used as the
base charge in their individual holes, while ANFO
was used as a deck or column charge to enhance the
performance of each of these explosives in their respective
holes during charging operations. Electric
detonators were used with each respective charge.
The tonnages of blasted materials produced were recorded.
The weights of explosives consumed were
also recorded. The summary of the results is presented
in Table 5.
4 Results and discussion
The study is limited to only two level of operation
i.e., levels 0/19 m and 19/38 m, where laborious
blasting work was needed to fragment the overburden
material. Therefore, the two drilling machines were
used under the same operating conditions in order to
evaluate their performance. Tables 1 and 2 present a
day sample field records for drilling operations carried
out using machines DMNo406 and DM405,
clearly showing that it takes machine DM405 more
time to drill and accomplish the same depth of hole,
compared with machine DMNo406. The result of the
analysis of the drilling operations when the statistical
equations were used as shown in Table 3, indicate
that machine DMNo406 is more efficient, given its
average utilization coefficient K0.40. The cumulative result of the drilling operation
in Table 4 and its graph in Fig. 1 shows clearly
that the cumulative time spent by Drill Master
DM405 is within 260 min and 413 min while the
cumulative time spent by the Down the Hole Hammer
Drilling Rig, DMNo406 is between 169 min and 198
min.