Abstract:
Newmont Ahafo Mine (NAM) operates an open pit gold mine in the Brong-Ahafo Region
of Ghana. One important cost centre in mining is drilling and blasting. Effective ways of
reducing drilling and blasting cost significantly while delivering desired results in
fragmentation for shovel loading, hauling and milling was the focus of this research.
Drilling and blasting at Newmont Ahafo Mine, open pit operation is generally
characterised by drilling patterns parameters in ore and waste zones. Since the start of
mine NAM employs a 3 m × 3.5 m blast pattern in its open pit operations. For the year
2017 a 4 m × 4.5 m has been substituted and is intended to deliver better cost savings. In
this research, the assessment of cost reduction was testing the cost implication of four
blast scenarios in an order of widening the burden and spacing as well as the use of a more
potent explosive. Furthermore, comparing their cost over equal areas against the Drill and
Blast budget approved for a 3 m × 3.5 m blast pattern. In addition to the old and new blast
pattern design parameters at NAM, additional two pattern scenarios were considered and
tested to compare the extent of cost savings possible and recommend most prudent
parameter accordingly. Four blasts scenarios were tested in all and while three of the four
scenarios returned positive results with regards to cost, fragmentation, noise and
vibrations, there was a trend of significant cost savings as pattern parameters were
widened. There were significant savings, but the optimum pattern of 4 m × 4.5 m pattern
currently in use at Newmont Ahafo Mine was elected to save about 46% annually of the
Drill and Blast budget for a 3 m × 3.5 m . Recommendation of a research into a possible
4.5 m × 5 m was further recommended for waste zones to further reduce cost was
proposed.
