Abstract:
Spotters and samplers working around surface drill rigs can be
exposed to high dust concentrations. In this study it was found
that individuals were exposed to as much as 14.2 mg/m3, which
exceeds the Occupational Exposure Level of 10 mg/m3. The work
on which this paper is based included an extensive literature study,
as well as field investigations on a surface mine in Namibia. A
number of additional dust suppression interventions were
identified. These improvements, listed below, will assist in
reducing dust concentrations around the drill rigs:
• Increase maintenance frequency on the shroud, sealing ring,
suction pipes and filters of the drill rigs,
• Design and install new overlapping rubber belts on the shroud
of the DM45,
• Install an air-blocking shelf on the inside perimeter of the
shroud of the DM45,
• Install an airflow meter to ensure that the QC: QB ratio never
drops below 3:1,
• Only allow wet drilling,
• Flush the dust collector system more regularly with compressed
air to ensure that it does not become blocked,
• Introduce stricter supervision to ensure that the suction pipes
are always connected to the shroud,
• Give drill rig operators more advanced training to ensure more
effective drilling in order to reduce dust levels.
It can be concluded that the implementation of the recommended
improvements in engineering controls, better maintenance
practices and better operating practices will assist in preventing
any potential respiratory diseases and the degradation of the
surrounding environment.
