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Combined Diamond and RC Drill Rig

In most jurisdictions environmental authorities need to be
consulted prior to and after drilling to ensure that drilling
activities are approved in a particular area and to ensure that
sites are properly rehabilitated. Often a bond is required by
the jurisdiction to encourage explorers to satisfactorily
complete land restoration.
Continued landholder liaison from the initial design to drill-
site rehabilitation at the completion of drilling is important.
Many landholders like to be involved throughout the process
and may provide support with earthworks and camp
facilities. They have a vested interest in seeing their land
returned back to the pre-drilled state.
Traditional landowners may also need to be consulted and
approvals given to ensure that any impact to cultural
heritage in the area is kept to a minimum.
With approvals in place, sites can be cleared and earthworks begin. This usually involves the building of
access tracks, construction of drill pads and the digging of sumps.

Drill Programme Supervision and Safety
Exploration companies are responsible for the health and safety of their staff and drilling contractors
during a drilling programme. The supervising geologist is usually the nominated staff member for
performing safety checks on a drill rig. These safety checks are done at the start of the programme and
after every rig move as well as at random times during drilling. The safety inspection is done in the
presence of the head driller and involves carefully going through a checklist of items. Any problems or
hazards need to be corrected before drilling can start.

Diamond Drill Hole Monitoring
Diamond drilling holes can extend hundreds, even thousands of meters below ground. However, as any
child who has pushed a garden hose into the ground only to find the end of it coming up several metres
away, knows drill holes can go badly off-course. The same happens to a length of drill pipe. Although
made of metal, over hundreds of metres it can bend significantly. I have heard of drilling done without
surveying with the same outcome as the garden hose. On this occasion, the drill bit was seen exiting the
ground hundreds of metres away from the rig!
A survey instrument is lowered down the drill hole to record the direction and angle of the hole at that
depth. The geologist plots drill-hole depths and surveys using 3D modelling software. Given the
information about how the drill-hole is tracking relative to the target the driller, can make corrections.
The driller can adjust the torque to change the direction of the drilling to ensure that the target is
reached.
The type of rock that is being drilled through has a great effect on the behavior of the drill bit, stem and
pipe. If the rock has a strong fabric such as schist, the drilling direction tends to migrate towards the
plane of the foliation. Sometimes adjustments are extremely difficult or impossible to make to the
direction of the drilling. If the hole is way off target and cannot be corrected even with navigational
drilling techniques, the hole may need to be abandoned before its completion.

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