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REC Ltd News - First use of Sonic Drilling in
UK
Coal Reserve Analysis
A bing is the Scottish term for a
colliery waste tip. REC Ltd. were contacted by
a client who as owners of the Waterside Bing at
Kirkintilloch were interested in sampling throughout
the bing to determine the coal content and so the
possibilities for the recovery of the coal as an
economic activity. The former Waterside Colliery
was noted for the production of high quality anthracite
coal and so recovered coal would be of particular
value. Consequently accurate and representative
sampling would be most important.
Bings are the waste piles containing discards
from the working of a coal mine. The greater part
of this will be stone brought to the surface as
a result of necessary excavation to gain the coal,
while there will also be colliery washer discards,
and other waste materials from the mine operation.
Thus while the majority of the bing may be sand
and gravel sized pieces of sandstone and mudstone
there will be boulders present, as well as timber,
steel girders or rails and other debris possibly
including mine tubs and larger equipment.
| Cable percussive (shell and auger) drilling
has been regarded as the only traditional method
capable of forming boreholes through the bing,
but the method does have its limitations and
the materials present are difficult to penetrate.
Boulders have to be chiselled, while timber
and metal obstructions will stop the borehole,
requiring the drilling rig to be moved and
the bore re-started from the surface.
REC had been aware that Boart Longyear were
about to introduce Sonic Drilling techniques
where a continuous soil sample can be obtained
using a rotary based technique with the addition
of low amplitude vibrations to assist the
casing and drill string in penetrating soils.
The continuous sample of the material penetrated
can be logged, photographed and sampled on
site. It is capable of penetrating boulders
and it was confirmed that metal and timber
could be penetrated. As a new technique the
rates of production were uncertain, but were
indicated to be very much faster than cable
percussive techniques.
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1. The rig tracking to the location of the
first borehole |
REC arranged for
the new rig to be trialled on the Waterside
Bing and so the very first operational use
of the rig was undertaken under the supervision
and direction of REC. On the first day, the
rig was mobilised, tracked to a position near
the summit of the bing and then produced 30m
of sample before being removed to a place of
safety for the night. The samples included
sections of timber and boulders of mudstone
and sandstone. REC were able to recover representative
samples for laboratory testing from throughout
the borehole, while the whole profile of the
material was laid out allowing the client to
see exactly what was present. It was considered
that in similar circumstances a traditional
cable percussive rig would have achieved less
than 10 metres of progress and would probably
have been obstructed by timber at 3.5m requiring
a new start at an adjacent location.
REC and the client were so impressed by
the performance of the rig that an immediate
order to undertake a further two days commercial
work was organised.
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2. The rig in place and drilling |
Through
their commitment to using the best and most
appropriate methods of working in the geo-environmental
field REC have supervised the first operation
al and first commercial use of the Boart
Longyear Sonic Drilling method in the United
Kingdom.
For further information
regarding the use of the Sonic Drilling Method
please contact Mr. Scott McGregor at REC
Ltd on Tel: 01355 574160.
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3. Sample Recovery
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