Geology Reference
In-Depth Information
railway from Seoul to Taejon in South Korea, one proposed
solution was to construct a concrete structure through the workings,
but this was considered politically unacceptable because the public
was already aware of the situation. Instead, the route for the rail-
way had to be moved several kilometres at considerable cost and the
completed works were abandoned.
Surface mining and quarrying are industries that have strong
demands for geotechnical expertise, including engineering geol-
ogy. Slope design is often very important and the design prac-
tices discussed earlier, used in civil engineering, also apply to
quarries and open pits and opencast mines. The main difference
is that in such enterprises many of the slopes are always chan-
ging in geometry as the works progress. One key to success is
establishing a safe layout for operations such as crushing and
processing plants and for haul roads, whilst avoiding sterilising
valuable resources because of the siting of infrastructure such as
site of
ces and treatment plants. Major haul roads also need to
be established in a safe manner to avoid disruption to operations
if instability occurs. Other faces may well be temporary and are
therefore formed at angles that would be unacceptable as per-
manent slopes in civil engineering. For large open-pit mine
operations, the scale of overall slope formation can be huge,
extending hundreds of metres, and predicting stability often
requires numerical modelling, tied in to monitoring systems.
Excavation of rock usually involves blasting and this is a specia-
list operation as it is for tunnelling. A good review is given in
Wyllie & Mah (2004). Key considerations for all blasting opera-
tions are fragmentation, to avoid producing large blocks that
cannot be handled easily and need secondary breaking opera-
tions, avoiding damage to the remaining rock, avoiding over-
break beyond the design pro
le, safety and risk from
yrock,
gases and vibrations.
Waste frommining needs to be disposed of. In open-pit coal mining,
the waste rock is back
lled into the void as part of the ongoing
operations and nowadays in the UK at least, the
final reinstatement
of the area is strictly controlled, with every attempt made to simulate
the natural countryside as it was pre-operations. Other wastes are
often wet and contaminated and held behind tailings dams that
should be designed and analysed with just as much care as a civil
engineering structure. Unfortunately, this is often not the case, and
there have been many major failures worldwide over the last
fifty years
which have resulted in severe contamination and many deaths (Rico
et al
., 2008).
