The management commissioned the snapshot audit
because they were concerned that the availability of their underground
equipment was low and their maintenance costs high. They believed that the main
problem was an inadequate structure for organising maintenance and engineering.
The audit was expected to answer the question:
‘
What
changes in the maintenance strategy and organizational structure were needed in
order to improve equipment availability and reduce maintenance costs?
’
Because
all three collieries operated in a similar way and had similar problems I
decided to concentrate my main effort on Colliery A. In addition, I interviewed
the Engineering Manager and the other colliery engineering superintendents in
order to acquire an understanding of the way the engineering effort across
COALCOM was coordinated.
FIGURE 6–2 COALCOM Senior
Management Structure
Colliery A
Equipment and Operating Characteristics
The
layout of the tunnels and production areas of Colliery A—a drift mine, the main
tunnel inclining down from the surface to three development areas and the
Longwall production area—is shown in Figure 6–3. The main tunnel carried the
trunk conveyor system and the personnel roadways. Continuous miners
(diesel-driven vehicles, each with a front-mounted driller–cutter for creating
the development tunnels through the coal measures) were used to develop the
production areas and the tunnels for conveyor or worker access.
Coal extraction was achieved by ‘Longwall’
cutting, an operation which employed a system comprising a shearer,
armoured-face conveyor (up to 100 metres long), main conveyors and various
services, such as an electricity supply (see Figure 6–4). The shearer cut
slices of the coal seam two metres thick by moving across a hundred-metre block
which had been developed between two tunnels by the continuous miners. The
removed coal fell on to the armour-plated conveyor and was then moved outwards
to the conventional conveyors. A balance had to be maintained between the rate
of development work and of production.
FIGURE 6–4 Longwall Process