Cradle to grave
Supplier of anchors for underground
mines Upat, recently customised a fischer
EXA Express Anchor. The new anchor
includes a cabling eye in its design,
as opposed to the traditional two-
component thread-on system
According to Clayton Dry, technical
specialist – mining and utilities at Upat,
fischer is being specified more and more
for mining applications in particular.
“This is because of the industry’s
stringent health and safety requirements,
as anchors are always safety-critical
components,” Dry explains.
A broad range of fischer fixings is
available that are suitable for most
sectors of the mining industry. These
range from massive mechanical anchors
for underground mining to chemical
anchors.
Chemical anchors, in particular, are
specified for rock faces with potential
cracks or voids. Mechanical anchors
are ideal for areas such as walkways,
handrails, or electrical works, where
the quality of the substrate is a known
quantity.
Here a good example is the fischer
FBN II through anchor, a cost-efficient
fixing for flexible use in non-cracked
concrete. It is a steel anchor with a long
thread and variable anchorage depths. In
addition to pre-positioned and push-
through installation, it is suitable for
stand-off installation. A stainless-steel
design makes it sufficiently flexible to be
Anchoring underground mines
A broad range of fischer fixings is available that is suitable for most sectors of the mining industry
applied for façade substructures, cantilevers,
and ladders on the surface.
Looking at the fischer EXA Express
Anchor, Dry explains that it is a quick
anchor for push-through and pre-positioned
installations. When the hexagon nut is
tightened, the tapered bolt is pulled into
the double expansion clips, expanding it effectively and quickly against the wall of the
hole. The clip’s stainless-steel construction
means it is Class III corrosion-resistant,
making it ideal for arduous mining
environments. The EXA Express Anchor is
produced in varying types of steel, such as
EN8 and stainless steel, for various climates
and operating conditions.
actual typical operating conditions in the
mining environment reveals that there
are levels of downtime beyond these two.
A closer approximation of actual
production time can be reached by
applying an OEE (Overall Equipment
Efficiency) analysis on a calendar
time-based approach, as opposed to a
loading time-based approach, since the
latter is based on theoretical total time
and is more likely to give an inaccurate
reflection of actual production capacity.
With a calendar time-based OEE
analysis, then, a number of additional
factors affecting productivity are taken
into account:
• Unscheduled downtime
(breakdowns/failures);
• Scheduled and unscheduled
maintenance;
• Idle time (e.g., operator lunch breaks);
• Waiting time (e.g., when a shovel
waits for a truck to be loaded/
unloaded);
• Inactivity during moves between
sites; and • Environmental disruptions (e.g.,
unsuitable terrain, etc.).
The true cost of downtime
The South African mining industry has
performed poorly over the past 10 years,
with its contribution to the national
GDP having halved since 1994.
Year-on-year production fell
by 3.3% in January, according
to Statistics South Africa, with
downtime, power outages and
uncertainty around regulatory policies
significantly hamstringing the sector’s
production.
Addressing the major constraints
impeding the sector’s growth and
development could result in annual
expansion of between 3% and 4% up
to the year 2020, and the creation
of thousands of jobs and greater
potential investor interest.
One of the major contributors to
losses in productivity and profit is
downtime, and on the surface this
is attributed either to maintenance
or mechanical failure, with these
alone having a significant impact
on production and profitability.
However, a deeper look into the
[38] MINING MIRROR AUGUST 2019
According to Hitachi Construction
Machinery, the modular design of its
equipment makes for timeous and
effortless maintenance routines, which
play a significant role in production
optimisation.
Improved horsepower output, efficient
engines, ergonomically designed cabs,
advanced hydraulics, tough frames, and
powerful arm- and bucket-digging forces
make for robust machines that maximise
production time to get the job done.
This also makes for lower total cost of
ownership. One mine, for example, has
achieved more than 25 000 hours on a
rigid dump truck’s wheel units through
the application of maintenance tactics in
partnership with Hitachi’s site support
personnel. With a very closely managed
and monitored maintenance plan, they
aim to manage these components to
50 000 hours.
www.miningmirror.co.za