Overhead Powerline Hazards
high-voltage conductors or "lines" are usually bare wires
supported by poles or structures,
traversing across mine
property. A risk of danger exists for personnel when mobile
equipment, such as trucks, drill rigs, cranes, etc. contact
these lines. Based on accident data recorded by MSHA from 1980
to 1997, there have been 106
accidents involving overhead lines. Of these 106 accidents 32
resulted in fatalities.
Overhead lines near the following sites and activities
can present a serious hazard:
- Storage yards and
delivery areas (where cranes may operate).
- Mobile equipment
maintenance, parking, and fueling areas.
- Haulage and access roads,
particularly those near dump/load points, and pull-off
areas on these roads (dump-bed trucks running with beds
up, cleaning beds, and raising tarps).
- Stockpiles, dumping
points, loading areas, and truck scales (raising truck
- Mining benches and active
pit areas in general, particularly near blast hole
- Adjacent to mine plant
structures, such as processing plants, slopes/hoists, belt
lines, transfer points, settling ponds, and waste dumps
(cranes and dump-bed trucks used in routine maintenance).
- Exploration/test drilling
- Construction sites,
particularly if cranes or scaffolds are in use.
- Unintentional buildup of
roadways under overhead lines.
There are several ways to
avoid accidental overhead electric power line contacts and
Spherical Line Indicators at Potential Contact Points
Position miners as "spotters" to alert equipment
operators of the proximity of their equipment to energized
- Install and maintain
commercially available non-contact powerline proximity
devices. These devices can:
- provide audible and
- shut down an entire
machine or desired functions of a machine,
- be designed to detect
powerlines from far distances, and
- provide protection
for the entire length of a boom or truck bed.
Recognize potential hazards. Train workers to
"Look up" prior to starting work.
- Install physical barriers
under overhead lines.
- Erect signs to identify a
- Raise problem sections of
overhead line to at least 40 ft. above ground.
- Have the electric power
utility company install insulating barriers or sleeve
conductors where equipment must operate.
- Have high visibility
spheres installed on energized lines to help make the line
location obvious to all workers.
- Have the electric power
utility company temporarily de-energize the power
15 If the
overhead line cannot be diverted or switched off, and there is
no alternative to carrying
out the work near it, you will
need to think about how the work can be done safely. If it
done safely, it should not be done at all. Your
site-specific risk assessment will inform the
Things to consider as part of your risk assessment include:
■ the voltage and height above ground of the wires. Their
height should be measured by a suitably
using non-contact measuring devices;
■ the nature of the
work and whether it will be carried out close to or underneath
line, including whether access is needed
underneath the wires;
■ the size and reach of any machinery
or equipment to be used near the overhead line;
■ the safe
clearance distance needed between the wires and the machinery
or equipment and any
structures being erected. If in any
doubt, the overhead line’s owner will be able to advise you on
safe clearance distances;
■ the site conditions, eg
undulating terrain may affect stability of plant etc;
competence, supervision and training of people working at the
16 If the line can only be switched off for short
periods, schedule the passage of tall plant and,
as far as
is possible, other work around the line for those times.
overhead lines that the safety an be infringed by people
standing on them.
overhead line an be infringed by people
standing on them.
someone or something comes into contact with an
overhead line, it is
Important that everyone
involved knows what action to take to reduce the risk
of anyone sustaining an electric shock or burn
Key points are:
never touch the overhead line’s wires;
assume that the wires are live, even if they are not
arcing or sparking, or if theyotherwise appear to be
■■ remember that, even if
lines are dead, they may be switched back on either
automatically after a few seconds or remotely after a
few minutes or even hours
if the line’s owner is not
aware that their line has been damaged:
■■ if you can, call the
emergency services. Give them your location, tell them
has happened and that
electricity wires are involved, and ask them to
contact the line’s owner:
if you are in contact with, or close to, a damaged
wire, move away as quickly
as possible and stay away
until the line’s owner advises that the situation has
been made safe:
■■ if you are in a vehicle
that has touched a wire, either stay in the vehicle
or, if you
need to get out, jump out
of it as far as you can. Do not touch the vehicle
standing on the ground. Do
not return to the vehicle
until it has been
confirmed that it is safe to do so;
Fire Retardant Painting
Fire Proof Painting