Transcript Presentation - 9

• Hauling and Mining Safety
• Source MSHA, web site
• Compiled By B.Arunachalam
• Manager
• MGVTS,
• Hospet
1
Who designs the haul roads at your mine? Do you have a crew that designs
the roads and lays them out in a pre planned manner? Or, do you, like many
companies, have a dozer operator who makes all the roads at the mine? The
foreman says, “I need a road from here to there,” and the dozer operator
makes one. The operator hasn't had any training on how a mine haul road
should be designed, and may build one that is too narrow or too steep for the
haul trucks.
2
With the weight of the truck at the speed it’s travelling, the
required stopping distance is as shown. You can see the line of
sight for this truck driver. The driver cannot see the hazard within
the required stopping distance. So even though we've spent a lot
of money on training the truck driver, made sure the brakes are
good, and maintained the truck; because the dozer operator didn't
3
build the road right, the driver can't avoid this accident.
If we give the dozer operator a little training maybe he’d build the
road like the lower drawing. We have the same truck, same
hazard, same required stopping distance; but now the driver can
see the hazard in time to stop. All he did was widen the vertical
curve. The same thing goes for curves (horizontal curves). We
have to be able to see far enough ahead to be able to stop. This
distance depends on the vehicle, its weight, and its speed. If we
can't stop within our sight distance, we need to slow the vehicle
down or reduce the weight so we can safely stop.
4
5
ion showing an average size haul truck (a 110-ton end-d
First, we're going to show a six-foot tall person in various areas
around the truck.
A truck comes up. The truck is a certain weight and going at a
certain speed. On the other side of the hill, let’s say at this little
green box, is some type of hazard. It could be something lying in
the road, another vehicle stopped in the road, a person in 6 the
road, or other hazard.
This truck driver cannot see the ground closer than 105 feet out
the right side, 16 feet out the left side, and 62 feet out the front.
Truck drivers are always operating "in the blind." They see only
what is far ahead and continue on, hoping the condition will be the
same when they get there. You can imagine the blind areas
around some even larger trucks that are 320 or 340 ton capacity.
It's over 200 feet away before the driver can see the ground. 7
This establishes what we call the “six-foot visibility line”
and “six-foot visibility point.” With an operator sitting in
the seat and looking out the right side, the six-foot
visibility point is 70 feet away. Looking out the front of
the truck it's 40 feet away. Looking out the left side of 8the
truck it's 9 feet away
This establishes what we call the “six-foot visibility
line” and “six-foot visibility point.” With an operator
sitting in the seat and looking out the right side,
the six-foot visibility point is 70 feet away. Looking
out the front of the truck it's 40 feet away. Looking9
out the left side of the truck it's 9 feet away
In this view from the driver’s seat you can see the convex mirror on the
right side. This mirror can be as much as 20 to 25 feet away from the
driver on larger trucks. You can see that the image is not very big, and it’s
often blurred. Sometimes the mirror is reflecting the same shade of color
as the background view. It’s very hard for the driver to see that far away.
Painting a bright colored border around that mirror could help the driver
pick it out quicker. Some companies add things to this walkway, such as
fire extinguishers on the handrails. These things reduce visibility. Anything
that blocks visibility increases the danger around these trucks. .
10
In this fatal mine accident scene you’re looking at the foreman’s red pickup truck.
The large truck in the background was the truck that ran over the pickup. The
sequence of events began with the foreman driving the pickup truck. He called the
haul truck driver and said that he was going to relieve him. The foreman was going
to drive the large truck for a while. He pulled up to the large truck, parked at its right
front corner, walked around the large truck, and entered the driver's compartment.
The regular truck driver went down and had just gotten into the pickup truck when
the foreman took off and ran over the pickup that he had just parked. Because he
couldn’t see the pickup, he forgot about it. Even the flag on the pickup’s "buggy
11
whip" did not alert the foreman.
In this fatal accident a service truck (larger
than a pickup) was run over by a large haul
truck. The man in the service truck was
killed. This truck also caught fire after the
haul truck ran over it.
12
This is the scene of a fatality. This Ford
Bronco ran into the back of a 300-ton
parked haul truck at an estimated
speed of about 50 miles per hour.
13
This is the scene of a nonfatal accident that
occurred when the back left wheel of a front-end
loader ran over this car. Tragically, the man driving
the car was the father of the man operating the
front-end loader. He survived, but it took 3½ hours
to cut him out of the car.
14
This shows another danger we have with these large
haul trucks. Notice that before the bumper ever
touches the tires of the vehicle in front, its truck bed is
all the way into the cab of the truck in back. Many times
it’s the truck in the front that backs into the one behind,
instead of the truck in the back running into the one in
front. On many newer trucks the operator’s cabs are
over 25 feet above the ground, so it would be difficult to
escape injury.
15
16
This road is very well designed. It’s wide
enough. You can see there are different
types of equipment on this road. It is smooth,
has good visibility, and has a good berm
17
Here are a couple more examples of well planned roads.
They’re wide enough and visibility is very good. 18
This example shows a very bad haul road. It’s
not compacted, and is only wide enough for
one vehicle. The trucks are operating next to a
bank, which has to be maintained. There’s no
19
room to pass, and the visibility is poor
This road was not planned; rather, it just “happened” over the
years. Notice that one truck has to get very close to the high wall
for the other one to pass. There is not a safe space between
these trucks when they meet. In this particular case it was less
than one foot between the mirrors. Also notice that the road gets
narrower and narrower, which means there’s not enough room for
20
an adequate berm.
Here’s a road with a lot of traffic. They would have to cut the high
wall back to make the road wide enough. One solution to this
problem is – one lane traffic only. When vehicles are going21out,
the others have to wait until the road is clear before coming in.
This haul road was next to a very dangerous highwall. Haul roads should not be located
next to a highwall, if possible. Any time you put a haul road next to a highwall, you have
to maintain that highwall so that nothing will fall from it. This wall would have to be
scaled, cut back, and supported so that nothing could fall off, if you’re going to maintain
the haul road next to the highwall. There was a fatality where one eight-inch-diameter
rock fell from the top of a highwall. As the foreman drove past in a pickup truck, it went
through the truck cab and struck the foreman in the head.
22
One lane traffic is used at this location. The empty truck on the right side is
parked and waiting on the loaded truck to come out. It’s forcing the loaded
truck to go on the outside edge (the left side of the road) where the road is
weakest. So you have the heaviest truck on the weakest portion of the road.
The driver of the empty truck needs a better location to wait, so the loaded
23
truck isn’t put in a hazardous location.
This particular mine used a left-hand traffic pattern which, in this case, properly
placed the empty trucks on the outside edge, the weaker part of the road. Lefthand traffic does have the general advantage of placing operator’s cabs on
opposite sides of the road for oncoming traffic. If there were a head-on collision or
a sideswipe, you wouldn’t have operator’s cab hitting operator’s cab.
Any time you put a curve in a haul road, you must make the curve wider than the
straight stretch, because the back wheels don’t follow the front wheels around a
curve. The back wheels cut the angle to a certain extent. A curve needs to24be
wider than a straight stretch of the road to provide adequate side clearance.
measures haul roads in percentages. We do this to maintain consistency.
We measure stockpiles, highwalls, and impoundments in degrees, but we
measure haul roads in percent grade. To determine percent grade of a haul
road, start at the toe of the road and measure horizontally back 100 feet. At
100 feet measure vertically up to the road. That vertical distance, for
example ten feet, is equal to the grade in percent. We would have a 10%
25
grade.
When you measure in degrees, you’re actually measuring the angle between
the horizontal section and the slope. So with a 10 degree angle you would
have a 10 degree slope. The question that arises is, “What is the difference?”
Well, there is a big difference. And that’s why we always measure haul roads
in percentages. Because if we don’t stay consistent...
26
you see that a 10 degree road would actually
be 17.06%. So it’s very important not to
confuse percent with degrees. There’s a
great difference between a 10% grade road
and a 17.06% grade road. We want to keep
27
everybody on the same basis
A truck, similar to the one depicted in this slide, was involved in a fatality because
it was being operated on a steep grade of 26%. The truck was not designed to
operate a grade this steep. Company personnel misunderstood the charts in the
operator’s manual as to how steep a road should be. Always check with the
manufacturer on interpreting those charts and make sure they designed that
28
piece of equipment for the slopes you’re using it on.
.
29
Berms are the subject of frequent problems at mines.
Berms must be maintained on the outside edge of all
haul roads where there’s a danger of overturning. 30
31
This shows a berm where a truck went through it. You can tell that
the tires cut right through the berm. The berm did not prevent the
vehicle from going over. It did not even slow it down. It was only
32
there for the purpose of warning the driver.
Tests have shown that, to stop a runaway vehicle, for
an 85-ton capacity vehicle or less you would need a
33
berm height of three times the axle height.
For trucks larger than 85 ton, you’d have to have four times the axle height.
For example, there are large trucks with a six-foot axle height. This means
we’d have to have a 24-foot-high berm, which means it would have to be
about 48 feet wide at the base because of the angle of repose for earth
berms. Our standards do not require that. MSHA states that a berm height
of one times the axle height is needed. So when a tire hits the berm it starts
a penetration. As the material underneath the tire compacts sufficiently, the
tire starts climbing the berm.
34
This shows a berm where a truck went through it.
You can tell that the tires cut right through the
berm. The berm did not prevent the vehicle from
going over. It did not even slow it down. It was 35
only there for the purpose of warning the driver.
Berm was higher than the mid-axle height. The contact
angle was such that the truck went along the berm
instead of directly through it, and it did bring the truck to
a stop.In this fatal accident scene the berm was within
specifications (mid-axle height), however, the truck went
right over it. It was a fatality because the man either out
or was thrown out. He was not wearing a seat belt, and
he was killed.
In this picture, notice the top road, a middle section, and
then down at the bottom where the truck landed. The
truck lying at the bottom went off the road at the top,
rolled down, lost its front axle on the middle road, and
landed at the bottom. The driver was killed. Here’s a shot
of the road in the middle where the front axle was torn
off.
36
These are what we sometimes barriers. "They’re usually made of
concrete, and are often used along interstate highways and at
construction areas. They operate on the same principle as an earth berm.
When a tire strikes this berm it tries to penetrate. Since this is made out of a
hard material, usually concrete, the tire cannot penetrate so it starts the
climbing action earlier. As it starts climbing, if it doesn’t have enough
momentum to carry it all the way over, the barrier will redirect the tire back
into the roadway. You’ve probably noticed black marks on these along the
highways where large highway trucks have hit them. The tire tried to climb
over couldn’t get all the way over it, so these devices directed the trucks back37
into the lane of traffic.
These boulders, like berms, must be mid axle height
to the largest vehicle that travels that road. They can
be spaced far enough apart to allow adequate
drainage or for other purposes, but they cannot be
spaced so far apart that a vehicle could go between
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them
Here’s an illustration that shows what happens when a tire hits the berm. Most berms in
the nation’s mines are constructed of a soft material. The first thing a tire does when it
goes into this earth berm is to sink in. Policy states that berms be at least mid-axle height
to the largest equipment that uses that road. For example, if the mid-axle height of our
largest piece of equipment, or half way up the wheel, is three feet, we would have to have
a berm that is at least three feet high. This berm is, by no means meant to stop a runaway
39
vehicle,. It is only there to be used like a curb on a city street It’s just to let you know when
you’re at the edge of the road not to prevent you from going over the edge
Tests have shown that, to stop a runaway vehicle, for
an 85-ton capacity vehicle or less you would need a
berm height of three times the axle height. 40
For trucks larger than 85 ton, you’d have to have four times the axle height. For
example, there are large trucks with a six-foot axle height. This means we’d have to
have a 24-foot-high berm, which means it would have to be about 48 feet wide at the
base because of the angle of repose for earth berms. Our standards do not require
that. MSHA states that a berm height of one times the axle height is needed. So when
a tire hits the berm it starts a penetration. As the material underneath the tire compacts
sufficiently, the tire starts climbing the berm.
41
This shows a berm where a truck went through it. You
can tell that the tires cut right through the berm. The
berm did not prevent the vehicle from going over. It
did not even slow it down. It was only there for the
42
purpose of warning the driver.
This illustration shows one of the problems with boulders, based on some actual
tests. An 85-ton truck, traveling at 20 miles per hour, and impacting the boulders
at a 20 degree angle, would strike three or four boulders. Some of these boulders
would roll up under the front carriage and it would push them along the ground.
The large brown line here could represent the drop-off, the edge of the road. The
truck traveled a total distance of 80 feet under these conditions. Which means that
these boulders, to actually stop that vehicle from going over the edge, would have
to be placed back from the edge about 22 feet. If we place boulders right on the
43
edge, all we’re going to do is take some of them off the edge with us.
Another alternative berm is shown here. It is permitted
to the use of guardrails or barriers or similar devices.
Again, they are not meant to prevent a runaway
44
vehicle.
Guardrails work very well around areas where
vehicles are moving slowly, ...
45
Guardrails work very well around areas where
vehicles are moving slow, such as around weigh
46
bridge and places like that.
The berm shown here looks very good, but is actually worthless.
Remember that when the tire hits this soft material it penetrates.
Then the tire starts compacting the material until it can hold the
weight that it’s being subjected to. When the material holds the
weight, the tire starts climbing. This berm is built of soft material.
The material was "down sloped" (pushed off the edge of the road).
47
It is not resting on a solid base.
48
49
50
This man was outside the truck. He was cranking the tarp on his truck.
He lost his balance, and as he fell, his ring caught on the edge of the
truck bed and ripped his finger off. Drivers should have a safe way of
putting their tarps on, levelling the load, or doing whatever they have to
do correctly.
51
52
A "center berm" is shown in this photo. It’s a mound of material, not
meant to keep you from going off the road, but to help drivers who
may lose their brakes going down the hill or have similar vehiclecontrol problems. The driver steers toward this mound of material in
the center of the road, places one wheel on each side of the mound,
and digs the undercarriage of the vehicle into the soft material. This
will help slow the vehicle or bring it to a stop. Center berms are not
required by MSHA. They have proven, however, to be very helpful in
53
emergency situations.
Here's the same center berm shown from the opposite
direction. Large trucks come down this hill. If they lose their
brakes, instead of trying to steer around the guard shack on
the left, they have an option of steering toward the runaway
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area on the right and bringing the vehicle to a stop.
The next few visuals are about dumping. Dumping is an area where we have
many fatalities and many accidents at mines.
55
This will be used to illustrate end dumping positions. We are looking from
above, down a slope. MSHA never recommends that you end dump over
the edge of the slope. MSHA recommends that you dump away from the
edge and push it over with a dozer or loader. But many companies choose
to end dump, or dump directly over the edge.
56
If a truck backs to the edge of a slope, both
57
wheels should touch the berm at the same time.
If a truck backs in at an angle, it should come in
58
so that the left wheel touches the berm first
A truck should not back in at the other angle where the right wheel touches the
berm first. Remember, the driver uses the left side mirror most of the time. As
the drivers back up, looking into the left side mirror they see that they have 10 -8 -- 6 feet to go and continue to back up. By the time the tire on the left side
touches, the tire on the right side has already gone through the berm and
59 the
vehicle trips over.
That happened here. The operator backed the truck in at an
angle, the right wheel touched the berm. As he continued backing
up, the right wheel went all the way through the berm and60 the
vehicle flipped over.
These illustrations show good practice. You should always be on level ground .This keeps the
center of gravity over the rear wheels, and any stuck material in the bed will usually slide out.
It’s even better if you’re uphill two or three degrees. The centre of gravity moves forward, but it
affects the angle for material sliding out of the bed very slightly. You never want to dump a load
when going downhill, because that moves the center of gravity back. If you have any stuck or
frozen material in the top of this bed, it will just topple the truck backwards. Also, if dumping
downhill, you may have water build up in front of the berm which will affect the stability of the
ground. Looking from the front, it should always be level. You never want to dump on asidehill
or slope. You also have to watch out for soft ground, where one side may sink
61
This shows a truck in an end dumping position. The berm is
required in the back, and it should be mid-axle height. Like side
berms, it is not there to prevent a vehicle from going over. It’s only
there to let drivers know, as they're backing, when they’re
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touching it, that is -- when they’re at the back.
Here's another berm at a dumping location. This
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35-ton truck can dump over that berm very easily.
Here is a different bed configuration. The berm
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could not be much higher.
This shows an end dumping situation. Again, dumping
directly over the edge is not recommended. Always
dump back from the edge and push it over 65
You can see as they dump over the edge on a
stockpile that it gets higher and the slope
66
continues to get steeper.
Here a truck driver is backing up a long road. The road is not
maintained and is not wide enough. It’s not constructed
adequately, and there are no berms. And on this particular truck
there are no mirrors. The driver is leaning out the window to 67look
back.
Here a truck dumps into a hopper or some kind of stationary
device. A berm or a bumper block is needed here as well. The
bumper block does not have to be mid-axle height, but it needs to
be substantial enough to provide some resistance to keep68this
This is a steel bumper block. If truck drivers are backing at a
reasonable speed, they should know when to stop when they hit
this bumper block. If they’re going too fast, it would be possible to
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bounce right over the top of the bumper block.
As the tire goes back, it strikes the bumper block. If the
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bumper block is too low, the tire will just go over it.
Here a truck is dumping into a hopper. Often the truck
drivers leave too early when dumping; they don’t want to
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wait until the truck gets completely empty
Zooming in on the tires here, you can see what is beginning to happen. The
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material is beginning to fall in front of the bumper block.
This photo shows that the bumper block is covered with material. Now we have a ramp.
These trucks are just backing right up the ramp. This has to be cleaned out so that the
bumper block functions as intended. No other truck would be allowed to dump here until
this spillage has been cleaned up.
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As we see here, a very important part of dumping is the ground
itself. Will it hold what it’s going to be subjected to? These cracks
are showing us that this ground is not solid. It will not support
a
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heavy truck backing out on the edge. It will collapse
These
areas
have
to
be
inspected.MSHA
regulations
for
metal
and
nonmetal mines require that thedumping area be inspected prior towork commencing and as groundconditions
warrant. It is goodpractice to inspect the area everytime a vehicle dumps there. Whodoes the inspecting? It could
be thetruck drivers. It could be the foreman. It could be the dozeroperator or loader operator. The inspector should
be someone whohas the ability to understand and todetermine if it’s safe or not. Withthese truck drivers
approaching thisdump site from this direction, they would be able to inspect this site
themselves. Remember, the drivers usually look out the left side window. In this case, they can see the ground
about 16 feet away out the left window. With these trucks approaching the dump site in a clockwise direction, they
can see out the left side of their truck to examine the area they will be backing into. If they approached this dump
site from a counterclockwise motion, it would be over 100 feet away that they could see the ground out the right
side of their truck, and they would not be able to inspect this area adequately.
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Refer slide above
These areas have to be inspected. regulations for metal and
nonmetal mines require that the dumping area be inspected prior to work
commencing and as ground conditions warrant. It is good practice to inspect
the area every time a vehicle dumps there. Who does the inspecting? It could
be the truck drivers. It could be the foreman. It could be the dozer operator or
loader operator. The inspector should be someone who has the ability to
understand and to determine if it’s safe or not. With these truck drivers
approaching this dump site from this direction, they would be able to inspect
this
site
themselves. Remember, the drivers usually look out the left side window. In this
case, they can see the ground about 16 feet away out the left window. With
these trucks approaching the dump site in a clockwise direction, they can see
out the left side of their truck to examine the area they will be backing into. If
they approached this dump site from a counter clockwise motion, it would be
over 100 feet away that they could see the ground out the right side of their
truck, and they would not be able to inspect this area adequately.
76
Notice that these trucks have parked far enough apart. If one of
them were to topple over with the body up, it would not make
77
contact with the truck beside it.
Another danger of dumping around mine sites is that the body of trucks or the
buckets of front-end loaders or cranes or similar equipment could contact highvoltage power line. Truck drivers and loader operators need to be trained on
what to do in this situation. Many times the most obvious thing is overlooked.
They
should just try to lower the bed or lower the bucket out of the power lines. Many
times they can’t. Sometimes the line breaks and falls across the vehicle or it
fuses to the vehicle because of the high voltage. If that is the case, the truck
driver or loader operator
should stay in the vehicle. That is the safest place for that person to be.
Electricity is traveling from the high voltage line down through the truck, through
the tires, into the ground, and trying to get back to the voltage lines. It’s trying to
complete that circuit. So if a person climbed out of a vehicle and contacted the
ground and the truck at the same time, he/she becomes a path to ground.
Electricity would flow through the person trying to get to the ground and to
complete the circuit. That’s why the truck driver or equipment operator needs to
stay in the vehicle. The only time you should get out of the truck is if it catches
on fire. That’s when you should jump. By jumping you will not be making
contact with the ground and the truck at the same time. Make sure when you
jump, that you jump far enough away from the vehicle that you won’t make
contact with it, or won’t fall back into it. Be sure you’re not going to land on any
live wires that may have broken and fallen down. Also make sure you land on
your feet, not on hands and feet. There could be dangerous voltage potentials
across a few feet of ground. If your hands and feet are on the ground an
electrical current could flow through the heart.
Slide below
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Another danger of dumping around mine sites is that the body of trucks or the
buckets of front-end loaders or cranes or similar equipment could contact highvoltage power line. Truck drivers and loader operators need to be trained on
what to do in this situation. Many times the most obvious thing is overlooked.
They
should just try to lower the bed or lower the bucket out of the power lines. Many
times they can’t. Sometimes the line breaks and falls across the vehicle or it
fuses to the vehicle because of the high voltage. If that is the case, the truck
driver or loader operator
should stay in the vehicle. That is the safest place for that person to be.
Electricity is traveling from the high voltage line down through the truck, through
the tires, into the ground, and trying to get back to the voltage lines. It’s trying to
complete that circuit. So if a person climbed out of a vehicle and contacted the
ground and the truck at the same time, he/she becomes a path to ground.
Electricity would flow through the person trying to get to the ground and to
complete the circuit. That’s why the truck driver or equipment operator needs to
stay in the vehicle. The only time you should get out of the truck is if it catches
on fire. That’s when you should jump. By jumping you will not be making
contact with the ground and the truck at the same time. Make sure when you
jump, that you jump far enough away from the vehicle that you won’t make
contact with it, or won’t fall back into it. Be sure you’re not going to land on any
live wires that may have broken and fallen down. Also make sure you land on
your feet, not on hands and feet. There could be dangerous voltage potentials
across a few feet of ground. If your hands and feet are on the ground an
electrical current could flow through the heart.
79
80
This truck got into a high voltage line. The truck driver
panicked and jumped. Luckily the driver made it, but
later on, somebody tried to jump back on the truck just to
lower the bed, made contact with the ground and 81the
truck at the same time, and was killed.
Not only do we have the hazard of the accident itself or whatever’s occurring,
but also the aftermath. This truck rolled off the top, went to the bottom of
82 the
mine, and landed on two wheels against another truck.
It’s going to be very difficult to safely correct this situation. It could
involve bringing in a large crane, big enough to handle the truck
83
on two wheels and safely get it off the other one.
Here's another small truck, a mechanic’s truck, that was
run over by a larger vehicle. We must respect the blind
84
areas around large equipment
This water truck was involved in an accident. The driver had only been on the
job for a few weeks. This very inexperienced driver lost control and the truck
flipped over. Many times the least experienced operators are assigned to some
of the oldest equipment at the mine, some of the hardest equipment to handle.
This is something that should be considered. Many times water trucks are
overloaded. The truck may not have been designed to haul as much weight as
85
the water tank can hold. The mine operator needs to make sure that the weight
of the water does not exceed the capacity of the truck.
This truck backed over the edge of a dump. The
86
truck overran the berm.
The driver was travelling along the haul road and the
ground collapsed underneath this truck. The ground was
not stable enough and it broke out from under him. 87
Another reason MSHA doesn’t recommend end dumping is that, in many cases, the material is
loaded out. The mine operator was end dumping at this mine. In this case, the loader operator had
gone in and started loading other trucks. He did not inform the truck driver at the top that he was
going to be loading out of the toe. As he continued to load trucks, the haul truck continued to dump
at the same location. As the angle became too steep, it would not support the weight. If the loader
operator is going to be digging in a pile like this that is actively being built, they need to go to 88
the top
and put a barrier or some kind of barricade or warning at the top so no one will dump in that area.
A person is being transported illegally here. Traveling in
89
a bucket of a front-end loader is very unsafe
Here's a similar situation, but the person is lower and further back in the bucket. But it's
still hazardous to be riding in a bucket like this. As the loader builds up speed, it begins
to lope and the bucket begins to move up and down. If the driver needed to stop
suddenly, there would be nothing for the person in the bucket to hold onto. The person
would go flying out, and the loader would probably run over him. Also, the operator
cannot see anyone down in the bucket like that. The operator has no way of knowing if
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someone is in there or not.
Many times truck drivers get out of their trucks and talk to the
loader operators as their trucks are being loaded. This is a
violation. They are not allowed to get out and ride on a vehicle
while it’s loading their truck, without being in a safe location91and
being tied off (using fall protection).
This photo shows a traffic condition. Recall the very limited driver visibility in these large
trucks. In this situation the large trucks were coming around this curve, and they needed
to come to a complete stop because of another road crossing the road they’re on. The
problem was that as these large trucks traveled around the curve, the stop sign on the
right could not be seen because it was in the driver’s blind area. This company installed
another sign on the left so that the large trucks could see the sign, and left the one on
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the right for the smaller vehicles.
Here is another variation of a stop sign. The company
can use whatever type of sign they like, as long as it 93can
be seen and be understood.
The speed limit is very important at a mine. Speed has a lot to do
with many mine accidents. You must be able to stop within the
limits of your visibility. If you’re going too fast you can’t see far
enough ahead, around a curve, or over a hill to stop within a safe
distance. Speed limits must be determined at each section of the
mine haul road, indicating how fast the vehicle should be able to
travel in that area. The mine operator must post the speed limits.
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This photo shows an example of a speed limit sign. They
have a speed limit of 10 miles per hour in this area. Also,
they have a warning sign that alerts people to heavy
equipment crossing this area.
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There is a traffic control sign for this condition (a yield
sign in the background). But there will be two trucks,
both of them loaded and travelling uphill in the same
direction. The problem with this yield sign is with two
paths (two roads) and trucks pulling up, which one’s
going to yield to which side? The interpretation has
been left up to the drivers and that’s not what should be
done. A sign is needed that everybody understands and
interprets the same way. If the right side should yield to
the left side, a sign is needed that tells that, or some
other means of communicating that intention. Don’t
leave the interpretation of the traffic pattern up to the
drivers. Also, many companies have rules that “loaded
trucks have right-of-way.” Such rules don’t work in this
case because both trucks are loaded. And being
accustomed to having the right-of-way when loaded, if
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neither one yields, an accident would occur
This is a restricted overhead clearance, and it has a sign
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warning of that. But this sign is not big enough
Here's a close up of the sign. It says "low head room.”
But it is not big enough to be seen in time to actually
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warn anybody of the hazard.
This sign is a very good one. It says “no
dumping,” using the international symbol for “no.”
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Most people understand it.
This one cautions against high voltage overhead. You
don’t want to be raising the truck bed. It’s a temporary
sign, but it is adequate and acceptable.
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This sign is not acceptable. It has too much information, it’s not
being maintained, it’s very hard to understand, and people will not
stop to read this. They would probably catch the first line as102they
drive past and that would be about it.
This sign is not acceptable. It has too much information, it’s not being
maintained, it’s very hard to understand, and people will not stop to read this.
They would probably catch the first line as they drive past and that would
be
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about it.
The upper sign shows a steep grade. But a sign like that alone is not adequate for truck
drivers to determine how safe that grade is. For example, if this was a 13% grade for a
length of one-half mile, drivers would make a determination how fast they should be
going and what gear they should be in. Or if it was a 7% grade for 300 feet those drivers
would drive the trucks much differently. So you need to determine, and let the drivers
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know, the information they need to safely descend grades
This sign combines speed limit and grade information. Drivers not only see that the
speed limit is 10 mph, but also that they will be descending a 15% grade for 1500 feet.
All of this information is important because, for example, a new driver on the property
may decide to descend the grade in a lower gear than he/she would have if the sign had
only stated the speed limit. Most drivers are familiar with the limitations of their trucks,
and will know how to safely descend varying road grades. This type of informative sign
may help drivers arrive at decisions that could save lives or prevent accidents.
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Do not drink while driving
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No distraction
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