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| In the photo above an electric
shovel loads magnetite ore. The post and dark lines are electric wires
that carry the electric current that powers the shovel. In the photos below the shovel is loading the truck. Notice the "cat" in the left photo. This is a full size caterpillar that cleans up after the shovel so that there are no sharp rocks that could puncture the tires on the truck. |
The above photo is a haul truck.
A truck can carry about 240 ton of material in one load. It is powered
by diesel motors that generate electricity to run the electric motors
at each of the rear wheels. Direct drive motors to a transmission is
not possible because the mechanical transmissions could not withstand
the forces required to turn the wheels. To give a sense of size, the windows on the shovel are about 5 feet tall. |
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| Above is a photo of a drill with a full sized van on the
right. The drill makes holes in the hard rock which is then blasted so
the shovel can pick it up to load it in the haul trucks. |
In this photo each "little" mound is surrounding a 16 inch
diameter hole. Ammonium nitrate (a common fertilizer) and fuel oil will
be packed in the holes and then detonated to blast apart the rock. |
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This is what the rock looks like after blasting. The force of
the explosion twists, cracks and lifts the hard slate and chert rock so
that the electric shovels can scoop it up. |
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| The full haul trucks travel at speeds up to about 30 miles
per hour. Two wheels on each side of the back axle are driven by
electric motors. The electric current for the motors is produced
by diesel engines. The tires on the truck are about 10 feet in
diameter. The trucks each have a GPS (Global Positioning Satellite)
receiver that sends information back to the control center. The person
at the control center directs the driver for the most efficient use of
the trucks. The GPS information also helps to determine fuel and
maintenance schedules. |
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The photo at left is of the mine overlook where the photos on
the previous page were taken. The red arrow points to the
building that is the overlook (almost invisible in the photo) and the
blue arrows point to a "road" that mine trucks used to take when
hauling ore out of the pit. The roads are no longer in use, they have
roadblocks at the top. The company that used them is out of business
and most of the equipment is either sold or moved. The only thing that
remains is an old "tin" shed causing a speck of sun glare to the left
of the roads. |
