The document provides information on various mining equipment used for both surface and underground mining. It describes the bucket wheel excavator (BWE) which is a large continuous mining machine that excavates and loads material using a rotating wheel with buckets. It also discusses power shovels which operate cyclically to load and haul material. For underground mining, it outlines the shearer, a cutting machine used in longwall mining, and load-haul-dump trucks (LHDs) which are used to transport excavated material cyclically within the mine.

1. (Balochistan University of Information Technology,
Engineering & Management Science, Quetta)
(Features of Mine-Machines)
SUBMITTED TO: Engg. Fawad-ul-Hassan
SUBMITTED BY: Ghulam Mehdi
SUBJECT: Mine Power ,Drainage & Material Handling
CMS ID: 23101
DEPT: BS Mining Engg. 6th
, (Fall-12)
DATE: 15-04- 2015
……………………Buitems,Quetta……………………………

2. Features of Machines
Continuous Operation:
The machines combine the breakage and handling functions, cutting, drilling and blasting are
eliminated, and extraction and loading are performed in a single function (excavation).
Cyclic Operation:
The machines performed the two principal operations loading and haulage, with hoisting an
optional third when essentially vertical transport is required.
Surface Equipment
Continuous Operation:
Bucket Wheel Excavator (BWE)
The bucket wheel excavator (BWE) is a machine that digs and excavates dirt continuously with
the help of buckets, chutes, and a conveyor apparatus. BWEs are used for cross-pit mining and
large construction projects.
BWEs Advancements including mounting them on crawler and wheeler bases to allow them to
move forward for continuous excavation developed through time. The power and complexity of
BWEs mean that they can take as much as five years to build but in return they are capable
of mining more than 313,908 cubic yards (240,000 m3) of earth per day.
BWEs are typically some of the largest machines on earth, weighing as much as 11,000 tons and
standing hundreds of feet tall.
Features:
The first BWEs were powered by steam and mounted on railway tracks. Traditionally, the
buckets would empty dirt into carts that could be driven on the railroads. Eventually they became
electric and were driven with hydraulics and oil engines.
In their early days, BWEs consisted of booms that were raised and lowered by cables pulled by
men. Eventually, manpower was replaced by winches that raised the cables of the excavator.
To excavate materials continuously, the BWE uses a rotating wheel that is positioned at the rear
of the boom. The wheel consists of backets, also known as buckets. It can have any number of
buckets, depending on the project and model. The rotating wheel penetrates the face while the
boom swings from both sides and the bucket collects the dirt. As the material falls onto the
conveyor belts, it is transported to further conveyors until it reaches a discharge point. The
conveyors used are usually connected so they can be dismantled when the BWE needs to be
transported.

3. Advantages
 Continuous operation; no swinging necessary.
 Long discharge range.
 Can be operated on a highwall bench or on the coal seam.
 Can easily handle spoil with poor stacking characteristic and poor stability.
 Can extend range of shovel or dragline when operated in tandem.
 Can facilitate land reclamation as it dumps surface material back on top of the spoil pile.
(Diagrammatic BWE Sketch)
Disadvantages
 Will not dig hard materials.
 Some surface preparation required.
 Lower availability.
 Large maintenance crew required.

4.  High capital cost compared with output.
 Can be susceptible to spoil slides and flooding.
 Can cause coal damage with resulting lower coal recovery.
 Poor mobility.
(Actual BWE)
Cyclic Operation:
Power Shovel
Since its creation, the shovel has evolved into many forms. Beginning as a steam-powered
device, inventors and manufacturers continued its development for the two centuries after its
birth.
The result is a long line of machinery, many of which have crossed industries and become multi-
functional and crucial to a majority of applications. The steam shovel, a simple device used to lift
dirt, has branched off first as cable excavators, and then as hydraulic excavators. The wide
variety of excavators is evidence of the impact shovels have had on the industry.

5. The shovel has also served as the basic prototype for other equipment, stripping
shovels, draglines, and bucket excavators, all of which have play important parts in how dirt is
extracted from the earth.
Features:
The earliest shovel was rail mounted but later versions could be wheeled or mounted on crawlers
for more mobility. Changes also included evolving from steam-powered to oil or gas-powered.
Many of the features of the first shovel have merely been improved upon, such as the slew. The
first machine was limited in its swing, but since manufacturers have devised a way to make the
arm capable of a 360 degree swing. The bucket can also be altered to lift a certain weight of
materials, usually measured in cubic yards.
The arm of the shovel, also known as the boom, is controlled by switches and gears. This can be
done by hydraulics, pneumatics, or in as in the cable excavator, by cable wires. The bucket
strikes the earth and scoops the material. In some situations, there is a dump truck or other
vehicle for the purpose of dumping. In stripping shovels, the shovel is capable of breaking
through hard rock for the purpose of uncovering raw materials or minerals.
Types:
The way shovels have evolved since Otis’s invention can be seen in the dozens of varieties have
materialized over the course of two centuries. They have taken many forms, but the most
important are listed below.
Cable Excavator
The first cable excavator originated in the form of the shovel but evolved when the mining
industry required heavy-duty equipment. Cable excavators extract dirt by the pulling of wire
ropes or cables. The Bucyrus 120-B, produced in the 1920s, answered the demands of mining
quarries with its capabilities. The cable excavator was made almost obsolete and suffered a
steady decline when excavators were made hydraulic. Manufacturers such
as Bucyrus and P&H still produce cable excavators and they are used mostly within
the mining industry; however, they are no match for the stripping shovel or walking dragline.
Hydraulic Excavator
The hydraulic excavator overtook the cable excavator because it was cheaper, faster and more
productive. Using hydraulic oil to function the arm and bucket, the hydraulic excavator is one of
the most popular machines. The earliest record of a hydraulic shovel appeared in 1882, by a
British Company called Sir W.G. Armstrong & Co.
Stripping Shovel
Stripping shovels are used to strip away hard materials and rock to uncover materials. They
differ from the cable excavator in its height and capability. More suited to extract hard materials

6. in heavy-duty operations, mainly mining, it is embraced for its size and power. It is also more
advanced in that it moves forward on the excavated surface to continually extract materials.
Stripping shovels, such as the 15,000-ton Captain shovel, are among the largest in the world.
Advantages
 Lower capital cost per yd3 (m3) of bucket capacity, although when boom length or
machine weight is considered, the capital costs are roughly equivalent.
 Digs poor blasts and tougher materials better.
 Can handle partings well.
Disadvantages
 More coal damage can result in lower coal recovery.
 Susceptible to soil slides and pit flooding.
 Cannot easily handle spoil having poor stability.
 Cannot dig deep box cuts easily.
 Reduced cover depth capability compared with a dragline of comparable cost.
 Difficult to move.

7. Underground Equipment
Continuous Operation:
Shearer
A coal shearer is an electrically driven hydraulic cutting machine also referred to as a power
loader, stage loader or shear loader used in the longwall mining of coal. The average coal
shearing machine is 15 meters long, weighs in excess of 90 tons and can travel up to speeds of 10
to 14 meters a minute. Other coal shearers such as those used in the Twenty mile Coal Mine has
the ability to travel at speeds of 45 meters per minute.
Coal shearers of different models are designed with varying dimensions and power output
depending on the manufacturer. The parameters for selecting a coal shearer for a longwall
mining operation is contingent on the type of shearer, dimensions of the shearer as well as the
haulage speed and power output of the machine.

8. (Shearer)
Features:
The shearer travels along the face of the coal seam, slicing large slabs of coal with a large drum
or cutting head mounted on a large number of picks. The drums featured on shearers consist of
two types. One type is the conventional pick-flushing drum that sprays water through spray jets
mounted on top of the cutter drum vanes which varies from two to six vanes. Spray jets located
in the front of the cutter pick are known as pick face flushing (PFF) and in the back as pick back
flushing (PBF). Wet cutting allows for dust particles to become wet as soon as the picks on the
drum impact the coal and cut it. The water gets mechanically mixed with the cut coal. With an
extraction drum, water is mixed with the cut coal as it gets discharged from the drum.
The shearers are designed to cut the coal seam in two different patterns:
 Bidirectional
 Unidirectional
Unidirectional cutting is the most common type of cutting pattern used in U.S. longwall mining
in which the shearer travels tail entry to head entry. A leading drum is raised and cuts the coal

9. while the trailing drum remains free from cutting or cuts the floor coal depending on the height
of the coal seam. On the return trip back along the face the cleaning of any loose remaining is
achieved. With bidirectional cutting, a web width of coal is cut in both directions of travel with
each cutting trip requiring involving two-faced end operations to turn the machine around. The
machine is usually operated by remote control from a safe working position inside the
underground mine.
Coal shearers also come equipped with self-haulage unit usually comprised of a conveyor belt
system that transports the coal away from the face after it is cut. The most common conveyor
belt system, called an armored face conveyor, travels under the shearers collecting the coal as it
is cut.
When using a shearer in a longwall mining operation a temporary mechanical hydraulic roof
support system is needed to stabilize the mine’s roof. The roof supports, positioned behind the
shearers, advance along the entire length of the coal seam face. As the coal shearer moves over
the face, the roof supports are lowered and get push hydraulically up to the newly positioned
shearer.
(Shearer)

10. Cyclic Operation:
Loud-Haul-Dump (LHD)
A load haul dump truck (LHD), also known as a scoop tram, is a specialized loading machine
manufactured for the underground mining industry. LHDs are used to scoop extracted ore, such
as coal, with a bucket, load it into the cart, and dump it in the bottom of the mine to undergo
primary crushing before being hoisted to the surface out of the mine.
LHDs are used in more than 75 percent of underground mines throughout the world and are
suitable for small and large tunnels, chambers, and stopes.
(LHD)
LHD Internal
The standard for LHD is a diesel engine with horsepower ranging from 78 to 145, but smaller
LHDs are outfitted with electric motors. The engine of the LHD are cooled either by water or air
and located on the chassis along with emergency and parking brakes, and hydraulic fluid
resistant to fire.
Other internals of the LHD include a diesel exhaust treatment device that uses water, catalyctic
fume diluter, or similar substances to spray or bathe the exhaust device with water. The LHD is
also commonly equipped with a device that automatically shuts off the fuel supply to the engine
in emergency situations such as exceeding temperatures of exhaust gases.

11. A ventilation system is required for the LHD to counter the excessive exhaust fumes it creates
inside a confined space. Ventilation systems are also incorporated into safety laws and
regulations defined by many countries. To accomplish a healthy working environment, it is
recommended that the velocity of air should be more than 98.4 feet (30 m) per minute.
LHD External
The externals of the LHD include the bucket, loading and dumping mechanisms and tires.
Buckets can come in a variety of sizes, from 1.04 to 13.1 cubic yards (0.8 to 10 m3) with
payloads of 1.5 to 17 tons. The standard type ranges from two to five cubic yards (1.53 to 3.83
m3).
The tires can be treaded or smooth and may be fitted with chains. Most mines tend to remove the
chains if the LHD includes them because they can prove dangerous in some conditions. Tires
account for 10 to 20 percent of the total operation cost because they have to be re-treaded or
replaced every 75 to 1,000 hours when they wear down. Tire experience such wear and tear as a
result of wet ground, too much wheel spin, and the unstable and sometimes ragged condition of
the road they run on.