1. Mehdi Balti (23101) 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: 11-05-
2015 Buitems,Quetta
2. Mehdi Balti (23101) 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. Conveyor
System: Surface/Underground Equipment Continuous Operation The most
common conveyor systems of haulage are the belt conveyors, but
there are also scraper chain conveyors and cable belt conveyors.
Portable Stacking Conveyor Belt Conveyor: Modern belts are made of
a number of materials, including cotton, canvas, leather,
neoprene,
3. Mehdi Balti (23101) 3 nylon, polyester, polyurethane,
urethane, PVC, rubber, silicone and steel. A belt conveyor consists
of two pulleys located at either end of the machine, and a
continuous belt that rotates on them. The powered pulleys move the
belt and any material on it, forward. There are mounted carrying
idlers and return idlers. In order to achieve a tough shape to
accommodate more and more fragmented material, the carrying idlers
mounted on the sides are fixed at 20-30 degree to the horizontal. A
driving unit installed at its one ends having a motor, gears,
driving drum and other fittings to start, stop, or run the belt. At
the other end a take-up pulley is fitted to provide necessary
tension to the system. At the discharge end a belt cleaner cleans
any adhered material. The belt conveyor classified into three
types, based on mobility from one place to another. Stationary
Mobile Portable The belt conveyor also classified into three types,
based on their path. Horizontal Inclined Combination of Horizontal
& Inclined Cable Belt Conveyors: In this type of conveyor
system the belt is relieved from the tractive force which is
transferred to the ropes, which are attached at both sides of the
belt all along its length. A cable belt conveyor system consists
of: Two endless ropes, which are supported on the rollers &
pass over the drum or pulleys at both ends. Spring steel strips
embedded in the body of the belt. To these strips are mounted the
steel shoes which grip the ropes. The belt conveyor itself, which
could be of a single ply construction. It is the cheap quality belt
with less number of piles. It could be of longer length. The only
problem is the complicated construction at both ends of this
installation. Scraper Chain Conveyors: These types of conveyors
have been designed to withstand rigorous mining conditions
particularly at a working face, which is always advanced ahead.
These conveyors can negotiate gradients of more than 18 degree.
These conveyors are easily extendible without dismantling but their
length is limited & usually not more than 200m. A scraper chain
conveyor consists of the
4. Mehdi Balti (23101) 4 troughs, endless chain, sprocket
wheel, drive head having motors, gears, tensioning devices and
other parts. Chains are the important part of the scraper chain
conveyors. Chains should be of high breaking strength and longer
life. Also their design should be such that damaged links can be
easily replaced Conveyors are used in a wide variety of industries
including industrial, mining and automotive. The technology has
even been adapted into moving sidewalks and escalators. Advantages:
Continuous operation High production Low operating cost
Disadvantages: Capital cost Material size Truck:
Surface/Underground Equipment Continuous Operation A truck is a
vehicle used for carrying materials or for towing other vehicles
and trailers. Trucks can be used for a variety of purposes, both
industrial and commercial. In addition to transporting materials
great distances, they can also haul and tow large objects not
feasibly towed by a car, such as farm equipment, cattle, supplies,
trailers, recreational boats, and homes. Features: The features of
a truck can vary from type to type. The typical truck, commercial
or industrial, contains only two passenger seats. Trucks,
particularly heavy-duty trucks, have a series of clutches, gears,
and pedals to help facilitate a smooth drive. Trucks without a
synchronizer to accompany the transmission use double clutching for
each shift to help change gears. Double clutching can help the
driver operate the engine and control the transmission power so the
revolutions are synchronized, allowing for a smooth shift to be
achieved. The internal configuration of a heavy-duty truck calls
for a manual transmission without synchronizers to cut down on the
bulk and weight that the synchronizers add. It is not uncommon,
however, to see synchronizers used in conjunction with some large
truck
5. Mehdi Balti (23101) 5 transmissions. Advantages: Handles
coarse materials Flexible and maneuverable Considerable speed 30 to
45 mph Diesel powered Good traction with maximum load applied
Disadvantages: Requires good haul roads High operating cost Slow by
bad weather Bucket Wheel Excavator (BWE)
6. Mehdi Balti (23101) 6 Surface Equipment Continuous
Operation: 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.
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.
7. Mehdi Balti (23101) 7 (Diagrammatic BWE Sketch)
Disadvantages Will not dig hard materials. Some surface preparation
required. Lower availability. Large maintenance crew required. 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. ....The End..
