Rocker Shovel Loader

A Rocker Shovel Loader, sometimes simply referred to as a Rocker Shovel or Mucker is a type of mechanical loader used in underground mining.[1]

A Rocker Shovel is usually powered by compressed air, or in some cases electricity. It is commonly mounted on steel wheels designed to run on
narrow gauge rails, with some later models using metal or rubber-tyred road wheels. The operator, standing on a raised platform to one side of the
machine, operates the controls, one lever to drive the machine along the tracks, and another to raise and lower the bucket. Once the bucket has been
filled by driving the loader forwards into the pile of material, the rocker mechanism throws the contents over the top of the machine and into a wagon
behind. Once full, the loaded wagon can be taken away and replaced with an empty one to allow loading to continue.

The above photograph and descriptive drawing will be used to describe function and operation of the EIMCO Rocker Shovel Loader. The photograph has been sized
to approximately the same scale as the drawing. In both the photograph and the drawing the bucket of the loader is shown in the “digging” position and resting on the
rails. The bucket is also shown in the “discharge position” on the drawing. The model 12B machine weighs 4200 pounds. (1905 kg.) The required air pressure is 60-
125 pounds per square inch (413-861 kPa). Air consumption is 250 cubic feet (7.1 cu. m.) per minute. When the bucket is loaded with rubble, the operator actuates the
bucket drive motor, which exerts force on the rocker pull chain, which is attached near the outer end of the rocker arms, and the rocker arms commence to roll toward
the rear of the machine. The bucket is attached to the rocker arms in a manner that provides maximum initial lift force on the bucket. As the arms roll, the geometry
causes the bucket, with its contents, to travel upward and rearward. During the bucket travel, its vertical velocity decreases, and its horizontal velocity increases until
the rocker arms strike shock absorbing stops on the frame. When the bucket stops, its contents continue to travel into a mine car attached to the Loader. The magnitude
of the forces required to lift and throw the contents is substantial, and the machine was designed to withstand them repeatedly. Cables are attached to the rocker arms
and to the frames to prevent the rocker arms from coming out of the machine. One set of the cables may be seen in the photograph below that shows a loader in
operation in a typical small mine tunnel in which the machine was designed to operate.

Gathering Arm Loader :

Extensively used for loading coal in the narrow workings. They are basically of two
types 1.Caterpillar mounted and 2.Track mounted.

It consists of 3 principle units.

(i). A gathering head. (ii) A central crawler mounted chassis. (iii) A rear boom or jib.

1. A chain conveyor extending from the gathering head up to the boom end is transporting
medium, conveying coal gathered from the face to the receiving mine car, tub, conveyor or
shuttle car.
2. The gathering arms are operated by twin crank discs. This discs are, flush with the
working surface of the head.
3. There is a separate driving motor for each of the arm.
4. The rate of loading depends upon the no of the strokes/men and the conveyor speed is
also related to the rate of loading of the gathering arms.
5. There variable speeds are available on the loader for gathering speed of the arms.
6. The ramp of gathering head can be raised or lowered usually through 0.5m.
7. Hydraulic jacks are used for elevation of the gathering head and they are controlled by
the operator form this position at the controls.
8. At the face as the loader loads cowl it has to move forward to be close to coal heap and
in a gallery width of 4 to 4.8 m to and for movement of the machine are frequent for cleaning
up the gallery.
EXAMPLE :-
LoaderJoy 14BU27
 Up to 36 tonnes/minute (39.7 tons/minute) capacity
 965 mm (38 in.) wide conveyor
 1,500 mm (59 in.) diameter loading arms
 Dual-drive gathering head with either high-output continuous loading arms or gathering arms available
 SMART conveyor package, including dual-sprocket conveyor, quiet tail, and hydraulic tensioning
system
 OptiDrive traction system for smooth transmission responsiveness
 Faceboss control platform to facilitate an optimal balance of production rate and cost
 Radio remote control for greater flexibility when working in hazardous zones
 Air-cooled motors mean no water lines or filters are required
 Thermo-siphon cooled controller case
 Single-bolting rig (optional)
 On-board camera (optional)

The advantages of track mounted machines are as follows:

1.It is less affected by poor floor conditions.

2.It is possible to do close timbering. the operator is well back from the loading head and under the
protection of bars and girders.

3.Selective mining of dirt bands is possible

4.Flitting speed on rail tracks are generally higher and hence saving in time.

Disadvantages: 1.Its application is restricted to low low gradients only.

2.The width of the working places which may be cleared is limited by the reach of the machine.

 It is ruggedly built 1092 mm high crawler mounted loading machine with a capacity of 12-25
te/min in coal 1245 mm and higher.
 The gathering arms have a reach of 2350 mm and the central conveyor extends 3.35 m beyond
the bumper and has a swing of 450 .
 The machine is 8.17 m long x 2359 mm wide x 1092 mm high.
 The machine is powered by five motors- 2 for traction, 2 for head and 1 for pump with a total
H.P. of 160 hp for A.C. driven machines or 118 hp for D.C. driven machines.
 After the coal has been undercut and blasted down or blasted down off the solid, the loader
advances on the crawler and thrusts its gathering head into the heap of coal.
 While it does so, 2 gathering arms acting alternatively sweep and pull the coal on to the chain
conveyor, which carries the coal onto the end of a flexible jib and delivers it into the tubs,
shuttle cars or conveyors).

Load Haul dumper (LHD):

 Also known as a scoop tram
 specialized loading machine manufactured for the underground mining industry.
 LHDs are used in >75 % of u/g mines throughout the world and are suitable for small
and large tunnels, mines, chambers, and stopes.
 It performs loading, hauling and dumping of bulk materials

LHD is categorized into two types:

1. Diesel LHD 2. Electric LHD
Selection: It depends upon the following factors:
1.Size of operation
2.Length of haul
3.Height of seam
4.Operating condition
5.Local permissibilities
6.Experience

 The main chasis is divided into two halves, front and rear frame.
 Bucket is placed at the front end of front frame and it is raised or lowered by two
hydraulic cylinders.
 The front and rear frame is joined by articulated joint provide to the front and rear
frame to swivel through 1000 .
 All the control points are in the operators cabin placed at the rear frame and also the
diesel and hydraulic brakes are placed on the rear frame.
 The brake system consists of 4 nos. of disc brakes.
 The braking system has 2 accumulators which maintain the oil pressure in the brake
system for a short duration, if the oil pump stalls due to any reason.
 Accumulators are charged with nitrogen under high pressure. Accumulators also
provide oil for applying brakes instantaneously in case of emergencies.
  Capacity varies from 0.7645 to 6.1 m3 , gradient 1 in 7, maximum speed 8-10 kmph
(empty) and loaded speed 3-5 kmph. Average output expected from each LHD/day is
200-500 te.

Advantages:

1.Greater flexibility
2.Higher speed of transport
3.Higher productivity
4.Minimum labour requirement
5.Variable gradient
6.Directional change
7.Limited roadway dimensions
8.Continuity of transport ( from surface to underground in case of drift mine)
9.Interchangeability of equipment- by quick detachment and attachment techniques,
the standard machine can be rapidly converted on site to perform a variety of tasks.
10.Greater safety
11.Less expensive as a total system.

Disadvantages:

1.Slower for bulk material delivery

2.Less maximum load/trip
3.Difficult in heavy load movement- heavy bulky items are difficult to handle on tyres.
4.Greater maintenance cost- the roads requires more maintenance than trucks 5.Larger
consumption of engine power in overcoming the rolling resistance.

Recent development in the design and construction

1.Improved diesel power pack- 4 cylinder model, FLP, control of toxic fumes, noise, temperature etc. are
incorporated.

2.Extension of electric capability- advantage of environmental condition, cheap, existing power supply
can be used, improve performance, extended tyre life, reduced maintenance, scope of remote control
facility etc favour the wider application of the equipment in the coming future.

3.Improved payload obtained by improving the power, improved component, mechanical and structural
design (20 te capacity) etc

4.Quick detachable system facilitates to attach or detach any of the items like bucket, drift material
platform, fork body etc.
5.Development of the hauler concept incorporated

6.Man riding is possible.

One of its latest model LF2HE tyre mounted load load haul dumper is a low profile high output machine.
Special features of LF2HE: outstanding power/weight ratio , Low heat generation ,Low center of gravity,
Low specific base pressure fall, safe parking brake; powerful flood lights, emergency stops, heavy duty
construction, dead man switch ;front and rear end of the machine linked by an articulated joint.

SPECIFICATION

Standard bucket capacity 1.6 m3

Breakout force at bucket blade 55kN

Lifting time 7.5 secs

Lowering time 6.5 secs

Time of roll forward 5 secs

Electrical components Flame proof for U/G gassy mines

Travel speed 0-8 km/hr (high speed mode); 0-3 km/hr(low speed)

System pressure(max) 400 bar

Traction motors variable axial piston type

Displacement 107 cc/revolution

Drive power(max) 45kW

Hydraulic medium HFDU 68

Tramming radius 2300mm

Side Discharge Loader (SDL):

1.mounted on a crawler track and is designed for loading the broken rocks onto a conveyor or into the
tub in coal or stone workings.

2.The high travel speed (0.7 m/s) makes it suitable for working with the discharge point upto 10 m from
the working face with no appreciable reduction in loader output.

3.The loader can be employed on gradients rising or dipping upto 180 (1 in 3).
4.It is totally flameproof.

5.The SDL may be adopted for discharge on the left or right side. Bucket capacity is 2.032 te (maximum).

Optional components:

1.Cable reel

2.0.1m3 coal bucket

3.Head light

4.Dust suppression kit

5.Dump valve with lock and key

 Average output expected from each SDL/day is 200 to 500 te/day.

 At Bankola and Bahula colliery, ECL, India from development panel, average production per SDL
achieved 125 te with an OMS 1.9 te/man/shift.
 This equipment is used for applications in underground mining.
 It is indigenously designed and developed by in-house R&D.
 This equipment weighing 9 tonnes, is fitted with 1cu.m. bucket.
 Fitted with powerful 55 KW motor operating at 525V, 50Hz, this equipment ensures very high
productivity.
 It is ideally suitable for deployment in underground mines where intermediate or Semi-
mechanization is used.

Specifications:

Standard bucket capacity 1.0/1.5m3

Travelling speed: 2.6 kmph (max.)

Total weight 8500/9000 kgs

Ground pressure 0.9 kg/cm2

Tractive force 5200 kgs

Break out force 3000 kgs

Electrical components Flame proof for U/G gassy mines

Negotiable gradient for driving and loading: 1:4,

cross gradient 1:6

System pressure (max) 125 bar

Traction motors: Radial piston fixed displacement type

Payload(max): 2.0 MT

Drive power (max): 55 kW