An LHD (load haul dump machine) is a specialized loading machine used in more than 75% of underground mines worldwide. LHDs are available in diesel or electric versions and are used to transport material in tunnels, chambers and stopes. The internal components of an LHD include a diesel or electric motor, hydraulic system, ventilation system and diesel exhaust treatment. External components include buckets of various sizes for loading material and treaded tires. Safety features include emergency brakes, lighting, alarms and fire suppression. LHDs transport material by loading buckets then dumping the material after transportation underground.
1. LOAD HAUL DUMP (LHD)
Prepared By:-
Neelesh Pandey
(Asst.Prof)
COURSE NAME:MINING MACHINERY
DEPARTMENT OF MINING ENGG.
VITS SATNA (M.P)
2. INTRODUCTION
1.A load haul dump (LHD) is a specialized loading machine
manufactured for the u/g mining industry.
2.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.
3. TYPES OF LHDs
1. LHD are available in
i) Diesel
ii) Electric versions.
2. Diesel version is easily transportable from one location to another and have
diesel engines as power drive of 75 to150 HP or more.
6. COMPONENTS OF LHD
The LHD is a machine that travels at modest speeds and consists of a
internal and external components
LHD INTERNAL COMPONENTS
The standard for LHD is a diesel engine with horse power 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.
7. Other internals of the LHD include a diesel exhaust treatment
A ventilation system is required for the LHD to counter the excessive
exhaust fumes it creates inside a confined space.
8. LHD EXTERNAL COMPONENTS
The externals of the LHD include the bucket, loading and dumping
mechanisms and tires. Buckets can come in a variety of sizes, from (0.8 to 10
m3) with payloads of 1.5 to 17 tons.
The tires can be treaded or smooth and may be fitted with chains.
9. SAFETY PROVISIONS
Emergency and parking brakes with fire resistant hydraulic
fluid is used .
Head lights, audible warning signal, back up alarm and
portable fire extinguisher are provided.
Special cabin/canopy is also provided for safety of operator. A
safety device is provided to shut off the engine if exhaust gases
exceed temperature of 85 °C (or as per set value).
For electric shock safety these LHD's power source(gate end
box) are equipped with earth conductivity protection using
pilot core in electric trailing cable, which isolate complete
power when earth continuity is broken
10. MECHANISM OF LHD
It is driven by a synchronous motor fed with power
from a gate end box suitably placed with a flexible cable
of about 100 metres in length .
If it may also be remotely controlled .
The speed of the vehicle is controlled mechanically.
11. It is driven by a synchronous motor fed with power from a gate end box
suitably placed with a flexible cable of about 100 meters in length .
If it may also be remotely controlled .
The speed of the vehicle is controlled mechanically.
12. LOADING AND TRANSPORTATION
The operate hydraulic pumps and hydraulic
motors for further operation of various movement
of bucket and vehicle steering.
15. Advantages of LHDS
1. Availability of spares parts to reduce breakdown hours
2. To withstand difficult conditions.
3. For easy maintenance.
4. Portability:Easy to move from place to place.
5. Safety:Proper guides and covers and Electrical
protective devices.
