Load-Haul-Dump (LHD)

Overview

A load-haul-dump machine, or LHD, is the underground equivalent of a wheel loader, reshaped to fit a mine. It is built low and narrow to clear tight drifts, centre-articulated so it can bend around sharp corners, and fitted with exhaust aftertreatment because it runs in confined, ventilated workings. One machine does three jobs in a single trip: it loads broken ore into its bucket at the drawpoint, hauls it down the heading, and dumps it into a truck, ore pass, or stockpile.

The work tool is the Loader Front End, a wide bucket on a lift arm, raised by lift cylinders and rolled by a tilt cylinder to dig and dump. The carrier is the Articulated Chassis, two frames joined at a centre hinge so steering cylinders bend the machine to turn rather than steering the wheels, a layout that gives a tight turning circle in a low, square cross-section.

How it works

Power comes from the Diesel Engine, a turbocharged diesel whose pistons fire on injected fuel to turn the crankshaft, breathing through a turbocharger and shedding heat through an oversized cooling pack because the surrounding air is hot and still. Its exhaust passes through a particulate filter and catalytic purifier so the machine can run underground. Engine torque feeds the Torque Converter & Transmission: a fluid torque converter multiplies torque and lets the machine stall against the muckpile without dying, then a powershift transmission selects gear on the move.

Drive reaches the ground through two Drive Axle units, each with a differential and planetary wheel ends that split and multiply torque to the Wheel Assembly on mining tyres. A single Hydraulic System, engine-driven pump, valve bank and reservoir, powers the steering, lift and tilt cylinders, which all share a common ram design. Stopping is handled by the Brake System: oil-cooled wet discs at the wheel ends plus a spring-applied park brake backed by an accumulator, so the machine fails to a stop on the grade. The operator works from the Operator Cab, a low ROPS/FOPS station seated across the machine for a clear view both ways down the drift, with electrical loads carried by the 12 V Battery.