Wirtgen 4200SM Surface Miner

When it comes to surface mining, most techniques involve drill & blast methods to loosen the rock ready for hydraulic or rope shovels to load the broken material into haul trucks. One alternative is the use of a machine to directly grind away at the surface, breaking up the material and self loading it into awaiting trucks. For years, Wirtgen have produced a number of cold milling machines for road repair and resurfacing tasks and the 4200SM surface miner is a super sized cold planer with an enormous appetite for eating rock.

At the heart of the machine is a 4200mm cutting drum which is supplied with different pick arrangements depending on the type of rock being mined. The drum is fixed to the chassis with a large drive belt connecting to the power unit and this is modelled on the replica with opening side doors revealing the rubber belt and adjustable side plates preventing material from spilling out at the side of the cut.

Mounted low down within the chassis is the powerful diesel engine with plenty of service space provided in the compartment, complete with a folding front access ladder while ladders also lead to the upper works which are surrounded by scaled metal safety railings and service walkways giving access to the dominant exhaust and air intakes rising up into the air. The large side panels have a fine etched grill pattern which really looks authentic and offers glimpses of the interior.

Cutting height is controlled by the four large arms, each holding a pivoting track frame with independent hydraulic steering and height control with each track frame having individually linked track pads that have good surface detailing. Due to the impressive weight of the model, several holes are visible in the lift hydraulics allowing pins to be inserted to keep the cutter in the raised position.

The large cabin is mounted high in the air for an unobstructed view of the area and can be rotated for the optimum view although the range of adjustment on the replica is limited.

The rear of the machine features a large discharge conveyor, complete with rubber belt that has raised chevron cleats moulded into the surface. The entire frame can be rotated to 90 degrees on either side of the chassis allowing different loading options with height adjustment of the conveyor controlled by metal cables with hydraulic cylinders which are stiff enough to hold the conveyor in any position.

When discharging to the sides of the machine, the frame has a counter-balance system with ballast plates extending out to counteract the weight of the material to keep the machine in balance and this is also fully functioning on the model. One nice addition is the ability to raise the discharge conveyor to the service position to gain access to the primary conveyor which is also fitted with a rubber belt.