Published in March 2008 Australian Longwall Magazine

Longwall Hydraulics announced its expansion into the market late last year and appointed former Inbye Mining Services man Mark O'Toole to head up the new business.

To bring a new monorail concept to Australian shores Longwall Hydraulics signed Agency Agreements with West Virginia firm Swanson Industries and German companies Weinhold and Neuhauser.

Swanson supplies and services monorails to the United States underground coal market; Weinhold manufacturers high-pressure pipe which has been proven in longwall installations in the US; and Neuhauser already has a significant quantity of its heavy duty monorail sections in Australia.

Longwall Hydraulics aim to introduce Swanson's “Over-Under” monorail system to the Australian market, while providing services for the repair, maintenance and refurbishment of monorail systems. It will also supply a range of monorail accessories including traction drive units, trolleys and rail and project management services for monorail mini-builds and overhauls.

The majority of the fabricated components of the system will be manufactured in Australia and the drive components will be manufactured by Swanson in the US. Longwall Hydraulics said the design principles incorporated into the system are consistent with systems meeting industry standards in Australia and the US.

Longwall Hydraulics' system includes Swanson's “Push-Pull” traction units – powered by Solsenic fluid. To provide hydraulics power during a power move, Longwall Hydraulics offers a Monorail Mounted Mini Pump system. Mounted on the monorail, the unit uses the readily available compressed air to drive a high torque air motor which drives a small capacity plunger pump. An additional small capacity emulsion tank is also mounted on the unit.

During the power move, the system is isolated, and the mini pump provides a small amount of flow into the monorail hose system sufficient to operate the Push-Pull unit at a satisfactory speed to conduct the power move.

"Longwall Hydraulics Agency Agreement with Swanson Industries enables us to offer a unique monorail system which is unconventional in that it substantially replaces most of the hoses in the monorail system with High Pressure Piping," Longwall Hydraulics told Australian Longwall.

This system has already been installed at Mach Mining in the US, and according to Longwall Hydralics offers a "new level of efficiency and safety" into the longwall hydraulic system.

"The immediately obvious advantage of this system is that the amount of hydraulic hose in the monorail is reduced by up to 80 percent. Yet the system is still capable of achieving typical power moves of two pillars (220-260m). This is a significant reduction in the number of hydraulic hoses and hose joints."

The company said by reducing the number of hoses used it decreases exposure to hose damage wear and breakage; exposure of personnel to the risks associated with hydraulic hoses; replacement costs of hydraulic hoses; and decreases the pressure drop experienced due to all the hose joints and hose sizes in a conventional monorail.

"Pressure drop in conventional verses pipe systems has been quantified by Swanson at a US installation where a single DN80 pipe has replaced three DN50 hoses on the pressure side, or a single DN100 pipe has replaced three DN65 hoses on the return side. In either case the pressure drop from the pipe is a third of that from the hoses," Longwall Hydralics said.

The complete system is assembled with the longwall installation. Once the pipework has been installed it remains assembled for the length of the longwall block. Likewise the over-under rails system and the “Loop Free Zone” remain assembled through the length of the block.

The fixed pipe section on the monorail has take-off points every 50-90m on the outbye end and may be up to 400m long.

During operation, “mini moves” are performed: the hydraulics are disconnected at the pump station cut through and the fixed section is driven outbye to the next “take off” point. This continues until the outbye end of the fixed section is aligned with the next pump station cut through, and then a power move is undertaken.

The system includes a roof-bolting and pipe installation platform on the outbye end and mini-trolleys to carry services out to it. The platform has its own push-pull unit to propel it up the heading.