The first is a filtration device aimed at reducing solenoid failures related to debris contamination of fluids. According to Longwall Hydraulics managing director, John Abercrombie, approximately 95% of solenoids fail through debris related problems. The newly developed device by-passes the existing coarse filter and includes a filtration system that has much increased debris holding and flow capacity.

The new improved system to protect the solenoids gives a 10 micron absolute filtration protection," Abercrombie said. "From our experience, solenoid failure decreases dramatically with this level of filtration."

At present Longwall Hydraulics is installing the device progressively onto a second longwall which is in NSW by retrofitting 7-10 chocks at a time. For the price of one solenoid repair a longwall mine can fit this unit to each support, thereby reducing the incidence of solenoid debris related failures" said technical manager, David Saint. At this stage the retrofit is applicable to Joy Mining Machinery chocks but Abercrombie said the company is already developing one for DBT supports which will be available in the near future.

The company has also released the Safety disc, a replacement option for intensification protection to roof supports hydraulic cylinders.

"One of our customers approached us and said they were having problems with the intensification devices on their chocks which was costing them a lot of money," Saint said.

Longwall Hydraulics designed their device to overcome problems such as damage to the thread of the port where the device is fitted, and incorporating a left-hand thread to ensure that a standard plug is not fitted to by-pass the safety devise. Longwall Hydraulics custom design the Safety Disc to suit individual customers equipment using its internal CNC machinery.

Appin and Elouera are in the process of fitting the new intensification devices to their longwall chocks. Longwall Hydraulics is also the Australian agent for German pump manufacturer, Kamat Pumpen. Elouera, Kestrel and Cumnock are using Kamat pumps and the Ulan mine is currently trialing a Kamat pump for evaluation in the lead up to tender for a new pump station. Following the overwhelming acceptance of Kamat pumps in USA longwalls over the last five years. Longwall Hydraulics objective over the next two years is to firmly establish Kamat pumps in Australia and strive to become the market leader in this area in Australia.

At the BHP Billiton San Juan longwall mine in the USA a four pump Kamat configuration has just been commissioned on the surface and will be installed underground in the near future. It is the biggest such longwall pump configuration in the world. Each Kamat K35060 pump is capable of pumping 523 litres per minute at 350 bar for a total roof support supply of 2100 litres per minute.