Some five years ago, while employed by Joy Mining Machinery, Lindsay Auston

visited a mine in West Virginia. It was the first time Auston saw a single KH power

supply unit powering an RS20 Control System.

"We were impressed by its power and reliability," Auston said.

Auston left Joy three years ago, recently forming NSW-based Longwall Advantage to

provide an alternative source for longwall control system services. The company has

the agency for KH Controls.

Between 45 and 50 of the roughly 60 longwall systems in the United States have

controls systems powered by KH Controls power supplies. In addition, the longwall

lighting system introduced by KH in 1997 will be in service on 15 US longwalls by

the end of the year. Auston said Longwall Advantage was also reviewing whether to

introduce the lighting system into Australia.

Auston said he first saw an opportunity to introduce the KH Controls systems into

Australia when the safety related aspects of IS power supplies were first brought into

doubt some two years ago. Auston contacted Roger and Kevin Huczko of KH

Controls in the United States to review the design acceptability to Australian

Standards. An application for a Certificate of Conformity was submitted in March

1999 to SIMTARS.

"After 18 months of exhaustive testing we now have a certificate of conformity that

allows the coal industry access to the highest rated capacity IS supply in Australia

today," Auston said.

Testing of the power supplies is due to begin at a Bowen Basin mine in late October.

Compatibility compliance testing with the power supplies has been completed by Joy

and is due for completion with DBT.

The company said the certificate confirms an Ex (ia) I IP55 power supply conforming

to AS 2380.1 and AS 2380.7 with the following parameters:

Um = 125 VAC

Uo

Io

Co

Lo

The power supplies are available in a range from 10V, 750mA to 13.4V3.2A under

the same Certificate of Conformity and can be custom designed for specific

application such as AFC CST drives or gas monitoring systems. The power supplies

are available as stand alone electronic assemblies or as a complete assembly

including Ex d I flameproof enclosure.

"The model ISS1 power supply provides battery-like power quality while complying

with the strictest of international standards for intrinsic safety," Auston said.

The original version of the power supply expanded into a family of various ratings

and certifications for specific customer needs. The USA MSHA version is available in

output ratings up to 13.0 volts and 8.1 amperes. The EN version is available in output

ratings up to 13.4 volts and 3.2 amperes. The recently certified Australian Standard

version is available in output ratings up to 13.4 volts and 3.2 amperes.

KH Controls is a leading supplier of intrinsically safe power and lighting systems for

the US underground coal mining industry. Products include a family of intrinsically

safe power supplies, lighting systems, integrated systems and custom electronic

solutions. Power supplies are available in USA MSHA, European Norm and

Australian Standard versions.