Brisbane-based Cutting Edge Technology Pty Ltd (CET) have revisited an underground coal mining technique first pioneered in the 1930s. They have now produced a robust underground auger mining system that allows miners to access irregular shaped reserves and seams with poorer ground conditions that are not suitable for conventional mining methods.

The South African underground auger (BUA 600) successfully passed through the commissioning period achieving all of the design targets in terms of hole depth, drilling rate, coal conveying and clearance, flight handling and cutter head control. The target depth of 80m was first reached in only the third hole drilled. The unit has successfully completed over 600 holes to date.

Building on their experience in South Africa, CET is manufacturing an underground auger in Brisbane, which will be specifically suited to local conditions. The development of the Australian underground auger is now close to completion and has been aided by a Federal Government START Grant.

The Australian underground auger is larger and more powerful than the BUA 600, with a cutter head of 1.6m driven by a 600kW motor, compared with the 1.2m cutter head and 450kW of the BUA 600. It has a penetration depth capability in excess of 100m.

The Australian underground auger has been designed to operate in a roadway of 5.2m wide and 2.1m high (or greater), with a lower 1.8m minimum traveling height. Due to the more gassy nature of Australian coal mines, an internal 330mm bore has been incorporated into the flight string to ventilate the coal face.

CET have established a joint venture with SBD Services to offer a contract underground mining service through a new company, SBD Mining. This company will provide underground augering services on a cost per tonne basis. SBD Mining are targeting a production rate of 400,000tpa with mining costs typically between longwall and bord and pillar operations.

More information can be found at www.cetpl.com/Underground_Mining_Tech/underground_mining_tech.html