Augering Down Under (ADU) and Cutting Edge Technologies (CET) both have working prototypes of their underground augers, but have a long way to go yet before full commercialisation.

ADU is a joint venture managed by Brian Woolnough, who retired from the role of managing director of Colrok Australia last year. With a change in focus for Colrok, away from the small specialised niche area of augering, Woolnough picked up this part of the business and has established a new and separate business. The operator of the equipment will be another newly formed company, Eastern Mining Construction Company (EMCC), run by Vince Martin.

EMCC plans to offer auger technology for two main applications: developing 1.8m-diameter cut-throughs and recovering reserves that would otherwise be sterilised.

Martin said developing cut-throughs via current methods cost about $1000-2000 per metre, while augering methods could drag the price down to about $300/m, with only minimal roof support required. A conveyor system has also been designed to permit coal transport through the augered cut-through hole.

Until recently EMCC was mine site testing its production method for the second application at the Southland mine in the Hunter Valley region, New South Wales. The two﷓man operation operates with a 1.5m coal auger machine and a recovery device. The auger recovery unit both recovers the 2.4m length auger drills (weighing 0.9 tonnes) from the previous hole and moves each of the auger drills onto the auger bed-plate for use in the next hole. Auger holes are nominally 1.5m diameter and 50m long, leaving 0.7m web of solid coal between auger holes. Recovery of coal employing this method varies between 25-40%.

The next step for ADU is to assess the results of its augering trials and obtain NSW Department of Mineral Resources approval for minor safety issues.

Meanwhile, CET is pitching a roadway development system for underground mines using augering methods. CET director, Bret Leisemann, said the roadway development system would be ready for trials in April next year.

CET has been conducting trials of a USA designed auger in South Africa in collaboration with the BryDet Development Corporation of the US and Eskom of South Africa. According to CET, BryDet has been designing and building surface coal recovery augers equipment for more than 12 years and is the world’s leading manufacturer of auger mining equipment.

The main aim of the collaborative project between BryDet, Eskom and CET was to develop and demonstrate an underground auger mining system able to provide economic access to the thinner (less than 1.8m) coal seams of South Africa.

In order to facilitate the re-use of auger flights between auger holes, the system was designed with two main modules: a Drill Unit and a Retrieval Unit. CET said underground augering offers particular advantages when attempting to recover reserves “locked” between panels and against geological features such as faults or igneous intrusions.

According to CET, some of the reasons underground augers failed in the past were related to lack of sufficient power to drill a large diameter hole to sufficient depth, lack of effective cutter head steering to avoid cutting roof and floor, lack of an effective method of loading, unloading and storing auger flights while drilling, and lack of a haulage system to remove the cut coal from the throat of the borehole and keep the machine from becoming coal bound.

BryDet and CET recently embarked on a major project in Australia looking at utilising an underground auger to significantly improve longwall roadway development rates. This technology will be based on, but different from, the auger machine still on trial in South Africa. Leisemann said the technical details were still under wraps but that further information should be available by December this year.

* This article originally appeared in the September 2000 edition of Australia's Longwalls.