Published in Australian Longwall Magazine
Recent sales of ABM25 machines include two each at Newstan and Mandalong, one ABM25 low height machine for Glennies Creek, two for Moranbah North for year-end delivery and two for North Goonyella for late 2004-early 2005 delivery.
According to Voest Alpine business line manager Barry Wright three guiding principles governed the redesign of the ABM25 - safety, increased capacity along with simpler maintenance, and real-time performance measurement.
“An analysis of the safety statistics database on continuous miner accidents from Coal Services was undertaken,” Wright said. “A further analysis of the database revealed that the majority of the job tasks involved manual handling, (eg. cables, supplies etc) operational, (eg. bolting) and maintenance /inspections.”
Wright said this analysis and discussions with customers resulted in the inclusion of a vast array of safety and ergonomic features such as larger platforms with ‘bump bar’, integrated rib protection, improved dust curtains, improved bolting pattern, larger operator space/increased work area, improved ventilation design, increased pick spacing, auto TRS (temporary roof support) stabilisation, improved bolt station positions, improved materials handling (effectively no one handles supplies until they are on the machine), integrated mesh carrier and improved housekeeping.
On the engineering side Wright said the perception in the Australian coal industry was that the old ABM20 was a good machine in poor to fair conditions, but was unable to perform in good ground conditions.
“This was mainly due to the very low load out rate (about 14 tonnes per minute) and small bunkering capacity of the old ABM20.”
VAMT has addressed this issue by utilising the ‘battle proven’ apron and conveyor components from South Africa’s ABM30 machines that produce somewhere between 90,000–160,000t per month.
“This has increased the load out rate of the ABM25 to 30t per minute with a bunkering capacity of approximately 8–10t. With this increased coal clearance capacity, the ABM25 has retained its face to bolt distance at a minimum without the need for major component change-out to suit changing roadway conditions,” Wright said.
Other engineering design improvements included simplified/more accessible hose and cable management, use of hose manifolds and exterior routing for cable management, HP oil filtration to reduce contamination, ‘water save’ mode to reduce water consumption, simplified hydraulics - load sensing and single in line pumps, machine operational and engineering management including data logging and process control reports, removed sector controls, higher improved apron extensions (a much cleaner roadway) and load locks on cutter head extensions
During the ABM’s redesign significant emphasis was placed on monitoring the development system and measuring each of its critical processes in an attempt to eliminate downtime.
The ABM25 data logger system is capable of measuring the entire machine’s engineering parameters and generates an accurate account of engineering downtime for root cause analysis and meantime between failure.
“VAMT’s philosophy with respect to process control is to enable the measurement of the machine’s performance during ‘uptime’ as this available cutting time represents potentially the greatest leverage for increasing development advance,” Wright said.
VAMT’s machine history database indicates an average gateroad development panel has approximately 60% available cutting time (uptime), approximately 35% panel downtime (ie. stoppages other than the miner – eg. belts, power, other panel equipment breakdown) and approximately 5% miner downtime.
“Therefore, improving performance during the uptime (about 60% of total time) will potentially have more impact on the overall development advance. This means a focus on measuring metres per hour or cycle time (minutes per complete cycle) against what has been planned by the mine, according to a predicted geotechnical /roadway support intensity plan,” Wright said.
Specially developed ‘cycle time reports’ enable mine management to review ABM performance during uptime and removes much of the time-keeping role of panel supervisors. It allows them to focus on other duties such as statutory inspections, panel supplies, planning, and crew morale. It also facilitates investigation of the ‘real’ issues that may be constraining development performance and allows direct comparison between crews as well as potentially transferring best operational practice across crews and shifts.
The cycle time reports may also be used to measure the impact of changes in the development system (eg. changes in pillar length, the effect of using monorails or different support sequences) and provides a way to objectively assess process improvements.
In one example, a cycle time report for an ABM25 indicated three shuttlecars were required each cycle, which was having a detrimental effect on cycle time. The information allowed the mine concerned to upgrade their fleet of shuttlecars to a larger capacity to enable two shuttlecars to operate per cycle in a much shorter cycle time.
At another mine, consistent shuttlecar delays were slowing down cycle times as the mine neared the completion of a pillar. Using the cycle time report allowed the mine to assess when to introduce the second shuttlecar for optimum impact on minimising cycle times.
VAMT are progressing the use of these cycle time reports in conjunction with the panel production reports to assist minesites with measuring development performance.
The aim is to facilitate a faster response to the real development system bottlenecks as well as have objective discussions with development crews in achieving planned advance rates at the end of each shift.
VAMT believes the ABM25 performance levels have a lot of upside with the use of the data logger and the process control reports in conjunction with the safety/ergonomic changes and the engineering design changes made.
The company predicted the next changes in development improvement in Australia would be in automatic bolting technology (being trialled in Queensland by Hydramatic/Crinum) and the commercial development of the self-drilling bolt.
“To achieve consistent advance rates (day in day out) of 8m plus per hour is physically challenging for the operators. The development and implementation of these technologies will remove much of the physically challenging work from the drill rig operational people and make it easier to achieve consistent performance levels of this magnitude,” Wright said.
In another development Voest Alpine are developing a shuttlecar to be trialled in the US in the first quarter of next year.
Details are yet to be released, but VAMT claims they can deliver an improvement on currently available equipment as well as further improve development performance levels.
