MINIMISING exposure to Diesel Particulate Matter (DPM) can lead to significant productivity gains by improving the mining workplace environment, according to the Australasian Mine Safety Review and BHP Billiton .
The Mining Industry is a very competitive business operating under a great deal of operational, statutory, occupational safety, health, industry requirements guidelines and procedures.
There has been a strong movement at the government, union and corporate level to improve safety and health performance throughout the industry. Certainly in the safety area there are many examples of good programmes which have achieved significant improvements in recent years and now the focus is starting to shift to concerns on health issues.
Many concerns are being expressed over the effects of exposure to exhaust emissions and the potential for adverse health effects that may follow from that. Most countries around the world are reviewing this situation and considering what actions should be taken. This is a very complex issue in view of the conflicting scientific evidence as to adverse health associated with exposure to diesel particulate however statutory controls are potentially going to be introduced in future.
Efficient operation of coal mines has become extremely reliant on the use of diesel equipment for personnel transport, supply of materials and equipment to support continuous miner and longwall operations, including longwall moves. The number and type of units at each mine varies but generally they are increasing in number, size and power output.
Rather than wait for statutory controls to be introduced some companies are taking a pro active approach and implementing Diesel Emission Reduction Strategies in their operations. A key success factor for these schemes, like any programme, is recognition and commitment by senior management of the importance of the issues and the need for an appropriate management plan to be developed and implemented.
A typical scheme would incorporate assessment, monitoring, a disciplinary team approach, good communication, agreement of actions, regular audits, an implementation plan with targets and keeping abreast with research and technologies.
Significant research within Australia and overseas and operational trials has developed various control technologies that may be implemented to reduce diesel particulate emissions and exposure to them. Such a strategy should be designed for the operation in question and its effectiveness should be established upon implementation.
Some of the potential actions to reduce emissions or exposure to them, which can be implemented, are:
o Introduction of low emission fuels
o Utilise disposable exhaust filters
o Control the numbers of vehicles in accordance with ventilation and emission output
o Implement consistent testing of machines possibly via an underground testing station
o Routine and engine monitoring
o Education, training and communication programmes
o Consider technology
o Update equipment and engines
o Introduce engine management systems preferably electronic
o Audit and update the plans and communicate to everyone.
It should be recognised that more than one action may be necessary to achieve an acceptable outcome. In Australia there are monitored results, from some mines, that have showed it is possible to achieve up to 90% reductions in exposure to diesel emissions which would also reduce any associated health risk.
Certainly any programme does cost money, however the benefits of implementing such a programme at the site can be substantial with significant gains being achieved.
The actual economic effect on an operation may vary according to circumstances, type of coal produced, whether the mine is development constrained etc. The diesel exhaust emission debate has certainly been a topical issue over the years and has caused, directly or indirectly, reduced workforce motivation and industrial disputation.
With most longwall mines being development constrained just about everything that occurs in the mine has an impact on longwall production, through discontinuity and or duration of longwall changeouts.
It is not unusual for a longwall mine to produce around 15,000 tonne per day. If we assume the current value for clean coal is around $US 120/tonne and the mine has a clean coal yield of 75% and the exchange rate is $A0.75 to the US$ then the revenue lost for a days production is in the order of:
15000tonne/day x 0.75 x $120/tonne / 0.75 = $1.8 million.
It is not hard to see over a year how the cost of implementing a Diesel Emission Reduction Strategy could be far exceeded by the financial and health benefits that can be achieved.
Story by Steve Pratt, Chairman of BHP Billiton Illawarra Coal Diesel Emission Research Group 1991-2003.