The mining industry continues to work towards greater safety and environmentally-conscious methods around the world. In South Africa, Anglo American remains a major player in the domestic market, but has called upon worldwide expertise to bolster its two-pronged approach to these important issues.
At the New Denmark Colliery for example, the introduction of 17 CoalSAFE refuge chambers, built by Australian company MineARC, looks set to further heighten safety for miners at a location renowned for the depth of its shafts.
New Denmark colliery is situated in the Highveld coalfields, some 30 kilometres north of Standerton, Mpumalanga – and is one of the deepest coal mines in South Africa and is one of few in the country to employ the longwall mining method.
The mine was commissioned in 1982 and currently extracts four seam coal from its Central and Okhozini shafts, reportedly producing 5 million tonnes of coal for Eskom’s Tutuka Power Station per annum. The mine acquired a new R720 million longwall at the end of 2009.
Longwall mining is a form of underground coal mining where a long wall of coal is mined in a single slice. The longwall panel (the block of coal that is being mined) is typically 3–4 kilometres long and 250–400 metres wide.
Investment at the mine extends beyond refuge chambers and the company has collaborated with UK company Gemini Carbon – a company that focuses on improving emissions and specialises in Clean Development Mechanism projects and sustainable energy systems.
The result has been a world first in methane flaring, as Anglo American’s website explains:
“When it comes to coal mining, methane is unfortunately part and parcel of the job. Recognising the harm to the environment and potential dangers the gas posed to our workforce, Johan Janse van Rensburg decided to do something about it.
“Motivated by an intense dislike of waste, together with a passionate concern for the environment, Johan – a ventilation and occupational hygiene engineering specialist – instigated a groundbreaking methane gas flaring project that is now improving safety and reducing our carbon footprint at New Denmark colliery in South Africa.
“Traditionally vented via boreholes and up-cast shafts, the colliery sought a more environmentally acceptable way of dealing with the annual 7,000 tonnes of methane it is required to release into the atmosphere to safeguard its employees and underground workings.”
Working alongside Gemini Carbon, Johan and his team were able to create a groundbreaking system when they developed 2 mobile flaring-off mechanisms which were introduced into the mine’s methane drainage system.
“As well as eliminating the risk of underground explosion or fire caused by the highly flammable gas, flaring methane renders it 18.5 times less harmful to the environment – significant when considering the gas has 21 times the global warming potential of carbon dioxide,” the website continues.
Anglo American suggests that the initiative has helped to reduce annual methane emissions at the New Denmark Colliery by 15 per cent, and with income derived from carbon credits, the company anticipated that the cost of the $1.3 million project would be fully recouped in approximately 3 three years.
New Denmark was also one of the settings in 2010, for a series of FOG risk audits, undertaken at 12 Anglo American sites on 4 continents. The corporate website explained what happened:
“The audits were undertaken by a group of highly experienced geotechnical engineers, mining engineers and safety professionals, assessed the nature and scale of the FOG risks in our platinum, zinc, thermal and metallurgical coal operations and the quality of the controls in place.
“The audits, which focused on 3 key dimensions: risk-control systems, infrastructure and the human element, identified a number of good practices. These include the introduction of in-stope netting in our platinum mines, systematic roof support in mines, the use of an acoustic energy meter at New Denmark colliery and the introduction of borehole cameras to determine the presence of open areas in the roofs of coal mines.
“The team also found several opportunities for improvement, including the use of predictive technology to help identify, manage or design-out risks, as well as real-time monitoring and roof mapping, which involves the monitoring of roof conditions using drilling equipment to detect soft layers or voids in roofs or hanging walls.”
With safety of paramount importance, Anglo American has also invested in education for its workforce at New Denmark and a few years ago implemented an adult basic education and training programme called Accelerate.
Accelerate uses recognition of prior learning as the basis for its increased efficiency in the training process and was created by training experts Media Works..
Accelerate aims to have learners complete programme levels in 4 months, rather than the 6-month period used in previous Abet courses. This takes into consideration peak production times, leave periods, strikes and sick leave that affect mineworkers throughout the year.
The reduced duration makes the training more applicable in mines where time restraints often impact on the effectiveness of training but also mine efficiency.
With Eskom’s Tutuka Power Station a focus for New Denmark Colliery, Anglo America’s mine recently proposed to establish a coal de-stoning plant to meet the energy provider’s requirement for improved quality coal, by removing impurities such as stone and shale from the raw coal, and supplying improved quality or ‘washed’ coal.
The company appointed SRK Consulting as the independent Environmental Assessment Practitioner to undertake the environmental authorisation and associated stakeholder engagement process.
Environmental considerations were also high on the agenda when the colliery required 2 new dams, which were designed to collect brine water from the mine and were originally to be constructed using natural clay and an HDPE liner.
However, when natural clay was unavailable to line the dams, engineers recommended Kaytech‘s geosynthetic clay liner, EnviroFix. Consultants, Golder Associates, decided that it would be the ideal product in this application to replace the layer of natural clay.
The chemically-reinforced liner prevents any contaminates from the mine from entering the ground water, thus providing a protective barrier which is ultimately beneficial to the environment.
As one can see, the day to day running of Anglo America’s New Denmark Colliery is anything but straight forward and puts an emphasis on environmental considerations, training, safety and collaboration.