Mining investment firm Menar will implement a programme comprising the installation of filter press systems at both of its Zululand Anthracite Colliery (ZAC) processing plants to maximise water reuse and recycling.
The commissioning of the first filter press system is planned for next month, with the company having invested R14-million. The second filter press is planned for the first quarter of 2022. The construction of the first plant has started, says Menar KwaZulu-Natal operations COO Bradley Hammond.
“The most important mine water management measure at ZAC is the implementation of a closed water system. This will ensure that water from the pollution control dams, wastewater works and coal processing plants is not released into the environment. The water is reused for coal processing purposes, as well as dust suppression measures.”
Hammond adds that the mine will install a filter press at both processing plants to reduce the amount of water required for coal washing.
ZAC is also lining its pollution control dams, which will prevent any seepage and pollution of groundwater resources, and improve water use efficiency.
All the water management measures implemented by ZAC will also ensure the protection of freshwater resources against pollution.
Hammond points out that ZAC’s water use licence allows it to extract 519 000 m3/y of water from the Umfolozi river.
In 2019, ZAC extracted only 249 782 m3 of water, showing its reduced reliance on freshwater resources for coal processing purposes.
Further, ZAC has successfully ensured that potable water is being supplied to the surrounding communities through communal taps. This has assisted downstream users, as less water is extracted from the Umfolozi river system and has ensured that ecological lives flourish, even in dry seasons.
A total of 30 140 m3 from the extracted 249 782 m3 was distributed to the surrounding communities as potable water in 2019.
Hammond states that this is all attributed to the closed water system.
“The main challenge with mine water management has been the scarcity of the resource. The area receives below-average rainfall while being humid, with high average temperatures. This always leads to high evaporation rates when conducting dust suppression.”
He adds that the mine is evaluating various environment-friendly dust suppression chemicals that bind the dust for a longer period, thereby reducing the dust suppression frequency and, ultimately, water consumption.
South Africa is ranked forty-eighth driest country in the world. This becomes problematic from a mining perspective, as most mines require large quantities of water for mineral processing and other purposes.
The mining sector is constantly investigating cleaner technologies that will maximise water reuse and recycling.
Hammond highlights that the Financial Provision Regulations (2015), published under the auspices of the National Environmental Management Act, require all mines to take into account the latent and residual environmental impacts that could arise from the mining operation as well as the remediation thereof. An example of this, is the pumping and treatment of polluted water.
The assessment of the latent and residual environmental impacts will encourage the mining sector to invest in technologies and research that will ensure water reuse for various purposes. “Currently, the available reverse osmosis option is very expensive and has its own issues in terms of the resulting brine management plus the associated energy costs.
“Mining companies should invest in educating their employees and their surrounding communities about water-saving tips and the situational awareness on water availability in the country,” Hammond concludes.