Advertise on Mining Online

Heeding environmental responsibilities

When caught up in their everyday operational and maintenance routines, companies often lose track of its environmental responsibilities. [END BLURB]

Historically regarded as a so-called ‘soft issue’ in mining, environmental issues today play an increasingly important role in the bottom line of any profitable mining operation. To be sustainable, mining companies — big or small — would be well advised to keep abreast of the latest studies, products, and regulations. Two interesting snippets of news is explosives provider BME’s research into determining how much nitrate could leach from their emulsions into groundwater, and the new, more relaxed stance of the Department of Water and Sanitation (DWS) in terms of the linings of tailings dams and stockpiles.

In South Africa’s increasingly water scarce and environmentally regulated mining industry, BME’s emulsion explosives help keep nitrates out of mine water, thereby preventing possible groundwater contamination and allowing optimal recycling of water on site.

“Recent international studies suggest that up to 28% of nitrates from traditional ammonium nitrate fuel oil (ANFO) explosive can leach into water, draining through underground mine workings during a blasting campaign,” says BME operations manager Neil Alberts. “These levels can be reduced to as little as 2% by applying best practice; however, the long-term solution lies in explosives that do not release nitrates into water sources.”

According to Alberts, BME’s emulsion range is extremely water resistant, which means that the explosives material does not dissolve readily in water. This reduces the amount of nitrate leaching to negligible levels. Tests conducted by BME indicated that, after being immersed in water for a month, its emulsion released only about 0.7% of its nitrate content.

“The key factor here is the effectiveness with which the oil in the emulsion — the fuel phase of the mixture — surrounds and isolates the small droplets of saturated oxidizer salt, preventing them from dissolving in water,” says Alberts. “On the other hand, our tests confirmed that ANFO dissolves completely when it comes into contact with water,” Alberts adds.

High levels of wastage of ANFO (the mining sector typically accepts that about 30% of ANFO delivered to a blast site is not consumed in blasting) suggest that it may be a contributor to nitrate levels in water passing through mine workings.

Another advantage of emulsions (highlighted by the tests) is that no oil is released, which ensures that water contamination by oil is prevented. The emulsifier bonds both the nitrate and the fuel phases of the mixture tightly.

“BME emulsions have already contributed to environmental sustainability on mines by both incorporating and consuming previously used oil in its emulsion products, which helps mines to dispose of these liquids safely and cost-effectively,” says Alberts. “The way we have evolved the matrix also ensures that no oil is released when our emulsion comes into contact with water at the stope face.”

As mines work to prevent or mitigate environmental damage, pollution, or ecological degradation, the levels of nitrate in water are usually monitored, since high nitrate levels can render water unsafe for drinking.

“By removing the possibility of nitrate leaching from blasting chemicals underground, mines can reduce the risk of groundwater contamination as water drains from working areas,” says Alberts. “At the same time, where mines are making efforts to recycle water from underground, lower nitrate levels will enhance the overall quality of recycled water and increase its applications on and off the mine site.”

Blanket approach to linings
Given the significant negative environmental impact that mines can cause, proper environmental management regulation is crucial. However, the past few years have seen the introduction of several stringent legislative requirements that do not necessarily ensure proper environmental management and can cripple the already fragile mining sector due to significant implementation costs. According to the recent article “Breathing space for mines as Department of Water and Sanitation relaxes tailing lining requirements” by Sandra Gore and Alecia Pienaar of Cliffe Dekker Hofmeyr, these requirements also do not follow the constitutionally entrenched principle of sustainable development, which provides that the environmental impact and the costs of implementing the requirements must be weighed against the socio-economic benefits that a mine can produce.

One such example is the DWS’s blanket approach over the past three years in requiring mines to install lining systems for mine residue deposits and stockpiles (MRDS) as a condition for obtaining a water use license (WUL), even if the MRDS are not hazardous and will cause minimal disruption to water resources. The costs of such lining systems can amount to millions of rands, and could result in mining projects becoming economically unviable, as well as the loss of the mining project’s socio-economic benefits.

According to the authors, the DWS recently agreed to apply a risk-based approach provisionally when processing mining WUL applications (WULAs). This will offer temporary relief to a financially stressed mining sector. Representations made by the Chamber of Mines influenced the DWS’s decision to alleviate its imposed challenges on the mining industry as caused by its blanket approach.

The National Environmental Management Waste Act, 2008 (Act No. 59 of 2008) requires the Minister of Environmental Affairs to set national norms and standards for (among other things) waste storage, and the planning and the operation of waste disposal facilities. National norms and standards for the assessment of waste for landfill, and national norms and standards for the disposal of waste to landfill (collectively ‘Norms and Standards’) were published in August 2013, together with the Waste Classification and Management Regulations. The Norms and Standards set stringent requirements for the design of landfill containment barriers that have been included in applications for waste management licenses.

The DWS sought to extend the applicability of the Norms and Standards beyond the intended scope, making WULs under the National Water Act, 1998 (Act No. 36 of 1998) conditional upon installing lining systems as containment barriers for MRDS. This catch-all approach is problematic, as it fails to have proper regard for the actual impact of the MRDS on water resources and whether the MRDS constitutes waste. The approach has also been criticised since the Norms and Standards were drafted for landfill disposal that contains waste material, which can — by nature — differ significantly from mineral waste.

Consequently, the incorporation of the Norms and Standards into the WULA process resulted in significant wasted costs where MRDS did not adversely affect watercourses and cause significant negative financial consequence for the mining sector. The frustration of the mining sector was evident when Aquarius Platinum brought a High Court application in 2015 to seek the review of the DWS’s reliance on the Norms and Standards. Aquarius Platinum had applied for a WUL to deposit tailings generated by its mining activities into a pit. The DWS refused to grant the WULA unless a lining system was installed. However, the court’s focus was directed to an alternative issue and it postponed the review proceedings on the lining issue. As a result, the application failed to provide certainty on whether the DWS can apply its blanket approach.

During the course of this year, the Chamber of Mines met with the DWS to propose the application of a risk-based approach when processing WULAs relating to MRDS. According to the DWS, the “Chamber of Mines illustrated the occurrence of unintended consequences when applying Norms and Standards for landfills to MRDS material”. The DWS therefore made the decision to — on a case-by-case basis when processing WULAs — consider whether alternative proposed barrier systems will prevent water resource pollution and have the equivalent effect of the barrier systems prescribed in the Norms and Standards.

The decision will have interim application, as the DWS recommended that the Department of Environmental Affairs amend the regulations relevant to MRDS to ensure alignment of decisions between the two departments. The temporary relief is nevertheless to be welcomed by the mining sector, as mines are currently free to employ a more suitable and cost-effective approach in preventing pollution of water resources by MRDS.


Pin It
Home Features Sustainability Heeding environmental responsibilities

Connect with us

Talk to us

Available Monday - Friday, 8 AM - 4 PM
Call usemail us