Quarry Southern Africa September 2018 | Page 33

ENVIRONMENT IN FOCUS regulations, which prescribe how a mining / quarry operation is required to set money aside to rehabilitate the operations and to address any latent environmental risks post closure. It is an update to existing regulations, but there is no timeline yet as to when it will be implemented,” says Hex.

Regulation 1147 addresses mining with closure in mind.“ With a quarry, specifically, one of the problems faced when assessing for closure, is to attempt to instate a free-draining land form by closure. There are several safety risks associated with a closed quarry— that of people falling into the quarry pit, and the risk of people drowning( depending on the size, depth, and location of the quarry, as this equates to the potential for filling with water). An effort must be made to return the area to its pre-mining state or an agreed upon sustainable state; though, with a quarry, you’ re removing a significant amount of material that cannot be replaced on closure, so there has to be a compromise.”

Quarries’ other uses

For this reason, she explains, one common option on closure is to transform closed quarries into other uses such as residential estates with a dam feature. When undertaking the initial planning of the quarry, the desired end land use has to be assessed and costed so that money can be put aside throughout the operational lifespan of the quarry. One means of preparing for this is by having a planned matrix / grid throughout the life of the quarry / mine where overburden is placed in the optimal location, which can be easily reinstated to the pit with minimal doublehandling to achieve the final end state.

“ The DMR is increasingly policing the Financial Provisioning Regulations. This responsibility is something relatively new in quarrying and mining. Previously, mining with closure in mind was unheard of— mines used to simply remove the resource with profit in mind and walk away. There’ s been a complete paradigm shift in people’ s thinking, which has been guided by the legislation,” says Hex.

“ From a surface water quality perspective, in terms of quarries, what people are most concerned about is an increase in the turbidity or suspended solids, as fine dust often lands in the water, as well as hydrocarbon spills from the heavy machinery on site. For this reason, it is often advised not to service vehicles on site. Depending on the depth of mining and other aspects, the applicant may be required to apply for a water use licence for dewatering. However, before undertaking that process, an investigation to determine whether the removal of that water will have an impact on the surrounding water table should be undertaken, and that’ s normally where stakeholders are most concerned. The public perception is typically that when a quarry is dewatered, the water table will inevitably be lowered, to the detriment of surrounding landholders who may receive a lower water yield,” says Hex.

“ In fact, it may be a different aquifer,” says Jones & Wagener director and head of the environmental sciences department, John Glendinning,“ and each case is sitespecific and dependent upon what resource you are removing. On a quarry, the potential for contamination is much lower than for a mine— nonetheless, a small amount of hydrocarbon can pollute a large amount of water.”

It is not uncommon for a quarry or mine to be identified as a pollution culprit. In fact, it often has neighbours consisting of industries that pollute, or farmers who add chemical fertiliser onto their crops. As to why a quarry might become the target, Hex explains that the establishment of a quarry requires an EIA process, which gives a voice to people who previously never had a public platform to voice complaints about noise, dust, vibrations from blasting,

1. Jacqui Hex, head of the environmental management department at Jones & Wagener as well as a technical director and environmental practitioner.

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