Air quality management
- Sulphur dioxide (SO2) emissions of 11.9 tonnes per dayLA (t/d) against the licenced limit of 17.9 t/d.
The management of atmospheric emissions is an integral component of our Environmental Management Strategy. We are guided in this regard by the cause and effect approach advocated by the National Environmental Management: Air Quality Act (NEM:AQA). Our commitment is re-iterated through the independently audited and certified ISO 14001 environmental management system, in place across all of our operations. That system is aligned to the requirements and conditions of our Environmental Management Plans and our AEL.
Our primary atmospheric emissions are sulphur dioxide (SO2) and total suspended particulates (TSP), which include particulate matter (PM10 and PM2.5) and total dust fall-out from our mining and processing activities. Our emissions are classified into point sources and non-point sources; where point sources the release of emissions from a single identifiable and fixed location, and non-point sources are emissions not associated with a single identifiable source or fixed location.
The year under review was characterised by several regulatory changes in air quality management. In terms of NEM:AQA, all registration certificates had to be renewed to an atmospheric emission licence (AEL) by 31 March 2013. This was undertaken for the Laboratory, the PMR and the BMR. The Smelter had an existing AEL.
We operated well within our licence conditions this year, recording average emissions of 11.9t/dLA and an average concentration of 889mg/Nm3.
This marks a 40% increase from 2012 (8.5t/d), due primarily to our increase in production, and to a specific period of maintenance on the sulphur fixation plant in February 2013, during which time the fixation plant had to be bypassed. Provision is made for these maintenance requirements in our operating licence, and the relevant regulatory authority was duly informed during the process.
Our AEL stipulates a variety of conditions with which we need to comply, including an SO2 emissions limit of 17.9 tonnes per day (t/d), (as per our reduction strategy) an SO2 concentration level limit of 3,500mg/Nm3, as set for our industry at a national level, and various air pollution control equipment availability and efficiency requirements.
The majority of our SO2 emissions are released from the Smelter at our Marikana operations, through the smelting of concentrate. SO2 is associated with potential respiratory health risks and can be a precursor to various environmental hazards.
We continued with the implementation of our approved SO2 and TSP emissions Reduction and Fugitive Management Plan. The plan addresses the capture and measurement of fugitive atmospheric emissions – as per our aim to ultimately determine the appropriate equipment necessary to meet the requirements of the 2015 and 2020 emissions standards.
During 2013 the fitting of converters with secondary hoods was completed. The hoods are intended to capture and stack 80% of the Smelter's fugitive emissions, targeting the reduction of ground level concentrations of SO2. Through the monitoring data generated by our SO2 passive sampling network, we have observed significant reductions in average ground level concentrations, both in the immediate vicinity of the Smelter, and at our sampling site located further out in the community.
The operation of our SO2 pollution control equipment effectively reduces our atmospheric SO2 emissions, but the chemical processes involved generate calcium sulphite (CaSO3) as a product. We are doing research in this regard, with the aim of implementing technology to enable us to generate an environmentally neutral by-product rather than a hazardous waste. More information on our handling of this waste stream is available in the section: Waste management.
In addition to the SO2 passive sampling network, we further operate a continuous monitoring network, which monitors PM10, PM2.5 and SO2. This network is currently being upgraded to ensure suitable data recovery.
- NOx, SOx, and other significant air emissions by type and weight.
TSP emanate from various sources related to our operations, most notably, tailings dams, stacks, general mining activities such as drilling and blasting, materials handling, crushing and screening and from vehicle movement on paved and unpaved roads.
Dust has been raised as a concern among community members at our stakeholder environmental forum meetings. While we acknowledge that dust is a nuisance and contributes to poor visibility, we are undertaking steps to ensure that our impact is minimised. We have a comprehensive monitoring network in place and the monitoring information it provides indicates that our dust mitigation measures are indeed effective.
We have extensive dust suppression measures in place on our tailings dams to manage particulates. These include irrigation, chemical suppression, side slope and surface grassing, hessian netting and covers. The efficacy of our dust suppression mitigation measures on all our tailings dams is externally audited every two years as required in terms of the MPRDA. The chemical composition of the dust fallout from our operations has also been tested and does not pose any health risks.
Ambient air quality in our areas of operation
Our Marikana mining and processing operations and our PMR in Gauteng are both located in declared Air Quality Priority Areas, as defined in terms of NEM:AQA. This means that detailed studies are undertaken on all sources impacting the ambient air quality in these areas, with specific actions outlined for varying activities. In the Highveld Priority Area, where our PMR is located, we are members of a multi reference stakeholder group that meets on a quarterly basis to review the implementation requirements for all stakeholders. An air quality management plan for the Waterberg-Bojanala National Priority Area, which hosts our Marikana operations, is currently in development
We are currently in the process of ensuring that we understand the presence and effects of other emissions at our operations. These include ozone-depleting substances, persistent organic pollutants and volatile organic compounds. We are on track to report fully on these emissions next year and to disclose any other significant emissions associated with the PMR, BMR and the Laboratory, in 2014.
- State any specific limitations on the scope or boundary of the report.
- Emissions of ozone-depleting substances by weight.
- Operations with significant potential or actual negative impacts on local communities.
- Prevention and mitigation measures implemented in operations with significant potential or actual negative impacts on local communities.