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Closing mines safely

Published:01 April 2017 | Mining Mirror

James. I’d like to start by asking how you found your way into the role of environmental scientist at SRK Consulting, and what comprises your focus in that position? My studies and career are a bit of a 'mixed bag' in that I trained as a life scientist and followed those degrees with a Master of Science degree in geochemistry. I am now working in the mine closure planning and liability assessment :field. My work makes me responsible for the land contamination and rehabilitation group at SRK, so I manage teams that undertake land contamination assessments in the petrochemical and mining environments. These assessments in tum can lead to the development of rehabilitation plans for the contaminated areas.
My current focus is to assist mines in planning for eventual closure, and then determining the costs of implementing the closure actions. I have not moved completely out of the field of geochemistry, though, as I still assist with geochemical assessment.

What does geochemistry entail? And why is it important for mining projects to undertake geochemistry studies? Geochemistry is the investigation of how the inherent mineralogy of an ore or waste material interacts with water to change water quality, potentially leading to an environmental impact. A large number of ore bodies are associated with pyritic materials, with pyrite potentially responsible for the generation of acidic, metal-rich and saline waters, depending on how the pyrite interacts with oxygen and water. As the products from the reactions of pyrite can significantly alter water quality, it is important to understand the reaction pathways to predict potential impacts. There are also other reaction pathways in geological material that do not contain pyrite, which can release a variety of metals and salts, so geochemistry is not just limited to pyrite oxidation, but all reactions of minerals with the environment. This understanding is then used to develop both operational and closure measures to mitigate the impacts.

Can you explain what is entailed in an environmental impact study in particular the geochemistry study - for a mining project? An environmental impact study involves identifying potential impacts at a high level and then using a variety of specialists to investigate the potential impacts in more detail. These specialists are tasked with quantifying the impact and developing methods to mitigate these impacts. An example of a specialist study undertaken during an environmental impact study is a geochemical investigation. The geochemical investigation would commence with gaining a high-level understanding of the mineralogy of the materials under consideration. We would focus on determining whether there are minerals that, when exposed during mining, have the potential to react with oxygen and water, thereby potentially changing water quality. An outcome of this high-level investigation would be to identify which lithologies are associated with the potentially reactive minerals and how these are distributed through the waste or ore bodies.

Once we understand what the minerals are and what lithologies they are associated with, we would develop a sampling programme to understand the distribution and reactivity of the minerals, using a variety of laboratory tests. The test data would then be incorporated into geochemical models and other numerical models to simulate conditions on site; this helps us predict how the materials under consideration would react in the natural environment. Once these predictions are made, we are in a better position to understand how to interrupt the chemical or hydrological processes - potentially to mitigate the impacts on water.

In your view, does the mining industry in South Africa – and more broadly in the rest of Africa – pay enough attention to environmental issues in terms of land rehabilitation and proper impact studies? Where are the shortcomings and how can these be rectified? As with any sample, there is a wide distribution of performance, with many outliers. In general, however, I believe that South Africa's generally pragmatic and appropriate set of environmental regulations has led to a definite move over the past 20 years towards compliance with regulations - particularly those associated with impact studies. The mining industry largely recognises that they have both a legal and moral obligation to undertake mining activities in a responsible manner, and they generally do what is required to obtain legal  compliance.

I think we have regulations in place that - if applied appropriately – would assist mines in focusing attention on environmental issues and land rehabilitation. However, given the large number of mines that the authorities are tasked with overseeing, it is inevitable that the government capacity would be stretched; the authorities simply do not have the time or resources to police all operations. Predictably, this has resulted in some mines neglecting their obligations, often at a cost to the environment. To mitigate the constraints to the authorities' capacity, South African legislation contains an element of 'self-policing', where mines are required to assess environmental performance and compliance and then report to the relevant departments.

In the past five years, my observation has been that the more responsible miners are certainly improving their environmental performance; they are moving past the point of merely complying with regulations to actively managing a mine's risk of affecting the environment. In other words, these operators are moving into a space where they are proactively taking measures to mitigate impact, whereas previously they may only have been reacting after an impact has occurred. However, significant costs are associated with land rehabilitation. It is, therefore, not unusual that in difficult economic times, mines would focus on production and let rehabilitation take a backseat. The lack of resource allocation is the major obstacle to implementing effective rehabilitation strategies.

In my opinion, mines are realising that if sufficient resources are not directed towards managing environmental impacts, their operations can rapidly build up a significant liability that demands to be addressed at closure stage. New legislation currently under development in South Africa may assist mines in focusing their resources, so that they improve the way they manage the liability that will fall due at the end of an operation's lifespan.

What are your views about current environmental legislation in South Africa?
Certain aspects of the legislation are too onerous for the mines in that the criteria they impose on the mines are not necessarily the most appropriate means to mitigate the risks associated with mining activities. Overall, however, I believe that we have good legislation that provides appropriate guidance to the industry.

What big challenges are facing the mining industry in terms of environmental issues?
In my mind, security of water supply is likely to be one of the biggest issues facing the industry. While this is exacerbated by the drought in the short term, the growing pressure on water resources may begin to affect mines' production in the long term. In an environment where mines are using water – and then returning poor-quality water to the environment – the fitness of use of remaining water is also impacted.

Please take us through the most important steps in rehabilitating land, especially when soil has been contaminated?
In a situation where soil contamination has occurred, the first step is to quantify the extent of the contamination; this looks at both the vertical and horizontal distribution of the contamination across the site. One would then look at the chemical behaviour of the contaminants in the soil to understand whether they are mobile and what exposure pathways n1ay be associated with the soils – both currently and in future. In other words, we assess whether a risk is associated with the presence of the contamination and whether that risk would require mitigation. The determination of extent, distribution and chemical behaviour is done by physically collecting soils and subjecting them to laboratory analyses. Only once this information is available can a rehabilitation plan be considered, as rehabilitation plans typically involve interrupting an exposure pathway through the implementation of mitigation measures. The steps in rehabilitating contaminated land can therefore be summarised as describing the contamination, understanding the risks, and then implementing measures to interrupt the pathways by which risk is manifested.

The interruption measures, which are the implementation of the plan, could include removing the contamination for disposal off site; using chemical and biological processes to degrade the contamination on site; or isolating the contaminated soils from the environment. The solution could be relatively simple, such as access control, or more complex, such as placing covers over the contaminated areas.

Mining companies often fall short of finances when closing a mine. How can they prevent this from happening? What do they need to do to not only comply with regulations, but also to really improve the area that they have left behind?

This can be answered in a single word: planning. If mines have invested in a closure planning process that has included the assessment of the risks that will exist at the time of closure, they should know how they are going to close the mine and what it is going to cost them at any stage of the life cycle. Mines are dynamic by their nature, as is the socio-economic environment around them. A closure plan should, therefore, not be viewed as a once-off, but should be revisited regularly to ensure that the closure actions are still relevant.

What would be your advice to a new entrant into the mining industry in terms of developing an environmental plan – from setting up the mine to the mine closure phase?
In my mind, it is simple. View the authorisation process not as only ticking the correct legal boxes, but as an opportunity to gather data and assess impacts so that the long-term effects on the environment can be limited. When undertaking your environmental impact assessment, ensure that the appropriate baseline investigations are undertaken; this makes it possible for your operation to fully understand the environment in which the mine will be developed.

It will allow for the robust assessment of potential environmental impacts and the development of pragmatic mitigations measures. By investing in the correct baseline investigations and impact assessment, you have the chance to proactively implement  management measures that are likely to be more effective and economical than those measures that are implemented reactively. Robust baseline data can also assist in any future disputes around impacts, if necessary.

When developing the environmental management plan, consider the full life cycle of the operation, and do not leave closure considerations too late. A high-level treatment of closure at the authorisation phase may not appropriately identify the impacts and risks that may exist at closure; as a result, the mine may have to rectify operational decisions at great cost to get the mine into a configuration where the risks at closure are acceptable.

What are the benefits for a mining company to undertake an in-depth environmental impact study?
As I explained earlier, an appropriately detailed impact assessment – with the correct baseline data – can assist operations in identifying the potential impacts to allow for the proactive implementation of mitigation measures and to avoid potentially costly reactive measures.

SRK  has extensive experience in undertaking environmental impact assessments. It has covered most of the commodities in South Africa and sub-Saharan Africa, and also a wide range of socio-economic and biophysical environments. This has given us vast experience in identifying various impacts and developing pragmatic solutions.

SRK's team of experienced environmental practitioners are also very familiar with the legal processes required to obtain authorisation. Furthermore, we have a number of in-house specialists who support the environmental practitioners with detailed investigations, including into aspects such as biological impacts, hydrogeology, hydrology, geochemistry, and air quality.

How much should mining companies invest in their environmental programmes, and how could environmental managers convince the board and shareholders that more should be done to mitigate environmental risks? There is no easy way to answer that question, as the impact of mining on the environment is unique to each operation, depending on the type of mining activity and the environment in which the mine operates. In principle, however, mines should invest sufficient money – within the constraints posed by the economic environment – to minimise the impacts of their activity on the environment.

Motivation to the board would include identifying the risks associated with not complying with legislation. These could include financial and reputational risks, and directors could possibly be held personally liable for non-compliance. Under difficult economic conditions, deferring expenditure may be a solution in the short term, but holding back on sufficient spending to manage impacts only delays the expenditure – it does not make the impact disappear.

Inevitably, when future cash flow allows for expenditure, the costs associated with implementing environmental management activities could be significantly higher, as expenditure may now involve not only mitigating the source of the impact, but also remediating any damage that may have occurred prior to impact mitigation.

Which major projects are you currently working on?
My personal project work is currently largely compliance-related, where I am assisting various mines in the platinum industry with the annual updates of the closure liability. I am also involved in a project that is preparing for the anticipated change to waste regulations, which will allow mines to undertake a risk-based approach to the design of barrier systems for new waste residue facilities. The intention is to provide a similar level of environmental protection as that provided by geosynthetic material, to balance costs against risk.

Can you give us insight into some of the worst-case and best-case scenarios you have been involved with?
Some of the most highly-contaminated soils are those that are associated with the petrochemical industry, where waste management activities were historically very different to what they are today, despite being legal and acceptable when they were undertaken. This has resulted in wide areas of soils being contaminated with both organic and inorganic chemicals.

Soil contamination is not only associated with the petrochemical industry. I have seen examples in the Democratic Republic of the Congo, where mining waste and process chemicals have been allowed to spill across vast tracks of land. This has led to an ongoing problem where the contaminated soils continue to be a source of significant water contamination, as the contaminants are flushed from the soil profile. One area of a site was so badly contaminated with acids that my site boots and pants started dissolving while I was working in the area!

The best cases that I have been involved in are associated with newer petrochemical plants and mines, where legislation  has governed how materials are handled, which limits spillage to soils.

In terms of environmental issues, what would the ideal mine of the future look like, both while operating and after closure?
Mining has an environmental impact that cannot be avoided, but that can be mitigated to a large extent. An ideal mine would be one where a proactive approach is adopted and measures put in place to mitigate the effects of its environmental impacts. This would require detailed planning and ongoing monitoring so that prompt warning systems would detect potential unexpected impacts, allowing for the early implementation of additional mitigation measures, if required.

In the closure stage, it would be ideal if no traces remained of the mine ever having existed – but this is a utopian scenario. The best that can be hoped for in closure would be a situation where there is a productive, sustainable use of the land previously occupied by mining activities, and where the residual risks are acceptable to stakeholders and not likely to manifest in impacts after closure.

The country has many derelict sites that could be rehabilitated and, in the process, create jobs. Do you think the environmental rehabilitation of old mining sites in South Africa offers business opportunities that are not currently being exploited?
I agree that there are many old, derelict sites around the country, and their rehabilitation is currently being undertaken by the Department of Mineral Resources (DMR) through a number of initiatives. These rehabilitation activities are indeed providing numerous short-term employment activities to local communities.

Given the large number of sites around the country, the cumulative cost of undertaking all of these rehabilitation activities is enormous. Therefore, the DMR has ranked the sites according to risk and – within the limitations of the funds made available by Treasury to undertake the rehabilitation – are in the process of addressing the high-risk sites. Ultimately, all the sites on their register will be tackled.
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