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AMD FEASIBILITY STUDY FOR A LONG-TERM SOLUTION:

LINKS & FAQ’s

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FREQUENTLY ASKED QUESTIONS

 

1. Has government allocated adequate resources and funding to address the AMD challenge?

Government is committed to address the matter, but as per the Minister, cooperation between the mining sector and other important role players is critical to finding a long-term solution to deal with the AMD challenge.

 

2. What areas are covered by the long-term solutions study?

The study area lies in the Witwatersrand Goldfields area covering the Eastern, Central and West Rand underground mining basins, between Randfontein in the west and Nigel in the east. The study area is being considered in the context of the water resources of the Vaal River water supply area and associated catchments.

 

3. What are the effects / consequences of low pH on humans and the environment? – i.e. the effect of untreated AMD?

Environment: Aquatic life generally cannot survive in a low pH environment, and hence the receiving rivers may become sterile with little aquatic life (except if such receiving rivers poses sufficient buffer capacity).

Humans: The water will have a metallic taste due to the metals that may be in solution. Due to the low pH significant quantities of various heavy metals may be dissolved in the water that may render it toxic.

A direct relationship between the pH of drinking water and human health effects is difficult, if not impossible to establish since pH is very closely associated with other aspects of water quality.

The taste of water, it’s corrosivity and the solubility and speciation of metal ions are all influenced by pH. At low pH water may taste sour.

The potential toxicity of metal ions and chemicals which can be protonated, for example ammonia, is influenced by pH. Changes in pH affect the degree of dissociation of weak acids and bases. This effect is of special importance because the toxicity of many compounds is affected by their degree of dissociation.

Corrosion of the water supply system is a major source of metal contamination in drinking water. Metals that have the potential for causing such contamination are lead, copper and zinc. Lead is subject to corrosion at a pH higher than 12. Corrosion of cadmium is only significant below pH 6. Other metals which are frequently used in household plumbing and that may be affected by pH are copper and zinc.

 

4. What are the effects/consequences of high sulphates on humans and the environment?

Consumption of excessive amounts of sulphate in drinking water typically results in diarrhoea. Sulphate imparts a bitter or salty taste to water, and is associated with varying degrees of palatability.

SA does not explicitly specify a guideline value for the environment. High values may have an effect on the aquatic environment, although it has been said that aquatic eco-systems are able to adapt reasonably well to gradual and mild changes in salt levels.

 

5. What dangers will the neutralized and desalinated water hold for humans and the Environment?

There are no dangers in drinking the neutralised and desalinated water from AMD if treated to potable water standards. Though the water could be perfectly safe the public have the perception that it may be unsafe. Society will need to be informed that fully treated water will be safe. All possible toxic constituents can be removed to the levels specified by the South African National Standard (SANS) 241 – 2011 Standard.

 

6. For what use will the water be treated?

The water can be treated to the quality required by the potential users, these being either potable water users, industrial water users, or eventual release to the rivers.

 

7. Which towns/industries will use the treated water?

The Feasibility Study recommends that it be mostly utilized in the Vaal River water supply area. It is possible that it can be supplied to either domestic or industrial users or both.

 

8. Are any high-rise buildings (or buildings with deep basements) in Johannesburg under threat because of AMD?

The Johannesburg Central Business District (CBD) is in the Central Basin and the decant level in the Central Basin is well below the lowest foundations of the buildings that were reportedly considered by the press to be a high risk.

If the water level is maintained at the Environmental Critical Level (ECL), the level will be even lower than the expected decant level.

 

9. What is the Environmental Critical Level (ECL)?

The level above which the water in the mine voids at the critical locations (that is where the environmental features to be protected are at the lowest elevations) should not be allowed to rise, to protect specific environmental features, including groundwater resources.

 

10. What is the Socio-Economic Critical Level (SECL)?

The level above which the water at the critical location in the mine void must not be allowed to rise, to protect specific social or economic features, such as Gold Reef City museum and active or planned mining.

 

11. Is there a difference in the Central Basin between the ECL and the SECL?

Yes, the ECL is the level that is required to protect the environment, including shallow aquifers and that is estimated to be safe and should not be breached. The level that is required to protect the Gold Reef City museum(at the current position on level 5) can be considered as the SECL and is lower than the ECL.

 

12. How will the ECL be implemented in the Western Basin?

In the Western Basin the water is at the surface, and actions are being implemented to lower the water level until it reaches the proposed ECL at 1 600 m amsl. During this process, continued monitoring will be required in order to ensure that the associated dolomitic aquifers are suitably protected. If this is not the case, the water level will be lowered further.

 

13. How will the ECL be implemented in the Eastern Basin?

In the Eastern Basin, the LTS proposes a higher ECL than the Short-Term Intervention (STI). The way to implement this is to stop the water conservatively at the lower level and monitor to determine if pollution occurs. If it is found that the situation has stabilised without any pollution the underground mine water, the level can be allowed to rise gradually to a next increment whilst monitoring. In this stepwise way the “highest” level where it can be considered as “safe” can be determined and considered as the designated ECL.

 

14. Is it possible to work towards a solution if the water quality and volume in the basins are unknown or uncertain?

With future pumping and monitoring the understanding of the dynamics of the water flow, quality and quantity in the mine voids, etc. will be enhanced and will it be possible to improve on the management of the system.

 

15. What are the volumes of AMD that need to be treated?

The treatment of AMD by the High Density Sludge (HDS) process results in neutralised water which would then need to be desalinated. It is expected that the long term average volume of water to be pumped and treated is as follows:

Western Basin – 23 Mℓ/24h

Central Basin – 46 M ℓ/24h

Eastern Basin – 80 M ℓ/24h

 

16. Will the pumps be underground multi-stage dry pumps or submersible multi-stage pumps?

They will be submersible multi-stage pumps.

 

17. Is ingress management and control part of the LTS?

Studying or planning control of ingress from surface sources is not part of the Feasibility Study. It is an on-going separate project by the Department of Mineral Resources (DMR), driven by the Council of Geoscience (CGS). The LTS Feasibility Study is looking at how much the volumes could be reduced if ingress is managed and the potential cost benefit. The study looks at the effect of ingress prevention and makes predictions of prevention percentages and the effect on the LTS and design sizes. The Mine Voids Report, which is available on the DWA website, will provide related information.

18. Where will the treated water be pumped to and will it be desalinated?

In the STI the water from the underground mine voids will be pumped to the HDS plants at the surface where it will be neutralised and the metals will be removed before releasing it to streams. For the LTS it will be treated through neutralisation, metal removal and desalination for distribution to users. It is important to neutralise the water where it is pumped as there is a high risk associated with pumping or to transport acidic water over long distances. Alternative points for discharge or use of the desalinated water are possible.

 

19. Where will the water in the Western Basin be treated and where will the neutralised water be discharged to?

The STI works that are currently implemented and partly operational will neutralise the AMD and remove metals. The partially treated AMD (still containing elevated sulphate levels) will flow into the Tweelopies Spruit until the implementation of the LTS. Two treatment “trains” are being upgraded at the existing Rand Uranium treatment plant to treat the water.

 

20. When can the long-term solution be expected to be implemented?

Certain implementation actions can already start and from the LTS proposed program it is clear that desalination works can possibly be operational within 4 years. It is slightly different for the different basins.

 

21. Who will be responsible for implementing the solution?

Government has mandated DWA for implementing the solution as well as for operating and maintaining the works. DWA might contract the implementation of the solution to a third party, but will hold ultimate responsibility.

22. Who will operate and maintain the works?

The DWA takes ultimate responsibility for it and will decide if they need an agent such as the Trans-Caledon Tunnel Authority (TCTA), Rand Water or a private institution to run it.

 

23. Who will pay for the capital, and operation and maintenance cost of the Long-term Solution?

The Government will take responsibility to ensure that funds are available for the establishment of the works and construction contracts. Some of the mines have contributed land, infrastructure (such a pumps), mine shafts for pumping purposes, etc., while funds will be sourced from the normal Government sources such as the budget, loans etc. for the LTS. The funding of the works should not be misconstrued with cost recovery.

 

24. How will the cost of the AMD works be recovered

The Department supports the polluter pays principle, i.e. the polluter contributes to the costs for the remedial action taken. Apart from the contributions by the polluter, there are other revenue streams that can also be considered, such as that the water users pay. Water users in the Vaal River System will benefit in two ways, i.e. the treated AMD can be supplied for use and it will also limit the need for dilution releases from the Vaal Dam, which will defer the need to implement other water augmentation schemes. In addition, there may be other beneficiaries (e.g. existing and/ or future underground mining) who may require a static water level in the mine void that is kept below the Environmental Critical Level who will need to contribute. The sources for cost recovery must still be confirmed by the DWA.

 

25. Will the Polluter Pays Principle apply?

DWA does support the Polluter Pays Principle. It is difficult to commit to a timeline at this stage, but the Polluter Pays Principle will be applied. Government needs to engage with the mining industry soon about various aspects, e.g. access to land and infrastructure and partnering options etc. The apportionment of liability issue is sensitive. The study report on the apportionment of liability will inform DWA’s legal strategy and will thus be a confidential document until such time that the necessary negotiations/ actions have taken place. The DWA is to engage with the DMR on the subject in due course.

 

26. How will the costs of desalinating water for discharge into the Vaal River ultimately impact on the cost of water to the Vaal River users and agricultural sector?

The operational cost of the infrastructure for desalination is very high. How the cost will be recovered and from whom has not yet been decided. The cost of water to the users of raw water is determined in terms of the Departmental pricing strategy. The polluter pays as well as the user pays principles will be guiding principles in this discussion.

 

27. Were passive treatment technologies considered for the treatment of AMD? What will happen to the STI infrastructure if an alternative option is decided upon? Will this not constitute wastage of taxpayers’ money?

All the options mentioned require the water to be neutralised. If a technology for desalination that does not require any neutralisation can be proven, the HDS infrastructure may then become redundant. The operational costs for the treatment of AMD by means of the HDS process and reverse osmosis will be high in comparison to the capital expenditure (indications are that for approximately every 8 years, the operational costs may be equivalent to the capital cost). The LTS looks at the solution for the next 100 years or more and it would thus be in society’s interest to come up with cheaper technologies. Hence, the cost spent now on some infrastructure that may become redundant in future can be justified.

 

28. What is neutralisation?

Neutralisation is a chemical reaction in which an acid and a base interact with the formation of a salt. In this circumstance the acidity of the water is being reduced by dosing with alkaline substances such as lime to increase the pH and precipitate out metals such as Iron to form salts.

 

29. What is desalination?

Desalination is a process where the salts causing the increase in salinity of water are removed from the water. This can be achieved by chemical, physical or biological processes. Chemical processes entail chemical precipitation of certain elements in the water. Physical processes entail processes such as Reverse Osmosis (RO), where water is pressed through a membrane that retains the salts. Biological processes entail the biological reduction of substances such as sulphates by biological processes. These substances can then be precipitated in a chemical process.

 

30. What is the recommended treatment process?

The Study recommends a reference solution based on proven Ion Exchange for the removal of Uranium, HDS technology for neutralisation and metal removal and Reverse Osmosis for desalination. During the tender phase the private sector could come with alternate proposals if it can perform the same function and be more cost effective.

 

31. What waste will be generated and how will it be managed?

The Feasibility Study endeavoured to obtain a holistic solution that will limit the waste products generated by the processes. The reference project will produce sludge from the HDS and RO process that will be disposed of at a Sludge Storage Facility and brine that will be disposed of in an evaporation facility.

Although uncertain at this stage it is envisaged that through subsequent technology development and implementation, the waste products should be in a state where it could be re-used, and if that is not possible, then it needs to be disposed of in a safe manner.

Uranium will either be dealt with as hazardous waste, or it can be sold, if commercially viable.

 

32. Will hazardous waste be generated from the treatment process?

There are toxic and hazardous substances in the AMD. The treatment processes will concentrate these, and therefore the treatment, possible re-use and disposal of the waste products will take this aspect into account to ensure that the waste handling is conducted in a safe manner.

 

33. How will the Uranium be managed?

The first step in the handling of the Uranium is to quantify the problem i.e. establish the state and the volumes of the Uranium. All waste products will then be analysed to determine the Uranium content, where after the safe disposal methods and the fate of the Uranium will be established.

 

34. Will stakeholder inputs be included in the Long-Term Solution Feasibility study?

The Feasibility Study is a planning study to consider all options for the Long-Term Solution, and the communication efforts for this study will be conducted from this perspective.

The inputs from stakeholders will be important in the study. As such, focussed consultation with key stakeholders and stakeholder sectors/ groups will be undertaken to assist in identifying sustainable solutions, technical options, management scenarios, etc. at technical workshops, focus group meetings, one-on-one meetings and presentations to existing forums.

The wider stakeholder group will be kept informed of progress and key outcomes of the study through newsletters and press releases distributed at milestones in the study. Information will be distributed electronically to representatives of sectors of society/ stakeholder groups, through the media and on the DWA website.

Stakeholder issues and comments will be picked up in a Frequently Asked Questions (FAQs) document, which will be updated at intervals during the study when new information becomes available.

Public participation is to commence as part of the anticipated EIA process for the LTS.

 

35. Who is a key stakeholder?

Key stakeholders are parties whose input is critical to the success of the study and who are able to provide insights that can assist in directing the study and its outcomes (for example: representatives of National, Provincial and Local Government, various Non-Governmental Organisations (NGOs), organised business, mining, industry, labour, agriculture, water utilities, community leaders, academics etc.).

 

36. Was the business sector represented on the Study Stakeholder Committee (SCC)?

Yes, the National Economic Development and Labour Council (NEDLAC), which represents organised business, and organised agriculture were part of the key stakeholders represented on the SSC. Other sectors of business were also involved in focus group meetings, etc.

 

37. What provision will be made for the remediation of the receptor dams (e.g. Robinson Lake, Hippo Dam, and Aviary Dam), Tweelopies Spruit east and eco-systems in the Western Basin?

Diffuse pollution sources, remediation of affected dams, river systems, soil, etc. and compensation for affected parties falls outside the mandate of the LTS Feasibility Study. Recommendations for rehabilitation are however provided in the Implementation Strategy and Action Plan (Study Report 9). Government (including Departments other than Water Affairs) will have to consider this in future.

 

38. Will some of the reports always remain confidential? Tax payers are paying for the treatment of AMD, and have a right to information.

The Feasibility Study, being a planning study, did not allow for extensive public participation. Instead, key stakeholders were consulted as the Feasibility Study progressed, while information was made available to the public through newsletters and the AMD website. Wider public participation is foreseen during the implementation stages, including the EIA. With this being said, it must be stressed that there are certain reports that cannot be made public until the appropriate implementation process stages have been reached.

The reports dealing with Liability matters will remain confidential until the objectives of the strategy to engage the mines, have been achieved. The other confidential reports are linked to the procurement process, which will be kept confidential until the procurement and tender process is concluded. The intention is not to keep reports confidential in definitely.

 

 

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