- Total water withdrawal by source
- Water sources significantly affected by withdrawal of water
- Percentage and total volume of water recycled and reused
- Total water discharge by quality and destination
- Size, protected status and biodiversity value of water bodies and related habitats significantly affected by discharges of water and run-off
In 2013, the total withdrawal of water amounted to 76,636Ml, with 12,410Ml (16.19%) from municipal sources (potable water) and 64,227Ml from ground fissure sources. This compares with a total withdrawal of 64,788Ml in 2012, 12,852Ml (19.84%) from municipal sources and 51,936Ml (80.16%) from ground fissures. Ground fissure water is encountered during the process of mining and is trapped within the rock strata. Fissure water is often referred to as fossil water, and there is no relationship between it and surface groundwater.
Sibanye focuses on achieving integrated dynamic mine water management through the SibanyeAMANZI Project. This is aligned with the Group’s business model in terms of the integrated mine water plan and management, compliance with permits, reducing the total cost of mine water ownership and footprint and mine water account management. See the case study: Towards dynamic mine water management.
All three of Sibanye’s operations are water-positive, which means they need to pump significant quantities of underground water to dewater for safety purposes. Neither the quantity nor the quality of water sources (fissure or potable water sources – Rand Water supplies potable water to Driefontein and Kloof, and Sedibeng Water supplies Beatrix) are under threat, and no current or future constraints are foreseen. However, the future cost of water remains a risk.
Beatrix dewaters a connate saline aquifer, which limits water use (unless appropriately treated) and prohibits discharge into the surface-water regime. Due to this constraint, excess water is evaporated in line with issued permits. This water is, however, used for mining purposes, and in the refrigeration and gold plants.
At Driefontein and Kloof, dewatering takes place from the dolomitic aquifers, which yield water of a fair quality. Some of this water is used for mining purposes – in the refrigeration and gold plants and, to a limited extent, for drinking water. Excess water is discharged into the Wonderfonteinspruit and the Loopspruit sub-catchments. At Driefontein and Kloof, continuous efforts are made to limit pollution underground by separating fissure water and mine service water in the underground workings. Where applicable, underground settlers are used to precipitate salts and remove solids from the mine service water. The sludge from the settlers, which also contains gold, is transferred to the gold plants for processing.
As with all mines, water is used extensively underground and on surface. The type of water used depends on availability, water quality and the requirements of the application.
Underground water is mainly used for cooling, drilling and watering-down purposes. The source of this water is mainly fissure water that, when used in the processes, becomes mine service water. On surface, fissure and/or mine service water is used in Sibanye’s gold-plant processes and to transport slurry to the TSFs. The supernatant water from the TSFs decants to return-water dams where, depending on the need, it may be recycled or disposed of through evaporation dams.
Recycling and optimisation
Recycling is not Sibanye’s primary focus. It is dictated by water availability, water quality and legal requirements. Driefontein and Kloof recycle water from their return-water dams whereas this is constrained at Beatrix due to the quality of the water source.
Water-optimisation projects are being planned to reduce water consumption, especially potable water use. This will be achieved by management plans, which set targets and allocate responsibilities. They are backed by strict monitoring programmes, benchmarking exercises, feedback sessions and regular reporting as well as feasible infrastructure projects.
Water balances are undertaken on a regular basis, ranging from Group-wide balances to site-specific and detailed business-unit water balances.
Integrated water use licences
The receipt of integrated water use licences (IWULs) remains a concern for the mining industry as a whole, with a significant backlog in their issuances by the DWA. In the absence of issued or valid IWULs, water management is conducted, taking cognisance of the conditions of the current legislative authorisation such as the permits, exemptions and directives that have been issued.
See the Sibanye Water Management Policy.
Case study: Towards dynamic mine water management
The Liquid Gold project, initiated by Gold Fields in 2005, advanced into the next phase as SibanyeAMANZI in February 2013, under the leadership of Johan Wagner, Group Water Consultant for Sibanye.
Aimed at achieving compliant discharges from the Driefontein, Kloof and South Deep mines owned by Gold Fields at the time, the initial aim of the Liquid Gold project was to develop “end-of-pipe water-treatment solutions” to treat 120Ml/day of surplus fissure and mineralised mine service water, and to purify it to drinking-water standards.
Extensive research and development (R&D) work was done to find appropriate technologies to purify the water, followed by the development of technology assessments, extensive bench and pilot-plant work and prefeasibility studies.
The outcome of the Liquid Gold study led to the following recommendations:
- design, construct and operate four 35Ml/day ion exchange (IX) treatment plants at Driefontein, supplying water to Rand Water;
- design, construct and operate a 7.5Ml/day IX kidney plant parallel to the main process at Kloof;
- provide for an estimated capital cost of about R1 billion and operating cost of about R6.50/kl; and
- a R70 million definitive feasibility study for the establishment of infrastructure.
Gold Fields had approved an application for expenditure on revised terms of reference in December 2012, following a shared cost approach between the three participating mines.
Wagner’s joint-venture team of multi-disciplinary engineering consultants has since conducted detailed assessments of mine-water resources and systems at all three mines, mapped the systems, developed flow and solids water balances, identified potential issues, and confirmed usage and compliance.
The following work packages were delivered during the course of 2013:
- A water supply model: Static current and life-of-mine water systems, maps, and flow and solids water balances were developed for each participating mine.
- Water management turnaround plans: Issues and findings were grouped and analysed, and water action plans were developed. In some instances, immediate implementation of these plans began, resulting in immediate water cost savings and/or improved compliance.
- Water demand plans: Studies were conducted to assess the water needs of regional stakeholders, including the long-term mining, agriculture, and industrial and urban-development requirements. Inter-basin transfer was also considered.
- Compliance framework: A regional and mine-to-mine water quality compliance framework was established. Several workshops, including the DWA, were completed.
- Feasibility study: Using the outcomes of the abovementioned work packages, a feasibility study was conducted for the treatment of surplus fissure water and mine service water at the Kloof Operation. The study found that the Driefontein Operation could achieve compliance if the current North shaft water-treatment plant upgrade and the 8 shaft fissure-water separation projects were completed. This mitigates the need for an expensive treatment plant.
The next phase of the Liquid Gold project was renamed SibanyeAMANZI – meaning “one water” – to emphasise the concept of dynamic mine-water management. Liquid Gold had been about creating one large, central treatment facility to treat all surplus fissure and mine water, whereas the SibanyeAMANZI approach is more focused on proactive, integrated mine-water management.
“This really means supporting all water-related operational activities on the mines, including drinking-water treatment plants, effluent-treatment plants, cooling-water treatment, pumping and pipelines, catchment management and TSFs to ensure that policy objectives are achieved,” Wagner points out.
In 2013, a team of geohydrology and water-modelling professionals developed an integrated, dynamic mine-water model for the region. The thesis was to determine when, where, at what quantity, what quality and under which conditions water would leave the properties of the participating mines.
This is the first model of its kind to be developed for the West Wits Goldfield. The model comprises three sub-models on surface water, groundwater and in-mine workings. The model was calibrated where data was available and achieved an acceptable level of correlation – to predict the location, annual quantity and total salt load over time. Deliverables focused specifically on three time frames: pre-mining, current production and post-mining.
The model provides valuable information with respect to the impact of increasing mineralisation (salts and metals) in the regional waters over time and after closure, under different closure strategies. The study produced the following important findings:
- Mine-water mineralisation, including the potential for AMD, if managed as proposed, will not be a material risk for the mines in the Far West Rand Basin.
- Relatively low volumes are expected to ultimately decant, and the environmental impact will be manageable.
- Urban development and other sources of pollution contribute substantially to the salt load and will be more of a factor than the mining impact after closure.
A water-technology innovation hub was established at the Libanon workshops in 2013 after certain patents and associated intellectual-property rights were acquired.
The facility has the following capabilities:
- pilot plant testing equipment, including reverse osmosis, various IX configurations, by-product recovery, ultra- and nano-filtration, activated carbon filtration and sand filtration;
- bench-scale research and testing facilities with analytical support for flocculation optimisation; and
- R&D projects (AMD treatment, economics of uranium recovery, fissure softening alternatives, improved cyanide recycling, IX recovery of gold compared to carbon and hybrid IX membrane processes envisaged).
The hub is supported by the Driefontein Mine Water Laboratory where an upgraded facility is being established at 9 shaft.
The SibanyeAMANZI project continues to add net positive value with the following results to date:
- savings in the purchase of municipal potable water;
- improved water compliance;
- better adherence to WUL requirements;
- greater awareness and stakeholder visibility;
- reduction in planned capital expenditure;
- safe underground drinking water;
- reduced fissure-water pumping cost due to improved Wonderfonteinspruit systems management; and
- developing closure proposals that will minimise mine-water mineralisation.
The following is reported in respect of the status of Sibanye’s IWUL applications:
|Type of authorisation||Status|
|Beatrix||Valid permit and exemptions in terms of the previous Water Act, 1956 (Act No 54 of 1956)||Beatrix applied for its IWUL in October 2011. The DWA has since requested that Sibanye is reflected as the applicant, which has been done. Beatrix continues to operate in line with previously granted water permits. The DWA has not raised any material concerns about the application. However, the reserve determination for the catchment area must be conducted as a prerequisite to finalisation of the WUL application. The DWA has appointed a consultant to conduct the determination but this has not yet been completed.|
|Driefontein||WUL in terms of National Water Act, 1998 (Act No 36 of 1998) – 16 October 2010||Driefontein received its IWUL in 2010 and this licence is valid for 20 years. However, the licence was issued with inaccuracies and omissions, which have been discussed in detail with the DWA and amendments are underway.|
|Kloof||Directive in terms of National Water Act – 9 December 2011||Kloof received its IWUL in 2008 for a three-year term. Despite an amended application being submitted to the DWA before its expiry, the review and adjudication of this application are still underway. In the meantime, Kloof has received a directive, which allows the Group to continue with its water-use activities until the renewal licence has been issued. Although the DWA advised the Group that the surface groundwater reserve determination associated with the mine had been completed, the DWA has since indicated that this should be redone. The reserve determination is a prerequisite for the Kloof WUL to be evaluated and issued.|
|Water withdrawal (Ml)||49,197||64,788||76,636|
|– Potable municipal (Ml)||13,003||12,852||12,410|
|– Ground fissure (Ml)||36,194||51,936||64,227|
|Total water recycled (Ml)||34,684||49,141||50,451|
|% water recycled||71||76||66|
|Water discharged (Ml)||25,249||39,682||32,729|
|Quality of water discharged (µS/cm)||85||81||118|
- The calculation method for water withdrawal changed in 2013.
- *Rand Water
- **Sedibeng Water
Case study: Beatrix saves millions by saving water
Sibanye’s Beatrix Operation in the Free State is saving R1.4 million a month by reducing its consumption of potable water, which is supplied by Sedibeng Water, the local water services provider. Monthly consumption has been reduced by 321Ml over the past three years.
Beatrix is required to purchase potable water from Sedibeng Water as its only other local source is fissure water, generated and pumped from underground, which is naturally saline.
According to Hennie Pretorius, Environmental Manager for Sibanye, the savings were achieved through focused efforts by management, diligent monitoring and reporting, and by educating mine employees on the importance of saving water.
An assessment and benchmarking exercise revealed that potable water usage at the Beatrix Operation was inefficient and costly, particularly in the metallurgical plants, high-density residences, change houses, 1 shaft gland services and conveyor belts.
Readings from more than 40 water meters were recorded on a monthly basis and reconciled with the bulk water-supply meters installed by Sedibeng Water. This information was used to evaluate each of the four business units’ consumption history and, following a benchmark exercise to define consumption targets for each business unit, “water champions” were selected and trained to drive the strategy at each business unit.
The benchmarking exercise set consumption targets using best-practice target values and, where that information was not available, an initial consumption target was set by applying a percentage reduction from historical consumption levels. The benchmarking reconciliation also highlighted the unaccounted-for water volume, pointing to possible water leaks and/or consumptive use not measured.
Currently, water consumption by each of the four business units at the Beatrix Operation is tracked and then discussed at monthly meetings where the water champions present plans to identify and implement water-saving initiatives.
The water champions are appointed to implement the EMS, which includes water management, in their areas of responsibility, and to supervise the respective business units. The EMS is based on the principles of ISO 14001.
The water-saving initiatives include replacing the use of Sedibeng Water with excess fissure water as first make-up water for plant process water and gland-services water, as well as an improved leak-detection and repair management system, pressure-reducing valves and water-efficient showerheads. Inspections, diligent reporting and prompt repair of reported leaks have proved successful. These initiatives are explained and communicated through regular awareness campaigns.
Monthly water-usage graphs are compiled for each unit, indicating their performance and whether or not the benchmark target has been achieved.
The mine’s environmental department regularly engages with the water champions, assisting them in identifying and implementing the water-saving initiatives. The business units with the highest consumption have to present action plans designed to achieve their respective targets during weekly Engineering meetings.
Most areas at the Beatrix Operation have significantly reduced their water consumption but there are still opportunities for further reductions, says Pretorius. “This would not only benefit the mine by reducing costs but also meet the requirements of the national water-resource management strategy. An additional spin-off is the saving in electricity consumption by not pumping vast quantities of water over long distances or heating a significant portion of wasted water.”