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Tailings, Heap Leach & Waste Management

Mining involves the removal and processing of ore—the rock containing economically recoverable amounts of desired metals.

To access the ore deposits, waste rock must be removed and stored in waste rock dumps and, after processing, mine tailings may be produced and stored in engineered tailings storage facilities (TSFs). Alternatively, the crushed ore may be placed in heap leach facilities (HLFs) for irrigation with process solutions and recovery of the desired metals.

If not properly managed, TSFs can fail and lead to harmful impacts on the environment and nearby communities. This is why we have established internal requirements based on accepted best practices, and why these facilities are carefully designed and monitored by internal and external experts.

Barrick has put in place a Tailings and Heap Leach Management Standard to help our sites comply with applicable laws and regulations and help us to align with accepted international practice.

Following the failure of the TSF at the Samarco mine in Brazil, the International Council on Mining & Metals launched a review of the TSF standards, critical controls and emergency preparedness of its 23 members. After the Mt. Polley TSF failure in British Columbia, the Mining Association of Canada undertook an extensive re-assessment of its TSF management practices (already described as “best available practice”) and made that report public. Barrick has been active in both efforts, which helps demonstrate that the mining industry is taking concerted action to improve industry practice and mitigate the risk of TSF failures.
For more information on these initiatives see the ICMM and MAC websites.



  • Barrick did not experience any TSF or HLF geotechnical incidents in 2016.
  • In 2016, Barrick updated its Tailings and Heap Leach Management Standard. The updated Standard incorporates heap leach management and establishes a more formalized inspection and review schedule. Barrick’s updated Standard aligns with the Canadian Dam Association (CDA) Dam Safety Guidelines, the CDA Technical Bulletin: Application of Dam Safety Guidelines to Mining Dams, and the recently revised Part 10 of the Health, Safety and Reclamation Code for Mines in British Columbia.
  • Barrick conducted ten formal internal assurance audits of our sites’ adherence to the updated Tailings and Heap Leach Management Standard in 2016. The company also had third-party reviews conducted on the TSFs at Pueblo Viejo, Goldstrike, and Cortez.

Priorities in 2017

  • Target zero tailings or heap leach management incidents.
  • Barrick is continuing to work to implement its tailings stewardship program in 2017. Through a tailings stewardship program, we aim to further improve, company-wide, our in-house capability to undertake basic TSF monitoring, planning and reporting work while ensuring the quality of results; further develop the overall technical and reporting capability of our site staff; promote identification and sharing of best practices among sites; and better demonstrate to the public and regulators our commitment to ensuring TSF safety. As part of the program, Barrick will work to engage and regularly communicate with senior management on the status of our TSFs.

Tailings Management

Barrick has a Tailings and Heap Leach Management Standard that requires our sites to locate, design, construct, operate and close their TSFs in compliance with applicable laws and regulations and in alignment with accepted international practice.

The Standard establishes the minimum geotechnical, hydrological, hydrogeological and environmental design, construction, operation and closure criteria and procedures for Barrick’s TSFs.

Our target is to have zero TSF-related incidents.

We conduct daily routine inspections at our operations, and annual dam safety inspections are conducted by the Engineer of Record. Independent third-party reviews are conducted at a minimum of every two to four years at high-risk TSFs, and independent assurance audits of TSFs are conducted every one to three years.

Over 90 third-party reviews of Barrick-operated TSFs have been conducted since 1998.

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Heap Leach Management

At some sites, gold ore is processed using heap leaching. With heap leaching, ore is crushed to approximately the size of large gravel particles and placed on an impermeable geomembrane liner system. The ore is then irrigated with a chemical solution that dissolves the desired metals; this solution is typically sodium cyanide (for gold recovery) or sulfuric acid (for copper recovery). The composite liner – a combination of clay soils and impermeable synthetic membranes – is designed so that no solution escapes the leach pad. Equally important, the composite liner system also allows Barrick to recover the leach solution carrying the dissolved metals for further processing. In critical areas, we often double the synthetic liner system. Leak detection, down-gradient monitoring and other safety features are also typical of our designs. The crushed ore in HLFs remains after the copper or gold has been extracted and the leach solution has been recovered.

At the end of operations, the heap-leached ore is rinsed by recirculating solution and then is allowed to drain down, ensuring both maximum gold or copper recovery and environmental protection. Any residual seepage, captured by the liner system after closure, is treated to meet water-quality standards before being released to the environment. We then work to re-integrate the closed HLF with the existing, surrounding environment. For example, at some sites we have re-contoured the HLF and capped it with a multi-layered soil cover that minimizes rainwater infiltration and allows revegetation.

Management of Barrick’s HLFs is covered under the Tailings and Heap Leach Management Standard. The Standard establishes the minimum geotechnical, hydrological, hydrogeological and environmental design, construction, operation and closure criteria and procedures for these facilities.

Waste Rock Management

Mining involves the extraction of ore – the rock containing economically recoverable amounts of desired metals – from the host rock. The waste rock – the rock that does not contain economically recoverable amounts of desired metals – must also be removed, though mining plans minimize as much as possible the amount of waste rock relative to extracted ore. In 2016, Barrick deposited 151 million tonnes of waste rock.

Because waste rock naturally contains concentrations of potentially harmful elements, the material must be properly managed to reduce the risk of contamination associated with acid rock drainage (ARD) and/or metals leaching (ML). Across Barrick’s operations, approximately 31% of the mineral waste produced in 2016 had the potential to generate ARD/ML. To manage this risk, Barrick has implemented mitigation management at operations where the waste rock, heap leach and/or tailings have demonstrated the potential to generate ARD/ML.

Waste rock is generally placed into engineered waste rock storage facilities which, once full, can be re-contoured, covered with soil, and revegetated. In some cases, waste rock can also be used to backfill open pits or underground tunnels. Waste rock that has high potential to generate ARD/ML can be encapsulated by non-reactive waste rock or co-disposed in tailings storage facilities where it is submerged to significantly limit geochemical reaction rates, thus minimizing ARD/ML. At times, non-reactive waste rock – material that does not have the potential to generate ARD/ML – may be used to construct road beds or tailings dams.

Barrick is a member of the International Network for Acid Prevention (INAP). We have participated in the ongoing revisions of the INAP Global Acid Rock Drainage (GARD) Guide, a worldwide reference for ARD prevention and mitigation. Experts from Barrick and several countries contributed their knowledge to the Guide’s development and revision. The GARD Guide will continue to be updated as knowledge increases. INAP is also currently working on identifying key areas for further research, including waste rock cover guidance.

Mercury Waste Management

Mercury is a naturally occurring element that is present, at some operations, in the ore we process. As a result of processing, mercury is separated from the ore. Depending upon mercury concentration in ore and other risk factors, Barrick employs a variety of controls, including scrubbers and condensation towers, wet gas condensers, and activated carbon filters, to trap mercury vapor before it can be discharged to the atmosphere.

Mercury wastes generated from these air pollution control devices must be responsibly managed to minimize potential risks to human health and the environment. Barrick promotes responsible management of mercury by following our Environmental Management System and the ICMM position statement on mercury risk management. In 2016, Barrick captured and stored 275 tonnes of mercury.

As required by the Mercury Export Ban Act (MEBA), Barrick ceased the export of elemental mercury from U.S. facilities in January 2013. MEBA mandated that the United States Department of Energy construct a federal mercury repository to accept elemental mercury generated by mining and other activities, but to date the repository has not been built. Therefore, elemental mercury captured from air pollution controls at our U.S. operations is currently stored pending the construction of the federal mercury repository. Mercury compounds are disposed of at a licensed hazardous waste facility in compliance with applicable law. Strict handling, packaging, and transportation procedures are in place to help protect both people and the environment against mercury exposure during shipping.

In the case of operations at Latin American sites, mercury is currently securely stored on site in compliance with applicable law.

Barrick continues to evaluate long-term disposal options for mercury.


Non-Processing Waste Disposal

A number of non-process wastes are generated each year at our operations. These wastes may differ by country and by operation, but typically include scrap metals, waste oils, cans and bottles, spent tires, and office and camp waste. While we try to recycle these wastes as much as possible, this is not always feasible at some of our remote sites or at operations located in countries where recycling is not available. Non-hazardous waste that is not recycled is usually landfilled (either in municipal landfills or landfills constructed on the mine property) or incinerated, on or off the site.

We also generate a relatively small amount of hazardous waste each year. These wastes include batteries, fluorescent lights, certain oils, solvents, electronic waste and laboratory assay wastes. As with process materials, the types of hazardous wastes vary among our sites; however, all are recycled or disposed of according to the appropriate regulation in the countries where we operate.