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As part of the mining process, large volumes of mine wastes—including waste rock and tailings—may be produced. We manage these wastes based on accepted best practices.

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, these facilities 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.

Priorities in 2018
  • Zero tailings or heap leach facility incidents.
  • Automate data collection at TSFs.
  • Improve internal Tailings communications by developing a Tailings Stewardship Dashboard.

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

Managing Mine Waste

Mining involves the extraction of ore—the rock containing economically recoverable amounts of desired metals—from the host rock. 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).

Mine Waste

Tailings Management

Under certain extraction and processing techniques, large volumes of mine tailings may be produced and stored in engineered tailings storage facilities (TSFs).

The TSF can include a tailings dam(s), the impoundment, access roads, diversion channels, downstream seepage collection ponds, and other facilities. If not properly managed, TSFs can fail, leading to potential significant impacts on the environment and nearby communities. Barrick did not experience any TSF geotechnical incidents in 2017.

Our target is to have zero TSF-related incidents.

In early 2016, a revised Tailings and Heap Leach Management Standard was introduced at Barrick to help our sites 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.

We conduct daily routine inspections at our operations, and annual dam safety inspections are conducted by the Engineer of Record ? An Engineer of Record is an appropriately qualified, licensed, experienced and competent geotechnical engineer employed by the retained consulting firm selected by Barrick.. Independent third-party reviews are conducted at a minimum of every two to four years at high-risk TSFs, and independent internal Management Assurance Reviews (MARs) of TSFs are conducted every one to three years.

Nine TSFs at eight sites ? Cortez has two TSFs, both of which had MARs in 2017. received MAR’s of their adherence to the Tailings and Heap Leach Management Standard in 2017. The company also engaged with the Review Team on several occasions to review ongoing designs or studies at Pueblo Viejo and Hemlo.

Third-Party Reviews

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

 

According to the Standard, an Engineer of Record (EoR) must be identified for all design and construction work, and must remain engaged during operation and into closure. A Responsible Person (RP) is also identified for each TSF, whether in design, construction, operation, or closure care and maintenance.

We also require that each RP establish and maintain a dedicated management system. This includes preparing and updating key management documents such as life-of-mine tailings generation and storage requirements; closure plans; a compliance plan; an organizational chart; an operation, maintenance, and surveillance manual; a formal risk assessment; and an emergency preparedness and response plan.

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

  • They must be designed, constructed, operated, closed, and reclaimed with the consideration of protection of: human health, water and air quality, domestic livestock and aquatic, avian and terrestrial wildlife. Where cyanide solutions are present, the requirements of the International Cyanide Management Code must be followed.
  • They must be designed, constructed, operated, closed, and reclaimed to prevent the uncontrolled release of solids and/or fluids, and the compromise of (i.e. unacceptable damage to) buried elements including filter zones and/or geosynthetic liners, resulting from large-scale structural instability such as slope failure or deformation. Adequate controls must be provided for all phases to prevent unacceptable erosion by wind and water. Potential physical and chemical degradation of structural elements such as TSF embankment fills and HLF ore must be considered.
  • Reclamation and post-operation performance requirements must be incorporated in the design and operating plans to reduce closure construction costs and long-term liabilities. Where regulatory and property-ownership conditions allow the possibility of returning a closed TSF or HLF site to the state, the design, permitting agreements, and reclamation strategy should avoid perpetual care.
  • Each active TSF and HLF must be monitored and subjected to routine technical inspections and reviews.

Among other performance obligations, the Standard requires that the results of daily inspections by trained site staff be reported the same day to the RP. All operating TSFs are also inspected at least once a year by the EoR responsible for the design of the TSF or by a suitably qualified and experienced geotechnical engineer outside of Barrick with a comprehensive understanding of the TSF design and operating phase. Barrick also conducts formal internal assurance of sites’ adherence to the Standard, as overseen by our corporate assurance group. 

In addition, Barrick conducts Dam Safety Reviews (DSRs) carried out by an Independent Engineer at a minimum of once every seven years. Facilities that have a higher Failure Consequence Classification have DSRs carried out every five years. DSRs involve detailed analysis of the design, construction, and operation of the TSF, which the Independent Engineer will compare to best international practice.

The company also contracts independent, internationally recognized geotechnical experts to conduct third-party reviews at many of its planned, operating, and closed TSFs at a frequency based on perceived risk, site conditions, and other factors (at a minimum, every two to four years at operating TSFs assigned an Extreme or High Failure Consequence Classification under Barrick’s Standard). Barrick began its third-party TSF review program in 1998, and has completed over 90 reviews. While these third-party reviews normally focus on the technical aspects of tailings management, they may also include (or in some instances be dedicated to) the geotechnical and hydrological performance of waste rock dumps, heap leach operations, and water management structures.

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. In 2017, Barrick was able to develop its Tailings Stewardship Program at Pueblo Viejo and will continue to do this on a site-by-site basis. 

Heap Leach Management

At some sites, gold ore is processed using heap leaching. With heap leaching, ore is generally 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).

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. Leak detection, down-gradient monitoring, and other safety features are also typical of our designs. 

The crushed ore in HLFs remains after the 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, facilitating both maximum gold 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.

Barrick did not experience any heap leach facility geotechnical incidents in 2017.

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 the amount of waste rock relative to extracted ore as much as possible. In 2017, Barrick deposited 52.2 million tonnes of waste rock to waste rock facilities.

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 53% of the waste rock deposited in 2017 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 retorts, scrubbers, condensation towers, and activated carbon filters, to trap mercury vapor before it can be discharged to the atmosphere. Mercury condensation and safe storage are part of our safe practices on site.

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, applicable regulatory framework, and the ICMM position statement on mercury risk management. In 2017, Barrick captured and stored 158 tonnes of mercury at our mine sites. ? In addition, the Veladero mine captured and stored 57 tonnes of mercury and the Porgera mine captured and stored 19 kilograms in 2017.

Managing Mercury Waste

Barrick employs a variety of controls, including retorts, scrubbers, condensation towers, and activated carbon filters, to trap mercury vapor before it can be discharged to the atmosphere.

Mercury ProducedMetric Tonnes

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, elemental mercury is currently securely stored on site in compliance with applicable law. However, the company is actively seeking responsible ways of stabilizing the elemental mercury in a solid form (as mercury sulfide or cinnabar) and then continuing with a safe and final disposal of this residue on a long-term basis. The objective of this initiative is to align with current international efforts, such as the UN Minamata Convention, to find alternative technologies for certain industrial processes that depend on mercury and to avoid, if possible, the availability of elemental mercury in the global market.

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 ? Incineration is the process of treating waste by combustion of organic substances contained in waste materials., 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.

Riverine Tailings Management

The Porgera mine in Papua New Guinea is operated by Barrick Niugini Limited (BNL), an independent operating entity which is jointly owned by Barrick and Zijin Mining. The mine deposits the majority of tailings material into a nearby river under government permit and regulation and BNL’s own internal oversight.

When Barrick acquired the Porgera mine in 2006, we extensively investigated alternative waste management methods to replace the existing riverine tailings disposal process. No practicable alternatives were found due to a number of factors, including the steep and unstable terrain, high rainfall, frequent landslides, and seismic activity surrounding the Porgera mine.

Ongoing monitoring results show that the river system is operating as expected and that, downstream of the mixing zone, water quality and sediment are consistent with the stringent metal limits established by the Australia and New Zealand Environment and Conservation Council. To date, the mine has not exceeded environmental permit water quality compliance levels.

In the future, Barrick will build mines that rely on other methods of disposal of mining and processing material, and avoid riverine tailing disposal methods.

Despite this, in the future, Barrick will build mines that rely on other methods of disposal of mining and processing material, and avoid riverine tailing disposal methods.

More information about Porgera and riverine tailings disposal