Tailings and Waste Management
Why are tailings and waste management important?
Mining operations generate waste rock (non-economic material) that can be in the form of open pits, underground portals and shafts, waste rock dumps, processed ore piles, tailings or sludges. Tailings dam failures in other parts of the world have demonstrated the potential for damage to communities, employees, and the environment. As a result, safe management of tailings facilities is a global priority for the mining industry, as well as governments, insurers, and investors. Mining processes also generate hazardous and non-hazardous waste materials, such as solvents and scrap metal. Pan American Silver works hard to ensure stable and long-term management of tailings and other mining wastes, as well as proper waste management and disposal. Both are imperative to maintaining community and environmental health, and essential to our social acceptance.
We take responsible management of tailings, heap leach pads, waste rock dumps, spills and solid waste very seriously. We work to ensure that all tailings storage facilities, dams, heap leach pads, and waste stockpiles are robustly designed, built, operated, maintained and closed in accordance with the Towards Sustainable Mining (TSM) Tailings Management protocol, the Canadian Dam Association (CDA) guidelines, and known global best practices in order to prevent any incidents or failures. Our tailings storage facilities and water dams are subject to routine inspections, audits, geotechnical and environmental monitoring, annual reviews, and independent reviews to continually improve systems and methods in order to minimize potential harm associated with these long-term facilities.
- Mining Association of Canada (MAC) Tailings Working Group – We participate in this working group, which is responsible for developing best practice industry guidance.
- Global Tailings Review – Through MAC we have participated in the Global Tailings Review, an initiative of the International Council on Mining and Metals, the United Nations Environment Programme, and the Principles for Responsible Investment aimed at establishing global best practices for tailings storage facilities.
- TSM Tailings Guidelines and CDA Dam Safety Guidelines – We use the guidelines to conduct risk assessments and manage our facilities.
- Tailings, Water, and Heap Leach Facilities Corporate Environmental Standard – This standard provides guidance for sites on proper design, monitoring and maintenance of critical facilities.
Programs and initiatives
- Independent tailings storage facilities safety reviews – We conduct safety reviews and audits in order of priority based on a facility risk assessment.
- Predictive modeling – We complete predictive models based on geochemical data and studies for acid drainage and metal leaching from tailings, waste rock, and heap leach facilities prior to mining and update those studies through regular monitoring during operation and closure.
- Waste management plans – Each mine has a site-specific hazardous and non-hazardous waste management plans that include actions to maximize waste reuse and recycling.
Monitoring and evaluation
- TSM Tailings Management Protocol, Tailings Guide, and Operation, Maintenance and Surveillance Guide – Each site has conducted a review against the protocol and guidance and developed a corresponding action plan to implement improvements.
- Geotechnical and environmental monitoring – We conduct regular monitoring at our tailings, water, waste rock, and heap leach facilities.
- Water and soil quality monitoring – Operations monitor downstream water and soil quality to ensure compliance with predictive models and water quality regulations.
- Waste monitoring – We monitor waste generation and disposal at all operations.
- Our Vice President of Mineral Processing, Tailings & Dams, oversees the performance of our critical facilities.
Tailings Facilities Management
Tailings are the by-products of precious and base metal ore processing and mineral and metal extracting. Tailings are created after the ore is mined and hauled to a processing plant where it is crushed, ground and processed in wet slurry to extract precious or base metals using leaching or flotation. The residual non-economic ground rock is the tailings. Tailings facilities are used to store the tailings and allow separation of water for recycling or discharge.
Tailings are storage with one of the following configurations:
- Sub-aerial: Above ground storage facilities where tailings may be in slurry, thickened, or paste form with an internal pond of clear water. Dry stack placement is another type of sub-aerial storage where water is separated by thickening and filtration before dry tailings are placed into a stack.
- Sub-aqueous: Underwater storage where tailings are entirely submerged within an existing pond.
Tailings facilities are often based on a dam structure which can be constructed using upstream, centerline, or downstream methods, or combination of these methods. All tailings dams begin with a starter dyke, which is raised periodically as tailings are deposited in the facility.
- In upstream construction, the dam is raised with the crest moving upstream over in the deposited tailings.
- In centerline construction, the dam is raised vertically from the starter dam.
- In downstream construction, the dam is raised by shifting the crest downstream over structural fill on the downstream face.
We store tailings in specialized engineered facilities using construction methods that vary according to the context of each mine and local conditions. Our objective is to ensure that our facilities and systems are safe and designed, built, operated and closed in accordance with the Canadian Dam Safety Guidelines and the TSM Tailings Management Protocol. During 2019, Pan American Silver managed seven operating tailings facilities, one dry stack tailings facility at the Escobal mine, and one large water storage dam at Dolores. Of the seven operating facilities, three are downstream raise type, one is downstream-centerline raise type, two are centerline type and one is downstream-upstream-centerline raise type.
During the year, we completed the first cycle of independent safety reviews of tailings and water storage facilities at former Pan American Silver operations. An independent safety review of our new Bell Creek plant tailings was conducted in 2018, prior to our acquisition. Our newly acquired Escobal mine is currently on care and maintenance, while two of our other newly acquired mines have heap leach pads. Independent safety reviews will continue on a five-year basis, depending on the facility risk profile. In 2020, we will conduct independent safety reviews of facilities at Huaron and Alamo Dorado, and a safety review with the Engineer of Record at Escobal.
|Operating Mine||Type of Tailings Facility and Heap Leach Pads||Tailings Store Raise Type||Independent Facility Safety Review|
|Bell Creek||1 operating tailings facility||Downstream-Centerline||2018|
|Shahuindo||1 operating heap leach pad||N/A||2020|
|La Arena||1 operating heap leach pad||N/A||2020|
|Dolores||1 operating water storage dam and heap leach pads||N/A||2017|
|La Colorada||2 operating tailings facility||Downstream & Downstream-Upstream-Centerline||2019|
|Huaron||1 operating tailings facility||Centerline||2014 and 2015|
|Morococha||1 operating subaqueous tailings facility||Downstream||2018|
|San Vincente||1 operating tailings facility||Centerline||2017|
|Manantial Espejo||1 operating tailings facility||Downstream||2018|
In response to the Investor Mining and Tailings Safety Initiative conducted during 2019, we have provided additional information on our tailing facilities for the Public Tailings Facility Database which is updated periodically.
As shown in the above table, we also operate heap leach facilities at our Dolores, Shahuindo and La Arena mines. These mines utilize sodium cyanide heap leaching technologies for metal extraction process. In order to ensure best practice, these sites are applying the relevant standards set out in the TSM Tailings Protocol. We will conduct independent safety reviews of the heap leach pads at Shahuindo and La Arena in 2020 subject to COVID-19 pandemic impact adjustments for site visits.
All our mines have waste rock dumps except La Colorada where all waste rock is used as backfill in the underground mine. San Vicente and Manantial Espejo have waste rock dumps on surface however all waste rock generated in 2019 was used as underground backfill.
In 2019, our sites focused on the implementation of our Tailings, Water, and Heap Leach Facilities Corporate Environmental Standard and improving their performance on the 2019 TSM Tailings Protocol, which includes enhanced risk-based controls. Our sites are also updating their operating manuals and emergency preparedness and response plans to comply with the TSM protocol and guidelines.
We achieved our 2019 goal related to environmental incidents and had no spills that are considered “Significant Environmental Incidents”. Three reportable spills occurred at our operations. A gear oil spill happened at our Timmins operation and two spills from our tailings transport pipeline occurred at San Vicente. All spills were immediately cleaned up, reported and investigated with corrective actions identified in all cases. Corrective actions related to the Timmins spill have been fully implemented and all short and medium term actions are complete at San Vicente. Our longer-term corrective action of replacing the entire tailings transport system at San Vicente is still in implementation and due for completion by the end of 2020 subject to COVID-19 pandemic impact adjustments.
Our operations generate quantities of hazardous and non-hazardous materials, which require end-of-life recycling or disposal. When possible, we recycle or reuse these products at our operations. For example, used oil can become a heating fuel if using equipment that ensures complete combustion and emissions compliance. For other waste, we follow local regulations in disposing of these materials either on site or at local certified disposal facilities.
|Non-Hazardous Waste||Hazardous Waste|
TYPES OF WASTE AND DISPOSAL METHODS 2019 – COMPANY WIDE
In 2019, our waste management plans and worker training programs at our silver segment mines were successful in reducing our hazardous, non-hazardous and domestic waste generation and increasing reuse and recycling. Our Morococha mine has a series of recycling agreements with local social welfare NGOs in Lima, where they coordinate the sale of our recyclable materials.
|2019 (silver segment only)||2018||2017|
|Hazardous or dangerous waste (non recyclable)||749||999||1023|
|Non-hazardous inert waste||465||925||1288|
|Domestic waste to landfill||1,610||1,712||1,169|
(1) Silver segment consists of the six silver mines in existence prior to Pan American Silver’s acquisition of Tahoe.
- Continue site-level implementation of our Tailings, Water, and Heap Leach Facilities Corporate Environmental Standard and the TSM Tailings Management Protocol.
- Conduct independent safety reviews of facilities at Huaron and Alamo Dorado, as well as heap leach pads at Shahuindo and La Arena.
- Conduct a follow-up on the recommendations of previous independent tailings dam reviews.
- GRI 306-2 Waste by type and disposal method
- GRI 306-3 Significant spills
- GRI MM3 Total amounts of over burden, rock, tailings, and sludges
Material Topic: Tailings and waste management.
- Tailings facility management
- Waste rock dumps and heap leach facilities
- Industrial and domestic waste management
Definition: Managing tailings facilities and waste disposal.
Feedback from COIs: Governments, communities, investors, and insurers want to know that our tailings facilities are safe and that our management aligns with global best practices.
How we’re responding: We expanded our disclosures on tailings management in response to the Investor Mining and Tailings Safety Initiative.
We actively advocate for improved tailings management through Mining Association of Canada (MAC).
We have set and achieved goals on Significant Environmental incidents, including large spills, and reducing hazardous and non hazardous waste.
Potential risks and impacts
- Tailings, waste rock, or heap leach facility failure could result in impacts on human and ecosystem health, property, and community livelihoods
- Potential spills, acid drainage, or metal leaching resulting in water and soil contamination
306-2 Waste by type and disposal method.
MM3 Total amounts of over burden, rock, tailings, and sludges.