Mining activities – extracting, processing and refining – generate air emissions and waste including tailings – the rock slurry that remains after removing the desired minerals.
Our Sustainability and Stakeholder Engagement Policy and a set of global standards outline our commitment and set minimum requirements to manage the risks posed by mineral and non-mineral waste and emissions in a manner that protects the environment and human health; promotes beneficial post-mining land use; and reduces post-mining closure and reclamation liabilities.
After mined ore is reduced into sand-sized particles and mixed with water, the valuable minerals are removed and the remaining milled rock slurry – called tailings – flows to an engineered impoundment called a tailings storage facility (TSF).
The recent TSF failures at Imperial Metals’ Mount Polley mine in Canada and Vale and BHP Billiton’s jointly owned Samarco mine in Brazil highlighted the potential for catastrophic failure at facilities that are operated in highly regulated jurisdictions and, in the case of Samarco, jointly owned by a member of the International Council on Mining and Metals (ICMM).
In response to these high-profile tailings dam failures, the ICMM completed a global review of tailings storage facility standards, guidelines and risks. From this review, the ICMM developed a position statement on Preventing Catastrophic Failure of Tailings Storage Facilities, which addresses the following six key areas of governance that members commit to implementing by November 2018:
- Accountability, responsibility and competency
- Planning and resourcing
- Risk management
- Change management
- Emergency preparedness and response
- Review and assurance
Since 2014, Newmont – which actively participated in the global review and position statement development – has operated all TSFs according to three standards:
- Tailings and Heap Leach Facility Management Standard
- Water Management Standard
- Surface Ground Control Standard
These standards were updated in 2017 to explicitly include the six elements of the ICMM governance framework and integrate cross-functional and regional feedback. Other aspects of TSF management were also reviewed, and the standards were modified to include minimum design criteria and to use a risk-based approach for establishing hydrology, engineered material properties and seismic criteria.
Our engineered TSFs and heap leach facilities (HLF) are designed to withstand extreme weather or seismic events. In addition to daily performance monitoring and inspections conducted by on-site staff, qualified independent senior geotechnical engineers inspect every TSF at least once a year. Emergency response procedures are tested periodically and, at a minimum, reviewed annually. A key addition to the updated standard is the requirement for sites deemed to have higher technical, social and/or political risks to establish an independent tailings review board (ITRB). Additional detail about the ITRBs is discussed in the featured case study.
Each operation is required to manage waste rock and ore stockpiles in a manner that promotes beneficial post-mining land use and reduces closure and reclamation liabilities. Sites must also minimize the risk to surface and groundwater quality from acid rock drainage (ARD), which is generated when water comes into contact with certain minerals in the rock that are oxidized by exposure to air, precipitation and naturally occurring bacteria. In instances where prevention is not possible, we collect and treat ARD in a manner that protects human health and the environment.
Newmont is an active member of the International Network for Acid Prevention (INAP), an industry-led group that promotes best practices in handling potentially acid-generating materials such as waste rock and tailings.
Hazardous and non-hazardous materials
We minimize the use and amount generated of hazardous materials – inclusive of hydrocarbons and cyanide – by replacing hazardous chemicals with less hazardous products whenever possible. For example, we often use citrus-based solvents in our maintenance facilities instead of chlorinated ones.
Hydrocarbon wastes (e.g., fuels) are the largest portion of our hazardous waste stream, which also includes shop waste, such as grease and solvents, and laboratory chemicals. Our sites minimize the volume requiring disposal by recycling almost all waste oils and greases, either through third-party vendors or on-site processes, such as using waste oil for fuel in combustion processes or explosives.
We also make every effort to recycle or reuse non-hazardous waste. Through Full Potential – our global continuous business improvement program – we have identified opportunities such as increasing the tire life on haul trucks, optimizing the use of reagents and other consumables, and identifying materials (e.g., HDPE pipes and valves) that could be recycled rather than disposed of.
Our material air emissions are sulfur and nitrogen oxides (SOx and NOx), particulate matter (PM) and mercury. SOx emissions are primarily generated at coal-fired power plants and during thermal processes that heat pyritic ore. NOx emissions are produced during combustion of diesel fuel, coal, natural gas and propane in stationary sources such as furnaces and power plants. Our fugitive PM emissions are primarily dust from mining activities such as blasting, excavating and crushing ore. Our approach to managing emissions characterized as greenhouse gases (GHG) is detailed in the Energy and Climate Change section of this report.
All sites must comply with the local laws and regulations for source air emissions, fugitive dust emissions and ambient air quality. For those jurisdictions where laws are non-existent or incomplete, we apply the U.S. Environmental Protection Agency (EPA) national ambient air quality standards.
We annually report our air emissions through the U.S. EPA’s Toxic Release Inventory (TRI) program and Australia’s National Pollutant Inventory.
Our approach to responsibly manage mercury byproduct aligns with ICMM’s position statement. We commit to not use mercury to mine or extract gold. However, naturally occurring mineralized forms of mercury exist in ores at our KCGM (Australia), Carlin and Twin Creeks (Nevada), Yanacocha (Peru) and Merian (Suriname) operations, and ore processing can generate mercury compounds and gaseous elemental mercury.
We capture point-source mercury from air emissions using maximum achievable control technology (MACT) standards, and we continuously evaluate opportunities to reduce emissions.
We are committed to permanently removing mercury byproduct from circulation using long-term safe storage solutions. In the U.S., we are precluded from exporting mercury, and the U.S. Department of Energy (DOE) oversees the long-term storage of elemental mercury. Until the DOE constructs a permanent facility and begins accepting mercury, we are safely storing mercury on site. In 2017, we continued work to enter into an agreement with Switzerland-based Veolia subsidiary Batrec Industrie to transport and permanently retire all the elemental mercury currently stored at Yanacocha. A final agreement is expected in early 2018.
Newmont generated 346 million tonnes of waste rock and 111 million tonnes of tailings in 2017 – an increase of 3.0 percent and 14.4 percent, respectively, compared to an overall increase in annual consolidated gold production from continuing operations of 8 percent. Approximately 26 percent of our total waste rock is characterized as potentially acid-generating, down from 29 percent from 2016 and 52 percent in 2013 as we improve our ability to minimize ARD risks.
|Total waste rock generated||568.7||406.6||340.1||335.9||346.0|
|Total non-hazardous waste||60.4||49.5||46.0||34.8||38.1|
|Total hazardous waste||63.6||38.9||40.0||12.0||12.2|
We generated a total of 12,192 tonnes of hazardous and 38,125 tonnes of non-hazardous waste at our operations in 2017, representing a slight increase from 2016.
Around 6,227 tonnes of our hazardous waste were treated and/or disposed of on site, 4,081 tonnes were recycled, and 1,885 tonnes were treated and/or disposed of off site by qualified service providers.
Of our non-hazardous waste, 26,172 tonnes – more than two-thirds of the total – were recycled, 7,543 tonnes were disposed of on site, 4,359 tonnes were disposed of off site, and a trace amount was incinerated.
Our global elemental mercury production increased in 2017 to 27 tonnes, reflecting the variable mercury content in our ore and our efforts to remove mercury from our air emissions.
Because variations in ore composition can impact air emissions, our sulfur dioxide emissions increased from 0.13 kilotonnes in 2016 to 1.46 kilotonnes in 2017,and mercury emissions increased from 0.40 tonnes in 2016 to 0.71 tonnes. These levels remain significantly lower than in 2014, prior to the decommissioning of the Gidji roaster at KCGM, which previously accounted for around 99 percent and 95 percent of Newmont’s total annual sulfur dioxide and mercury emissions, respectively. Our selenium emissions remained unchanged year over year at 0.10 tonnes.
Improving our tailings stewardship approach was a significant focus during the year. A cross-functional team engaged with the regions to receive feedback prior to finalizing the updated Tailings and Heap Leach Facility Management Standard. All sites began work on gap assessments and action plans to achieve compliance with the new standards ahead of the November 2018 deadline to align with ICMM’s framework.
Based on initial assessments under our updated standards, we identified five sites with TSFs deemed to be high priority – Akyem and Ahafo in Ghana, Boddington and KCGM in Australia, and Merian in Suriname. Although best practices for construction and operation are regularly employed at these sites, each operation will establish an independent technical review board (ITRB) and seek input from the site ITRB to continue to reduce the risk and potential liabilities. We initiated ITRB member selection with the goal of having all boards in place by mid-2018.
Efforts at our operations to address our risks and improve our tailings, waste and emissions management approach include:
- Our Boddington operation experienced heavy rainfall in August, which elevated water pressure and led to tailings seepage through a pathway at one of its tailings saddle dams. The site took a number of actions to reduce pressure and eliminate any imminent risk to the dam’s stability. To improve the dam’s factor of safety (a metric used to measure slope stability), the site increased dewatering from underdrains and internal extraction wells, and designed and will build a buttress to the dam.
- KCGM’s annual TSF risk assessment led to a re-evaluation of tailings characterization data based on new interpretation methodology developed as part of lessons learned from the Samarco event. The site has ceased deposition in one of its impoundments until further review.
- Our Tanami operation in Australia is building a paste backfill plant that transforms tailings waste into a paste-like material that is used as backfill to stabilize previously mined areas in the underground mine. The operation is also currently storing all waste rock material underground to minimize ARD risks.
- At our Ahafo operation in Ghana, we engaged extensively with the Ghana Environmental Protection Agency to reach agreement on the final design specification for the site’s TSF expansion project. Both Ahafo and Akyem finalized plans to install a partial high-density polyethylene (HDPE) liner as part of their TSF expansion projects.
- For the second straight year, our Cripple Creek & Victor mine received the “Best of Best” award from the Colorado Mining Association for its leadership in recycling and repurposing materials.
- A report coordinated by the government of Indonesia’s Ministry of Research, Technology and Higher Education concluded the sub-sea tailings placement at the now-reclaimed Mesel gold mine in North Sulawesi, Indonesia, which Newmont operated from 1996 until its closure in 2004, did not contaminate fish sources or negatively impact the marine environment. The report summarized the findings from the independent panel of scientists who conducted post-closure monitoring of fish tissue, marine ecology and physical and chemical oceanography from 2006 to 2016.
|Elemental mercury (Hg)||24.8||20.9||12.5||19.0||26.6|
|Carbon monoxide (CO)||2.5||2.3||2.6||3.4||3.0|
Our focus in 2018 will be on ensuring full compliance with the ICMM governance framework by November 2018. Activities to support this goal include:
- The five high-priority sites will establish ITRBs and implement site visits and reviews by the second quarter, and all sites will work toward achieving compliance with the updated standards by the end of the third quarter.
- For all our tailings facilities, we will work to establish critical controls that will be tracked at a site, regional and corporate level to evaluate and manage risks proactively.
- As a member of ICMM, Newmont will participate in the organization’s newly formed Tailings Aspirational Goal Working Group. The goal of the group is to identify innovative technologies and practices that can minimize or replace conventional wet storage facilities (such as TSFs) over the next 10 to 15 years.
- We are a sponsor of a three-year program with the University of Western Australia to develop a better methodology to interpret tailings storage performance. The research will focus on our Boddington and KCGM operations.
- Once a final agreement with Batrec is reached in early 2018, we plan to begin safely transporting and permanently retiring all liquid mercury byproduct from Yanacocha starting in the second quarter. Batrec will convert the liquid to a mineral sulfide and dispose of the solid material in an engineered underground salt mine in Germany.
- Following initial discussions in 2017 about ways to use our resources in a more sustainable way, we will hold internal workshops to begin developing a circular economy strategy. With a focus on process stewardship, strategy objectives include maximizing mineral resources, reducing environmental liability and using resources more efficiently throughout the mine lifecycle.