Waste and Hazardous Materials Management

Mining and processing gold produces waste by-products in the form of tailings, waste rock, sludge, as well as some hazardous and non-hazardous materials.

Tailings are the by-product of minerals processing. They are finely crushed and ground rock particles from which the valuable mineral portion has been extracted. We use retention dams and raised embankments to store and manage tailings. We strictly enforce the design and operational requirements of our tailings facilities, regarding their location, water management, maintenance, operation and monitoring.

In some cases, tailings are used as backfill in underground and open pit projects. The Marlin mine, for example, uses filtered tailings to backfill one of the two open pits. We do not dispose of any tailings in riverine systems or marine environments.

Waste rock management is a key environmental aspect of our operations. Depending on the characteristics of the waste rock, appropriate waste rock and tailings management procedures are developed as required by the SEMS. Most of the waste rock produced in our underground mines is returned underground to fill mining voids. In open pit mines, the waste rock is moved to waste rock dumps on the surface. In some limited cases, we are able to sequence mining in different pits or pit sections to allow for some use of waste rock as pit backfill. At the end of the mine’s life, the waste rock dumps are re-contoured and re-vegetated to provide stable, long-term containment of the material.

Sludge produced at our operations is typically from water treatment plants. This material is usually disposed of in our tailings dams, although final disposal depends on the environmental characteristics of the sludge.

Our SEMS recognizes the important environmental aspects of mine waste management, and includes specific standards to address them. We recognize tailings management as a significant issue shared by us and our stakeholders. We are committed to managing tailings in a manner that effectively mitigates environmental, public health and safety, and community impacts while maximizing the long-term security of the tailings facilities and sustainable land use options.

In 2014, we developed a Tailings Stewardship Strategy to ensure good practices in construction, operation, maintenance, monitoring and, ultimately, closure of our tailings storage facilities. The strategy addresses stakeholder concerns and assures stakeholders that tailings facilities are well managed, providing secure storage, reduced costs and impacts, improved operational excellence and consistent monitoring. Implementation began in 2015.

Tailings stewardship ensures planning, design, construction, operation and closure of our tailings storage and water retention facilities will be carried out in a manner such that:

  • Structures are physically stable under all anticipated conditions
  • Solids and water are managed within designated areas
  • Facilities meet or exceed regulatory or standard engineering guidelines
  • Facilities are chemically stable so that the quality of any seepage or surface runoff does not endanger human health or the environment
  • Facilities can be closed in a manner that is compatible with the surrounding land use and that will have a manageable impact on the environment

Waste Rock, Tailings and Sludge

The quantities of waste rock, tailings and sludge generated are shown in the table below.

Waste Rock, Tailings and Sludge

2016 2015 2014 2013

Waste rock (Mt)

157.8

207.1

189.5

169.4

Tailings (Mt)

42.7

48.5

47.1

46.6

Sludge (kt)

33.7

17.2

11.2

2.9

Waste by Type and Disposal Method

Responsible storage, handling and disposal of solid and hazardous waste are central components of sound environmental management. At our operations, our practices are based on minimizing the generation of wastes and residues, recycling and reusing wastes or by-products, and, when materials cannot be recycled, disposing of them in an acceptable manner.

Our most significant non-hazardous waste streams include scrap metal, used tires, used oil, used antifreeze, inert industrial garbage and organic waste. All our scrap metal and some tires are recycled. Many of our operations have implemented recycling programs for materials such as paper, pallets, glass and aluminum, and some of our sites have implemented composting programs for organic wastes.

Waste hydrocarbons, when not reused on-site, and glycol/antifreeze are removed by licensed waste disposal or recycling operators for reuse, recycling or incineration. Where permitted, we reuse waste hydrocarbons on-site as a substitute for fuel oil in the ammonium nitrate and fuel oil (ANFO) blasting program.

Waste Management

Material (in tonnes) 2016 2015 2014 2013

Scrap steel

18,400

30,400

25,700

19,200

Tires

3,800

5,300

3,300

3,650

Waste hydrocarbons

2,740

2,790

2,150

3,270

Waste glycol/antifreeze

130

110

100

150

Inert industrial garbage

13,730

7,250

3,950

3,990

Organic waste

3,800

4,600

2,870

3,110

Batteries

110

120

110

110

Laboratory waste

660

780

340

550

Mercury occurs naturally in some ore deposits and is typically recovered along with the targeted metals. Mercury requires specific management. In 2016, our operations generated 24.9 kilograms of mercury, all of it at the Peñasquito mine. The collected mercury was stored on-site at Peñasquito in accordance with International Cyanide Management Code (ICMC) best practices and standards.

Spills

All spills reported are tracked, investigated and analyzed to identify root causes. We then implement actions to mitigate any consequences and to prevent recurrences. Spill incidents are classified in ascending order of severity, from Category I to Category V, based on their actual and potential impacts. Incidents of Category III and above are reported to the corporate level and are classified internally as “reportable” spills. There were 24 reportable spills in 2016, compared to 22 in 2015.

Reportable Spills

Spill category Number % of total Estimated Volume Spilled

Hydrocarbon spill

10

40

10 m3

Cyanide-related spill

3

12

5 m3

Other material spill1

11

48

450 m3

Total

24

100

470 m3

All our sites are certified under the Cyanide Management Code, which provides direction for the appropriate management of cyanide-related spills. All spills were responded to immediately and did not result in any significant environmental impacts or financial liabilities.