Newmont’s Environmental Standard for Tailings and Heap Leach Facility Management sets the minimum requirements for the design and management of TSFs to protect human health, wildlife, flora, groundwater and/or surface water, prevent uncontrolled release to the environment, manage process fluids, and identify requirements for closure and reclamation.
Tailings Management Standard
The standard works in conjunction with other standards and incorporates the International Council on Mining and Metals’ (ICMM’s) position statement on ‘Preventing Catastrophic Failure of Tailings Storage Facilities.’ All Newmont sites identify, assess and comply with laws, regulations, permits, licenses, external standards and other relevant or appropriate requirements.
Planning and Design
- Sites complete a baseline of conditions prior to design of the TSF, including evaluation of land use, hydrology/hydrogeology, geochemistry, biodiversity, cultural resources, geology, seismicity, soil and visual aesthetics.
- Tailings Management plans must be developed to restrict potential releases to the environment.
- Tailings Management plans are expected to include: design and operating criteria, schedules for inspections, monitoring and maintenance, applicable regulatory, legal or other requirements, management methods, risks assessments, overview of instrumentation including KPIs/critical controls, organization structure (roles and responsibilities), training requirements, emergency response plans (inundation mapping and analysis) and concurrent reclamation.
- Fluid management plans describe management of solution levels based on the site-wide water balance. The plan will also identify trigger alert levels and contingency plans during operations, closure and reclamation phases.
- Characterization and specifications for geochemical and physical properties of the construction and tailings materials are performed.
- Engineering requirements for seepage control, liners, and leak collection recovery systems are specified. With excess solutions that may require discharge, compliance with applicable quality and quantity discharge limits based on downstream beneficial use.
- Engineering requirements for geotechnical and erosional stability including such measures as internal filters and drains, buttressing, and systems for storm containment and runoff.
- Requirements for piezometers to monitor solution pore pressures in the embankments, tailings and foundation. Groundwater monitoring wells to establish baseline and monitor potential seepage.
- Risk-based assessments to evaluate whether the design criteria provide adequate levels of protection.
- Quality control and quality assurance protocols are required to document that construction complies with engineering design.
Implementation and Management
- Facilities will have critical controls to mitigate significant risks with risk assessments conducted annually or at major milestones or when significant changes occur.
- Tailings and Fluid Management Plans must be reviewed and updated annually.
- Site-wide water balances are updated over the life of the operations to reflect changes in mine plans, processing and operations, and are regularly calibrated.
- TSFs must be operated within design specifications including piezometric head in embankments and tailings and the management of the pond with design and operational criteria.
- A closure and reclamation plan shall incorporate the requirements of the fluid management plan and support stormwater and erosion management while achieving post-mining land use.
- The TSF is managed to be protective of the environment and adheres to the requirements of the International Cyanide Management Code, permit/license/regulatory requirements, and any other legal obligations or voluntary commitments.
- TSFs shall be inspected regularly for erosional and geotechnical stability, material characterization (geochemical and geotechnical properties), trigger levels and critical controls.
- Annual geotechnical reviews are required by a qualified independent senior geotechnical engineer. Independent Tailings Review Boards (ITRBs) have been implemented at select operations based on technical, social and/or political risks identified by Newmont leadership.
- Routine inspections to verify integrity and to support maintenance and repair programs as defined in the monitoring plans. This includes monitoring instrumentation such as piezometers, inclinometers, and survey monuments as defined in the monitoring plans. Inspection and maintenance activities are also completed following extreme events (rainfall, seismic etc.).
Newmont’s Technical Services team has developed Tailings Facility Geotechnical Guidelines that define minimum requirements for TSFs:
- Definitions for tailings embankments
- Responsibilities of engineering and management staff
- Geotechnical input design criteria guidelines for:
- Foundation settlement and consolidation
- Seismic loading
- Hydraulic properties of the foundation, soil liners and drainage layers
- Water management systems
- Tailings rheology and characteristics
- Geotechnical process design for:
- Geotechnical field investigations
- Laboratory testing
- Engineering design
- Geotechnical design requirements for each level of Project Design
- Risk analysis
- Quality assurance/quality control
Newmont’s Technical Services team has also developed Seismic Design Criteria Guidelines that define minimum requirements for design, construction and operation of TSFs to ensure safe and stable operations for region-specific seismic events. Each operation develops and implements site-specific Standard Operating Procedures (SOPs) and manuals based on the TSF design. Site-specific SOPs consist of per shift activities including inspections of pipelines, exposed liner, embankments, pond levels and leak detection systems.