TAILINGS.WATER.WASTE

A comprehensive approach to Facility Closure

Overview of ATC Williams Facility Closure Services

Facility closure is pertinent to the overall lifecycle management of tailings, waste and water storage facilities associated with mining and landfill operations. It involves the treatment of disturbed land or water for the purpose of establishing a safe, stable and non-polluting landform.

At ATC Williams, we pride ourselves on three decades of leadership in sustainable tailings, water and waste management solutions, covering a diverse range of complex local and global projects. A dedicated team of highly experienced and specialised engineers provide facility closure designs that cater for sustainable management of the environment and enhance the social wellbeing of local communities.

ATC Williams facility closure services complement our tailings, water and waste management facility designs. We consider and design for closure liabilities at project inception with a closure plan routinely updated throughout the design and operating facility life cycle.  This enables forward planning for rehabilitation and closure, offers an understanding of closure requirements and cost implications while improving rehabilitation efficiency and minimising risks to optimise facility closure success.

Exceptional Facility Closure Services

We have extensive experience in all facets of facility closure, from approval support and preparation of closure plans to detailed closure design, construction support services and post-closure monitoring.

Our facility closure services include:

  • Regulatory liaison and approvals
  • Quantitative closure risk assessments
  • Rehabilitation cost estimations
  • Progressive Rehabilitation and Closure Plans (PRCP’s)
  • Pit closure design
  • Waste rock dump rehabilitation
  • Erosion modelling
  • Closure water balance modelling
  • Management of acid sulfate soils and acid rock drainage
  • Technical support services during closure construction
  • Design of closure monitoring instrumentation
  • Post closure monitoring

In addition, we have specialised expertise in Tailings Dam Closure Designs, Capping of Soft Tailings Deposits, Landfill Closure Designs and Waste Dump Closure Designs, as outlined below.


Tailings Dam Closure Designs

Facility closure of a tailings dam is a complex multidisciplinary undertaking requiring the design of long-term stability and sustainability of the site’s landform, soils and hydrology. This requires careful consideration of physical and chemical stability and land use assessment.

Working closely with clients and key stakeholders, we provide tailings dam closure designs that produce safe, stable, non-polluting landforms consistent with the surrounding environment. Dam design capabilities and expertise in cover designs, site water management and groundwater hydrology are brought to each closure project. We utilise our extensive experience in numerical modelling techniques to simulate the long-term behaviour of tailings, containing embankments and groundwater conditions for closure design. Our in-house NATA accredited laboratory can properly characterise and evaluate tailings, soil and rock behaviour under a range of expected closure conditions.

All our closure designs are conducted in accordance with regulatory requirements, site-specific licence conditions and industry best practices.

Our tailings dam closure services include:

  • Regulatory liaison and approvals
  • Closure plans
  • Closure costs estimations
  • Capping cover designs
    • Specialist capping of soft tailings deposits
    • Store and release cover systems
    • Water shedding and barrier cover systems
    • Capillary break cover systems
    • Wet storage cover systems
  • Tailings consolidation settlement predictions and landform design
  • Embankment stability and rehabilitation design
  • Hydrological and hydrogeological assessments
  • Construction closure support services – construction supervision, quality assurance and technical support during construction
  • Design of closure monitoring instrumentation
  • Post closure monitoring
  • Third party review

• Tailings Dam Closure Designs

Capping of Soft Tailings Deposits

Capping of soft tailings deposits can be inherently difficult due to tailings materials with poor consolidation characteristics resulting in tailings deposits with low densities and shear strength characteristics.

ATC Williams specialises in the investigation and design of capping systems for soft tailings deposits. For more than 30 years, we have assisted clients in developing tailings management techniques that enhance the opportunity for safe placement of capping fill materials and reduce capping closure costs. We encourage our clients to take a holistic view of facility closure and consider facility design and operation with rehabilitation in mind.

When it comes to capping and closure of the facility, significant time and cost are saved by implementing carefully considered tailings deposition practices that facilitate the development of a deep surface crust of tailings, increase density and minimise water table development.

The primary objective of closure and rehabilitation of a soft tailings deposit is to provide a final landform that is inherently stable in terms of erode-ability and overall stability. At ATC Williams, we tailor capping design solutions to site specific characteristics to ensure that capping layers are placed in a safe, economically efficient, and controlled manner.

Landfill Closure Designs

Landfill Closure Designs

ATC Williams provides containment designs that meet client needs and maximise available on-site materials. Our comprehensive understanding of current geo-synthetic technologies delivers robust and sustainable engineering solutions.

Innovative landform design capabilities and expertise in site water management specific to waste management operations govern each project. We possess extensive experience in leachate management for landfills, with high-level modelling capabilities to estimate leachate generation potential. Predictive mass-balance/inventory analyses assist our clients in understanding operating issues and making informed decisions.

We perform environmental monitoring of groundwater, surface water, leachate and landfill gas to site-specific licence conditions and industry best practices. Extensive knowledge of landfills and waste management provides our clients with innovative and practical closure design solutions.

Our landfill closure services include:

  • Closure planning and closure plan preparation.
  • Design of remediation and closure works.
  • Specialist landfill capping design.
  • Regulatory authority liaison and negotiation.
  • Closure construction support and QA/QC.
  • Third party review

Waste Dump Closure Designs

Waste Dump Closure Designs

Successful closure of waste dump facilities for a waste rock dump, heap leach pad, or dry tailings stack requires a thorough understanding of the composition of the waste. Failure to properly characterise the material waste can result in geotechnical instability, the release of contaminants to the environment and the inability to support vegetation or an ecosystem.

ATC Williams waste dump closure services are founded on a thorough investigation and characterisation of waste dump materials to enable a closure design that is safe, physically stable, chemically stable, and supports a viable vegetation community.

Our waste dump closure services include:

  • Material characterisation studies
  • Geochemical characterisation of waste materials
  • Mine waste dump closure and rehabilitation
  • Construction closure support services
  • Post closure monitoring
  • Regulatory authority liaison and approvals

 

Cradle-to-Grave Outcomes

Facility Closure is a critical phase of a mining or resource project, such as a mine tailings dam, waste rock dump, water management structure or solid waste landfill. Our approach to closure takes a holistic cradle-to-grave view of the facility, aligning the facility design approach to post-closure performance outcomes centred around cost-efficiency, safety and environmental sustainability.

Please reach out to the ATC Williams Melbourne Office on 03 8587 0900 or contact Darren Pemberton via email to discuss how we can assist with your project.

 


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