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Dams and Tailings Management

Newcrest recognises that good environmental practice is critical to good operational performance and to building community trust and acceptance. Waste rock and tailings management are paramount considerations in our safety and risk reviews, project development assessments, and land rehabilitation and mine closure planning and implementation.

Background
Tailings are the resulting material from finely-ground processed ores that have been through a number of sizing, grinding, and processing steps. Tailings are generally discharged as dense slurry into containment areas, a tailings storage facility (TSF) or through deep sea tailings placement (DSTP) in suitable deep-ocean locations.  Modern gold and copper processes seek to maximise the extraction of chemicals and reagents before the tailings are deposited.

Tailings Storage Design
Every location of our mines is unique and, as such, our tailings facilities are designed to take into account a range of factors including the local topography and climate, the geotechnical, geological and seismic activity, its proximity to people and infrastructure, land rehabilitation, and future land use considerations.
There are three main tailings construction methods:

  • Downstream design continues the construction of the embankment wall on the external side of the compound with the batter extending on to what we call natural surface (or land that previously has not been disturbed), by depositing more support rock and bunding against the previously built tailings wall, thereby expanding the footprint, width and height of the initial embankment wall.
  • Centreline design involves the continuation of the embankment construction on the external side of the compound however, does rely on the deposited tailings adjacent to the top of the initial embankment wall to support the raises.
  • Upstream design allows the embankment wall to be constructed on the inner side of the compound and relies on the strength of the deposited tailings to support the structural material for each lift of the embankment. This method allows for smaller quantities of earth and rock fill to be built on top of the tailings and therefore does not expand the footprint of the facility.

Over a number of years each new tailings wall moves upwards creating a layered or contoured hill for all methods. The tailings wall needs to lift to allow the facility to contain the design capacity of tailings being generated by the operation, and to reduce the overall land disturbance of tailings placement.

Newcrest Tailings Facilities

As of March 2019, Newcrest had 13 terrestrial tailings storage facilities of which three were in active use. Newcrest tailings disposal activities are summarised below:

  • Gosowong, in Indonesia, has two facilities with one in operation, which is based on downstream design.
  • Telfer, in Australia, has one facility in operation with six small facilities no longer in use. The operating TSF commenced as downstream design and has had lifts added in an upstream configuration.
  • Lihir, in Papua New Guinea, uses the deep-sea tailings disposal (DSTP) method given proximity to suitable deep-ocean deposition, its volcanic setting, high rainfall, and the lack of available land.
  • Cadia, in Australia, has three facilities. The Cadia Hill open pit is being utilised as a tailings facility. The Northern Tailings Storage Facility (NTSF) and Southern Tailings Storage Facility (STSF), which both commenced as downstream design, have had lifts added in upstream configurations.  At Blayney, near Cadia, there is a historic copper mine and an associated small remnant tailings facility that is currently under care and maintenance.

In Ecuador, Newcrest has an equity interest in Lundin Gold which is building the Fruta Del Norte gold project with an associated downstream TSF.

Newcrest’s Sustainability Report covers many aspects of our operations’ energy, water and land use, including ore extraction rates and the tonnage of waste rock and tailings generated at each site.

Reviews and Inspection

Newcrest’s tailings storage facilities are audited against criteria that aligns with industry guidelines and specifically against the Australian National Committee on Large Dams (ANCOLD) guidelines.

All of Newcrest’s operations have a program of annual external audits. 


Global Co-operation

Newcrest is a member of the International Council on Mining and Metals (ICMM) which is taking an industry leadership role on tailings management.

In February 2019 the ICMM announced, with the full support of member company Chief Executive Officers, the establishment of an independent panel of experts to develop an international standard for tailings facilities, for its member companies, and for review and use in the broader mining industry.

The standard will be developed by a review of current global best practice in the design, management and operation of tailings storage facilities in the mining industry.