Mineral waste is defined as materials removed from the mine void that are separated from the valuable minerals over various processing stages. These are handled, stored and disposed of according to their properties, environmental factors and regulations. Many wastes are returned to the mine void to enable landform restoration similar to the pre-mining environment.

The total amount of overburden, rock, mine and processing tailings – including sand tails and clay fines – for Iluka and Sierra Rutile in 2018 was 18,534,304 tonnes, representing 11,771,168 and 6,763,136  tonnes respectively.

Where mineral waste is contained in a slurry form, either within mine voids or in off-path storage, Iluka utilises engineered or semi-engineered tailings storage facilities (TSFs). We seek to minimise, and, where possible, eliminate risks to the environment, people and property associated with the use of TSFs. Mineral wastes stored in TSFs include clay fines, sand tails, co-disposal (sand and clay) tailings, and tailings from mineral separation and synthetic rutile plants. Currently, Iluka operate active TSFs at J-A and Sierra Rutile, which are audited annually.

We reduce the risk of a tailings dam failure with the following controls:

  • tailings facility design by suitably experienced and qualified specialists, according to the Australian National Committee on Large Dams (ANCOLD) guidelines;
  • downstream raising design method or final height embankments;
  • there are no upstream raised tailings containments at any of our operations;
  • review of storm water spillway requirements in high rainfall areas;
  • construction supervision and quality assurance;
  • surveillance systems (inspections and monitoring);
  • internal geotechnical risk reporting for operational and rehabilitation sites (monthly); and
  • independent external geotechnical audits.

Since acquisition in December 2016, Sierra Rutile has significantly reduced the geotechnical risk of its tailings structures. Quarterly inspections by external geotechnical specialists have continued and their recommended actions incorporated into work plans managed by means of monthly tailings management meetings.

Naturally occurring radiation and mineral sands

Mineral sands, as with other minerals such as clay, soils, rocks and many ores, contain levels of natural occurring radioactive material (NORM). This is associated with low level, naturally occurring uranium and thorium contained within the grains of the minerals monazite, xenotime, zircon and sometimes ilmenites.

While the level of NORM in most natural substances is low, any operation in which material containing radiation is extracted from the earth and processed, can potentially concentrate NORM in the mineral sands products, by-products and waste (residue) materials. For this reason, stringent, internationally-accepted radiation management standards are adopted to minimise the risk to human health and the environment.

We apply radiation management practices that are aligned with international best practice according to the publications of the International Commission on Radiological Protection, the International Atomic Energy Agency, as well as the relevant country legislation. We identify, assess and control risks associated with NORM, radon gas and man-made sources through all phases of our activities; exploration, project development, operations, rehabilitation and closure. Our Group Radiation Management Standard and site specific radiation management plans ensure exposure to radiation meets the prescribed statutory limits and is as low as is reasonably achievable.