OPERATIONS Australia

Australia

Gold Fields' mining assets in Australia (GFA) include a 100% interest in the St Ives, Agnew and Granny Smith mines and a 50:50 interest in the Gruyere JV project with Gold Road Resources located in the Yilgarn area of Western Australia.

OPERATIONAL PROFILE
      ST IVES   AGNEW   GRANNY SMITH   GRUYERE  
  Mining method   Open pit and underground   Underground   Underground   Open pit  
  Operational infrastructure   St Ives has four underground mine areas and seven open pits contributing to the Mineral Reserve. There are seven underground mines and 12 open pits contributing to the Mineral Resource. Current ore stockpiles contribute 3.7% of the Mineral Reserve at the reporting date. There is a centralised administrative office, processing facility and engineering workshop complex.   Agnew operates two underground mines, namely Waroonga and New Holland, now amalgamated into the Agnew One Mine Complex. At Waroonga, ore is sourced from the Waroonga North, Kath, FBH, Main and Kim lodes, accessed via declines. New Holland mining occurs in the Sheba South and Simba ore body areas. These areas are accessed via declines. There are also centralised administrative offices, engineering workshops at Waroonga and one active CIP processing plant (1.35Mtpa capacity).

A hybrid renewable power plant was commissioned in 2019/2020 including solar, wind turbine, gas generator, battery power storage and diesel back-up power solutions.
  Granny Smith has one underground mine contributing to the Mineral Reserves and Mineral Resources estimates. The Mineral Reserves estimates do not include any open pits, but one open pit contributes to the Mineral Resources. The mine has one ore stockpile in the LOM plan. Granny Smith has centralised administrative offices and engineering workshops..   The Gruyere JV Mineral Reserve comprises five open pits plus ore stockpiles. The Mineral Resource includes seven open pits and one underground deposit. The operation has a processing plant with a TSF and is supported by a power station with gas pipeline and power distribution lines, including a 12MW solar facility. Borefields and water supply infrastructure, centralised administrative offices, engineering workshops, accommodation village, airstrip and road networks are all developed.  
  Mineral processing and TSFs  
  • St Ives operates a 4.7Mtpa processing plant that consists of primary crushing, closed circuit SAG/ball milling, gravity and leach/CIP circuits.
  • TSF 1 has a High C ANCOLD consequence classification, was decommissioned and is being used for tailings reclamation for underground paste backfill material, using excavators, loaders and trucks.
  • TSF 2 has a High C ANCOLD consequence classification, was filled to the final design height and decommissioned.
  • TSF 3 has a Significant ANCOLD consequence classification and was decommissioned in 2016.
  • TSF 4 is a paddock-type facility with a current maximum embankment height of ~14.5m. The facility is inactive and has a High B ANCOLD consequence classification.
  • The North Orchin in-pit TSF has a Low ANCOLD consequence classification, reached its storage capacity and was decommissioned in 2015.
  • The current active Leviathan in-pit TSF (with a Low ANCOLD consequence classification) has a remaining capacity of 16.7 million metres cubed. Assuming a tailings in situ dry density of 1.2t/m3, the Leviathan TSF will be at its design capacity by the end of 2029.
 
  • The Agnew processing plant consists of a tertiary crushing circuit, followed by a two-stage ball milling circuit with gravity and a conventional leach/CIP gold recovery circuit (1.35Mtpa capacity).
  • Agnew’s TSFs 1 and 2, and an adjoined above-ground paddock storage facility, are decommissioned.
  • TSF 3 is an in-pit facility at the Redeemer pit, operational since it was commissioned in 2004. TSF 3 has been irregularly topped up since the commissioning of TSF 4 to achieve the closure profile. TSF 3 has a Very Low ANCOLD consequence classification.
  • TSF 4 is an in-pit facility located at the Songvang pit with a Low ANCOLD consequence classification. The Songvang pit has approved storage up to elevation RL 404 until the end of Q4 2023. Approval to increase the fill level to RL 422 is imminent. This will increase the available storage by 3.29Mt up to the end of 2026.
  • Studies to investigate the feasibility of Songvang to RL 442 are currently ongoing. This could potentially increase the available storage by an additional 4.74Mt.
  • All the Lawlers TSFs are closed and rehabilitated.
 

Ore is processed at the milling/leach/carbon in pulp (CIP) processing plant under campaign milling conditions located 15km north-east of the Wallaby underground mine. Granny Smith operates a single TSF complex that comprises four compartments, known as cells one, two, three and four. Cell three is currently operational while commissioning for cell four began in late 2023. Deposition will then alternate between cells three and four.

Cell 1 has a High B ANCOLD consequence classification and was raised to its final permitted crest elevation of 448m relative level (mRL) in late 2016. It has a remaining LOM storage capacity of ~0.50Mt and is currently being used for contingency storage.

Cell 2 was raised to its final permitted crest elevation of 448.5mRL in 2012. This cell has a High B ANCOLD consequence classification, is filled to capacity and is harvested for paste fill.

Cell 3 has a High B ANCOLD consequence rating and was raised to an elevation of 434mRL (final permitted elevation of 437mRL) in March 2022 (raised 3F). This will provide additional storage in cell three of ~4.15Mt.

The construction of cell four was completed in July 2023 and commissioning for cell four began in late 2023. The first stage of cell four provides available storage of ~2.44Mt. The LOM capacity for cells three and four is ~14.11Mt while the anticipated LOM throughput is 11.3Mt.

 

All ore mined is processed in the Gruyere plant, which consists of primary crushing, semi-autogenous grind (SAG)/ball milling, gravity and carbon in leach (CIL) circuits. The processing plant was originally designed with a capacity of 7.5Mtpa for treating the deeper fresh (harder) ores. However, subsequent optimisation work and upgrades increased actual and planned throughputs to range between approximately 9.5Mtpa to 9.8Mtpa. This ongoing improvement work includes the installation of a new larger pebble crusher, which is scheduled to be commissioned by Q1 2024.

The TSF perimeter embankment is constructed in a downstream manner (in stages) to enclose a surface area of ~203ha at stage one (starter) and 231ha at stage six (final). The TSF has a High B ANCOLD consequence classification. The stage three capacity is currently being utilised. The stage four wall raise construction has commenced and will be completed in March 2024, increasing the available capacity by 16.2Mt.

The remaining LOM storage capacity (stages four to six) is ~58Mt. Studies are in progress to increase the existing storage capacity by 29Mt – 34Mt (stage seven).

 

COUNTRY information

St Ives, Agnew, Granny Smith and Gruyere JV gold mines located in Western Australia

Australia operates a portfolio of predominantly low-cost, relatively long-life mines and has a strong pipeline of projects configured to drive Mineral Reserve replacement and life extension. The Gruyere JV, Granny Smith, St Ives and Agnew gold mines are located in Western Australia. The summary Mineral Resource and Mineral Reserve estimates for Australia are presented in the Group highlights section.

The Australian mines continued to see the real benefits of consistent annual investment in extensional and near-mine exploration (US$56m invested in 2023 and between US$48m and US$76m invested per year over the past eight years).

Salient points

ATTRIBUTABLE MINERAL RESERVES

7.7Moz gold

Measured and indicated

ATTRIBUTABLE MINERAL RESOURCES (EMR)

4.7Moz gold

Proved and probable

3.6Moz gold

Inferred

 

AUSTRALIA MINERAL RESOURCES AND RESERVES 2023 – PDF 9MB

 

DETAILS FOR OUR AUSTRALIA KEY STAKEHOLDERS CLICK HERE – PDF 3MB

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