OPERATIONS West Africa Region

West Africa region

Tarkwa has now fully transitioned to contractor mining and is well positioned to deliver sustained value, while the best long-term option for Damang to create future cash-flow is being realised through the implementation of the Damang Reinvestment project.

OPERATIONAL PROFILE
      Damang   Tarkwa   Asanko  
  Mining method   Open pit   Open pit   Open pit  
  Operational infrastructure   Damang has one open pit constituting the Mineral Reserves, seven open pits comprising the Mineral Resources, one ore stockpile, a centralised administrative office, engineering workshops and residence villages.   Four large open pits currently exploit the stacked narrow auriferous conglomerates. Tarkwa has an ore stockpile and “spent ore” on the south heap leach (SHL) pad included in Mineral Resources and Mineral Reserves. Tarkwa has a centralised administrative office, engineering workshops and residence villages.   With cessation of mining at Esaase in May 2022 and in-situ Mineral Reserve depletion at Akwasiso in July 2022, since August 2022 Asanko has been treating stockpiles until prefeasibility work supporting a viable LOM plan has been completed. The Nkran Cut 2 pit Mineral Reserve ore was depleted in June 2020 with approximately 68koz gold deferred to Cut 3 because of the pit wall failure in Q3 2019. Ore is hauled from Esaase via the 27km haul road to the Obotan plant. Asanko operates with several stockpiles at Esaase and at the Obotan plant area. Asanko has a centralised administrative office, engineering workshops and residence village.  
  Mineral processing and TSF   The processing plant treats predominantly fresh ore, comprising a three-stage crushing circuit, SAG/ball mill with a pebble crushing circuit, a gravity recovery circuit and a CIL gold recovery circuit. The plant has been optimised to process 4.6Mtpa.

Deposition of tailings is currently occurring on the Far East TSF (FETSF), which was commissioned in January 2018. In addition, the second stage of the downstream embankment lift, which commenced in November 2019, has been completed. Construction commenced on the third stage raise in Q4 2021 and was completed in Q3 2022. This increased the embankment crest elevation from 985mRL to 990mRL. Construction of the downstream waste rock shell in preparation for the stage four wall has commenced.

The East TSF (ETSF) was constructed as a combined TSF and waste dump using compacted earth fill and fresh waste rock for the embankment construction. Closure deposition of tailings into the ETSF commenced in early 2017 until January 2018 when deposition ceased.

The FETSF is located south of the existing ETSF abutting the ETSF’s south embankment. The FETSF has been designed and constructed with a compacted clay liner across the facility basin and upstream slopes. The facility is planned to be built in five stages and has a remaining LOM storage capacity of approximately 18Mt. The ANCOLD consequence classification for FETSF is High C. The South TSF (STSF), also with earth fill embankments, has been closed and is fully rehabilitated. The ETSF and STSF have an ANCOLD consequence classification of High B and Significant, respectively
  Ore is processed through a conventional gold recovery plant, consisting of two gyratory crushers with one gyratory crusher followed by an additional two-stage crushing circuit, both feeding a SAG/ball mill circuit, thickeners and twin CIL circuits. Gold is recovered from a gravity recovery circuit and the CIL carbon elution circuit pregnant solution by electrowinning and smelting in an induction furnace. The current plant capacity is 14Mtpa.

LOM tailings deposition requirements are met in the short term by wall raise sequences on TSFs 1, 2 and 5. In the longer term, LOM tailings deposition requirements will be catered for by additional raises at TSFs 1, 2 and 5. LOM TSF requirements are reviewed and updated annually by the Engineer of Record. TSF 3 is decommissioned and is in the process of being closed. The ANCOLD consequence classifications for TSFs 1, 2, 3 and 5 are High C, Extreme, High A and High C, respectively.
  The Asanko processing plant, located at Obotan adjacent to the Nkran deposit, was commissioned during Q1 2016 and is currently operating at a throughput of circa 5.9Mtpa, achieving metal recoveries of 68% – 94%, depending on the proportion of fresh Esaase ore fed. The plant consists of primary crushing, a SAG/ball milling circuit and a gravity recovery circuit, followed by a conventional CIL circuit.

Plant tailings are deposited into a single TSF fully lined with a high-density polyethylene liner and raised downstream. The TSF is raised periodically and designed to contain the Mineral Reserve LOM ore volume.

The facility’s safety classification has been carried out following the requirements of the Minerals and Mining (Licensing) Regulations 2012 (LI 2182) and ANCOLD. Based on the LI 2182 classification criteria, the TSF has a Class A hazard classification. Under ANCOLD, and based on the dam breach assessment conducted in 2019, the existing facility’s consequence category rating is High B.
 
REGIONAL INFORMATION

Tarkwa, Damang and Asanko JV gold mines located in Ghana

The West Africa Region comprises Tarkwa, Damang and Asanko JV gold mines located in Ghana. Tarkwa continues to be a long-life surface mining operation and a core asset with robust Mineral Reserves supporting a 13-year LOM.

The Damang Reinvestment Project (DRP) is in its latter years of operation with current Mineral Reserves scheduled for depletion in 2025. Consequently, drilling programmes and studies are progressing at both Tarkwa and Damang to assess opportunities to extend the LOM plans for both mines. The region’s summary Mineral Resource and Mineral Reserve estimates have been presented in the Group highlights section.

Gold Fields has determined that Asanko is not material to its business or financial condition and therefore has excluded Mineral Resources and Mineral Reserves estimates for the Asanko JV (see below)

Salient points

ATTRIBUTABLE MINERAL RESERVES   ATTRIBUTABLE MINERAL RESOURCES (EMR)
5.2Moz GOLD
Proved and probable
  5.6Moz GOLD
Measured and indicated
    0.8Moz GOLD
Inferred

* 90% attributable to Gold Fields and excludes Asanko joint venture (JV) 45% attributable to Gold Fields

WEST AFRICA REGION MINERAL RESOURCES AND RESERVES 2022 PDF 8MB
REGIONAL LEADERSHIP

JOSHUA MORTOTI

Executive Vice President:
Head of West Africa Region

Mr Mortoti is a mechanical and mining engineer with over 26 years' experience in the mining industry. His areas of expertise include managing mine operations, engineering, strategic planning and business development. He joined Gold Fields in April 2021 as Vice President Operations for the Ghanaian operations and became acting EVP for the region on 1 January 2022 and appointed full time in August 2022. Prior to joining Gold Fields, Mr Mortoti spent 15 years with Newmont in various managerial roles, including General Manager of the Akyem mine. Prior to moving to Newmont, he was the Business Development Manager for AngloGold Ashanti's West Africa operations. Mr Mortoti also served on the technical committees of Ghana's Public Utilities Regulatory Commission and the Energy Commission and was involved in developing Ghana's power regulatory framework.

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7,035

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