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 two open pits 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.   Two open pits (Akwasiso and Esaase) are currently exploiting the auriferous lode deposits. 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 treating predominantly fresh ore consists of a three-stage crushing circuit, a SAG/ ball mill with pebble crushing circuit, gravity recovery circuit and a CIL gold recovery circuit. The plant has been optimised to process 4.5Mtpa.

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. The third stage of construction activities commenced in 2021.

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 was embarked upon in early 2017 until January 2018 when the 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 constructed through 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 (EoR). 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 86% – 94%. 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 (HDPE) 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

Tarkwa continues to be a long-life surface mining operation and a core asset with robust Mineral Reserves supporting a 14-year LoM. Delivery against the Damang Reinvestment Plan (DRP) advanced ahead of schedule in 2021 and has been enhanced with the inclusion of a pit cutback to the adjacent Huni pit. Current Mineral Reserves at Damang are scheduled for depletion in 2025. Importantly, drilling programmes and studies are progressing at Damang and Tarkwa in 2022 to assess LoM extension opportunities. Gold Fields has excluded Mineral Resources and Mineral Reserves estimates for the Asanko JV at the time (see below).

Exploration drilling and expenditure

In 2021, Damang’s exploration focused on early-stage target definition programmes at Epieso and Tomento East, and infill drilling of the Damang Mini Cutback (MCB) volume in support of the mine’s next pit-expansion study. Aimed at continuing the success of the past two years, in 2021 Tarkwa’s exploration programme remained focused on the on-lease palaeoplacer potential by delineating new ore body extensions and upgrading known resource areas at Underlap East and South, Teberebie East and Akontansi Ridge. At Asanko, exploration focus was on infill drilling at Esaase, Miradani North, Midras South and Kaniago West, together with down-dip extensional drilling at Dynamite Hill.

Salient points

Mineral Resources   Mineral Reserves
14.4Moz*   6.4Moz*

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

WEST AFRICA REGION MINERAL RESOURCES AND RESERVES 2021 PDF 21MB
REGIONAL LEADERSHIP

JOSHUA MORTOTI

Acting Executive Vice President:
Head of West Africa Region

Mr Mortoti is a mechanical and mining engineer with over 25 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. 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.

OUR CONTRIBUTIONS TO HOST COMMUNITIES AND GOVERNMENT IN 2021
Workforce

7,138

Procurement

US$371m

SED investments

US$9m

Tax and royalties

US$197m

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