OPERATIONS West Africa Region
|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.