Far West Gold Recoveries

Operation overview

Far West Gold Recoveries Proprietary Limited (FWGR) operation to the west.

FWGR comprises:

Driefontein plant 2, a processing plant with a capacity of 600 000tpm
Driefontein 4, a tailings storage facility with a capacity of 500 000tpm

Location map

FWGR

The company has two major production footprints - the Far West Gold Recoveries Proprietary Limited (FWGR) operation to the west...

Mineral Reserves of

2.26Moz

1 processing plant with a capacity of

600 000tpm

(Driefontein 2 plant)

1 tailings storage facility with a capacity of

500 000tpm

(Driefontein 4 TSF)

A two phased approach

Phase 1

The first phase of the FWGR capital project entailed the reconfiguration, upgrade and refurbishment of the existing DP2 in order to treat 500ktpm of reclaimed material from the Driefontein 5 tailings dam.

This development included:

The construction of the Driefontein 5 reclamation and pump station to collect, screen and transfer the repulped tailings from the reclamation site to DP2 including all relevant pipeline infrastructure
The construction of a high-pressure process water pump station and associated pipeline infrastructure to supply 30bar water for the slurry guns
The re-configuration of DP2 from the nameplate capacity of 180 000tpm to 500 000tpm further processing of higher tailings volumes
Refurbishment of the DP2 conventional CIL plant inter-stage screens to cater for the higher volume
Classifying and milling circuit upgraded to allow approximately 24% of the coarser material to be milled for gold liberation
Upgrading of Driefontein 4 TSF from the conventional day wall depositing method used previously to cycloning to cater for the additional volumes and rate of rise

FWGR reached commercial production on 1 April 2019.

Phase 2

The second phase of the FWGR project involves a consolidation of what remains of the Phase 1 materials and the remaining material we acquired, and we envisage a monthly production rate of 1.2Mt once complete. The key features of this phase are the construction of an ultra-high volume deposition facility and a large centralised plant.

The Phase II project is considered a key project to deliver into our strategic objectives to grow our business by replicating our business model, as well as to optimally, profitably and sustainably mine our large surface gold resource and extend beyond to potential resources in the West Rand.

We are therefore pleased to announce that the Definitive Feasibility Study (DFS) for Phase II was completed in third quarter of the 2021 financial year and the project was found to be economically viable in a number of scenarios.

We engaged an external consultant, Sound Mining, to perform an independent review of the available information and studies that have been performed regarding the Phase II expansion project. These included, but were not limited to:

A DFS performed by DRA Global (DRA) regarding the construction of the Central Processing Plant (CPP) and related pumping and pipeline infrastructure
A detail design of the Regional Tailings Storage Facility (RTSF) performed by Beric Robinson and related capital costing performed by DRA
Review of the exploration databases, Mineral Resource and Mineral Reserve estimates of FWGR assets and other future potential assets
Legal tenure, permitting, environmental and compliance status
An economic analysis of the project

Sound Mining concluded that “the Project is a low risk, profitable operation based on current methodologies and systems. The FWGR management team, employees and mining contractor have the necessary technical knowledge and experience to manage any planning and design uncertainties. There are no material technical or geo-metallurgical risks that could significantly impact the production forecasts.”

How we work at FWGR

At FWGR, we follow a five-stage process to reclaim, retreat and deposit tailings.

Tailings reclamation

Process water is pressurised through a four-stage pumping system and pumped through a 450mm diameter pipeline to monitoring guns at the Driefontein 5 reclamation site to form slurry. Repulped slurry then flows across a scalping screen into a sump where three slurry pumps pump the tailings into reception tanks at DP2.

Slurry classification

Classification of the slurry to determine whether it goes to the mills or the thickeners takes place through a three-stage cyclone system. The slurry reception tanks’ contents are firstly pumped into two cyclones and underflow from these flows to a secondary sump and the overflow transfers to a tertiary sump.

Cyclone processing

The slurry in the tertiary sump is then pumped to two tertiary cyclones and additional underflow is transferred to the secondary sump. Slurry in the secondary sump is pumped to a secondary cyclone, and the underflow from the secondary cyclones reports to the mill. After milling, the slurry is pumped to the carbon in leach (CIL) circuit.

CIL circuit processing

The CIL circuit consists of seven leach tanks each with a capacity of 1 600m3. Cyanide is added in either the first or second tank and oxygen is injected into the first four tanks. During this process, gold metal is absorbed on to activated carbon. The gold-loaded carbon is removed at a rate of 9t per day and bagged. The bags are then transported to Sibanye-Stillwater’s Driefontein 1 plant for elution, electrowinning and smelting.

Tailings deposition

Tailings from the CIL circuit are pumped to a residue tank and then to the Driefontein 4 TSF. Driefontein 4 TSF has been converted to a cyclone dam consisting of six banks with 140 by 250mm cyclones. Water is drawn off the dam through a newly installed floating penstock and is then reused for reclamation activities.

FWGR projects

At any given time, several projects are underway at FWGR to achieve our strategic objectives.

These are detailed in special features:

FWGR converts to closed circuit slimes milling for finer grind, more gold

The Far West Gold Recoveries (FWGR) surface retreatment operation of DRDGOLD Limited, near Carletonville in South Africa’s Gauteng Province, is nearing completion.

Carbon in Leach circuit and kilns [photo]

FWGR conducted test work to determine how to reduce the copper levels in its bullion. This testwork indicated that up to 74% copper could be desorbed from carbon without significantly desorbinggold. Based on the test work results, FWGR embarked on the construction and commissioning of a copper elution circuit.

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