https://www.miningweekly.com

Joel mine, South Africa

16th February 2018

By: Thabi Shomolekae

Creamer Media Senior Writer

     

Font size: - +

Name: Joel mine.

Location: Joel mine is located in the Free State, on the south-western edge of the Witwatersrand basin, about 290 km from Johannesburg.

Holding and Controlling Company: Harmony Gold Mining.

Brief Description: The mine comprises two interconnected shaft complexes, the South Shaft complex, which is currently in operation, and the North Shaft complex, which is still to be completed.

The South Shaft complex has two shafts, namely Shaft 3 (men, material and minerals) and Shaft 4 (ventilation and services).

The North Shaft complex is a single-shaft system, sunk and lined to 1 471 m below collar, but not yet equipped to hoist people.

Brief History: Prospecting began in 1981 on the Leeuwbuilt 580 and Leeuwfontein 256 farms, while construction of the twin shaft began in September 1985 and was completed in December 1987.

Previously known as HJ Joel, the mine changed its name to Joel in 1998 when AngloGold was established. The mine was renamed again in 1999 to Taung and in January 2002 reverted to Joel, when the Freegold Joint Venture between Harmony and ARMgold assumed responsibility for the operation.

Products: Gold.

Geology/Mineralisation: The main structures at Joel are associated with the Platberg extensional event, which formed the De Bron and associated faults.

These faults are north–south striking, steeply dipping and typically have downthrows to the east from 10 m to 100 m. These form a graben against the De Bron fault, which has a 450 m up throw to the east. East of the De Bron fault the reef has been truncated/ eroded against the Karoo Supergroup.

Minor east–west striking faults are also present; however, displacements on these faults are generally less than 10 m, which are believed to be Klipriviersberg in age. Low angle reverse faulting is also present. These structures trend north–south, have small displacements and dip towards the east. These structures may be related to the Central Rand contractional event.

The Klippan Formation has been preserved as an east–west trending erosional channel that has eroded deeply through the Witwatersrand sediments and has eliminated the Beatrix/VS5 horizon in the eastern portion of the mine and cut out a significant chunk in an east–west direction through the middle of the lease area. Regionally the Klippan Formation is preserved in the north–south-striking basin, known as the Virginia basin in the southern Free State, which parallels the De Bron fault.

A deep erosional channel of Platberg Group volcano-sedimentary rock, known as the Klippan Channel, truncates the Beatrix reef about 1.8 km to the north of Joel South Shaft. This washout feature is wedge-shaped with its apex to the west and widens to the east.

The estimated dimension from the apex to the eastern property boundary is about 1.8 km. The reef has been shown to be continuous to the north of this feature.

Reserves: Total proven and probable reserves as at June 30, 2017, were estimated at 4.5-million tonnes grading 5.19 g/t gold.

Resources: Total measured, indicated and inferred mineral resources as at June 30, 2017, were estimated at eight-million tonnes grading 8.46 g/t gold.

Mining Method: A predeveloped scattered mining system is used. This system allows for un-pay and geologically complex areas to be left unmined, with some cognisance taken of the overall panel configuration and stability of footwall development. This allows for mining to be selective, based on the proven ore reserve during the development phase.

Minor falls of ground owing to geology, bedding, shale and jointing do occur but are mostly addressed with a proven in-stope support system. As the largest portion of Joel production currently being mined between 121 and 129 levels, production is relatively concentrated to four or five raise lines.

Major Infrastructure and Equipment: The Joel plant currently receives reef from only Joel at a rate of about 45 000 t/m. Reef is transported from the shaft using trucks which tip the ore into the plant feed bin. The reef is then transported from the feed bin by conveyor belt to the mill silos.

The ore is fed from the concrete silos using two mill feed conveyors into the mills. Fully autogenous milling is a milling process in which the entire run-of-mine (RoM) ore stream is fed directly into the mills. The average feed rate to the mills is between 50 t/h and 75 t/h. The milling circuit consists of two single-stage RoM mills that are controlled on maximum power and load for optimum milling. Each RoM mill is 4.27 m in diameter and 10 m long, the mill grind varies between 70% and 80% passing minus 75 microns.

The carbon-in-pulp circuit at Joel plant comprises six tanks in which carbon is transferred counter current to the flow of pulp. The carbon is retained in the respective tank using Kambalda screens, the slurry is pumped to the residue tank and from there to the tailings dam.

Prospects: The decline project, from 129 to 137 levels, which started in 2011, is scheduled to be completed in 2018 and production from the 137 level E5 raise is expected to start in March 2018.

Contact Person: Harmony investor relations manager Lauren Fourie.

Contact Details:
Cell +27 71 607 1498
Email HarmonyIR@Harmony.co.za
Website https://www.harmony.co.za/our-business/our-operations/joel

Edited by Sheila Barradas
Creamer Media Research Coordinator & Senior Deputy Editor

Comments

The content you are trying to access is only available to subscribers.

If you are already a subscriber, you can Login Here.

If you are not a subscriber, you can subscribe now, by selecting one of the below options.

For more information or assistance, please contact us at subscriptions@creamermedia.co.za.

Option 1 (equivalent of R125 a month):

Receive a weekly copy of Creamer Media's Engineering News & Mining Weekly magazine
(print copy for those in South Africa and e-magazine for those outside of South Africa)
Receive daily email newsletters
Access to full search results
Access archive of magazine back copies
Access to Projects in Progress
Access to ONE Research Report of your choice in PDF format

Option 2 (equivalent of R375 a month):

All benefits from Option 1
PLUS
Access to Creamer Media's Research Channel Africa for ALL Research Reports, in PDF format, on various industrial and mining sectors including Electricity; Water; Energy Transition; Hydrogen; Roads, Rail and Ports; Coal; Gold; Platinum; Battery Metals; etc.

Already a subscriber?

Forgotten your password?

MAGAZINE & ONLINE

SUBSCRIBE

RESEARCH CHANNEL AFRICA

SUBSCRIBE

CORPORATE PACKAGES

CLICK FOR A QUOTATION