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Moab Khotsong mine, South Africa

1st May 2015

By: Sheila Barradas

Creamer Media Research Coordinator & Senior Deputy Editor

  

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Name: Moab Khotsong mine.

Location: The Moab Khotsong operation, to which the Great Noligwa mine was added in 2014, is situated near the towns of Orkney and Klerksdorp, about 180 km south-west of Johannesburg. The mining lease area lies to the south-east of the Kopanang mine.

Controlling Company: AngloGold Ashanti.

Brief History: Moab Khotsong is a relatively new mine. Stoping operations began in November 2003, with full production achieved in 2010.

In 2014, the Great Noligwa mine was included in the part of Moab Khotsong known as the Top mine. The mine was developed so that it would be well positioned to exploit surrounding ore blocks. The most important of these blocks is the Zaaiplaats blocks to the south-west of the current Moab Khotsong infrastructure and extending about 400 m deeper than the existing mine.

Brief Description: The Moab Khotsong mine exploits three distinct portions of the Moab Khotsong lease area – the Top mine (above 85 level), the Middle mine (85 to 101 level) and the Lower mine (101 to 118 level), which exploits the Vaal reef and the C reef at depths of between 1 500 m and 2 600 m below surface.

Geology/Mineralisation: The Vaal reef is the principal economic horizon at Moab Khotsong and the C reef is the secondary economic horizon. Both reefs are part of the Witwatersrand Supergroup and are stratigraphically located near the middle of the Central Rand Group. The C reef forms the top of the Johannesburg Subgroup, while the Vaal reef lies an estimated 265 m below the C reef.

The geology at Moab Khotsong is structurally complex, with large fault-loss areas. The geological setting is one of crustal extension, bounded in the north-west and south-east by major south-dipping fault systems with north-dipping Zuiping faults sandwiched between them. The De Hoek and Buffels East faults structurally bound the reef blocks of the Middle mine to the north-west and south-east respectively and the northern boundary is a north-dipping fault. Drilling is under way in the Middle mine area to obtain structural information below 101 level.

Given the magnitude of the displacement across the De Hoek fault (more than 700 m down to the south), geological structures encountered on the up-thrown side of the De Hoek fault cannot be locally projected to the down-thrown side and vice versa. It is only once the development is through the De Hoek fault that geological mapping information will have any bearing on the reef blocks. A considerable amount of exploration drilling is required to accurately delineate these blocks in this structurally complex area.

Reserves: Total proven and probable reserves as at December 31, 2014, were 16.94-million tonnes grading 10.06 g/t of gold.

Resources: Total inclusive resources as at December 31, 2014, were estimated at 38.87-million tonnes grading 16 g/t of gold. Total exclusive resources were 24.22-million tonnes grading 15.17 g/t of gold.

Products: Gold.
Mining Method: Mining at Moab Khotsong is based on a scattered mining method together with an integrated backfill support system that incorporates bracket pillars.

Major Infrastructure and Equipment: The Moab Khotsong is the only mine in the world with vertical transport infrastructure that transports miners 3 km below ground in a single uninterrupted journey.

Horizontal travel is in carriages that transport 75 people at a time – unlike the traditional 20-person variety – four carriages per train, each carriage having the capacity to carry 75 people.

Prospects: Moab Khotsong was initially developed so that the new mine would be well positioned to facilitate the exploitation of additional ore blocks adjacent and contiguous to current mining areas.

The most important of these blocks is the Zaaiplaats blocks, positioned to the south-west of the current Moab Khotsong infrastructure and extending below the existing mine. The Moab Khotsong Top and Middle mines are expected to produce about 2.1-million ounces of gold. Zaaiplaats will provide an additional 3.3-million ounces of gold, extending the mine’s life to about 2040.

Based on AngloGold’s capital rationalisation needs in 2013, board approval was obtained for project deferral. In line with the latest 2015 business plan, the project restart date is scheduled for January 2017.

Additional study work began in the third quarter of 2014, considering the new geological information and trade-offs with alternative investment opportunities, such as the Middle mine below 101 extension. The study will also investigate the optimum growth opportunity for Moab Khotsong in accessing the Zaaiplaats orebody and the Middle mine below 101 level extension from a single common infrastructure. The results of the study is planned for early 2015.

Contact Person: Stewart Bailey.
Contact Details:
AngloGold Ashanti,
tel +27 11 637 6031,
email sbailey@anglogoldashanti.com, and
website http://www.anglogoldashanti.com.

Edited by Leandi Kolver
Creamer Media Deputy Editor

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