Name: Mponeng mine.

Location: The mine is near the town of Carletonville, about 65 km west of Johannesburg, in South Africa.

Controlling Company: AngloGold Ashanti.

Brief Description: The Mponeng mine is a deep-level gold mine operating between 2 800 m and 3 400 m below surface and is currently the deepest mine in the world. All production is currently from Ventersdorp Contact reef (VCR), with future expansion on VCR and the Carbon Leader reef (CLR).

Brief History: Formerly known as the Western Deep Levels South Shaft, or No1 Shaft, Mponeng mine is the most recently sunk of the three mines in the West Wits operations. The original twin shaft sinking from surface started in 1981 and was commissioned along with the gold plant complex in 1986, when mining began. Production started using two hoisting shafts, a subshaft and two service shafts. The name changed to Mponeng mine in 1999.

Products: Gold.

Geology/Mineralisation: The VCR is the main reef horizon mined at Mponeng and forms the base of the Ventersdorp Supergroup, which caps the Witwatersrand Supergroup through an angular unconformity. The overlying Ventersdorp lavas halted the deposition of the VCR, preserving it in its current state.

The VCR comprises a quartz pebble conglomerate, which can be up to 3 m thick in places. The footwall stratigraphy, following periods of uplift and erosion, controlled the development and preservation of the VCR. The footwall consists of a series of sedi- mentary layers from the Central Rand Group of the Witwatersrand Supergroup, which, owing to the VCR’s erosional nature, exposes the youngest sequences in the west to the oldest in the east.

The relatively argillaceous protoquartzites of the Kimberley forma- tion are covered by the best-preserved VCR conglomerates. The VCR is characterised by a series of channel terraces preserved at different relative elevations and the highest gold values are preserved in these channel deposits. The different channel terraces are divided by zones of thinner ‘slope’ reef, which are of lower value and become more prevalent on the higher terraces and on the harder footwall units. The Elsburg formation is situated to the west and is relatively more durable, while the eastern side of the mine is dominated by shales and siltstones of the Booysens formation. No VCR is preserved on the Krugersdorp formation on the far eastern side of Mponeng.

The other gold-bearing reef with a reported mineral resource for Mponeng is the CLR. This reef has been mined at the adjacent Savuka and TauTona mines, and it will be mined at Mponeng in the future. The CLR at Mponeng consists of (on average) a 20-cm-thick, tabular, auriferous quartz pebble conglomerate formed near the base of the Central Rand Group. The CLR is about 900 m deeper than the VCR. In recent years, extensive work has been done in refining the estimation model for CLR. This has resulted in a decrease in value of the mineral resource and an improved confidence in the estimation.

Reserves: Proven and probable reserves as at December 31, 2015, were estimated at 40-million tonnes, grading 9.91 g/t of gold.

Resources: Exclusive resources as at December 31, 2015, were estimated at 41.50-million tonnes, grading 17.92 g/t of gold. Mineral resources below infrastructure are estimated at 49.86-million tonnes, grading 19.13 g/t of gold.

Mining Method: To explore the ever-deepening mineral resource and remain flexible at a mine of this nature, the sequential grid mining method has been adopted. This has been proven as the most suitable method for the deep-level gold mining often associated with seismicity.

Major Infrastructure and Equipment: Mined ore is treated and smelted at Mponeng’s gold plant, which also receives ore from the TauTona and Savuka mines. Ore and waste material is hoisted separately, with ore being delivered to the plant using a conveyor belt and the waste rock to the low-grade stockpile. The gold is extracted using carbon-in-pulp technology. The plant conducts electrowinning and smelting (induction furnaces).

Prospects: The planned project phases will extract the portion of the mineral resource currently below infrastructure. The Phase 1 VCR project has successfully accessed ground down to 126 level. On-reef development has continued from the 123-42 lines and 123-45 lines. Production is expected to ramp up to 20 000 m2 a month.

The CLR Phase 2 project will extract the CLR south of the TauTona and Savuka mines from levels 123 and 126. The preparation for the shaft infrastructure started in 2013. In 2015, it was decided to defer the Phase 2 project to allow Anglo time to consider a possible footprint extension of the project. This work is at prefeasibility study level and is scheduled for completion this year.

Economic studies for future phases for the development of the VCR and CLR (phases 3 to 6), which are down-dip of phases 1 and 2 respectively, are under way and are dependent on the progress made from continued exploration work and design scenarios.

Contact Person: Senior VP investor relations and group communications – global, Stewart Bailey.

Contact Details:
AngloGold Ashanti,
tel + 27 11 637 6000,
email sbailey@anglogoldashanti.com, and
website http://www.anglogoldashanti.com.