Name: Siguiri mine.

Location: The mine is located about 520 km north-north-east of Conakry, in Guinea.

Controlling Company: AngloGold Ashanti holds an 85% interest in Siguiri, with the remaining 15% held in trust for the nation by the Guinea government.
Brief Description: Siguiri, which comprises multiple openpits containing oxide gold, is contractor-mined using conventional openpit techniques. The area has significant potential for gold mining and has long been an area of traditional artisanal mining. The mine’s gold processing plant treats about 30 000 t/d.

Brief History: The French became involved in the area in the late-nineteenth and early-twentieth centuries. From 1931 to 1951, the French reported that Siguiri produced gold, with figures varying between 1 t/y and 3.8 t/y; however, little exploration work had been completed.

There was a phase of Russian exploration from 1960 to 1963.

In 1980, Société Minière Internationale du Quebec (SOMIQ) gained the exploration rights for Siguiri and Mandiana. SOMIQ focused its work on the Koron and Didi areas. The Chevaning Mining Company was then created to undertake a detailed economic evaluation of the prospect, with more intensive work beginning in the late 1980s.

Société Aurifère de Guinea took over from its predecessors and continued work on the placer deposits. Production on the Koron placer reached a peak in 1992 with 1.1 t of gold being produced, but several difficulties resulted in the mine shutting down later that year.

Golden Shamrock started a feasibility study in 1995, after which Ashanti Goldfields invested in the deposit and the Siguiri mine started production in 1998 as Société Ashanti Goldfields de Guinea (SAG).

In 2004, the merger of AngloGold and Ashanti resulted in the operation being run by AngloGold Ashanti.

Products: Gold.
Geology/Mineralisation: The Siguiri orebodies are early Proterozoic orogenic quartz-vein-hosted deposits located in the Siguiri basin of West Africa. Generally poorly exposed, the basin sediments have been subject to greenschist facies metamorphism and consist of a well-bedded turbiditic sedimentary sequence, with some brecciated and possibly volcanic members. Mineralisation also occurs as secondary gold in alluvial and colluvial gravels in laterite cover.

A deep oxidation (weathering) profile is developed in the region, varying between 50 m and 150 m. The mineralised saprolite currently provides the main oxide feedstock for the carbon-in-pulp (CIP) processing plant, although a new treatment option has been approved to mine the fresh-rock extensions of the ore deposits.

Reserves: Proven and probable reserves as at December 31, 2015, were estimated at 87.47-million tonnes, grading 0.74 g/t of gold.

Resources: Exclusive mineral resources as at December 31, 2015, were estimated at 99.71-million tonnes, grading 1.02 g/t of gold.
Mining Method: Siguiri is currently a multipit oxide gold mining operation, operated by a contract miner. Selective conventional mining techniques are applied using excavators and trucks on 3-m-high flitches. Liebherr 994 and 984 excavators are the main loading equipment matched with CAT 777 dump trucks. A minimum mining unit size suitable for selective mining and nominated mining equipment of 5 m × 5 m × 3 m based on a historical mined-out grade control model is used to simulate the expected mining dilution and ore losses and built in the geologic block models.

Major Infrastructure and Equipment: The mine includes a processing plant, a tailings storage facility and other infrastructure, such as a mine village, water supply system, roads, power supplied by on-site generators and communications systems. Additional infrastructure includes on-site offices, accommodation and workshops to support remote mining.

A CIP plant processes the ore and has been successfully optimised to reach an average throughput of 11.8-million tonnes a year.

The existing processing facility was designed for the processing of only soft ore and only a small percentage of hard ore can be can introduced in the mill feed. The project is currently at the feasibility study stage to upgrade the processing plant to treat up to 50% hard ore.

Prospects: A feasibility study to consider the exploitation of the fresh rock material was completed in December 2015. The project will upgrade the current plant and allow for the processing of a combination of oxides and fresh-rock material. The plant throughput will remain at 12-million tonnes a year, with a flexible design allowing up to six-million tonnes a year of hard material to be processed. Targeted fresh-rock pits include Kami, Bidini, Tubani, Sintroko, Seguélén and Sokuno. The feasibility study has been conditionally approved by AngloGold Ashanti, subject to successful negotiations with the Guinea government on the Convention de Base and access to the required areas.

Conceptual studies have been initiated to evaluate the potential of mining Block 2 and Block 3.

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.