Geita

Overview

The Geita gold mine is located in the Lake Victoria goldfields of the Mwanza region of Tanzania, about 120km from Mwanza and 4km west of the town of Geita.

Gold was discovered at Geita by a German prospector in early 1900s at a time when Tanzania was a German colony. A gold rush ensued and a mine was established to exploit the 'Bismarck Gold Reef'. Nowadays the mine is wholly owned and managed by AngloGold Ashanti.

The Geita gold deposit is an Archaean mesothermal orebody, largely hosted in a banded ironstone formation. It is a multiple open pit operation with underground potential and is currently serviced by a 5.2Mt per annum CIL processing plant. 

In 2011, the mine produced almost half a million ounces of gold at $536 total cash cost.

Location

The Geita open-pit mine is situated in north-western Tanzania approximately 90 kilometers from the regional capital of Mwanza and 20 kilometers south of Lake Victoria in an area known as the Lake Victoria Goldfields.

The nearby town of Geita hosts a population of 40,000 people. Many of the inhabitants are engaged in destructive artisanal mining operations.

Geita covers some 373 sq km of prospecting licenses with the inclusion of the Nyamulilima Hill license (Anglogold) into the joint venture. Within this area a special mining license has been granted covering 114 sq km. (Dec/02).

Nyamulilima Hill is located south of Lake Victoria, about 9 miles south of the Geita project.

Geology & Mineralization

Geita is found within the typical Archaen greenstone belt terrain of northern Tanzania respectively within the Sukumaland Greenstone Belt of Lake Victoria which stretches 60 km east-west and is 15 km wide. The greenstones are mid-Nyanzian and consist of clastic sediments, intermadiate to felsic volcaniclastics and banded iron formations (BIF).

Gold mineralisation is generally associated with these thick ironstone formations (BIFs) which often rise above the plains to form a series of distinct ridges. Gold mineralization is associated with late stage ductile to brittle-ductile deformation.

To date, resources have been outlined on a number of deposits including Geita Hill, Lone Cone, Nyankanga, Kukuluma and Matandani. These deposits have the potential to increase Geita's mine life.

As of December 2011, mineral reserves were estimated at 55.81 million tonnes grading 2.64 g/t gold for 4.73 million ounces.

An Exclusive Mineral Resource at Geita comprises 7.82 Moz gold but these resources are not economic to be mined at current gold prices.

Mining & Operation

Geita is a conventional open pit mining operation with the possibility of going underground in later years as many orebodies continue below the final pit bottom. In these instances a 35 crown pillar is being left unmined under the pit.

Mining consists of drilling and blasting; ore and waste are loaded in 100t dump trucks by hydraulic excavators.

Processing

The Geita mine comprises a crusher, SAG and ball mill grinding circuit, a gravity circuit, a 6 million tpa CIL plant, and  a 14-tonne stripping plant.

In 2011, Geita mining operation produced 494,000 oz gold at $536 total cash cost.

Environment & Community

Design work was completed on the Geita Town Water Supply Project, which will be built in 2011. This project, which will draw water from the Nyankanga dam on the mine’s lease area, will include transfer pumping, a treatment and storage system and will deliver water at a rate of 4,800 cubic metres per day to the town. 

Cyanide management has been enhanced with the completion of the plant tailings dilution circuit. Improved control may be expected once the second oxygen injection system on the conditioning tanks is satisfactorily commissioned at the beginning of 2011. 

The key requirements of the cyanide code have now been met and the main remaining objective is to achieve compliance with the code requirement that weak acid dissociable (WAD) cyanide levels in the tailings slurry should not exceed 50 parts per million for a period of three to six months. This will be the objective for the first two quarters of 2011. 

ISO 14001 environment certification was maintained in 2010.

There is an ongoing concern related to numerous security incidents where locals and criminal gangs continue to clash with the mine's security team trying to either stole gold ore after open pit blasting or mine it on their own in disused parts of the mine, or to hijack the planes used in carrying the mine's gold production.