Small-scale gold mining in Tanzania

In 1999 GEUS performed a task entitled: A approach to mineral exploration and environmental assessment in southern and eastern Africa - a pilot study in Tanzania. The analysis was supported by the Danish Council for Improvement Investigation (RUF project number 90953).

A littlgravel belt feeders for salee element with the project comprised investigation on operating conditions and uses of extraction strategies by small-scale miners within the Lake Tanganyika region. It was found that the primary extraction strategy was mercury and that none in the small-scale miners had any understanding of methods to recycle the mercury.

The pilot project comprised compilation and integrated evaluation of current geoscience and environmental data from Western Tanzania, at the same time as field work carried out jointly by geologists from Denmark and Tanzania. The pilot project was for 1 year and terminated 15 March 2000.

The field work comprised detailed studies and sampling in the quite a few small gold deposits in West Tanzania close to Lake Tanganyika, with the aim of figuring out the way the deposits were formed and thereby offering tools for locating new gold deposits within the location. The gold deposits are presently all mined by a large number of small-scale miners. All mining, crushing and grinding are accomplished yourself and the ground ore is addressed with metallic mercury, whereby the very fine-grained gold amalgamates using the mercury. The mercury is subsequently burned off over tiny fires.

Large quantities of mercury are released in to the environment during the amalgamation. A number of this mercury is inhaled by amalgamists and nearby villagers. The residual mercury enters the drainage program where it really is incorporated within the food chain. The pilot project comprised investigations regarding just how much mercury and other metals had been dispersed in to the drainage system by sampling stream sediments. Furthermore examples of fish, porridge and human hair had been collected. The analyses demonstrated that many with the miners had extremely high items in mercury within their hair. The mercury used in amalgamation poses serious wellness issues to the population of West Tanzania and a single from the aims in the pilot project ended up being to reveal signifies to reduce the release of mercury in to the atmosphere.

The project was completed in collaboration with the National Environmental Study Institute, Denmark, the Department of Geology, University of Dar es Salaam and the Geological Survey of Tanzania with GEUS as project manager. The project was financed by the Danish Council of Improvement Research (RUF).