Testing Local Conditions for the Introduction of a Mercury-free Gold Extraction Method using Borax in Zimbabwe

Abstract

Background. Mercury is extensively used in artisanal small-scale gold mining in many parts of the world, including Zimbabwe. Mercury-free mining technologies are urgently needed to protect the biophysical environment and human health. Objective. The testing of local conditions for the introduction of a mercury-free gold mining technology entailing the use of borax in a field project in Kadoma/Zimbabwe. Materials and Methods. A one-day theoretical workshop and a two-day practical demonstration were conducted in Kadoma/Zimbabwe in December 2013. The willingness of the miners to change to another gold extraction technology other than mercury amalgamation, the local availability of appropriate materials and equipment, and the suitability of the ore for applying the borax technology for gold smelting were used as variables to test local conditions for introducing the borax method. Simple methods like trial and error and the collection of indices during discussions and observations were applied. Results. 1.11 grams of gold from half a ton of ore was the result of the demonstration. A number of potential improvements to the process were identified. A total of 50 invited local stakeholders took part in the theoretical workshop, and 30 to 40 decided immediately to also participate in field demonstrations. The project team noticed that the local miners were interested and impressed by catching very fine gold particles with the borax method. Conclusions. The project confirmed that the local conditions in Kadoma are appropriate for mining mercury-free gold. The optimization and comprehensive introduction of the borax method in the Kadoma gold mining region is recommended to eliminate the use of mercury. Competing Interests. The authors declare no competing financial interests.

Keywords

• Mercury
• gold mining
• borax
• Zimbabwe