MERCURY POLLUTION AND BORAX SUBSTITUTION IN ARTISANAL AND SMALL-SCALE GOLD RECOVERY  PRACTICE

@ 4th Commonwealth Chemistry Posters: 04-05 October 2023

By Evariste Umba-Tsumbu, 4IR Yako Consulting Services Pty Ltd 
Tel: 0027 79 091 0554    E-mail: evaristeu21@gmail.com

 

The Socio-Economic Impact of the Artisanal and Small-Scale Mining (ASM): ASM has 30 million of workers producing about 20% of global gold or 600 tonnes against only 7 million workers in large scale producing about 2,400 tonnes of gold globally (Buxton, 2013; IGF., 2017).

UN’S Sustainable Development Goals (SDGS): SDGS seeks to promote well-being for all ASM (Artisanal and Small-Scale Mining) by Reducing and eventually eliminating mercury use, and by professionalizing and formalizing operations by 2030. 

Mercury Cycle: Mercury is highly toxic, once in contact with human & environment is transformed into methylate mercury then enters in the soil and seawater to affect the food chain.  Kevin Telmer et al estimated 1000 t/a are emitted by ASM globally which  350 t/a in atmosphere and 650 t/a into hydrosphere (river, lakes,  soils, tailings). 

Mercury & Women: It was found to affect woman’s fertility (New Hampshire Dept. of Env. Sc., 2019). 

Dehybor Anhydrous Borax method used in the gold refining industry by 20 MULE TEAM BORAX / Rio Tinto whereby Bullion ingots or gold concentrate/unwrought gold are melted in clay crucibles under an anhydrous borax cover. Oxygen is passed through the metal which then forms oxides of the impurities. These oxides dissolve in the Dehybor cover and produce a fluid borate slag. This slag is periodically removed and replaced with fresh Dehybor. Further refining steps are then carried out to produce bars with at least 99.8-99.9% fine gold