The use of mercury to recover gold is a common practice amongst artisanal and small scale miners making the sector the largest mercury polluter in the world. Artisanal and small scale gold miners depend on mercury to amalgamate gold, which is a process where the mercury is combined (mixed with the hand) with the ore concentrate to separate the gold from other minerals. Mercury in this process, binds to gold and some other metals to form the amalgam—a soft alloy of approximately 50% mercury and 50% gold.
Mercury is a toxic chemical that can cause neurological damage, respiratory problems, kidney failure and birth defects. It also contaminates water sources, soil and food chains, affecting animal life and human health. The Minamata Convention on mercury, a global agreement to tackle mercury pollution, recognizes the dangers of using mercury in gold mining and calls upon member states to reduce and, where feasible, eliminate mercury-use in artisanal and small scale mining. Ghana ratified the convention in 2017 and has since introduced some interventions to meet its obligations. One of the key strategies has been to promote and support artisanal and small scale miners with mercury-free mineral processing equipment to increase their gold recovery without harming themselves and the environment.
Promoting Mercury-free Mining in Ghana
With growing campaign against the use of mercury in artisanal and small scale mining considering its negative health and environmental impact, the adoption of mercury-free mineral processing technologies is gradually increasing among artisanal and small scale miners in Ghana.
As part of their project “Promoting Mercury-free Mining in Ghana” funded by the United States Department of State, Solidaridad and Pact have supported six artisanal and small scale mines with mercury-free gold processing equipment. The six selected artisanal and small scale mines that received the equipment are Agyapa Ye, Benvico, Okutey, Dakete and Beeva in the Ashanti, Western and Western North regions of Ghana.
The equipment included gold concentrators (the Gold Kacha), concentrate upgraders (Gold Konka) and a shaking table (ST-30), all supplied and distributed in Ghana and West Africa by Commodity Monitor Limited, a Ghanaian trading, logistics and research company. The machines use gravity and centrifugal force to separate gold from other minerals, without the use of mercury or any chemical. Moreover, they are able to remediate mercury from mercury-contaminated tailings.
Technical team of Commodity Monitor Ltd demonstrating the operation of the Gold Kacha to small scale miners
Benefits of the Mercury-free Mineral Processing Equipment
The benefits of using these mercury-free equipment are manifold. Firstly, they improve the health and safety of miners, their families and community, who are no longer exposed to mercury poisoning. Secondly, they enhance the productivity and profitability of artisanal and small scale miners, which can enhance local economic development and poverty reduction. The machines enable gold recovery rate of over 90% as compared to the 40% recovery rate using the traditional processing methods. Thirdly, the environment is protected and safeguarded from mercury pollution and its irreversible and long-term impact on the ecosystem and human well-being.
Mr. Joseph Kofi Ababio (left) with the team from commodity Monitor Ltd (in reflectors) and Solidaridad
After witnessing the demonstration of the operations of the Gold Kacha and Gold Konka machines by the Technical team from Commodity Monitor Limited, Mr. Joseph Kofi Ababio a beneficiary and manager of Agyapa Ye Mine at the Atwima Mponua district of the Ashanti Region, expressed his utmost delight with the effectiveness and efficiency of the machines saying “the Gold Kacha will bring many changes to my operation. This is just the beginning and with what I have seen, I know my gold recovery rate will be very high onwards. With our traditional method, the concentrates are passed on boards and we could not monitor and control the flow of water, which made us lose most of our gold to the tailings at the benefit of third parties who buy our tailings for further processing. But with what we have right now, we know that we can recover a lot more gold than before.”
“Switching to mercury-free technologies brings many benefits. Mercury is expensive and using it daily comes with huge costs. Aside that, these mercury-free machines will put a stop to the toxic side effects that come with the use mercury in our operations. I would make miners in my community aware of these machines and even if they cannot adopt it now, in the long term I am sure they would switch as well” he added.
The mercury-free mineral processing technology supplied by Commodity Monitor Limited has proven to be a gamechanger in enabling miners minimize negative environmental impact while boosting their operations. The plants are manufactured to specifically remediate mercury contaminated areas, usually recovering significant quantities of gold in the process. The plants crush using the Jaw Crusher. It then mills using impact crusher and then concentrates the ore using the GoldKacha. The concentrates are further passed through the concentrate upgrader known as the GoldKonka which is simple to use and able to recover the finest gold particles. The GoldKonka comes with 3 consecutive sluice trays with a re-circulative water pump system. Heavy gold-bearing particles are caught on the surface of each tray which are then washed off with water into wash basins. The gold particles can therefore be smelted using the smelter furnace part of the mercury-free processing technology.