Wednesday, May 16, 2012

Is Borax the Miracle Chemical that Will Replace Mercury in Artisanal Gold Mining?

The Myth of a Miracle Cure

Can borax replace mercury in artisanal gold mining? – or is it better concentration that can replace mercury? Does Borax really have anything to do with it?

Is Borax a Miracle Chemical?

Those promoting borax as a replacement for mercury in small scale gold mining are overselling it and risk giving the impression that there is a miracle cure. They may be well intentioned but they are misleading the world by claiming that borax is a direct replacement for mercury. This is simply not true.

The bar of gold shown here was entirely produced using borax. It was also entirely produced using mercury. How can that be if the word going around is that borax is a replacement for mercury?

It is not. Borax is used in every Artisanal and Small Scale Mining gold shop in the world and has been for a hundred years. It has been used in pottery glazes for centuries for the same reason. It is a flux.

Background: if a miner has 10 kilograms of sand that contains 10 grams of gold, that is 0.1% gold or 1/1000 th. So she needs to concentrate by 1000 times to end up with the gold. How can she separate the gold from the sand? She adds mercury to the 10 kilograms of sand which dissolves the gold and is then easily separated from the sand as a heavy liquid. Then she evaporates the mercury and is left with the gold plus about 10% impurities - grains of sand for example. It is at this stage that borax is used in gold shops - for melting and removing the impurities in 10 grams of gold - not for concentrating the gold in 10 kilograms of sand by 1000 times. Borax is only used to assist in removing the impurities.

Everybody has always used borax (and other fluxes) to melt gold concentrates. It makes some impurities – tiny bits of other minerals – melt at a lower temperature and become thinner so that the mineral melt, a molten glass slag, and the molten gold can be separated easily. That is what fluxes do.

It doesn’t matter if you have a 25% gold, 75% sand mixture or a 90% pure piece of sponge gold (the porous product of mercury amalgamation), you’re going to use borax to melt it.

Borax does not replace mercury. It is not used at the same stage of the process as mercury. 

Mercury is applied to a big pile of sand containing a tiny bit of gold.

Borax is applied to a tiny pile of gold containing a tiny bit of sand. 

Therefore, the so-called borax method is nothing more than a method of better concentration that then uses borax as it has always been used. So there is no “borax method”. There is simply better concentration. Just ask any gold shop owner or his grandfather about borax... Its been around for a long time.

Borax is not a miracle chemical that can solve the mercury problem in Artisanal Gold Mining. For the millions of artisanal gold miners and the governments working with them to reduce mercury use, proclamations of borax miracles should be replaced by a proper explanation: If you can make a 25% gold concentrate, you don't need mercury. It is better concentration that can eliminate mercury, not borax. And better concentration usually requires a higher level of organisation.