Gold extraction from tailings of wet pan mill grinding circuit

[Sidi Mohamed Minehna]

Hello everybody

here in africa, there is a gold rush on hard rock gold artisanal mining. The process is simple : rocks are crushed and sorted manually then grinded by a wet pan mill and the mercury is added in the bowl of the wet pan mill. Gold recovery rate is at most 30%. So tailings would have a content of 70% and are then sold and transported to cynaide plants.

I am looking for a way to recover more gold from the tailings before they'v got sold and transported. Can anyone advise on how to do that by gravity or by mercury?

warm regards

 

[Yggdrasil]

Hello everybody

here in africa, there is a gold rush on hard rock gold artisanal mining. The process is simple : rocks are crushed and sorted manually then grinded by a wet pan mill and the mercury is added in the bowl of the wet pan mill. Gold recovery rate is at most 30%. So tailings would have a content of 70% and are then sold and transported to cynaide plants.

I am looking for a way to recover more gold from the tailings before they'v got sold and transported. Can anyone advise on how to do that by gravity or by mercury?

warm regards

Welcome to us.
We really do not recommend the use of Mercury due to its toxicity for both the ones handling it and the life down stream.
There are however methods of making sure handling and Mercury losses are reduced, but it requires knowledge and training.
If I'm not mistaken, Mercury need to be "charged" to be able to catch the smallest particles.

How much material are you processing on average per month?
Can you describe in more detail how you treat it, mechanically in drums or manually in containers?
Is it an option to learn how to leach or process all yourself?

 

[orvi]

Hello everybody

here in africa, there is a gold rush on hard rock gold artisanal mining. The process is simple : rocks are crushed and sorted manually then grinded by a wet pan mill and the mercury is added in the bowl of the wet pan mill. Gold recovery rate is at most 30%. So tailings would have a content of 70% and are then sold and transported to cynaide plants.

I am looking for a way to recover more gold from the tailings before they'v got sold and transported. Can anyone advise on how to do that by gravity or by mercury?

warm regards

Most of the times, problem is insufficient grinding - when gold is still locked inside of the host rock, inaccessible to mercury. But this can be tricky - as you mill the material finer, more gold is liberated, but also this liberated gold is so small in particle diameter, it cannot be catched by classic panning or sluicing. Second most probable scenario is that your gold is locked in sulfides and mercury cannot reach it. Third possibility is - you have something in your ore that render the mercury inactive in bonding the gold together. From local experience I know antimony sulfides have tendency to "poison" the mercury.

Try the better grinding first. If you have the ball mill, go with it, mill it very fine and then try to process small sample this way. Inexpensive would also be to collect all the gold as you are usually doing, and rest of the heavy material - let it smelt by somebody with experience. Then you will see if the gold is in the sulfide portion - that may be a bad discovery for you since it is much harder to get gold out of the sulfides with simple gear.

 

[Yggdrasil]

Most of the times, problem is insufficient grinding - when gold is still locked inside of the host rock, inaccessible to mercury. But this can be tricky - as you mill the material finer, more gold is liberated, but also this liberated gold is so small in particle diameter, it cannot be catched by classic panning or sluicing. Second most probable scenario is that your gold is locked in sulfides and mercury cannot reach it. Third possibility is - you have something in your ore that render the mercury inactive in bonding the gold together. From local experience I know antimony sulfides have tendency to "poison" the mercury.

Try the better grinding first. If you have the ball mill, go with it, mill it very fine and then try to process small sample this way. Inexpensive would also be to collect all the gold as you are usually doing, and rest of the heavy material - let it smelt by somebody with experience. Then you will see if the gold is in the sulfide portion - that may be a bad discovery for you since it is much harder to get gold out of the sulfides with simple gear.

How is Cyanides coping with Sulfides?
He sends the residues for processing so the ones buying the tailings would know if Sulfides or base metals could be an issue, won’t they?