Interesting questions on the website with potentially...

Interesting questions on the website with potentially interesting answers to come. Opaline, it sounds like one of your posts, is it you? If so keep up the good work!

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Feedback: Bob Hayward Heap Leaching


I understand you are examining the possibility of using heap leaching for zinc at Mehdiabad as a first step in a staged development of the resource. I am wondering if you have considered the possibility of heap leaching to recover silver from the oxidized part of the Irish type mineralisation.

I have three questions.

1. As you would know heap leaching for silver is a well established technology although I imagine there could be difficulties in gaining approval for the use of cyanide in a fauna protection area.

Is cyanide leaching for silver a possibility at Mehdiabad?

2. I imagine you would have included silver in any geochemical surveys of the surface mineralization but i would expect that in an area where mining has been going on for perhaps 3000 years most of the surface would have been gone over many times. If this is not the case, any surface silver in the horn silver form of ceryargyrite could be spectacularly valuable.

Are there surface concentrations of silver that could be worth heap leaching?

3. Looking at the cross sections of the deposit I would think that a likely place for high silver concentrations would under the recent alluvum where it disconformably overlies the Irish type mineralization.

Have any of your surveys looked at this zone?

Thanks for your interest.





Union Resources Reply:



Bob

Thanks for your email.

1. We would be using sulphuric acid to leach the zinc out. Whilst my understanding, is that silver and lead is not recoverable from the oxide ore. I would think that the heap will be too acidic for cyanide to work, but I will pass your ideas onto the metallurgists.

2. There has been very little historical mining at Mehdiabad and it all seems to have been reasonably modern and for zinc.

3. I will pass your question onto our geolgists for an answer, as I have not myself seen any evidence of this in the assays.

Kind wishes
Rob