Diagnostic Gold Leach Testing

Diagnostic Gold Leach Testing

A Gold Diagnostic Leach Test is used to evaluate the distribution or deportment of gold in various minerals is determined by a series of selective leaches, usually by increasingly stronger oxidative acid leaches. Between each stage, cyanide leaching is used to extract the released gold. In this study a total of ten analysis stages were carried out for the 8 composite at a grind size of 150µm P80.

The diagnostic leach results indicate that, on average, about 64 percent of the gold content occurred as free cyanidable gold. Lithology composite ore 4 and 5 were less than 50%. The remaining gold was associated with acid digestible minerals, such as iron sulphides and iron oxides, being, on average, about 27%. Lithology composite on Ore 4 had a significant proportion of the gold content locked in gangue minerals, being about 55% of the gold in the feed.

Diagnostic Leach Test Work
Gold Diagnostic Leach Test Work example

More on Diagnostic Gold Leach Test Work.

Diagnostic Gold Analysis

In order to determine the nature of the gold occurrence and associations within the ore; we do a multi-stage diagnostic analysis where a 1 kg portion was ground to a nominal grind P80 of 150 um and subjected to a sequential gold extraction test. Test conditions, assays and mass balances are supplied below. Here is an EXAMPLE.

Figure 1 depicts the analysis flow sheet and summarises the inferred deportment (occurrence) of gold with the respective distributions expressed in both grams per ton and percentage values.

The results show that a maximum of 83.2% of the contained gold is cyanide soluble (at a P80 of 150um). Note however that this result was obtained under intensive conditions with a 5% NaCN solution concentration. The next highest distribution of 10.5% is locked within arsenopyrite sulphides and therefore refractory to conventional cyanidation.



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