The steady increase in gold price over the last year or two has led to a renewed interest in the yellow metal and I thought it might be time to write a little about one of MinAssist’s favorite topics. I have spent many years now looking at all aspects of gold deportment programs and I wanted to share some brief concepts I find useful when implementing these types of programs.
The deportment of gold in plant feed, product or tailing samples is the primary driver behind how we can best recover that gold or in the case of tailings, why it was lost. As the gold price climbs, recovery of every available ounce of gold becomes more desirable and consequently developing a fundamental understanding of gold deportment should be the first action of anyone involved in gold processing.
While it is of fundamental importance, the analysis of gold deportment poses some unique challenges that if not addressed can result in a lot of wasted effort for little gain. These challenges are not insurmountable but do require the appropriate methods and expertise to be used. While I have looked in the past at ways to simplify the process, the reality is that gold deportment studies still require experts in the field for them to be completed well.
Before getting to any actual analysis the most important thing to consider in a gold deportment program is sampling. Gold by its very nature occurs in low concentrations as discrete grains. This means that a sufficient mass of sample is required to gain representative results. The key consideration in a gold deportment study should be the determination of the ideal sample mass. With a basic understanding of the sample genesis and grade this can be achieved using sampling theories, such as Gy’s theory of sampling. It is not unusual that the optimum sample mass could be in the order of 10’s or 100’s of kilograms and this should be considered when looking at appropriate methods.
Examination of the methods available for gold deportment analysis is a topic that I will cover in future posts. The key consideration for any method or technique should be that it provides representative analysis for each potential gold form and carrier. The form of gold relates to whether it is visible, sub-micron or occurs as a gold mineral. The carrier relates more to the host for gold. A good method should take all the types of form and carrier into account so that key populations are not missed.
Overall, if you are undertaking a gold deportment program the most important thing to think about is that all stages are comprehensive as possible. If the sample collected is of insufficient mass or not representative of the bulk material then even the best gold deportment methods will not give good results. Conversely, if the method used does not account for all possible gold populations then there is the chance that key populations will be missed.
If you have any questions about setting up or reviewing gold deportment programs then feel free to contact us and we can try to help.