As soon as the engineering team receives the scoping results, the ore feed and final product characterization must be specified so that the metallurgical testwork program can confirm the preliminary conclusions obtained at the beginning of the project. By preparing three or four master composites and testing some variability samples will be possible to estimate the low and high levels of ore feed and the effects on gold recovery. For example, it is important to estimate the size analysis of the plant ore feed or mine due the presence of fines material obliges to have special considerations in the crushing and comminution circuit, open pit mines can adjust the run of mime top size to the primary crusher requirements. Underground operations are used to provide a finer material according to the handling capabilities.
During the first ten months only two months reached the projected values
Geological properties are related to rock structure and rock mechanic, and these properties have an effect on the ore to be fed to the plant and the final product. Then, it is important to link geological parameters and rock properties with metallurgical performance; more even is gold is a metal very complex many times. Plant feed must be correlated to the lithological classification. Without any doubt, there is a variable ratio of gold values, grain size, and hardness that affect the comminution product or recovery process. Try to identify the critical zones of the ore body is the task that geologist, metallurgist and process engineers have to face and propose the solutions if any problem arise during this analysis.
The study must be focused on evaluating the effects of variables on feed plant and final product so the critical variables can be detected. In general, geometallurgical forms are dependent of the quality and effectiveness of the sampling program. This relationship plays an important role in any projection of the gold production or process efficiency.
Once all master composites of the entire deposits are specified, it will be necessary to perform a comminution testing in order to find out the different rock properties of the composites. Basically, the program must include point load tests (PLT), unconfined compressive strength tests (UCS), crushability work index, drop weight tests, SAG mill comminution tests (SMC), abrasion tests, and work index tests. By employing mathematical modeling will be possible to establish the estimated power required to design the crushing and comminution circuits and the variability of the material to be sent to the recovery process. Differential grinding causes each ore type to be ground to a different size distribution, some finer and some coarser than the average.
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12.4 |
15.2 |
13.2 |
16.5 |
14.3 |
11.1 |
|
10.3 |
12.8 |
14.8 |
15.7 |
12.4 |
10.4 |
|
11.8 |
14.6 |
15.7 |
15.1 |
14.2 |
10.1 |
|
11.5 |
15.5 |
15.9 |
14.4 |
12.5 |
11.2 |
|
11.6 |
14.9 |
14.2 |
14.3 |
12.1 |
10.8 |
|
11.3 |
12.8 |
11.5 |
12.4 |
12.0 |
10.5 |
The same master composites must be evaluated through the same recovery processes (e.g. gravimetry, flotation, leaching) in order to know the respond of each composite. Probably, some ore types will give good recoveries, but others no. Then, the geologist, mining engineer and metallurgist must study the importance of the sample through the life of mine. It must be noted that some ore types will be processed short time and the impact on the economy of the project must be evaluated. For example, if the process includes cyanidation and the presence of oxidized copper minerals has been only detected in specific zones of the ore body, the analysis must be focused on its effect on gold recovery and the cash flow. If the impact is serious, one solution could be to reclassify the ore types or mix the problematic material with ores with high gold content and low content of oxidized copper. The idea is to get a solution to this problem. As can be seen, the interrelationship among Geology, Mine, and Metallurgy is fundamental in the testing program.