These studies are necessary to determine gold particle size and mineral surfaces. Measurement of gold particles plays an important role in the test work program, design and operative conditions required to get high gold recoveries. In this way, the comminution circuit is an important part of the design. The behavior of ore particles in concentration and leaching processes is strongly dependent on their size.
It will be important to determine the degree of liberation of gold particles, interlocks, associations with sulphides and gangue minerals. Obviously, optical examination will let us know the type of gangue present and the quantities of carbonaceous matter into the ore. Basically the process comprises several steps: sampling, size analysis, assays, head mineralogical analysis, and products mineralogical analysis.
Sampling is a key stage in all mining project because all the samples to be selected represent the different mineralized zones of the ore body. The mineralogical program must be oriented to highlight different ore types and be combined with geological distribution and logging information. In this way the different structures or rock formations provide indication on the behavior of the ore. If the samples will be selected from a drilling program, the different holes give information about the hardness, abrasion, and mineralogy of some areas. By studying the faults and structures is possible to get information on the different ore classes and the degree of oxidation, which must be considered in the mining plan. All these criteria help to take the decision on how to take the samples and perform composites.
It is important to study the material with low mineralization. Typically this material is considered as waste material and dilution material. In some cases, some of these materials can have a negative effect on gold recovery due to the potential presence of carbonaceous compounds or organic matter. Then is important to take some samples and include them in the mineralogical study. Some mineralized zones have higher gold content than other zones and the dilution material will be mixed to balance the gold content to be sent to the operation.