The treatment of auriferous ores presents several challenges to the metallurgists and plant operators due to there are some factors that have an important impact on the process. Without any doubt the mineralogy is the key aspect of the process performance. Basically, there are several options to be considered at the moment of evaluate the ore. The first alternative is a gravimetry process and to reprocess the tails by flotation and/or cyanidation. No matter the number of processes involved because the mineralogy is different in each deposit and governs the success of the precious metals recovery. The resolution of problems in process performance requires an understanding of the ore mineralogy. The next lines explain the main impact on the process.

The mineralogical characteristics are determined from the ore composition and textural properties. Such date is used in conjunction with metallurgical testwork results and information from other similar orebodies for process selection and flowsheet development. The metallurgical response of an ore to a proposed treatment scheme directly determines the economics of the process. Gold occurring in fine-grained minerals and penetrating small cracks and pore spaces, even in relatively coarse grains, may need finer grinding for exposure. Fine grinding may also be needed when to treat slimy ores due to solutions will not decompose calcareous materials which may be coating or encapsulating part of the gold minerals. Primary gold mineralization in veins is often more massive than in secondary deposits, but primary occurrences as disseminations in fine crack network of the host rock usually needs very fine grinding.

Native gold hosted by quartz	Gold grain detected at 63x