Gold has been important as precious metal since early times. Techniques of extraction and treatment trend to improve gold recovery each time more and more. Process selection is an iterative procedure which usually starts as soon as exploration has established the presence of gold mineralization in sufficient grade and tonnage for the orebody. The effort devoted to process selection is related to the degree of certainly of the grade and reserve estimations and their absolute values, such as attractiveness of the deposit. The risk associated with the development of gold projects can be minimized planning a good work metallurgical program, and considering aspects that have been considered in the project: capital, profitability, risk and environmental factors. Sometime, gold recovery is not simple and is required to study a special process to recover gold.

A metallurgical problem can appear during the initial steps of the project or during the operation of plant. No matter the case, the solution sometimes is not easy and the solution must be founded with perseverance. The first step to solve a metallurgical problem involves the mineral and rock identification and classification; study the mineral occurrence and the characteristics upon which the treatment depend. The microscope may save much time and money in qualitative determinations which frequently will demonstrate the uselessness of more elaborate quantitative investigations. Mineralogical studies can help to solve problems because they can tell us more details of the minerals presents in the ore. Of greater importance is the knowledge given by the polished section as to particle size and method of occurrence of the valuable minerals. The first fact can be established with coarse grained ores by a sizing sorting assay test, for such ores, the second fact is of minor importance, but with finely disseminated and complex ores the polished section quickly gives essential information obtainable in no other route.

The metallurgical response to a proposed treatment scheme directly determines the economics of the process, or combination of processes used. The factors to be considered in the evaluation are: Recovery of gold and other valuable minerals; Quality of product, and the need for further processing; Treatment rate; capital cost; Operating cost; Environmental impact; and Technical risk. When there are problems, sometimes the solution is not simple and the most unexpected suggestions can give a preliminary idea of the solution. But, the most important tool is the knowledge and practical experience obtained because they can tell us where and what is necessary to do to find the solution. If there is a recovery problem during a cyanidation process will be required to review step by step all metallurgical parameters. For example the fineness to which the ore was ground, alkali employed, pulp density, strength of cyanide, residence time in leaching tanks, activated carbon dosage, and perhaps the most important, find out if the ore changed in mineralogical composition. The latter one can indicate presence of refractory ore or perhaps the unexpected presence of any oxide copper ore. Analyze all the factors take time, but the reward is satisfactory.