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The development of a metallurgical project is a business adventure rather a technical exercise, and the real goal is to obtain the maximum return on investment which can be consistent with the restrictions imposed by the owners. At the same time, demand for profits is the driving force for new technical advances which lead to improve the process, equipment and plant design strategies. Thus, in the mineral processing field there have been few processes developed since the introduction of gravimetry and froth flotation. Perhaps, one of the tactics employed have been to introduce equipments of big size with the only idea of minimize operation costs. However, plant designers have not always utilized this criterion or the opportunities for functional and economic design presented by the development of bigger equipment.
The design of a mineral processing plant involves many factors. Thus, the importance of a sample can not be overemphasized. Competent and through mineralogical examinations are very important as an aid in designing the testwork program. Designing and conducting the laboratory testwork is basic to the design of a preliminary flowsheet. The type and amount of sample varies widely but there is the common idea of gathering a representative sample of the ore body. Maybe, this initial task is the most important at the beginning of any design.
Usually, a few hundred tons of representative sample are needed to carry out the initial testwork and later to operate a pilot plant in order to verify the initial design or change any mistake found in the previous steps. Obviously, it is not very easy to manually sample thousands of tons of material to obtain a representative sample. Basically, there two possibilities: prepare a sample of run of mine ore and ship to the metallurgical lab, or process the sample in a plant at the same mine. The last option is more appropriate when a plant wants to improve its operation according to a particular philosophy.
The use of appropriate equipment reduces the plant capital cost. Both in terms of process equipment cost and in reduced cost for foundations, buildings, piping, electrical, and instrumentation. It will also reduce operating cost although many times the impact is not seen easily. Further significant improvements in plant design and reductions in capital costs may be made if functionality and economy are continuously kept in mind by the mill designer as well as the owners.
Normally, most of designs are appropriate and functional. So, most of the design features can be found in existing and operating industrial plants facilities. Some times, the remaining features are a logical outgrowth of the equipment selected and the requirements of the outlined process in a particular flowsheet which can be slightly changed by the designer in order to treat other ore almost similar. Always, the designer must have present that the common sense is a useful tool at the moment of take any decision, mainly when some mistakes were done in the design of a similar plant. It means that there is not a perfect plant for any metallurgical process. Perhaps, an element very important is the people that started a plant and could note mistakes which were fixed in the right moment.
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