Metal mining operations use a huge amount of water in their processes, from milling, flotation, thickened, counter current decantation, leaching and some others according to the metal, once the values have been separated, the residue known as tailings, is sent to a dam, in this article we will mention some of the characteristics of these structures.
The tailings dam is a structure that contains or impounds the tailings and its main functions are to deposit the minerals without values that came from the processing plant at the bottom and pumped via a reclamation barge back into the process.
The design of each tailings dam is different since it adapts to the topography and the availability of materials to build it, in ancient times the tailings were poured into the waterways, they settled on the banks of these roads forming tailings beaches in the rivers and streams, later the advances in soil mechanics came to improve the construction of the dams.
The dam is built in the form of an embankment or rock slope usually residual from the beginning of the construction of the mine, the tailings are piped from the plant and deposited from the crest of this mound where the solids rush to the bottom forming a sandy sediment; these embankments aren’t water retention structures, they are meant to hold back solids.
Although liquids can be contained up to the top of the embankment this will eventually erode the structure, so the liquid level must be constantly monitored. Over the years the level of the dam rises to keep up with the production of the mine, these increases are planned within the life of the mine.
Some of the main characteristics with which the dams of dams must comply are that they are designed to withstand the force of possible earthquakes, an adequate drainage to their capacity, and take into account the soil conditions, in some cases such as in the extraction of gold where cyanide is used, coatings are used to prevent some filtration.
Finally, the maintenance of the dams must include the complete water recovery systems, the liquid level monitoring, and the constant monitoring of possible deformations within the general structure.
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