Abstract

ZAMBRANA MARTINEZ, Rubén Néstor. Retreatment of final tails from c-4 mining plant of catavi (Potosí-Bolivia); an economical technical and enviromental proposal. REV. MAMYM [online]. 2016, n.1, pp.12-19. ISSN 2519-5352.

The sand-grained tailings of Catavi, are a sulfide-rich mining waste that is currently retreated by the Cooperativa Multiactiva Catavi Siglo XX Ltda., to recover cassiterite (SnO2); the operation consists in a gravimetric process in vibrant tables and processes about 250 tons for day. The final tails product of this activity, are discharged as a pulp directly to the Catavi River. It has been determined that this material still contains: 0.20% to 0.25 % tin, 76.4% quartz (SiO2), sulfide minerals as pyrite that may cause contamination, and others. To recover cassiterite from the final tailings, we have conducted five metallurgical tests at laboratory level: the first two to establish the best gravimetric process; resulting centrifugal concentration test, table and sulphide flotation; and three tests were performed with regrinding to -65#, -100# and -150# Tyler. Test is recommended with regrind to 100; for two reasons, first: it was improved recovery of 47.67% tin to 67.53%, and second, in the flotation step has succeeded in separating 50% of sulfur, which is an essential component of sulphides. It has also been determined the presence of potentially toxic elements: mercury 0.09 mg/kg, cadmium <0.01%, 0.07% arsenic, antimony 0.03% and 0.01% lead From the environmental point of view, the chemical analysis of mining waste has determined the presence of heavy metals as are mercury, arsenic, antimony and lead, and on the other hand static geochemical testing has classified residue in the area of uncertainty, which involves making other studies. The metallurgical indices obtained encourage the proposal to implement a pilot plant for two years retreating the tailings after final grinding to -100#, while the construction of the tailings dam starts. After two years, it is recommended to extend a complete plant for 8 years and 1200 TPD is recommended. We have obtained the following economic-financial indices: estimated capital cost $US 9'840,908.00; net present value $U.S. 667,323.17; internal rate of return 15.28%; B/C ratio of 1.60; capital recovery period of six years, duration of the Project ten years. These results encourage carrying out the project.

Keywords : Mining waste; Retreatment; Cassiterite; Tails-sands; Centrifugal concentration; Tin mining; Potentially toxic element.

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