Tailings mineral processing

Processing costs include those for size reduction, size classification, minerals concentration and separations, soHd—Hquid separation (dewatering), materials handling and transportation, and tailings disposal. Size reduction, one of the most expensive unit operations in minerals processing, could account for as much as 50% of the total energy consumed. This cost varies considerably from deposit to deposit and quite often from one area of a deposit to another. Ore bodies are extremely heterogeneous and the associated minerals Hberation, complex. 

Once the comminution process is completed, the succeeding operations in mineral processing are taken over by what is known as separation. Regardless of the method or methods used, the aim is always the same-to take a natural aggregate of minerals (an ore) and separate it into two or more mineral products. In general, the products of separation are (i) the concentrate which contains the valuable minerals and (ii) the tailings which contain primarily materials of little or no value. It may be borne in mind that minerals have been liberated, either by grinding or by chemical means, must usually be sized prior to... 

Many of the applications of colloid and interface science to the mining and mineral processing industry can be found in the hydrotransport, flotation, and tailings processes. Although suspensions feature prominently in each of these, a range of emulsions, foams and suspensions can be found in this industry. Some examples are given in Table 10.1. 

To avoid the occurrence of tailings ponds, and their associated problems, some mineral-process tailings are drawn off from the rougher and scavenger stages, thickened, de-watered in centrifuges, and then dried in, for example, gravity-fed, direct-fired driers for dry disposal. 

Mine wastes, tailings, and smelter slag and emissions can contain complex mixtures of minerals that are typically a predictable function of the geologic characteristics of the deposit type being mined, coupled with the ambient climate/ environmental characteristics and the mining or mineral processing method used. See Chapter 9.05 and Plumlee (1999) for a detailed discussion. 

As mineral processing techniques have improved, the head grade of treatable ores has diminished, in essence, the mining industry is generating more tons of tailings per ton of product, but more efficiently and more economically. This means that for the same metal production, the tailings impoundment must be larger for today s operations than similar operations from several years ago. 

GEO Minerals, sediments (freshwater, estuarine, marine bottom sediments), rocks, ores, concentrates, coal, coke, ash, fly ash, mineral processing products, mill tailings, blast furnace slags, other min-eralogical and geological materials, meteorites, lunar and other extraterrestrial materials. 

From the soil data from all sampling sites, it can be seen that the total, soluble and extractable antimony contents are highly correlated with each other (r from 0.873 to 0.926 and P < 0.001). However, rather different situations are found among the soils from the cultivated sites (SI, S2 and S3), the mine dumps (S5) and the mineral processing tailing pond (S6). In the first sites, only the total and extractable Sb are correlated (r = 0.786, P < 0.05) in the second, only the total and soluble Sb are correlated (r = 0.857, P 0.05) m the last, both the soluble and extractable anti mony are correlated with the total Sb (r = 0.900, P < 0.05). 

Table 5. Sb contents (mg/kg) in plant species of S6 (mineral processing tailing pond) ...

The antimony levels in cultivated species most probably constitute a minor risk both for human and animal consumption. The risk of Sb transfer to food chains also appears not to be very high, in view of the usually low Sb contents that we found in plants and the low bioaccumulation properties inferred for this element (Ainsworth et al., 1990b, 1991). However, such a risk must be considered more carefully for the species growing at the mineral processing tailing pond, which have Sb contents near or above 1000 mg/kg. 

Bold B, Fondbote L. (2001). Element cycling and secondary mineralogy in porphyry copper tailings as a function of climate, primary mineralogy, and mineral processing. Journal of Geochemical Exploration 77 3-55. 

The material properties of the various categories of mineral processing wastes are influenced by the characteristics of the parent rock, the mining and processing methods used, and the methods of handling and/or disposing of the mineral by-product [99-112]. The physical and chemical properties of waste rock, mill tailings, and coarse coal refuse are summarized and discussed in Table 12. 

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