Ecology

Medvedeva N.P., PhD in Economics, Filippov P.A., PhD in Technical Sciences

Novosibirsk state technical university, Russia

Institute of Mining, Siberian Branch, Russian Academy of Sciences, Russia

On timeliness of technogenic raw materials processing

ANNOTATION: In Siberia about 200 Mt of wastes of the iron ore dressing processes are stockpiled and occupy the area of more than 100000 m². Technogenic formations of aged mine wastes and tailings contain ferrous, non-ferrous and noble metals (Fe, Co, Zn, Au, and Ag). The modern mineral-dressing processes allow the efficient processing of available dump materials to produce marketable products: iron-ore concentrate, base gold, sulfide concentrates and construction materials.

For the last millennium on the territory of the Russian Federation more than 60 billion t of industrial wastes has been stockpiled. These wastes were located on the soil surface as dumps resulting from operating mines, smelters, heat power stations and other works. The largest part of the wastes (up to 90%) is the mining industry wastes. In the Siberian region about 800 million t of the tailings are produced by mining and processing and every year they are increased by 18-20 million t.

The intensive mining activity is followed by an ecological effect of mining on the local environment. The materials sector accounts for more than 40% of disturbed lands, 30% of harmful atmospheric emissions, and up to 20% of sewage water release into natural water basins in Russia. The Kuznetsk Basin, one of the leading metal, coal, ferrous, and non-ferrous producers in Russia, bears the heaviest ecological load.

The West Siberian metallurgical complex is supplied with local raw materials by six mines with underground (4) and open cut (2) methods of mining. The mined ore is processed at crushing and preparation plants to produce the marketable product and tailings. At the moment about 200 million t of tailings (technogenic formations) are stockpiled in dumps occupying the territory of more than 500 thousand m2. A part of them is hazardous and must be isolated, another part contains useful elements and can be a subject to processing.

The presence of sulfide minerals in the iron ore wastes contributes to the intensive development of oxidation processes which causes the release of gold, nickel and other metals from the crystal lattice. The same oxidation processes cause the formation of ecologically hazardous compounds of sulfur, arsenic and other elements which negatively affect the biological environment. Arsenic and hazard category 1 zinc exceed the allowable heavy metal concentration level in the mining wastes significantly (3-5 times), as well as copper and hazard category 2 cobalt (2-3 times). By the toxicity index the dumps are referred to class IV, by the value of the total pollution index they are ranked as high and medium degree of pollution. The technogenic formations contain many useful elements (Fe, Co, Au, and others) which are of commercial interest for the secondary raw materials processing from the mining wastes.

The researches [1-3] state that the usage of technogenic mineral materials at the mining objects is rather cost-effective and by its economical parameters comparable to the processing of natural resources extracted from mining of natural (geogenic) deposits. The commercial value of technogenic formations is sure to account for the ecological component, the preventable damage to the environment caused by the release of hazardous components and their compounds to the water basins and emissions into the atmosphere from the dumps. To process the technogenic formations of Siberian mines an innovative technology of iron-ore waste dumps is developed [4, 5].

The technology provides placing a mobile modular complex on the dumps territory (Fig.) to process the wastes for the production of iron-ore concentrate and fractioned construction materials.

Fig. Technological flowsheet of the modular complex for waste processing

The modular complex consists of a receiving bin, two separators, a screen and belt conveyors to transport the concentrate. The primary material is unloaded to the receiving bin by excavator, bulldozer or scraper facilities

It is planned to invest US$ 1,500,000 into construction, assembly works and purchase of mineral dressing equipment. With the expected annual seasonal processing rate of 1 million t of wastes at one of the mines it is possible to obtain 400 thousand t of construction crushed stone and 250 thousand t of iron-ore concentrate correspondingly. The production cost of the concentrate is US$ 5.5 per 1 tonne. The project payback period is one year.

The waste processing within the minetake of Sheregeshsky mine solely will restore more than 50 hectares of reclamated lands for the economy.

The technical result ensures higher efficiency, more complete recovery of valuable components, and less ecological impact, thanks to the optimal operating modes of magnetic separation of iron-ore tailings, heterogeneous in granulometric composition and content of valuable components. In the new millennium the science can and must suggest the mankind new “green” technologies of consumer goods production.

References:

1. Filippov, P. A. 2008. Potentials of technogenic formations in mines of West Siberia. Journal of Mining Science, No. 4, 2008, pp.71-77

2. Filippov, P.A., Neverov, S.A., Freidin, A.M., Gaidin, A.P. 2009. Technogenic formations of Siberian mines as the most important source of secondary raw minerals. Proceedings of the Conference in partnership with the foreign scientist «Fundamental Problems of the Technogenic Geomedium Formation». Two Volumes. Vol. I. Novosibirsk: Institute of Mining, Siberian Branch, Russian Academy of Sciences, pp. 536-539.

3. Freidina, E.V., Medvedeva, N.P., Filippov, P.A. 2010. Opportunities and assessment of diversification for mining companies. Proceedings of the Conference in partnership with the foreign scientist «Fundamental Problems of the Technogenic Geomedium Formation». – Three Volumes. Vol. II. - Novosibirsk: Institute of Mining, Siberian Branch, Russian Academy of Sciences, pp. 141-147.

4. Freidin, A. M, Filippov, P. A. and Gaidin, A. P., 2002. Process for treatment of iron-ore bearing wastes. Patent of the Russian Federation 2190027, publ in Bull Inv No27.

5. Filippov, P.A., 2009. Recycling of iron ore tailings in Siberia as part of the regional eco-policy and higher sustainability. Innovations. St. Petersbourg, pp. 84-87.