Methodology for thermal desorption treatment of local soil pollution by oil products at the facilities of the mineral resource industry

The analysis of the main environmental consequences of leaks and local spills of petroleum products at the enterprises of the mineral resource complex is presented. It is established that the problem of soil contamination with petroleum products at the facilities of the mineral resource complex and enterprises of other industries is caused by significant volumes of consumption of the main types of oil products. Based on the results of the author's previous field research, a series of experiments was carried out, consisting in modeling artificial soil pollution with petroleum products such as gasoline, diesel fuel, highly refined oil, motor oil, and transmission oil, followed by their purification by heat treatment at temperatures of 150, 200, and 250 °C. The 250 °C limit of the heating temperature was set due to the need to partially preserve the structure and quality of the soil after heat treatment to preserve its fertility. When the processing temperature rises to 450 °C, all humates are completely burned out and, as a result, productivity is lost. Confirmation is provided by the results of experiments to determine the humus content in uncontaminated soil and soil treated at different temperatures. It was found that at a maximum processing temperature of 250 °C, about 50 % of the initial organic carbon content is preserved. According to the results of the conducted experimental studies, the dependences of the required processing temperature on the concentration of petroleum products to reduce the concentration of petroleum products to an acceptable level have been established. The methodology of thermal desorption cleaning of soils with varying degrees of contamination at enterprises of the mineral resource complex is presented

Element Accumulation Patterns of Native Plant Species under the Natural Geochemical Stress

A biogeochemical study of more than 20,000 soil and plant samples from the North Caucasus, Dzungarian Alatau, Kazakh Uplands, and Karatau Mountains revealed features of the chemical element uptake by the local flora. Adaptation of ore prospecting techniques alongside environmental approaches allowed the detection of geochemical changes in ecosystems, and the lessons learned can be embraced for soil phytoremediation. The data on the influence of phytogeochemical stress on the accumulation of more than 20 chemical elements by plants are considered in geochemical provinces, secondary fields of deposits, halos surrounding ore and nonmetallic deposits, zones of regional faults and schist formation, and over lithological contact lines of chemically contrasting rocks overlain by 5-20 m thick soils and unconsolidated cover. We have corroborated the postulate that the element accumulation patterns of native plants under the natural geochemical stress depend not only on the element content in soils and the characteristics of a particular species but also on the values of ionic radii and valences; with an increase in the energy coefficients of a chemical element, its plant accumulation decreases sharply. The contribution of internal factors to element uptake from solutions gives the way to soil phytoremediation over vast contaminated areas. The use of hyperaccumulating species for mining site soil treatment depends on several external factors that can strengthen or weaken the stressful situation, viz., the amount of bedrock exposure and thickness of unconsolidated rocks over ores, the chemical composition of ores and primary halos in ore-containing strata, the landscape and geochemical features of sites, and chemical element migration patterns in the supergene zone

Recyclability of Ore Beneficiation Wastes at the Lomonosov Deposit

The article presents the data based on the long-term observations of the Lomonosov mine tailing storage impact on the natural environment. Study of the chemical, mineral and phase composition of waste, sampled at the tailing site, was carried out. It is determined that the ore beneficiation waste in the Lomonosov deposit is generally represented by minerals of the smectite group. According to the X-ray diffraction analysis data, the beneficiation wastes are a bi-mineral mixture of montmorillonite and talc with pyrophyllite impurities. Wastes of this composition are potentially magnesia raw materials used in the production of construction materials, such as cement, ceramic bricks, etc. Experimental studies have justified the use of the method of wastes recycling based on the roasting of the ore beneficiation tailings, with the number of process options, depending on the temperature regimes and the exposure time

Water Quality Management at the Tailings Storage Facility of the Gaisky Mining and Processing Plant

The paper justifies the waterproofing technology for waste storage conservation. The paper presents the results of full-scale monitoring of the quality of surface and groundwater affected by the tailings of the Gaisky Mining and Processing Plant. The determined chemical composition of enrichment waste is described. The existing methods of waste storage waterproofing are reviewed. The studied residuals of copper ore enrichment can be insulated with a mixture of processed secondary polyethylene and polypropylene pellets. The physical and mechanical properties of recycled polymers are investigated. The proposed technology of covering with a waterproofing coating can be applied to preserve technogenic deposits aiming at their future secondary extraction, as well as to ensure the environmental safety of newly designed facilities. The implementation of this technique will improve the regional environmental situation and reduce the migration of potentially hazardous substances as a result of seepage, thus reducing the pollution of natural waters