Forest recultivation of overburden dumps of the Kingisepp phosphorite field

The article is devoted to the study of the stages of forest recultivation of overburden dumps of the Kingisepp phosphorite field’s breed located in the North-West of the Russian Federation. 5 test areas with a total area of 63.7 hectares were laid to study the different stages of recultivation. In the course of the study, the author’s team identified four conditional stages of the formation of the spruce community of the forest recultivation of overburden dumps breed. The first stage, which has the conditional name ‘10 years’ is newly planted spruce trees on the recultivation territory. The second stage of the formation of the spruce community (‘20 years’) is that the European spruce passes into the stand. The third stage of community formation (‘30 years’) consists in the growth of all plantings to the level of a stand and in the creation of a birch-spruce or spruce-birch forest, since at the age of more than 30 years European spruce in recultivation by itself territories can occupy up to 50% of the stand. At the fourth stage, spruces displace birch trees from the community, remaining almost the only representative of the tree layer.

Development of Zoning Method for Man-Made Massifs

Contemporary mining industry is a complex system that is constantly expanding both in terms of explored sources of mineral raw materials and in terms of developing new approaches to mining and processing of minerals. Such a buildup in the scope of tasks set for the industry, as well as the technical progress, lead to various issues related to the quality, quantity and rational use of mineral raw materials. Rationalization, in its turn, should be carried out in a phased manner through the use of comprehensive measures, one of which is reclamation of man-made wastes, represented by waste rocks, tailings, slags, dust, etc. In addition, this approach simultaneously resolves several other important challenges the industry is facing, e.g. increasing the environmental safety of mining regions and increasing the economic feasibility of production by extracting additional components from waste materials. The scope of application of such a solution to the challenge of rationalizing production is immense and can be implemented at many deposits located in the territory of the CIS due to the presence of huge volumes of waste generated by mining raw materials. These wastes were accumulated because of the absence of full-fledged technologies to extract useful components from the rock mass in the past as well as other requirements to ore conditioning than those acting today. For example, in the Republic of Bashkortostan, the overburden dumps and off-balance ores that have been created by mining enterprises amount to more than 1 billion tons, hydraulic-mine dumps of processing plants reach 50 million tons, manmade waters exceed 9 million m3 annually. At the same time, the amount of useful components contained in these man-made deposits can be up to 1.5 million tons for copper, 2 million tons for zinc, about 100 tons of gold as well as significant amounts of other associated components, including various non-metallic formations.

Inhalable Particulate (PM10) Emission Externalities From Overburden Dumps and Associated Health Risk Assessment in Densely Populated Coalfield

Overburden (OB) dumps and associated haulage are the significant contributors to increased respirable particulate levels in mining areas. Earlier studies have only focused on reporting seasonal variation of size-segregated particle mass concentration, limiting the role of specific emission sources on sensitive receptors nearby. This study estimated the impact of OB dump expansion (between years 2016 to 2018) with associated haulage on spatial pattern of particulate concentration, associated health effects, and health cost. Furthermore, a model to identify critical health risk zones was also developed. Haulage of OB and its unloading contributed to a significant increase in particulate concentration on the windward side. Moreover, OB dumping resulted in a higher respiratory dose for workers and inhabitants nearby the OB dumpsite. The results indicated that coughing along with lower respiratory problems were the dominant health effects. Moreover, the cases of lower respiratory symptoms due to PM10 emissions from OB dumps increased in 2018. The risk potential model indicated a 4.9% increase in high risk category for population exposed to PM10 emission from OB expansion within two years. An alternative management option was proposed to reduce health risk potential. The control resulted in 73% peak concentration curtailment and 84% reduction in the surface area exceeding prescribed PM10 (100 µg/m3) levels. The said study will be useful in demarcating risk zones and findings have particular significance for dispersion of particulates emanating from OB dumps.

Investigation of the solubility of dust particles in soil solution at different temperatures (on the example of the tailings of the loparite ores' concentration)

A number of large mining enterprises are located on the territory of the Murmansk region. Dusting overburden dumps and tailings storage sites leads to a complex of long-term consequences for the environment. The output of the silty fraction (-0.071 mm) of "stale" tailings of loparite ore dressing (the first field of the tailing dump) is about 22 %. The investigated material is represented by nepheline, microcline, aegirine; loparite, analcime are diagnosed in impurity quantities; the average content of cerium, lanthanum, neodymium - rare earth elements of the light group - 0.18, 0.03 and 0.015 %, respectively. In laboratory conditions, a simulation of the ingress of a fine fraction of loparite ore dressing tailings into the soil has been carried out; the interaction of tailings material with distilled water and water extract from conditionally background soil at different temperatures has been studied. In the course of the study, it has been found that the introduction of dissolved organic matter intensifies the processes of destruction and partial dissolution of the aluminosilicate matrix of rock-forming minerals; an intensive transition of rare earth elements and heavy metals into soluble forms has been recorded. The research results indicate the ecological danger of the finely dispersed material of "stale" tailings of loparite ore dressing due to the ingress of dust particles into the soil and their interaction with soil waters.

Application of the Stabilizing Polymer Additives for Protection of Dump Overflow from Wind Erosion

The effectiveness of using the stabilizing additive StabOL for fixing the surface of overburden dumps has been studied. It was found that the average mass radius of supramolecular formations in the StabOL polymer solution is 593 nm. It was revealed that this polymer solution forms a high-quality film: transparent, homogeneous, without cracks and crystalline inclusions. The phase and granulometric compositions of overburden for the formation of organomineral aggregates of particles resistant to water and mechanical stress have been established. It is shown that the use of environmentally friendly polymer solution StabOL allows reducing the content of highly dispersed particles and is an effective way to protect dumping overburden from wind erosion.

Social and Economic Efficiency of Project to Use Overburden Dumps for Transport Construction in New Development Areas

The objective of the paper is to demonstrate a cost efficiency assessment methodology adapted to a major integrated mining and transport project. The sources of social and economic efficiency of the project to use overburden dumps for the needs of transport construction in the areas of new development are stated in the article. In order to assess such a large-scale and complex project, it is not enough to rely on a universal general project methodology; the methods must be adapted and customized. In particular, cross-sectoral and indirect effects arise that will require an adequate organizational and economic scheme for the project to be implemented. It has been concluded that a complex assessment of economic efficiency is only possible with the view of the entire national economy, taking into account not only direct but also indirect, including non-transport, effects. However, the basis for accepting the project for a detailed study is to compare the cost of the ballast material delivered to a specific point in the project network infrastructure of the development territory from the dumps of the mining pits and from the roadside pits, i.e. following the traditional method.