Faculty: Mining and geology
Speciality: Ekological geology
There are 120-138 waste dumps that covers 1000,71 – 1104,20 hectares within bounds of Donetsk city, 32 of them are functioning including 28 burning. Total rock volume is 336-337 millions of cubic meters. Waste dumps pose serious threat to environment. Toxic compounds and dust from waste banks (especially burning) falls into the atmosphere, hydrosphere and ground. Waste bank ablation leads to their enlargement. Waste dumps are often located near the residential area.
Waste dump related research topicality is conditioned by danger to environment and people. Furthermore waste dumps cover huge areas which can be used for various purposes. Along with that waste rocks are in interest as a mineral source. Finally presence of waste dumps is undesirable in view of the city evolution as a cultural and historical center.
Waste dump research in Donetsk was highly tailored and unmethodical. A lot of cumulative data have to be integrated, classified and analyzed using modern methods.
The main goal of this research is to study ecological consequences of waste dump mineralogical and geochemical transformation in waste banks.
Objectives covered by this research:
–Donetsk waste dump data systematization
–Mineralogically-petrographical and geochemical properties of the waste bank rocks are studied
–Mineralogically-geochemical features of the waste rock transformation processes are studied
–The complex estimation of negative ecological impact of the waste rock transformation processes is given
–Basic migration ways, conditions and localization processes of contaminants are discovered
– Some advices upon waste dump negative ecological impact minimization are suggested
Object of research – the waste dumps which are in limits of administrative border of Donetsk. Waste banks of following mines have been studied in details: Gorkogo, Zasyadko (¹ 1-7 Vetka).Grounds in next areas was investigated: area of waste bank influence, area of airing, water-containing adjoining rocks. Subject of investigation– stored waste rocks, grounds of the bases of buildings and constructions in Donetsk.
Methods of researches:
– Generalization of results of the preceding researches;
– Field researches of the waste dumps and soils;
– Laboratory researches of the ground samples which selected within waste dumps and platforms adjoining to them;
- Studying of mineralogically-petrographical features of the grounds;
- Processing of the field and laboratory data.
Scientific novelty – data ordering and unification about waste dumps in Donetsk is made. Mineralogically-petrographical features of transformation processes of the waste rocks which are the basic genetic sources of environmental contamination are studied. Ways of migration and a condition of localization of the polluting substances genetically connected with waste heaps are established.
Practical value of work – most ecologically dangerous factors of influence of the waste dumps are defined, including engineering-geological aspect, variants of use of the waste dumps in a national economy that will lead to decrease in man-caused loading on a surrounding environment are considered and will allow to receive additional resources of secondary mineral raw materials. The received results of research can be used at scheduling on suppression, restoration, gardening and dismantling of waste dumps.
Average lithologic structure of waste dumps reflects the structure of carboniferous thickness. Argillite (60—80 %), siltstone (10—30 %), sandstones (4—10 %), limestone (about 6 %, usually it is less), and also considerable impurity of coal (6—20 %). Besides, waste dumps contain an essential share of the man-caused materials — wooden linings, metal products, wires and so forth [1].
Getting to waste heaps, carbon breeds test considerable transformations. It is connected with processes of aeration which are accompanied by change mineral and a chemical compound of breeds. Along with aeration which is extended in an external part of waste heaps, inside of them favorable conditions for oxidation and the subsequent ignition are created. The leading part thus belongs to activity of microorganisms [2].
Oxidation and burning of breeds is accompanied by emissions of a wide spectrum of flying components. The basic component of emissions is water steam which is formed at evaporation and sublimation getting to a zone of burning of an atmospheric precipitation, and also at liberation of the interstitial and connected water of minerals and breeds. Water is mineral-forming environment for the most of neogenic minerals: sulphates, hydrocarbonates, carbonates, phosphates, arsenates, etc. Burning waste heaps allocate steams in which except water contain: sulfuric acid, carbonic acid, nitrogen dioxide. Due to lack of oxygen in the burning centers the steam-and-gas emissions contains hydrogen sulphide, hydrocarbons, ammonia, carbonic oxide.
The burning centers are sources of the hot water fluids that are mineralized, chemically-aggressive and sated with microelements. At an exit on a surface a part of components of fluids, getting to conditions of low temperatures and an oxygen abundance, it is allocated in the form of crusts, touches, wandering or crystal or spherulite units of new minerals among which sulphates, chlorides, sulphides and oxides prevail. Other part disappears in atmosphere, filling up with its harmful substances.
Around the burning centers the original zoning caused by redistribution of initial material structure is formed. In different places of a surface of waste heaps on black color of rock small sites where have remained primary friable bladed rocks are allocated. On periphery of these sites the border zone of replacement shown in change of primary color of rock to brown, cherry shades against which sulphates of yellow color develop is established. Further in a direction from sites of primary rocks the zone of development of a white sulphatic mineralization which impregnates the oxidized brick-red rocks is allocated. Outside of this zone extensive sites of the oxidized rocks of brick-red color without visible signs of development of sulphates settle down. These two zones (yellow and white) are intermediate between the oxidized and primary rocks.
The behavior of a considerable part of the components of rocks in the course of its oxidation has natural and quite explainable nature. So concentration growth in the oxidized rock in relation to the initial is established for the following rock-forming components: SiO2 (from 50,21 % to 54,36 %); Al2O3 (from 17,73 % to 20,86 %); Fe2O3 (from 6,31 % to 9,43 %); CaO (from 0,93 % to 1,3 %); Na2O (from 0,93 % to 1,05 %); SO3 (from 1,93 % to 3,27 %). Concentration of a water-soluble (mobile) sulphate-ion – SO42- (from 9796,1 mg/kg to 17463,7 mg/kg) increases almost twice. For a number of microcells concentration growth in the oxidized rocks also is marked: Pb (from 25 to 97,1 mg/kg); Cd (from 1,9 to 2,9 mg/kg); Hg (from 0,06 to 0,1 mg/kg); As (from 4,2 to 5,5 mg/kg).
The basic component of emissions is water steam. Together with gas-vapor emissions flying connections of toxic elements can get to atmosphere from outside waste heaps – mercury, arsenic, cadmium, etc.
The warming up of an organic part of coal in the oxidation centers is accompanied by its thermal decomposition similar to process of pyrolysis. Harmful flying organic components are thus formed. In the raised concentration in rocks of waste heaps are established:
1. Oil products in concentration to 548,0 g/t. The maximum concentration of oil products are observed in rpcks of waste heaps of mine Paravichnaya" ¹5 and 1-7 "Vetka".
2. Phenols in concentration to 0,22 g/t. The minimum concentration of phenol are marked in rocks of waste heaps ¹2 (mine ¹4 "Livenka") and ¹2 (mine «Centralno-Zavodskaya») - less than 0,01 g/t, maximum - in rocks of a waste heap of mine ¹11 – to 0,081 g/t.
3. Formaldehyde is established approximately in identical concentration (to 0,22 g/t) in all studied waste heaps.
4. Monoethylamine is fixed in tests with the maximum concentration 6,25 g/t in rocks of a waste heap of mine «Centralno-Zavodskaya». In rocks of a waste heap of mine ¹4 "Livenka" one test with monoethylamine concentration - 3,65 g/t is found out.
5. The maximum concentration diphenylpropane (2,36 g/t) is fixed in rocks of a waste heap ¹1 of mine «Centralno-Zavodskaya» [2].
Emissions from outside waste heaps can extend on hundreds meters, grasping the big areas, including built-up territories. Components of emissions, being besieged on a terrestrial surface, pollute soils. Dispersion auras are thus formed. The most polluted are boggy sites of valleys of the rivers and the bottoms of beams.
The negative geological processes connected with waste heaps, are shown in different aspects. Water erosion of their boards leads to expansion of the area of dumps. The rocks puts additional pressure on grounds of the base that can affect change of their filtrational properties and have local influence on a level mode of the first from a surface water-bearing horizon. However the most essential negative influence waste heaps render thanks to formation of zones of replacement in grounds of aeration zone and in water containing rocks. They are shown by development of a secondary mineralization. Naturally this mineralization is presented in the form of an abundance of the vein-interspersed carbonates developing in a zone of aeration and in water containing rocks.