The mining equipment of the Ukrainian extractive industry is rather old. For a long time during the Soviet era the industry was developed as a raw-material base for the Soviet industry, which caused a highly unbalanced development of the mining, metallurgy, chemical and other industries consuming excessive amounts of resources.
With the passage of time, the volumes of extracted resources and extraction depth and fields have increased. The major mining activities took place in the areas of Donbas, Kryvbas, Prycarpattia and Pridniprovia.
Extensive exploitation of the deposits with large extraction volumes and further rock processing inevitably heavily influenced the environmental situation in Ukraine. Following the disintegration of the Soviet Union, Ukraine inherited considerably exhausted mining regions in a critical environmental situation plus the old-style and worn-out equipment of the extractive industry.
The level and origin of influence on the environment by the exploitation of deposits depend largely on the characteristics of the geological structure, the type of mineral resources and extractive methods (see Table 3.29).
Extraction of most of the mineral resources in Ukraine is historically concentrated in regions with a well-developed mining industry. Each region has its own features. The only exception is exploitation of construction materials deposits, which are located throughout the country.
Coal mining regions.
Coal is being extracted in Ukraine within the boundaries of three large coal fields – Donbas, Lviv-Volynsky fields (bituminous coal) and Dniprobas (brown coal). The poor ecological situation in the major coal mining regions is largely caused by old mining equipment, which indicates that about 30% of the coal mines have been exploited for more than 50 years. Since the restructuring of the coal mining industry began in 1993, no mines have been closed at an adequate ecological and technological level, thus considerably complicating the environmental situation in the regions of the Donbas, Dniprobas and Lviv-Volynsky fields with a total area of 18,000 km2 (3% of the territory of Ukraine; Donbas alone occupies an area of 15,000 km2 ; the total area of mining works is up to 13,000 km2 ). Mining depths at these fields range from 10 to 100 m to 1,400 m, which has caused a considerable decrease in the resource volumes mined and a deterioration of the chemical composition of the ground water within the zone of active water exchange, as well as intensive drainage of its reserves. The large scale of mining works has also brought about a regional deterioration of rock masses and formation of technogenic jointing zones, a decrease in the thickness of the seams with serious displacement, and land surface subsidence ranging from 0.3-4.7 m over an area of up to 8,000 km2. Very often these territories are subject to ground water flooding. Large amounts of mining workings in the rock masses, and numerous artificial surface water reservoirs have enhanced the development of huge rates of mine water rising in the mining regions (28.5 m3/sec in general, 25.0 m3/sec in Donbas Region), as well as a complete disruption of the regime of local water system runoff. Additional factors complicating the environmental situation in the coal mining regions are the numerous pit refuse heaps, which pollute air, soil, surface and ground water in consequence of the active air and water migration of chemical compounds and mechanical dust particles.
In the process of taking the old coal mines out of service, a very important issue for restoring the natural balance is the maintaining of a proper level of the ground water, since rising levels, causing partial or complete flooding of coal mines, is the major factor worsening the ecological situation in the main coal mining regions of the country.
Regions of development of iron and manganese ore.
Iron ore is extracted from the Kryvorizskyi, Kremenchugskyi and Bilozirskyi deposits, while manganese ore is mainly extracted from the Nikopolskyi deposit.
The most dangerous ecological situation is in the Kryvorizskyi fields, where iron ore is mined in 10 open casts with a depth of up to 300 m, and 23 mines (including the auxiliary ones at a maximum depth of 1,125 m). Total area of mining in this region is 700 km2 with 360 km2 of just mining workings. Regional deterioration of the rock masses together with a development of technogenic jointing and increase of rock permeability cause a considerable increase in the rate of mine water rising (up to 45-50 million m3 per year) with up to 70% of its volume coming from technogenic water reservoirs and local river systems.
Low-permeable overlying rock areas together with the large number of the sludge settling sumps with a total area of 71.0 km2 , accumulating 1.4 m3 of waste, are responsible for the development of ground water flooding of an area of up to 500 km2 with a considerable worsening of the state of industrial and populated zones, dams, tailing dumps, etc. In addition, infiltration of technogenic and natural water into the mining workings enhances active washing out of soluble salts and raises the level of general mineralization to 20 g/dm3 and more, with salt washing out into the river system at a rate of 180,000 tons per year (17% of the general input by the mine water).
A complex of technogenic changes of the environment in connection with shutting down the mines in the Kremenchugskyi, Bilozirskyi and Nikopol-Marganetskyi deposits in relation to the limited depth of open cuts and mines, and thus inconsiderable deformations of the surface, are mainly related to local flooding of the surface, and a transfer of water from lower horizons to upper ones through destroyed water layers, which deteriorates water quality.
Oil-Gas Deposit Regions.
About 200 oil, gas and gas-condensate deposits are being exploited in Ukraine at present.
The most typical example of the loss of control over mineral resources is the open ejection of oil, gas and aquifer water while opening up productive deposits. These situations take place both during prospecting and when working deposits. These phenomena are rare, but still affect the environment drastically. Exploitation of oil and gas deposits with subsequent contamination of potable surface water and deep aquifers both by liquid hydrocarbons and by stratum waters with high contents of minerals and noxious salts, is a permanent threat to the environment. The increased gas content in the atmosphere and soils during exploitation of gas deposits and gas storage also represent a hard technogenic load.
Gas and oil deposits in the Carpathian region have been exploited since the 19th century, mainly under complicated geological conditions. Folded and disruptive damages, and the general crackiness of rocks foster upward migration of hydrocarbons and bottom waters to the ground surface. Poorly liquidated or in many cases abandoned holes, pits and wells in old oil deposits of the Carpathian region become additional ways of vertical migration of hydrocarbons, creating a danger of fire and explosion in the surface sediments.
The eastern oil and gas deposits (Dnieper-Donetsk depression) were opened in the 1950s. The majority of deposits are in the middle or late stage of exploitation. Ground water occur at a considerable depth, which in many cases allow using a barn method of drilling during hole construction. Natural conditions permit burying of drilling wastes after their utilization in the territory of drilling sites with further recultivation.
Current prospecting and exploitation of deposits in the Black Sea and Azov Sea basins and in the south-western shelf of the Black Sea have no negative effect on the oceanographical conditions.
Regions of sulphur and salt mining.
Sulphur deposits are located in Lviv and Ivano-Frankivsk oblasts. The Rozdilske deposit has been exploited since the 1950s, Podorozhnenske since the 1960s and Yazivske and Nemirivske since the 1970s. Quarrying of sulphur has been stopped due to economic and ecological reasons. Only underground melting out of sulphur in the Nemirivske deposit is still taking place.
Quarrying of sulphur has resulted in a considerable deterioration of the environment. Technological methods of sulphur ore processing have conditioned accumulation of residual products of beneficiation and ore processing (slimes and rejects) in large quantities. At present storages of rejects in the Rozdilske mining enterprise “Sirka” have accumulated more than 90 million tons, and in Yavorivske more than 25 million tons of slimes and rejects have accumulated. Waterproofing of bottom and side parts of waste deposits is practically absent, thus causing intensive contamination of the ground water. Ground and surface waters within the sulphur deposits are contaminated mainly as a result of filtration of industrial runoffs from accumulating basins, slime deposits and phosphorus-gypsum dumps and as a consequence of filtration breakouts through ditches. As a result, water intake in Zhidachev Region (Podorozhnenske quarry and Rozdilske mining enterprise “Sirka” area) is in a critical situation. Potable water has a pH of 8.3 with a general mineralization of 1.9 g/l, a content of sulphate ions of 1.2 g/l, and a phosphorus concentration of 1.4-34 mg/l. Levels of accumulating basins and slime storages approach critical limits especially during flood periods.
Exploitation of sulphur deposits has caused considerable emissions of noxious substances into the atmosphere. From the Yavorivske mining enterprise “Sirka” annual emissions amount to 456.1 tons, including 179.8 tons of hydrogen sulphide. According to annual measurements, the concentration of hydrogen sulphide in the air of villages and settlements outside the mining territories two times exceed the maximum allowable concentration.
Karst formation in the regions of sulphur mining is extremely dangerous (during the last three years more than 500 new dolines have appeared in the territory of the Yavorivske mining enterprise “Sirka”). Karst formation results in loss of arable lands and construction damages. Besides, shifting processes have been observed on the sides of Podorozhnenske and Yazivske quarries and slime storages, which create a real danger for neighbouring villages and settlements.
Deposits of potassium salts are located in the territory of Lviv and Ivano-Frankivsk oblasts. The Stebnik deposit “Polimineral” and the Kalush-Golyn deposit “Khlorvinil” are the most important deposits presently exploited. Discharge of drainage waters from slime storages with considerably increased salt contents into surface river runoffs from exploitation of potassium salt deposits is one of the major problems worsening the ecological situation in the region. Drainage waters also partially contaminate the territories of nature reserves and recreation zones of the Truskavets resort. Intensive karst formation is very dangerous as well. Accumulating basins with concentrated brines also jeopardize ecological safety. Brines from exploitation of the Kalush-Golyn deposits are filtrated through the damp of the accumulating basin without being collected and pumped out.