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ASSESSMENT OF THE ENVIRONMENTAL IMPACT OF OIL SHALE EXCAVATION IN ESTONIAN GEOLOGICAL CONDITIONS. Sergei Sabanov & Helena Lind Tallinn University of Technology, Department of Mining, Estonia. Kalmer Sokman
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ASSESSMENT OF THE ENVIRONMENTAL IMPACT OF OIL SHALE EXCAVATION IN ESTONIAN GEOLOGICAL CONDITIONS • Sergei Sabanov & Helena Lind • Tallinn University of Technology, Department of Mining, Estonia Kalmer Sokman Estonian Oil Shale Mining Company, AS Eesti Põlevkivi, Department of Environment, Estonia
Objectives The aim of the study is to assess the environmental impact different methods of oil shale excavation under geological conditions of Estonian deposit in comparison with other kinds of production
Environmental problems accompanied with OIL SHALE extraction Ground surface subsidence Groundwater level decreasing Waste water New landscape Waste dump Emission to airNoiseSurface fluctuation
Methodology EIA • Inventory data analysis Data collection and description of unit processesforsurface and underground mining methods • Classification of impact categories and environmental interventions Acidification, terrestrial eutrophication and ecotoxicity • Land use and geological disturbance • Mine water pollution
Characterisation factors and reference value for acidification and terrestrial eutrophication Impact category Emission Unit Factors for Estonia SO 0.369 2 Acidification eq/kg NO 0.194 2 NH 0.405 3 Impact category Emission Unit Fac tors for Estonia T errestrial NO e q / kg 1.483 2 eutroph ication NH 4.418 3
Mine water pollution • Annual water outlet 150 - 240 million m3 • Mining waters don't have major impact on the composition of natural waters
Mining water decontaminating Water decontaminating by flotation: Before ~40 mg/l After ~6 mg/l. Sulfate content 500-1000 mg/l Water quality friendly for fish growing
Revitalization of excavated area On area excavated by surface mining formation of new scenery:forest (~ 200 ha/year), lakes, nest.
Conclusions • Mining causes smaller impacts on acidification, terrestrial eutrophication and ecotoxicity in comparison with production of auxiliary materials and transportation of oil shale to customers. • This method assesses environmental impact of excavation processes and finds better way of doing proposed project. The results of the study will be used for new mines planning in according with environmental performances under geological conditions of Estonian oil shale deposit.
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