443 Geotechnical schemes to the multi-purpose use of geothermal energy and resources of abandoned mines I. Sadovenko, D. Rudakov & O. Inkin National Mining University, Dnipropetrovs’k, Ukraine ABSTRACT: The analysis of energy consumption in Ukraine and the growing needed for wider use of alter- native sources including those accumulated in abandoned mines is shown. Regarding to the rapid growth of various applications during last decades geothermal energy is considered by worldwide as one of promising energy sources, with the significant share and prospects of heat pumps. The paper describes concepts of combined use of ground source heat pumps, the resources of abandoned mines, and various geotechnologies including underground combustion of residual coal seams, mine drainage, water flow regulation in mining and post-mining areas, underground hydropower plant, mine and ground water treatment and water supply. The four geotechnical designs are economically feasible because of combining low-grade heat recovery or/and power generation with addressing economical and environmental challenges, primarily, in mining areas. 1 INTRODUCTION Last decades have been demonstrating the grow- thing geothermal energy share in the world energy resource balance (Lund et al. 2010). This process is also typical for Ukraine with some domestic fea- tures depending on economical, climatic, and geo- logical factors. The most common ways of using geothermal resources in Ukraine are deep boreholes and ground source heat pumps; besides, mine and municipal sewage waters can be leveraged as a technically achievable resource. Some of these sources have much bigger potential especially in the areas changed as a result of industrial activities and intensive building. Rock temperature within the Ukraine’s territory on the depth of 1000 m varies from 20 to 70 ºC, and on the depth of 3000 m it ranges from 40 to 135 ºC. Heat flux density ranges from 25–30 to 100–110 mW/m 2 (National Atlas of Ukraine 2007). The maximums of temperature and heat flux were measured in moun- tainous areas in Crimea peninsula and Carpathians. Potential geothermal resources amount to 27.3 mil- lion m 3 /day of thermal waters. Taking into account cogeneration capacity and thermal water specifics these resources can be estimated at 84 million GCalories per year (National report… 2010). The big thermal water resources are concentrated in West side of Carpathians (490 MW), Black Sea coastal area (4900 MW), and Crimea (37600 MW). About 9.3 million houses on homesteads in Ukraine have the total heated area of more than 510 million m 2 . They need roughly 160 million MWh for heating and hot water supply annually. In princi- ple, this demand can be met by ground source heat pumps. The total country’s potential that can be used by ground source heat pumps amounts 157530 MWh/year, with technically achievable resource be- ing estimated at 71.4%, but only 6.7% of that is profitable to use nowadays. Major limitations on putting heat pumps into wider practice are high in- stallation costs and long payback time. F. e., the costs for a heat pump device of 4–5 kW power range currently from 3000 to 7000 €; an increase in power to 10–15 kW raises the costs up to 5000– 10000 €. Passive cooling mode would be more prof- itable, which would ensure the savings 90–95% of costs; however this it is possible in summer time only during 100–150 days and is applicable to southern regions of Ukraine. Maximal estimated savings owing to reduction of fuel consumption amount 700–1000 € annually, which is not profit- able under the conditions of high interest rates. Besides, Ukraine has the vast resource of low- potential heat in mining lands. Annually more than 500 million m 3 of mine water are pumped just in Donetsk coal basin and discharged into ponds and rivers. The temperature of this water ranges from 16 to 22 ºC depending on the season; the mine waters temperature deeper than 800 m may reach 30–33 ºC. The annual low-potential heat loss is estimated at 5 million GCalories (Unlimited resource… 2007, Nechitailo 2011). Use of this resource is restricted by many technical problems including high salt con- Progressive Technologies of Coal, Coalbed Methane, and Ores Mining – Bondarenko, Kovalevs’ka & Ganushevych (eds) © 2014 Taylor & Francis Group, London, ISBN: 978-1-138-02699-5