1 9 th International Symposium „Topical Problems in the Field of Electrical and Power Engineering“ Pärnu, Estonia, June 14-19, 2010 The geological perspectives for Paleozoic carbonate raw material mining in Harjumaa County, Estonia Angela Notton Tallinn University of Technology Angela.Notton@kekkonnaamet.ee Ylo J. Systra Tallinn University of Technology ylo.systra@ttu.ee Abstract Harjumaa County surrounds a capital-city Tallinn and has the highest density of population, more than 121 residents per 1 km 2 .At the same time here is going active mining, mostly different building materials: limestone, gravel and sand are extracted. At dense population, network roads and railways there are very few places for new quarries, because the places of mineral resources of good quality are occupied by different settlements. By the Estonian laws underground resources belong to government and may be easily and without harm to environment extracted. Mined territories after put in order may be returned to owners. In many cases the soil conditions after mining is better than before. In this paper are discussed the problems of the Ordovician bedrock mineral resources using, development and their quality in the Harjumaa County. In paper are shown volumes of mining, some demands to limestone and dolostone material and their properties in some different deposits. Keywords Carbonate bedrock, Paleozoic, Ordovician, building stone, limestone, dolostone, technological material, chemical composition, compressive strength Introduction Harjumaa County covers 4333km 2 and is the biggest by territory and population in Estonia. Including the capital-city Tallinn with more than 400 000 residents here in 2008 lived 523 400 people or 38.5% of all population of Estonia. In Tallinn are concentrated transport junctions to Europe and Russia, industry, education, culture, the main harbors and airfield. After receiving back independency and joining the European Union in 2004 was initiated renovation of all types of transport, road- and railways, airfields and harbors. This action was financially supported by EU. For building were needed special materials: aggregate, gravel, sand etc. From 2001 extracting of different building materials grew very quickly and reached maximal level, 1800 000m 3 , in 2007 (Fig.1). After the Ida-Virumaa County with its oil shale mining for electric power stations about 15 million tons yearly, Harjumaa County is keeping the second place in total mining and the first in raw building material mining. In Harjumaa County in 2008 were extracted carbonate raw materials 1746 000m 3 and 49 800m 3 pure limestone for technological use, 289 700m 3 of building gravel, 1956 700m 3 of building sand and 49 000m 2 of sand for fillings. The bigger part of them was used in civil, industrial and road building. The renewing of road network and railways needs many million tons of building stone, gravel, sand and other materials. At the dense population the best places for quarries are occupied by towns, settlements, villages and farm houses, so it is the main problem to find places for new quarries. The local people are very clever to find reasons, why the mineral resources (which by Estonian laws belong to government) must not be mined on their domains and home places. They are involved into expertise foreign specialists, who after receiving rich “compensation” will find “underground rivers” in every place, wherever it is needed. If there were no protected rare plants, it is easy to seed them from other areas, only not to give rights for mining. The situation needs to be more carefully studied and it is possible, that will be found other territories with needed quality of mineral resources, where the mining is not so painful for local people. It was the main reason for initiating this doctoral study of different mineral resources in the Quaternary sediments and Paleozoic bedrocks for their economical and more effective usage in the Harjumaa County. This paper deals only the part of Ordovician carbonate rock. Geological setting Harjumaa County is located in the northwestern Estonia, on the southern shore of the Finnish Gulf, about 80km to south from Helsinki, Finland. Geologically this area belongs to the southern slope of the Fennoscandian shield, where the Precambrian Early Proterozoic crystalline rocks of age 2.0-1.3Ga