Materiały konferencyjne SEP 1993 - tom 2

Yladimir I. Bondarenko Protection of Earth Surface Against Sagging and Ground Waters Against Pollutions in the Process of Brown Coal Mining in the Ukrainę 1. Brief mine-geological review of the deposit The sedimentary rock deposits are characterized by the presence of the dispersed rocks which in welted state manifest floating. Among the kind is Dneprovsky brown coal basin. Its most generał geological and hydrogeologicall characteristic is that the sediments overlying the bedrock bear the multilayered useful minerals. The depth of occurence is 90-20m. Within the Dneprovsky basin three most characteristics types of ground waters can be singled out:jointing waters of the crystal massif waters of the tertiary and cuarteriary sediments. The preparatory mining operations are considerably influensed by waters of tertiary sediments. They appear as a unified water bearing horizon timed to the sands of Poltavsky, Kharkovsky, Kievsky and Bugaksky layers. The lower waters confining layer is constituted by primari koalines. The over-coal water bearing horizon is timed to the sands of the non-disintegrated neogene (fine-grained,clay). They contain fractions in the amounts: fine-grainted - 41.7%; super-fine-grainterd - 22.4%; dust - 18.35; clay - 15.8%. The sands thickness is 5-8m. The filtration coefficient determined in the field is 0.55-4.4m/day. These sands, particulary along the clay Kharkov sands, are characterized by floating. As it is proved by experience the mining operations are associated with the outbursts of the dispersed rocks into the mines which leads to the flood, roof support deformations, yiolates the structure of the overlying rocks and brings about the zones of shifts as far as the surfase. The coal winning rate is thus considerably cut and the plough land is lost irretrievably. The underground brown coal winning technology associated with floating within the enclosing rocks fetures: the pre-draining of the deposit surface followed by draining of the faces; special methods of supporting in driving the capital shafts and inclined drifts; Sekcja IV 151