Cretaceous sandstone is widely distributed in the Erdos Basin, which has specialhydrogeological conditions in the Luohe formation. The lower Jurassic coal mining roofcaving fissure formation overlying Luohe formation aquifer will communicate, so themine threatened by roof water inrush. Therefore, it has important realistic significanceto study the hydrogeological characteristics of cretaceous sandstone and to analyze therisk from the roof water inrush.This paper starts from geological exploration data of the coal in the Ningzhengmining area and combines with regional geological conditions to analyze cretaceoussandstone structure and hydrogeological characteristics. Sandstone of Luohe formationin the area east, west permeable weak, central for the medium permeability; mine aremostly medium-sized water-rich area, central distribution of strong water-rich area;Luohe formation of groundwater with high mineralization, circle is very slow, mainlystatic reserve. Through the calculation, the8#coal mining formed the water flowingfractured zone will be conducting the Luohe formation sandstone aquifer, water alongthe fracture zone in coal mine.Then use the "big well method" and the analogy method,mine system facing sandstone of Luohe formation water roof water inrush threat.The paper makes the divisional evaluation of the roof water partitioning risk inLuohe formation by means of the "three maps".Western mining area mainly to a dangerzone, central zone as dangerous in the strong water-rich area, the East-West zonaldistribution, to the east by watery weak becomes more dangerous and the relatively safearea; in the southeast area, is a dangerous zone, security zone is the water flowingfractured zone without conducting upper the aquifer region.The evaluation result hasdirective significance to the water hazard prevention of mine shaft, meanwhile, it hasreferential meaning to the similar mining areas in a region. |