Abstract
To solve the problem of water inrush from overburdened bedrock aquifers during thin seam mining of thick loose layers, we analyzed the fourth Neogene strata structure and found that the bottom was a “clay-grit-clay” structure. The clay is semi-consolidated at low liquid limits and possesses a high level of impermeability and low mobility, preventing water and sand in the upper sand gravel aquifers from collapsing. By analyzing the roof structure and lithology of rock in secondary seams, we found that the clay layer in the roof is water impermeable, while the aquifer layer is low in water abundance, imposing minor effects upon the mining of the working face and causing minimal serious flooding. The aquifer can be dewatered simultaneously during mining. From the “two zone” pores on the construction ground, the height of the caving belt and water conducting fractured belt are 13.1 and 29.2 m, respectively. Lastly, the technical measures to prevent and control water in and surrounding mines are proposed.
Keywords: thin bedrock; roof water inrush; overlying rock structure; caving zone; water conducting fractured
