| Rationally designing the heights of coal (rock) pillars and mining the overabundant pillars under loose aquifer are significant for mining shallow coal resources. This paper takes Liuzhuang Coal Mine for example, on the basis of systematically analyzing the geological and hydrogeological conditions, pumping tests and soil mechanical test results, a lot of research works have been done, including the thickness distribution characteristics and water-enrichment of the lower aquifer of loose layer, thickness distribution and watertihgtness of the lower clay layer of loose layer, and thickness distribution and water-enrichment of the bottom gravel layer of loose layer. Results show that the lower aquifer's water-enrichment is moderate, and the bottom gravel layer's water-enrichment is weak, which can be considered as composite aquiclude with the lower clay layer whose watertightness is excellent.The heights of overlying strata's destruction and water flowing fractured zone under different mining heights in 1100 and 1300 working faces are simulated and analyzed by FLAC3D software. The heights of water flowing fractured zone was calculated by numerical simulation, empirical formulas and analogous formulas of adjacent mining area, feasible and rational heights of waterproof coal (rock) pillars are confirmed, and the heights and range of mining working faces under the designed waterproof coal (rock) pillars are determined. Compared with the original design, the reduced height of waterproof coal (rock) pillars is from 44.0 to 80.6 metres. This makes it possible to mine the overstocked shallow coal resources and prolong mining life.
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