Hydrogeological feature and mechanism of reducing waterproof coal pillars in Panxie mines area

Panxie mine (PMA) lies in the north bank of Huaihe river in Anhui Province. Its designed total output is 2100×10 4t. The alluvium of Quaternay in the area is a rich aquiferous layer, the thickness of it is 169～437m. After the mining experiment of reducing the sizes of waterproof coal pillars under water\|bearing alluvium, we have reduced the designing width of waterproof coal pillars from 80m to 60m, partly to only 40m. By summarizing the successful mining practice in Panxie mine in the past ten years, we systematically expounded the hydrogeological feature of Panxie mine, failure law of the overburden and the mechanism of reducing waterproof coal pillars.