# A New Method for Calculating Prediction Parameters of Surface Deformation in the Mining Area
## 2 Overview of Huainan Mining Area  
The Huainan mining area is at 115\({}^{\circ}\)50\({}^{\prime}\)-117\({}^{\circ}\)45\({}^{\prime}\) E longitude and 32\({}^{\circ}\)25\({}^{\prime}\)-33\({}^{\circ}\)10\({}^{\prime}\) N latitude. It is mainly distributed in the north of 27\({}^{\circ}\)40\({}^{\prime}\) N latitude. It starts from the Tanlu fault zone in the east, ends at Fuyang fault in the west, connects with Minglong Mountain and Shangyao in the north, and Shunengshan and Bagong Mountain in the south. It adjoins with Huainan, east of Fuyang, Bozhou and other counties and cities. The mining area is about 180 km long in EW direction, 15-25 km wide in N-S direction and has a total area of about 3600 km\({}^{2}\)[30; 31; 32].  
The Huainan mining area lies in the Huaihe alluvial plain; the ground elevation is about +20-+30 m. It is divided into the old mining area on the south bank of the Huaihe River and the Panxie mining area on the north bank of the Huaihe River. The mines in the old area are distributed in the Huainan arc-shaped tectonic belt protruding southward from the Bagongshan area in the south wing of the Huainan synclinal structure. There are many faults, the dip angle of the coalfield is generally larger than 20\({}^{\circ}\), and the geological and mining conditions are relatively poor. The main mine field of the Panxie mining area is located in the south wing of Chenqiao anticline and Panji anticline in the Huainan synclinal structure. The coalfield has a small dip angle of generally less than 15\({}^{\circ}\), simple structure and good mining conditions. The coal-bearing strata are Carboniferous-Permanian, generally containing 40 coal layers, with an average recoverable total thickness of 30 m. The lithology consists of sandstone, siltstone, clay rock and coal. The coalfield stratum is a synclinal structure, and a series of thrust faults are developed on the edges of the two wings, resulting in upright, inversion and mapping of some strata.  
There are 9-18 minable coal seams in the Panxie mining area, and the total minable thickness is about 30 m. Coal seams are covered by loose layers whose thickness can reach 140-580 m. According to the statistics of the No.1, No.2 and No.3 mines, and the Xieqiao Mine and Zhangji Mine in the Panyi mining area, the total amount of coal pressure has reached 488.803 million tons in the original design of protective coal pillars of industrial and ventilation wells, accounting for 10.09% of the total reserves. In addition, there are a lot of coal resources under villages, railways and buildings (structures). The distribution of mines is shown in Figure 1.  
The surface of the Huainan mining area has a thick loose layer with a thickness of 140-564 m. Compared with the conventional mining conditions, the movement mechanism of the thick loose layer and the temporal and spatial evolution of the surface deformation are different. Compared with general geological and mining conditions (non-thick unconsolidated layers), the maximum subsidence value of the working face is larger under full mining or super-full mining in the trend and inclination and is generally greater than the mining height; the surface movement changes drastically, and the recession period is longer; the boundary converges slowly, and the range of surface movement is larger. In East China, Central China, North China and other regions, the upper strata contain extremely thick loose layers, and there are many mining subsidence monitoring stations in the Huainan mining area. Therefore, the research results on the Huainan mining area can be applied to other mining areas.