The in situ rock stress prevents the rise of confined water and water inrush for thick floor aquifuge,but for thin floor aquifuge the in situ rock stress wo.

With the0ry limit winding moment, the fomula calculating the floor aquifuge effect1ve thichness is made.

Hydrogeological conditions favorable to the preservation of the Nongle polyhalite deposit are as follows: landform favorable to surface water drainage, footwall and hanging wall as aquifuge, no faulted structure facilitated the flow of surface and underground water, aquifers characterized by confined aquifer, good drainage conditions and so on.

In the past ,focal point of the work is on rock thickness and lithology and combination and so on of macroscopic aquiclude characteristics.

Hydrogeological conditions of underground Baimiao Coal Mine are introduced,focusing on different aquifers,aquicludes,main geological structures and their relations.

Simulating test on the subsidence law of subsurface water resisting layer upon shallow coalbed mining;

On the basis of the investigation of the water bearing layers,moisture content, grain size,porosity and microstructure determination in loess profile at Yangwan village of Chang an county,the change of moisture and the distribution of the water bearing layers and water resisting layers,bearing water condition and correlation between them and Quaternary climate change are studied.

Through conventional rock thin section microscopic examination and modern scanning electron microscopic examination,X-ray diffraction and differential thermal analyses carried out integration testing of rock structure,texture and mineral composition of confining beds between No.

Exploration result demonstrated that owing to the existing of confining beds,salty and fresh groundwater.

There are 4 aquifers and 3 confining beds in the area.