Abstract: Taking Pittsburgh coal basin as an example,the paper gives an introduction to hydrological problems related with abandoned mines,such as underground water recharge;mine to mine interactions and discharge.They could result in pollution of rivers,water increase of neighbored mine and even water hazards of active mines.It is emphasized that mine hydro-geological mapping is necessary to solve these problems.Some American mine mapping achievements based on GIS and GPS have been illuminated in the paper.The experience in Pittsburgh coal basin would be a good reference for treating the similar problems in China.