In order to identify a solution to coal mining under buildings on the surface,a cooperation project is carried out between Hebei Jinniu Energy Co and China University of Mining and Technology on an experimental study on the application of solid material stowing comprising waste stones and fly ash,etc.

The result shows that building skygarden in upstream buildings actually enforces the natural ventilation of downstream buildings and that the influence on downstream buildings has no significant difference of building skygarden in the first row buildings and in front two rows buildings.