Behavior of twin inclined shafts excavated for +30 levels surface stability in Ha Lam coal mine

The process of excavating roadway, shafts, and exploiting coal seams located near the ground may cause subsidence surface, cracking, damage to structures on surface. Therefore, it is necessary rely specific conditions site calculate forecast level impact works when excavated ground. Based topographical conditions, geological hydrogeological current status technical design excavation twin inclined shafts from +30÷-300 levels in Ha Lam mine proposed. This paper uses numerical method by FLAC3D software build model with a height 450 m width 700 study effect construction deformation rock mass research has shown that after levels, area ​​each shaft 15.8 m2, surface deformed, maximum value vertical about 5 cm, horizontally 3 range within radius 25 m. So +30 mines constructing serving mining entrance area, consider shafts. But outside will not be affected. Recommendations for need install more monitoring stations monitor