Key　Techniques　About　Automatic　Forecasting Roof　Weighting　in　Longwall　Face

Based　on　the　theoretics　of　Model　Identifying,　Fuzzy　Mathematics,　Directional　Graph,　and　the　relationship　between　roof　movement　and　abutment　manifestation,　the　method　of　graph　element　and　nearing　predicting　span　for　analysing　the　information　of　roof　movement　are　proposed.　　This　is　the　key　techniqe　to　realize　automatic　forecasting　roof　weighting.　　The　technique　has　been　applied　in　four　mines.