... the process of fracturing of the immediate and main roof strata behind the longwall face. The finite difference element code FLAC2D, developed by Itasca Consulting Group, Inc. was used to perform modeling of the longwall gob area under both soft and hard roof. The purpose of this paper is to present...

.... metals & mining displacement pillar stiffness south african institute chain pillar relation coal proceedings stability longwall face height ratio pillar stiffness determination mechanics data mining Longwall Mining post-failure stiffness application pillar bump Rock Mechanics...

... in each of five coreholes to measure subsurface displacement. Survey data of an array coincident with the boreholes show that surface movement began when the longwall face was about 45 m in front of any point. Over 90% of the total subsidence was achieved when the face was one overburden thickness past...