CONTROL TECHNOLOGY FOR COAL ROADWAY WITH MUDSTONE INTERLAYER IN NUI BEO COAL MINE

Abstract

The insufficient effect of traditional supports (e.g. the U-shape structural steel support) has been verified from various vital accidents in terms of roof collapse in Vietnam coal mines. The situation is becoming more complex, particularly, where the overlying strata consist of series weak interlayers such as mudstone and/or coal gangue. This paper starts with the summary of the failure mode of existing supports used in Vietnam coal mines, followed by the FE simulation (RS2 programming) based on the given geological conditions. Then, a case study conducted at Nui Beo coal mine by using the high strength prestressed bolt to prevent the separation of mudstone interlayer is presented. The design based on systematic numerical simulation and careful discussion of the failure mode of traditional support technology has been successfully verified from practical application. The results revealed that the rheological strain is closely related to time, it is about 60 days from the firstly caving to be stable, the maximum displacement of the roof and ribs to ribs are 14 mm and 35 mm respectively. The first ever practical application of prestressed bolt in Vietnam coal mine roadway associated with mudstone interlayers indicated that, compared with current widespread passive support, it is an effective support technology for some other coal mines in Vietnam with similar geological conditions.