Document Type

Conference Paper

Publication Date


Publication Details

Cihan Kayis and Mehmet Siddik Kizil, Effects of front abutments around multiple seam mining operations, in Naj Aziz and Bob Kininmonth (eds.), Proceedings of the 17th Coal Operators' Conference, Mining Engineering, University of Wollongong, 8-10 February 2017, 17-31.


Abutments form due to the redistribution of stresses around excavations. In longwall mining, these stresses can redistribute in front of the longwall panel (front abutment), over the chain pillars and intersections (side abutments) and into the goaf (goaf abutments). Front abutments are a key factor for barrier pillar design and can significantly affect secondary support performance. Front abutments for single seam mining operations can be detected using empirical methods, however these methods are not useful for multiple seam mining operations. This paper investigates the effects multiple seam mining has on the extent of the front abutment, requiring the secondary support to be installed well ahead of the retreating longwall face. This paper focuses on the examination of longwall abutments by analysing GEL extensometer data in order to identify the point where the total displacement exceeds 3 mm. Preliminary results suggest that the remnant pillars located in upper workings increase the detection distance by 125% and the goaf abutments in the upper workings decrease the total range by 50%. The secondary support framework suggests that the bolting advance rate and the longwall retreat rate should be accounted for when determining the lag distance.