Document Type

Conference Paper

Publication Date


Publication Details

John Latilla and Batdelger Tumur-Ochir, Targeted Buffer Blasting to Control Movement Along Bedding Plane Shears, in Naj Aziz and Bob Kininmonth (eds.), Proceedings of the 16th Coal Operators' Conference, Mining Engineering, University of Wollongong, 10-12 February 2016, 500-508.


At the Ukhaa Khudag (UHG) coal mine, working part of the Tavan Tolgoi formation located in the southern Gobi desert of Mongolia, there have been minor to moderate slope failures in locations of relatively shallow overall slope angles. The majority of these events have been due to sliding along bedding plane shear zones that are generally associated with the coal seams. The bedding plane shears have low cohesion and friction angles. For economic reasons not all seams are mined progressively down dip from the base of weathering, leaving some coal and overburden in situ up dip of the excavation. A solution is required to enable slopes to be mined at a steeper angle than the strata dip dictates. Targeted buffer blasting has been trialled with encouraging results. Targeted buffer blasting is designed to disrupt identified plane(s) of weakness, disturbing them in order to increase cohesion and friction angle. The explosive charge weight per hole is generally significantly less than that used for a production hole of the same depth. Once exposed, the batter or slope will appear less damaged than it would in a normal buffer (or softwall) blast. A secondary advantage of buffer blasting is improved drainage, which lowers the phreatic surface. Seven individual targeted buffer blasts have been analysed of which four have been classified as successful, two were probably successful and one was unsuccessful. The unsuccessful case was probably influenced by a nearby major blast.