Reducing Coal Loss Through Improved Top Coal Mapping by Seismic-while-drilling
Blast damage to the top of coal will increase coal loss and dilution,which seriously compromises production and profitability in open cut coal mine operations in Australia.This damage arises during overburden removal largely due to incorrect blast stand-off distances resulting from inaccurate mapping of coal tops.Consequent exposure and dilution of the uncapped,damaged coal seam can cause coal losses of up to 10-15%.This translates into a loss of billions of Australian dollars or,equivalently,to the loss of production of one open cut mine for every 10 operating mines.The current approach for mapping coal seam tops is through drilling and pierce-point logging.To provide appropriate depth control with ±0.2 m precision for blast hole drilling,a 50m x 50m grid is required in advance of overburden removal.Pierce-point mapping can be inaccurate and expensive,especially when the seam is not flat due to rolls and faults.To date,there are no effective and economic techniques to map and characterise coal seam structures in the open cut environment where coal seams are shallow.In this paper,we propose two Seismic-While-Drilling (SWD)-based approaches to see the top of the coal seam ahead of the drill-bit: 1) reverse “walk-away VSP recording,in which the tri-cone bit is a seismic source and the geophones are planted on the surface near the drill rig;2) in-seam seismic recording of channel waves,which are evanescently driven by the approaching tri-cone,and guided by the seam itself to geophones,locked in the coal seam in a remote borehole.Numerical modeling and prototype-tested examples have been used to demonstrate the feasibility of these two approaches for predicting the approach of coal seams during blasthole drilling.
Binzhong Zhou Iain Mason Stewart Greenhalgh
CSIRO Earth Sciences and Resource Engineering, PO Box 883, Kenmore, QLD 4069, Australia ARCOLAB, School of Geosciences, The University of Sydney, NSW 2006, Australia Institute of Geophysics, ETH Zürich, Swiss Federal Institute of Technology, Zürich CH 8092, Switzerl
国际会议
长沙
英文
375-382
2012-06-15（万方平台首次上网日期，不代表论文的发表时间）