Thar Block Ii Lignite Resource Estimation Based on 3D Block & Gridded Seam Modelling Techniques (Published)
Pakistan holds 7th largest lignite resources in the world with about 200 billion tons of coal, mainly discovered in Thar region. Purpose of this study is to estimate total lignite resources of Thar Block II by comparing two different resource modelling techniques i.e., 3D block model (3DBM) and gridded seam model (GSM) for lignite resource of Thar Block II and discuss their benefits and limitations. In this study, drill hole data base with fixed stratigraphic information has been used to develop structural model of all layers within block boundary by using 3DMine. Resource models are developed in MineSight 3D software by using both 3DBM and GSM technique. Both models represent negligible difference in seam wise lignite volumes, tonnages, and overall quality. Lignite quality compositing criteria in both models are different i.e., GSM deals with seam constraints compositing but 3DBM offers fixed length compositing. Due to the different quality compositing techniques used in both the models, GSM generally calculates single composite value of each quality parameter for each seam within every individual borehole whereas Block model divides the composited quality values vertically using fixed lengths within each borehole. Therefore, based on quality compositing criteria, 3DBM offers more precise and detailed quality for small block outs. However, GSM provides a composite average quality of specific seam which is also considered as most reliable method for lignite coal seams (layer type deposit) with simple geometry.
Keywords: 3D Block, Estimation Based, Gridded Seam Modelling, Techniques, Thar Block Ii Lignite Resource