Modeling the dewatering and depressurization of the Lihir open-pit gold mine, Papua New Guinea

The open pit at the Lihir Gold Mine, Papua New Guinea, is planned ultimately to reach more than 200m below sea level. Cooling and depressurization of the geothermal resource associated with the gold mineralisation is an essential part of the mining operation. This paper deals with the development of a numerical model of the resource capable of representing reservoir processes associated with shallow dewatering, geothermal development and providing sufficient detail for pit-wall stability calculations. Use was made of iTOUGH2 [Finsterle, 1999. iTOUGH2 User’s Guide, Report LBNL-40040] running on a cluster of LINUX workstations to aid the fitting of some model parameters. Use of this program in a parallel computational environment was essential to complete the parameter fitting in an acceptable time. A detailed model containing almost 90,000 elements has been developed as an aid to pit-wall stability calculations and this has been run on a Cray and a LINUX cluster using a multiprocessor version of TOUGH2 recently developed at LBNL [Zhang et al., 2001. Parallel computing technique for large-scale reservoir simulation of multi-component and multiple fluid flow]. © 2004 CNR. Published by Elsevier Ltd. All rights reserved.