Integrated 3D geological modeling of Sonda-Jherruck coal field, Pakistan

Despite being one of the largest coal fields in Pakistan, the Sonda-Jherruck coal resource is yet to be exploited. Exploration studies were done between 1981 and 1989 by the Geological Survey of Pakistan (GSP) and the United States Geological Survey (USGS). While much exploratory data is available, computer-aided geological modeling has not been carried out. The resource estimation was carried out using the traditional circular 891 method. The specified distance between observational points remains constant, disregarding continuity in seam thickness that leads to higher uncertainty. Fault modeling and geologic mapping were not performed in preliminary reports. Fault lines based on aerial maps are indicated. This study generated 3D solid seam models and a fault model of the deposit. Coal seams were modeled to produce spatial distribution maps for seam thickness. The overall in-place coal resources of the deposit are estimated to be 4.66 billion tons, however mineable resources are estimated to be 1.59 billion tons. The method of fault detection is based on drill hole data. Dipping was calculated using regular grid data and the unknown points were estimated using the inverse distance weighting squared method. The assessed fault zones were compared with the USGS fault lines and an apparent similarity was observed.