The objective of the research project is to develop a useful, predictive model for hydraulic fracturing of coal through (1) determination and use of experimental data on coal properties, (2) development of a computer model of the hydraulic fracturing process, and (3) to develop a field testing program. This report is divided into three, mutually exclusive sections. The first section reports experimentally obtained results on the variability of the fracture toughness of coal. Section II contains a description of a numerical simulation of the hydrofracturing process. The last section provides a review of the hydrofracture stimulation literature. Each section provides its own pertinent references. The first section titled Fracture toughness of coal - variability between seams and correlation with its grindability and chemical characteristics was abstracted and indexed separately for inclusion in the Energy Data Base. 50 references, 26 figures, 11 tables.