A portion of Sandia's rock mechanics program has been directed at the study of the fracture and fragmentation properties of oil shale, with a goal of developing computational procedures for use in designing and/or evaluating blasting concepts for preparing in situ retort beds. A variety of experiments have revealed that the failure phenomenon in oil shale is highly strain-rate dependent. Data from the experiments have provided a base for a computational model for dynamic fracture and fragmentation. This model has been incorporated into a two-dimensional wavecode called TOODY and is now ready rudimentary assessments of practical blasting schemes. Such an application has recently been undertaken for a modified in-situ blasting concept which uses an array of vertically oriented explosive charges configured and sequentially detonated in decks. The charges are in boreholes drilled from a horizontal surface (floor or back) of a mined cavity. Within each deck the charges are in a square pattern. From deck-to-deck, the positions of the square patterns alternate so charges in one deck are centered with respect to charges in an adjacent deck. The computational procedures have been used to evaluate the fracturing and fragmentation that occur in the rock surrounding each charge and to determine some of the key parameters of the blast design (spacing between charges, burden thicknesses, explosive quantity requirements, etc.).