Methods for evaluating drill pattern parameters such as burden, spacing, borehole diameter, etc., at a blast site are disclosed. One method involves accumulating the burden contributed by successive layers of rock and matching the accumulated rock burden to a target value for a borehole having a length related to the average height of the layers. Another method relates to varying drill pattern parameters and characteristics to match blast design constraints, including the substitution of one explosive material for another by the proper balance of materials and/or output energies to the associated rock burden. Analysis of deviations from target rock burdens and corrective measures are disclosed, as well as cost optimization methods. The various methods can be practiced using an appropriately programmed general purpose computer.