An experimental investigation of blastability has been performed in small- and full-scale by continuous critical burden tests: A single inclined borehole is drilled into the rock face thus eventually exceeding a technically feasible burden. A useful definition of the “critical” burden Bcrit can be made by the study of the shape of the breakage area and it is defined by the maximum burden with complete breakage from the hole to the surface and by the shape factor SF that approaches a minimum at the same time. It has been shown that Bcrit is primarily a function of the specific charge and the prevailing rock conditions. Concerning the optimization of drilling and blasting patterns, an “optimum” burden Bopt can be found by systematic analysis. At this burden the specific charge shows a minimum and this has a positive influence on the size distribution of blasted rock, i.e. less fines. The full-scale experiments have shown that at smaller burdens the energy is sufficient for considerable breakage sideways whereas with increasing burden the shape of breakage becomes generally narrower, depending on the actual orientation of the strata. Bopt can be found at the section where the maximum area is obtained under the condition that Bcrit is still not exceeded and over-break ≥ 0 as well as 0 ≤ SF ≤ 1 at the same time. The study of experimentally derived breakage areas at Bopt can be useful in quantifying interactions between adjacent holes and thus be used in the design of spacing. Within operational possibilities the influence of the local rock conditions on the shape of the breakage area should additionally be considered in designing a blast. Considering the technically feasible drilling precision a drill and blast pattern optimized by using the described approach should lead to technical as well as economic benefits.