Hi Nishan. Not my area of expertise, but can provide a few pointers. Primarily, in a blast design, one can vary the pattern and powder to rock ratio to minimise vibration. To reduce the risk of structural damage, one needs to know what is the maximum tolerable particle velocity that the structure can sustain without or negligible damage. For man made structures, there is a maximum allowable deflection, while for naturally occurring structures, such as slopes (typically with blocks failure as the main failure type) one can work out the maximum particle velocity that will not reduce the shear strength along the discontinuity. Once you know your limits, one also need to now the rock mass properties, such as fracture distribution patterns and discontinuity characteristics. One can employ pre-drilling (split -blast with delays)along the back of a blast to achieve separation from the main rock mass, however, this will make the blast less economic and altering the powder ratio or the pattern may be more practical. But as always, one needs to know the conditions and limits before one can consider the solutions.