Study on site-specific characters of k and b of peak particle velocity (PPV) prediction model is important in generating a reliable PPV prediction model. In this study, the characters of k and b have been investigated at a coal mine in Indonesia in which 13 coal seams exist. This formation sometimes gives huge difficulty in controlling and predicting PPV. By considering the effect of the transmitting media, the ground vibrations induced by 182 shots of rock blasting were monitored in five directions. The square root scaling method of scaled distance was used to evaluate the site-specific k and b. The study showed that b increased with increasing k. It is also found that b was strongly influenced by the properties of the transmitting media, including the face of blasted bench. Meanwhile, k was strongly influenced by blasted bench.