Blast-induced ground vibration signature can be dissected into two characteristically distinct parts, viz., forced vibration and free vibration. The attributes of the forced vibration component of the waveform correspond to the blast design and rockmass, whereas the free trailing end of the waveform corresponds solely to the rockmass. In this research, it is intended to analyze the trailing free end of a production blast waveform in a full-scale dragline bench to characterize the rockmass and devise strategies to moderate the blast/explosive design as well as the outcomes such as fragmentation and vibration. Accordingly, a near-field ground vibration experiment was designed to achieve this end. The experiment consists of placing two near-field ground vibrations sensors (geophones) at distances 30 and 40 m behind the last row of dragline bench. The vibration signatures thus acquired were examined for their waveform character and characterize rockmass. An index is formulated from the trailing end of the waveform called Trailing Vibration Index (TVI), which is a ratio of reduction in PPV amplitude from forced to free vibration and the time duration for which the free vibration persists. Lesser the TVI, greater is the rockmass competency and vice versa. The TVI was also correlated with certain indices like seismic index (weighted in situ P-wave velocity acquired from Seismic Refraction Tomography (SRT)) for concept validation. The TVI was used for blast design optimization and enhancement of blast performance.