In this study the seismic blast vibrations generated by 91 multi-hole surface (open-pit) commercial explosions conducted in four different lithologies namely, 34 shots in Taconite, 33 shots in hematite, 19 shots in hard limestone and 5 shots in soft limestone in Michigan and Minnesota regions. The vibration records obtained in this study have three components of ground vibrations. The time and the frequency characteristics of the blast records, powder factor values and the vibration comparisons were carried out. The maximum particle velocities data show considerable scatter but the spectral maxima are consistently below 10 Hz over the distance range 300-2000m. Signal durations are longer for hematite and soft limestone than others. Powder factors of hard rocks are higher than soft rocks.