Cascade Drilling, LP has acquired Resonant Sonic International (RSI Drilling). This acquisition significantly increases the size of Cascade's fleet of Sonic, Geoprobe, PowerProbe, Hollow-Stem Auger, and Air knife/Vac equipment, and extending Cascade Drilling’s full service offerings, including Air/Mud rotary, Direct Push, Hollow-Stem Auger,  Subsurface Profiling with MIP/HPT/CPT/EC, Coring, Investigation Derived Waste (IDW) Management, and more to RSI's existing client base. With the expanded fleet of drill rigs, additional locations, and additional professional drilling crews this acquisition brings, both Cascade Drilling and RSI Drilling's client base will not only enjoy the uncompromising service they have come to expect from both companies, but the additional availability and flexibility in scheduling and service as well.