WorldWide Drilling Resource®

University Takes Advantage of HDD Adapted from Information by The Crossing Group and the University of Hawaii Coconut Island, a tiny island off the coast of Oahu, Hawaii, houses a private research station for the University of Hawaii at Manoa. The Hawaii Institute of Marine Biology at Coconut Island is one of the top marine research institutes in the world. Its location in Kaneohe Bay hosts an abundance of marine habitat, making the island an ideal location for ongoing marine biology research. However, the remote location also has its challenges. Initially, all utilities includ- ing sewer, electricity, telephone, and cable were run along the seabed floor. After decades of use, the conduit began to corrode and needed to be replaced. A challenging task for any project, but even more so when running utility lines from one island to another. The project included replacing utility lines to the island and rerouting a gravity sewer line. By replacing the island’s out- dated telephone wiring with fiber-optic cable, the school would finally have access to high-speed communication and real- time data sharing with research centers around the world. With limited space for construction projects, horizontal directional drilling (HDD) was selected. Instead of laying conduit on the seafloor, HDD would place the conduit 70-80 feet below it. Tying the island into mainland utilities involved drilling an 18-inch borehole under Kaneohe Bay. This borehole contains a bundle of two HDPE (high-density polyethylene) lines, one four-inch conduit for the telecommunications line, and another for a six-inch main sewer line. The drilling crew had to be careful with sediment suspension, runoff, and containing the drilling fluid so as not to damage the surrounding ecosystem so important to the Institute. The entry pit was set up on the Oahu side, while the exit pit was on Coconut Island; as the exit point, it offered very little space to contain the drilling fluid. That’s when the company hired for the project, The Crossing Group from Canada, proposed an innovative solution. They drilled the pilot hole about 164 feet shy of the exit and reamed back to the entry side multiple times. Using this push ream method on the plugged pilot hole, debris was mechanically removed, eliminating the risk of covering the island with cuttings and drilling fluid. With limited space on Coconut Island for the drag section, crews had to string the product lines around a walking path prior to installation. Since ground conditions were mostly basalt, with very soft beach sand on the exit, the geometry of the bore path required a horizontal bend at the approach to exit, which took incredible navigational precision. The project was successfully complet- ed within 64 days. 28 SEPTEMBER 2020 WorldWide Drilling Resource ® Forging for Stability Adapted from Information by Rockmore International One of the largest zinc mines in the world switched to Rockmore International’s GT60 rods and achieved up to 50% higher usage. The enhanced life performance is due to the different way of manufacturing. Traditional friction welding was replaced with a fully forged process, so there are no joints which could create weak points in the rod. Rockmore’s GT60 rod system has a longer life, which means a better cost-benefit equation for drilling and mining operations. MIN Photo courtesy of The Crossing Group. DIR