Equipment:StraightLine HDD® RockEye Air Hammer 5.0 on a Ditch Witch® JT4020, with a Sullair® 1150cfm x 350psi air compressor.
The Challenge: Roemer Utility Services of Boyne City, MI was awarded a tough 975′ rock bore in the Upper Peninsula, just miles north of the township of Moran. Conventional tooling proved to be no match for the Iron Ore and Limestone that reached up to 30,000 psi, leading Pete Roemer to call on StraightLine® HDD, Inc. and the 5.0 RockEye Air Hammer System.
Over the first 550′ the crew encountered both pockets of hard rock, as well as areas of soil. Little to no change was required in pitch or direction, as the air hammer made its way through the changing ground conditions, steering at a rate of 20 minutes per 15′ rod. The limestone rock varied in hardness from 25,000psi to 30,000psi at a depth of 20′.
The goal was to complete an efficient bore, while containing the cuttings and minimizing the environmental footprint of the construction site. The pull back was to install innerduct, running parallel to existing cable lines.
Outcome: A successful shot was completed in just four days of drilling, through some of the hardest rock in the northern part of the United States. “I thought it worked great,” stated Pete Roemer. “Compared to an AT or a mud-motor, the hammer was so simple to use, I mean the other options just take so much more manpower. With this system there’s no back pressure and no mess- you literally just turn on the air and start drilling.”