Equipment: Vermeer® D24x40II, STRAIGHTLINE® RockEye Air Hammer 4.0 coupled with an 1150cfm x 350 psi compressor.
The Challenge: Fambro Pipe & Construction Company, of Stephenville, TX was awarded a multiple bore contract with a combined length of approximately 300′ between the two shots. Ground conditions were level and consisted of hard white chalk, a porous sedimentary form of limestone. Environmental factors included dust and dry surface disturbance in a heavily trafficked setting, with strong winds and cool temperatures, approximately 20 miles outside of Austin, TX.
Conventional tooling was employed on the jobsite, prior to calling in StraightLine® Lead Field Engineer, Ron Becker, and a 4.0 RockEye™ Air Hammer System. The bore-plan called for the 4″ waterline to be installed next to an existing line, while crossing a fiber cable, a gas line and an additional waterline. “Each bore has its own, unique challenges,” stated Becker, “the surrounding existing lines called for precision steering and the chalk dust coupled with strong winds was also concern. With the utilization of drilling fluids, we were able to clear the cuttings from the bore, as well as, minimize any visual hazards to passersby.”
Outcome: Steering proved to be difficult from the onset, but greatly improved when the Fambro crew switched out a bent lead rod, which was cancelling the intended effect of bent sub. Once the problem was identified and corrected, the crew, with owner/operator Camron Fambro at the controls, hit their exit mark perfectly, with great precision. The crew averaged 15 to 20 minutes per rod on both bores.