REACHING HIGH IN PANAMA
TEI Rock Drills Excavator Mounted Drill Attachments used at Panama Canal Excavation
The Panama Canal is undergoing a $5.2 billion expansion to allow the passage for larger modern vessels. The entire project was staged as seven smaller sub-projects including: the construction of new Post-Panamax locks on the Pacific and Atlantic sides; excavation of the new Pacific Post-Panamax locks north access; improvements to navigational channels channel; improvements to water supply; dredging of the canal Atlantic entrance; dry excavation of the new Gatun locks; and design and construction of a third set of locks.
Drilling took place on the Gatun Locks excavation project. Excavation by the U.S. Corps of Engineers at Gatun began in the 1930s, but was abandoned after the U.S. entered WWII. The new excavations used hydraulic track drills for the bulk of the rock removal, but rock bolting and blasting was accomplished with the HEM550 excavator drill from TEI Rock Drills. This was the only drill that could adequately reach the holes, which are located at heights up to 40 feet.
TEI attachments only use the TE series of hydraulic drifters with the patented Automated Stroke Adjustment (ASA) system. This innovative design reduces impact energy when the hammer is not engaged, keeping parts usage to a minimum. In a similar fashion to a down-the-hole hammer, the TEI drifter only has full power when down pressure is applied to the drill string. Unlike bulky external dampening that only acts as a shock absorber, the TEI drifter shifts the piston into an idle mode, providing a much more user-friendly drifter in a shorter more simple design.
The drill and steel operators at the canal jobsite worked from an aerial lift to drill the holes and add/remove drill steels. The holes were 4 ½” in diameter and up to 30’ in length. An operator was also situated in the cab of the excavator to help position the drill. After drilling the hole, the drill basket returned to ground level to drop the drill steel out of the basket and load the bar into it. It is then raised again to maneuver the bar into the hole, while avoiding damage to the epoxy coating. The holes were loaded with #8, grade 75, epoxy-coated bars. These rock bolts have a design life of 100 years.
After drilling and loading the holes, the bolts were grouted in place at the end of each day with the use of a high-pressure grout plant. The high pressure allowed the grout to continuously flow from ground level up to the various holes in the face and ensured the hoses were kept clear of grout drying in the line.
Although this is a unique and difficult job, the Panama Canal project highlights the successful use of drilling attachments on excavators. Rugged TEI Rock Drill Excavator Attachments were the only option capable of accomplishing this tough geotechnical application.