Reaching high in Panama

TEI Rock Drills excavator-mounted drill attachments are being used during excavations at the Panama Canal

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The Panama Canal is currently undergoing a US$5.2 billion expansion to allow passage for larger modern vessels. The entire project is broken into 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 is taking place on the Gatun Locks excavation project. Excavation at Gatun was originally started in the 1930s by the US Corps of Engineers but was abandoned after the US entered WWII.

The current excavations are using hydraulic track drills for the bulk of the rock removal, but rock bolting and blasting is being accomplished using 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 drifters with patented internal hydraulic dampening system. This revolutionary design reduces impact energy when the hammer is not engaged thus 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 work 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 is also situated in the cab of the excavator to help position the drill. It takes a coordinated effort between these three people to undertake this difficult drilling work.  After drilling the hole, the drill basket is 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 manuver the bar into the hole, while avoiding damage to the epoxy coating, the holes were loaded with #8, grade 75, epoxy-coated bars. These rockbolts 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. This entailed getting a grout hose to each of the previously drilled holes. A high-pressure Obermann grout plant was used for this purpose.   The high pressure allowed the grout to continuously flow from ground level up to the various holes in the face. It also ensured that the hoses were kept clear of grout drying in the line.

Although this is a unique and difficult job, this project highlights the successful use of drilling attachments on excavators. While not suitable for every type of project, a TEI excavator-mounted drill was the only option capable of accomplishing this task.