Foundation Drilling

Center Rock Inc. was contacted by Malcolm Drilling to help with foundation drilling due to low production with conventional rock augers and core buckets on a job site for the Highway 56 and 15 Connector in San Diego, CA.

Center Rock sprang into action and manufactured a series of tools ranging in size from 48 to 96 inches for this project. CRI’s startup technicians arrived on site with the tools to assist Malcolm Drilling with the assembly and startup of the air drilling operation. This quite possibly was Center Rock and Malcolm Drilling’s most challenging project to date due to the 60,000 psi UCS rock strength. With Center Rock’s products, Malcolm Drilling was able to complete the project.

Since that project, Center Rock Inc, Malcolm Drilling, and other LP customers have recognized the need to improve the LP DRILL System’s ability to drill in fractured and broken rock. Past problems drilling these formations with gang hammer type drills (LP/Cluster drills), are related to individual bits passing over broken or fractured ground. In these formations, the bit is allowed to drop into the exhaust (low-pressure) flushing mode. This causes a significant drop in system air pressure resulting in a loss of energy transferred to both solid and fractured rock. The bit drop distance also causes an increase in operating torque. These problems result in a loss in productivity and increased wear rate of the drill bits.

CRI’s engineering team was challenged to develop solutions for these foundation drilling problems. The result of this challenge was the creation of the new CR65LP hammer and bit combination. CRI released the new CR65LP hammers to the market fourth quarter of 2009. The advantage of the new design versus the previous one was obvious. Center Rock’s solutions addressed a common problem in any multi-hammer application.

Malcolm Drilling recently had the opportunity to run the new CR65LP product on the Van Burren Bridge project in Riverside, California. They ordered a complete set of CR65LP hammers that were installed in the LP Canister to replace the tooling used in the past. The current project was started using the older product to establish baseline performance. A dramatic increase in performance was noticed when the older tooling was replaced with Malcolm’s CR65LP hammers.

Rod Maclean, General Superintendant for Malcolm Drilling, said, “The new hammers and bits are twice as fast, there is no maintenance between the shafts, and the bit wear is better.” One of the drill rig operators exclaimed, “The impact is better; you can hear the difference!”

This new technology allows Center Rock’s LP hammers to efficiently penetrate through broken, fractured, clay-seamed rock formations. It also maintains high pressure and reduces torque.