Due to its position in the western Pacific Ocean, Japan is beset by 30 or more powerful typhoons, packing strong winds and heavy rain, between June and October every year. Floods and landslides caused by the massive rainfall are very common and a constant headache for communities around the country.
Shikoku, the smallest of the four larger islands, receives more than its fair share of these typhoons. In a town called Hidakamura, the Kajima Corporation, one of the oldest and largest construction companies in Japan, is busily building a drainage tunnel called the Kusakagawa New River Tunnel at the request of the national government. A key component in the project is the Epiroc Boomer E2, an automated face drilling rig.
Once the wall is scaled with the help of a large breaker, the walls and ceiling are covered in shotcrete. It is then time for the whole process to be repeated. The speed and efficiency are impressive. “We are adamant about meeting our schedule for the residents in the area, who face the peril of more floods and landslides with every typhoon season without proper drainage of the rain water,” says Masakazu Matsuda, Kajima’s Project Manager for the Kusakagawa New River Tunnel.
The Boomer E3 is equipped with the Epiroc Rig Control System, allowing the operator to easily monitor and control all rig functions and maintain a better focus on drilling, as well as Advanced Boom Control (ABC) Total.
The latter is a smart function that allows for complete automation of the drilling process, even through employee breaks and shift changes.
"The rig is a crucial timesaver for us. Thanks to its automated features and its ease of use, we save a lot of time on both operator training and the actual drilling. Between 85 and 90 percent of the drill holes are drilled autonomously."
Kajima is an accomplished tunnel builder – with its mountainous landscape, Japan has more tunnels per square kilometer than any other country in the world – but there are always problems along the way.
“The rock here is quite varied, and even though we do geological surveys before we start, we often find that they don’t always correspond with reality. That’s why we truly appreciate how the Boomer E2 can sense the rock hardness and fractures while drilling and give us data about the rock some five meters in,” says Masakazu Matsuda.
Deputy Project Manager Hiroshi Fujii adds: “The quality of the equipment coupled with the computerized control of the drilling really cuts down our costs for service and consumables, not to mention less downtime. We estimate that we save around 50 percent on repair costs and up to 80 percent on consumables. Not having to manually mark the positions of the drill holes is another small but time-consuming operation we don’t need now.”
