By: Paul Drewes
(KHNL) - From the North Shore to Nuuanu, companies are hired to keep our hillsides safe. But they face a challenge, how to get the huge boulders down?
That predicament doesn't leave everyone between a rock and a hard place.
Kailua is one of the current rockslide mitigation projects underway on Oahu.
The crew has a hazardous challenge.
"Bringing that rock down safely without anyone getting hit by the rock is probably one of the biggest hazards," rockslide mitigation expert Cliff Tillotsen said.
Fencing can keep boulders from rolling down below. Also, crews can scale back loose small rocks by hand.
But when it comes to demolition of big boulders, this company shies away from explosives, using the boulder buster to blow apart a rock.
"We've had close calls with that boulder buster before so we decided not to use it," Tillotsen said.
Instead, they use a hydrologic splitter that can crack a boulder open using pressure.
"We like that one cause you can monitor your demolition as you do it and take off one piece at a time," Tillotsen said.
This method of breaking rocks has worked at the Kailua site.
Most of the boulders deemed hazardous have been removed or anchored in place.
Though rocks may loom overhead, the company insists the area will be safe.
"A lot of times you just put a bolt through a boulder that go deep in the ground and you pin it back and you can't even see the bolts that's very effective so you may see a boulder on the hillside thats looks like it could come loose but it has already been stabilized in place."
Using chemicals to slowly crack the boulders open is another method some companies use.