Crews that worked for nine hours in vain on Saturday brought down a giant slab of sandstone from the Rimrocks in just 18 minutes on Monday morning.
Two and half hours later and five blocks to the east, they brought down a second enormous chunk of sandstone, this time in about 25 minutes.
When the first slab, a 340-ton rectangular piece of sandstone, went tumbling end over end down the boulder-strewn slope above Granite Avenue, contractor Vern Balkowitsch shouted into his radio to his workers on top of the Rims, “Unbelievable job, guys! Unbelievable job!”
The sight was almost too much for Jon Lodge, who was inside his house at 1313 Granite Ave. last October, when a much larger piece of the Rims broke free and sent a huge boulder crashing into the house. Lodge was in the kitchen and just missed being hit.
After watching another cascade of rock rain down on his house on Monday, Lodge staggered backward, his right hand over his heart, and said, “Oh. Oh, God. That did hit me.”
Workers with Accurate Concrete Cutting, Balkowitsch’s company, pumped hydraulic jacks all day Saturday and managed to move the top of the slab a little less than 10 feet away from the face of the Rims. They called it quits at 6 p.m., figuring they’d let people return to their evacuated homes for Easter Sunday.
On Monday, workers started working the pumps again at 9 a.m. Balkowitsch said he didn’t want to use electrical jacks because he wouldn’t be able to control the pressure closely enough. He said the slab had four or five fractures running through it, and he was afraid that, if he pushed too quickly, the top half would go over and leave the base intact.
In addition to the jacks, on Monday he rigged up Plan B — a dump truck full of gravel attached to a cable, which was attached to a steel plate bolted to the back side of the slab. If the jacks couldn’t do the trick, he planned to use the truck — weighing 50,000 pounds loaded — to pull the slab off the Rims.
He was on the verge of using Plan B when, about 17 minutes after his workers started, they reported that the pressure on the jack was dropping almost to nothing. By then they had already moved the slab another 2 feet.
Balkowitsch said a worker told him by radio, “We’re going into failure. We’ve got zero in the pump.”
Within a minute, amid cheers from the workers up top, the slab started coming forward. The top half hit the slope below the Rims with a great rolling whump and a huge cloud of dust. Then the bottom half rolled over the top, breaking into smaller fragments.
Balkowitsch said three or four boulders, weighing perhaps 50 to 75 tons each, rolled down until coming to rest against and beside Lodge’s house. There was no damage to any nearby homes, and even Lodge’s house appeared no worse for wear.
When Lodge went to look a few minutes later with his wife, Jane Deschner, he found that two new boulders had come to a stop against the steel deck and east wall of their house. A large double-pane window on that side of the house, which lost one pane during the October event, was still intact Monday.
With that job done, Balkowitsch, of Vancouver, Wash., moved about five blocks east to begin removing another slab, this one estimated at 300 tons and sitting above Shady Lane.
He had predicted this rock would be much easier to remove because a pillar of stone beneath it fell away in February 2010, leaving the 300-ton piece on top with nothing to support it.
The second job started at 11:30 a.m., when workers on top of the Rims started cutting away at stone on the west side of the slab, where it was most firmly connected to the cliff face. When the diamond-toothed chainsaw had done its work, the crew slipped a jack behind the slab and starting pumping again.
In barely nine minutes, the slab moved about 8 inches, Balkowitsch said, then leaned forward, seemed to pause momentarily, then sheared away. It fell as a unit to the slope below, where it broke up into a shower of boulders, dust and rock debris.
That prompted Balkowitsch into another exclamation.
“All right, boys!” he hollered. “Yeehaw!”
Jon Lodge and Jane Deschner walked up at that moment, and Balkowitsch hugged them both, saying, “That’s how yours should’ve went.”
Balkowitsch then went over to the deck behind the home of Kevin and Erica Bruen, who live at the top of Rimview Drive. The Bruens and their neighbors, Dale and Margaret Vermillion, had arranged to pay Accurate Concrete Cutting $50,000 to have the rock above their houses removed, after the City Council voted not to fund that job.
The council did agree to pay Accurate Concrete $139,000 to remove the rock above Granite Avenue, though with the provison that it might come back later to seek payment from Deschner and Lodge or their insurance company. Most of the land on top of the Rims, and over the side to the slopes below, is city-owned park land.
On the Bruen deck, Balkowitsch was joined by the Vermillions, who live next door at the top of Shady Lane. They got home just in time to see the slab brought down, but Erica Bruen arrived about 20 minutes too late.
Joining them on the deck was Dan Nebel, a geologist with Terracon, an engineering consulting company, who had been hired by the city to do the engineering work on both projects. Considering how easily the slab above Shady Lane came down Monday, Nebel said, “I’m just really amazed it stayed there a year and a half.”
A bit later he added, “We’re all going to sleep a lot better tonight.”
Nebel also said that Terracon had vibration meters set up on either side of both project areas. He said vibrations of more than 1.2 inches per second are normally considered strong enough to cause structural damage to houses. The meters used Monday were set to trigger at two-tenths of an inch per second, and neither one reached that point, he said.
After the big rock came down above Shady Lane, an Accurate Concrete worker rappelled down the face of the Rims and used a big pry bar to send a few smaller fragments of loose rock skittering down the slopes.
Houses that had been evacuated in the vicinity of both projects were opened to their occupants almost immediately after both were finished, and neither event caused any damage, as far as officials knew.
From Shady Lane, Balkowitsch was planning to have his workers return to Granite Avenue to clean loose rock off the ledge that originally supported the rock that fell on the Lodge-Deschner house. He plans to spend a few more days removing dangerous boulders from behind and alongside the house, in addition to the 65-ton rock still inside it. After that, the house will be demolished.
Among the spectators on Monday was Diane Skillestad. She lives on Poly Drive now, but she said her family moved into what is now the Vermillion house when she was in the third grade, in 1964. Watching the rock brought down from above the house brought back lots of memories.
She pointed up to where the Accurate Concrete workers were standing Monday and said that, during the summer, a man used to stand on the same spot occasionally and play the bagpipes.
She also remembered climbing all over the Rims. On the rock that was brought down Monday, there used to be a kind of shelf that she would climb up to, lie down and just look out over the city.
“This was an amazing backyard,” she said. “We climbed up there all the time.”