‘Big Lift’ aims to save home

JEFF GEARINO/Casper Star-Tribune
Atlas Piers worker Andy Jackson compacts the dirt underneath the McAffee home on Pine Street in the Tree Street neighborhood of Rock Springs on Tuesday in preparation for a Big Lift project scheduled for this morning that aims to stabilize the house. The home was damaged in 2007 from a pilot subsidence project conducted by the state






BIG DROP
DAN CEPEDA/Casper Star-TribuneStar-Tribune
Dennis and Karla McAffee sit in the living room of their home in Rock Springs, Wyo., in January 2009. The McAffees’ historic home, which was built in the mid-1920s, started to crumble after a state project of ground compression was started to reclaim land for development.

ROCK SPRINGS - The ill-fated "Big Drop" subsidence project damaged the stately, historic Pine Street home of Karla and Dennis McAffee.

Now comes the Big Lift to try to fix some of it.

Workers began repairs on the McAffee home last week, more than two years after the state's coal mine subsidence project was halted amid complaints of damage by residents of this city's "Tree Street" neighborhood.

A Utah contractor specializing in the installation of foundation support systems plans to use a hydraulic system to raise the north front and the east side of the house this morning in an effort to better stabilize the house.

Karla McAffee said the family is footing the project bill until an agreement with state Abandoned Mine Land Division officials can be reached concerning payments for damages.

She said engineers were concerned about the structural safety of her damaged home and recommended beginning the repairs before winter.

"We just can't go another winter" with two sides of the residence slumping so badly, she said.

"There are significant safety issues, and though we still haven't got this resolved with the state ... I have to do right by my family and by the other people in my community, because if that (column and wall) falls over, somebody could be injured or killed," she said.

The state has yet to settle with McAffee and more than a dozen other homeowners in the Tree Street area of downtown Rock Springs for damages from the subsidence project. As part of the project, 25- and 35-ton weights were dropped more than 2,000 times on a nearby tract of undeveloped land.

The "dynamic compaction" experiment was part of a pilot project that began in July 2007 that intended to collapse old, abandoned underground mine voids and stabilize the land for housing construction. But days after the weight dropping began, residents began complaining that the seismic vibrations were shaking houses, cracking foundations and walls, shifting garages and driveways, and accelerating ongoing subsidence.

AML officials offered to pay for damages that an Evanston-based engineer determined may have been caused by the dynamic compaction during initial inspections of the homes.

Three of the 19 homeowners submitting damage claims to the state for repairs from the project accepted the state's offer. The majority of affected residents, however, including the McAffees, refused the settlement offer as not being adequate to compensate for damages to their homes.

Attorneys for the homeowners and the state have been negotiating for months on a new agreement that would allow state engineers to reinspect the homes, with an eye toward making new settlement offers.

State officials met with Tree Street residents last week to discuss the initial findings from more than two years of investigative drilling in the neighborhood that sought to better determine what's actually happening in the abandoned underground mine shafts and voids.

The study by engineers with the Colorado-based Tetra Tech revealed that there's still movement in the numerous mines, but the exact cause remains unclear. The subsidence risk, unfortunately, remains high for the neighborhood, officials said.


Historic home

The McAffees' stately old house is situated on tree-lined Pine Street about three blocks from the dynamic-compaction project.

The solid-brick house was built by a prominent local doctor in 1924 and is considered one of the original old homes in Rock Springs. Over the years, the couple invested thousands of dollars in renovating the showcase home.

Both the upstairs and downstairs were remodeled, the roof was repaired and redone, and new concrete sidewalks and driveways were poured.

Shortly before the compaction project, the family bought custom-built windows for the whole house. The windows are now stored in the garage and may never be installed.

McAffee said the subsidence created by the shock waves moving through the underground rock formations slowly destroyed their home. The basement rolls, floors in the upstairs portion now slant and slope, numerous walls were cracked, doors won't close right, the new driveway is separating from the house, and the brick fireplace wall is leaning.

A key column holding up the northwest end of the house separated from the wall shortly after the project ended.

Last year, engineers installed a 15-foot steel pole to temporarily support the front corner of the living room. Some 30 other temporary poles now brace the rest of the house. McAffee fears the front end of the house will collapse onto the street and injure a passer-by.

"The fireplace was becoming an issue in addition to the column, so it's just the critical areas of the house that this first work is being done on," she said.

In the summer of 2008, the couple hired a Cheyenne contractor to inspect the damage and make repair cost estimates. The contractor's estimate was $197,000.

The state's structural engineer also inspected the home. The state's settlement offer was $39,581.


Hydraulic jacks

The Big Lift aims to lift and then stabilize the McAffee home using a hydraulic lifting system, according to project foreman Sam Perry.

The first part of the project involved digging out the driveway, front porch walkway and the concrete near the column and fireplace last week.

Perry said holes were then dug under the house into the underlying rock formations. He said 14 steel piers with manifolds were secured in the holes surrounding the north front and east side of the residence.

"We had to dig through about 3.5 feet of shale rock just under the house ... and then go down anywhere from 7 to 9 feet" to anchor the piers into the underlying rock formation, he said.

Permanent, L-shaped devices with 25-ton cylinder jacks have been attached to the house's foundation that will be linked with the steel piers.

Perry said the plan is for workers to use a sophisticated, computerized hydraulic system to lift the house and then secure the piers into place.

"This should really do the job as far as we're concerned," Perry said Tuesday while working at the job site. "I have no doubt this will stabilize the house."

Perry said once the hydraulics are in place, it should take only a few hours to raise the sloping house to its previous level. When that's completed, the piers and jacks will be backfilled and buried, and the concrete driveway and walkway will be replaced.

Contact Jeff Gearino at gearino@tribcsp.com or 307-875-5359.