SANTA FE, N.M. (AP) - Efforts are coalescing to shore up a giant, man-made underground cavern in southern New Mexico before it collapses underneath a community of mobile homes and critical highway and rail transportation routes, nearly nine years after state officials sounded the first danger alarm, state Energy, Minerals and Natural Resources Secretary Ken McQueen said Tuesday.
He said his agency will be prepared as early as July to help commission engineering plans to stabilize the cavity left by the extraction of a salt formation underneath a crossroads at the edge of the small city of Carlsbad.
The formation was mined by flushing water through it to extract brine for use by the oil and gas industry for drilling operations. Operations were halted in 2008 in following cavern collapses at two similar brine wells in nearby unpopulated areas with similar geology.
“Basically the idea is to fill that void space, which is filled with water, with solid material which is designed to keep the cavern from collapsing at any time in the future,” McQueen said.
The subsurface cavity at Carlsbad lies between 450 feet and 600 feet below ground. Studies show a collapse would impact an area of roughly 1,000 feet (300 meters) by 1,700 feet (520 meters), with the likelihood of broader, gradual damage to pipes, sewers and structures as earth slumps and washes toward the depression.
The most likely and cost-effective solution is to drill holes into the cavern and backfill it with a gravel mixture, capped with cement, said McQueen, who will join other state and local officials on a new oversight authority commissioned by the Legislature and governor this month.
State lawmakers earmarked $250,000 to engineer a remediation project that can be put out to bid among specialized contractors. That initial financing won’t be disbursed without matching funds from local governments and remains in limbo as Republican Gov. Susana Martinez weighs vetoing major provisions of a $6.1 billion budget approved by the Democrat-led Legislature.
Michael Lonergan, a spokesman for Martinez, declined comment Tuesday whether funding for the brine well would be approved.
Carlsbad is a city of 26,000 best known for the synonymous outlying national park with majestic limestone caverns carved by nature over eons. Its city council has reacted to rising tensions about the stability of the brine-well cavern by proposing a moratorium on new development permits in the area, with a vote is scheduled for April 11.
McQueen acknowledged full remediation costs could run as high $25 million. The new Carlsbad Brine Well Authority will meet as soon as July to assess future funding sources that might include federal grants or bonds backed by state severance taxes.
The operator of the brine well provided just over $3 million to state and local authorities in bankruptcy proceedings, while the tab for monitoring the cavern as a precaution against collapse has topped $5.3 million, according to McQueen’s agency.
Carlsbad city councilor Dick Doss places blame for the cavern and its perils on state officials, noting they issued the original permits and collected royalties for decades.
About 100 people live near the cavern and Doss said many are elderly and cannot afford to relocate.
The endangered area includes two highways designated as transportation routes for the federal government’s only underground nuclear waste repository. Also nearby are an agricultural feed shop, a church and an irrigation canal supplying about 25 square miles (65 square kilometers) of farmland.
Studies show the cavern is likely to collapse within four to 20 years, said George Veni, executive director of the nonprofit National Cave and Karst Research Institute.
Local residents and businesses are depending on a combination of technologies designed to detect minuscule ground movements and changes in underground water pressure.
“We believe that will give us an indication of an imminent collapse,” McQueen said. “The hopes are that would give us enough time to evacuate the area.”
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