The city of Auburn is working to repair a sinkhole that occurred as a result of a faulty storm drain pipe that Auburn officials say is in desperate need of repair and could cost millions to fix.

The sinkhole, located in the Auburn Journal's customer parking lot, is roughly 8 feet deep and is the result of a storm drain pipe, about 42 inches in diameter, that has rusted out along the bottom and collapsed along the top.

"The pipe is part of a system that carries stormwater from one end of the town to the other," said Jack Warren, Auburn public works director. "The whole system is in serious need of repair and has been for many years."

The only problem with that, Warren said, is that the city doesn't know who owns the pipe, who built it or when it was built.

"The city has no title of easement that we know of," he said.

To fix the system, he estimates will cost the city millions of dollars.

There is currently money in the budget to study the problem, but nothing to help in construction efforts, pending investigation.

The pipe problem extends from Electric Street and runs to Old Town.

The threat of more sinkholes is why city officials say the problem needs a permanent fix.

For now, city crews are still working on a temporary solution, but will probably fill the sinkhole with dry concrete and pack it down around the pipe.

Officials estimate that will cost about $15,000.

"This will buy us some time until we can go back and analyze the entire system and find a permanent solution," Warren said.

Greg Baxter, a staff research associate in the geology department at the University of California, Davis, said sinkholes are a geological phenomenon and there are two ways they can form.

"The first is not so common in this area but it is a place where there is a lot of limestone beneath the surface," Baxter said. "Water under the ground will dissolve the limestone under the surface and create some kind of cavity and the material on top will sink onto the cavity that has been made."

He said this type of sinkhole is more common in Florida and other limestone-rich regions.

"The second, which is more common in this area, is where a manmade cavity is present - either from sewage pipes or former mines," Baxter said. "When material is removed from beneath the surface, it may not sink for years, but the soil on top could collapse in the cavity."

Baxter said this type of sinkhole is more common in the foothills because of the large number of former mine shafts underneath the surface in the area.

Fixing them, he said, is more of engineering concern, but that the best way to avoid them is not to build on top of the cavities, which is difficult because often people do not know about them ahead of time.

An abandoned mineshaft is believed to be the cause of 32-year-old Alta resident Jason Chellew's death.

In an April 22, Auburn Journal article, it was reported that Chellew died after the ground collapsed beneath his Sawmill Road home.

His pregnant wife was able to escape and call 911.

Recovery crews could not safely retrieve his body until two days later because of the instability of the area around the hole.

It initially measured about 10 feet in width and depth but had grown to 30 feet in diameter and a depth of at least 20 feet by the time his body was recovered.

The Journal's Jenna Nielsen can be reached at jennan@goldcountrymedia.com.