A sign in the corner of Dale Batchelor's idyllic downtown yard on Sonora's Wykoff Street reads "DANGER MINING AREA."

Although a friend gave the sign to him as a joke, every time Batchelor has to restabilize his sinking house, he is reminded that the workings of old mines are not far below his back yard.

Batchelor moved into the house built in 1890 20 years ago. When planting a vine-enclosed back yard across from Sonora High School, he covered a strange opening in the ground with dirt.

That opening leads into one of the many mine tunnels that catacomb Sonora's underground.

"I might have covered up more than I knew," Batchelor said.

Batchelor does know he has to re-shim his home which is supported by posts after things start to shake. And those shakes come about every six months.

"My house sinks all the time," he said without concern. "You see the stuff on the TV start to wobble."

Tunnels under town

Rumors have long circulated in the Mother Lode about interconnected mine shafts running under streets and towns.

But for two years Richard J. Lundin, archaeologist and director of the Wondjina Research Institute in Twain Harte, has used new technology to map the mine workings and find which tunnels are collapsed and which are still stable.

Lundin moved to Tuolumne County in 1999 from Prescott, Ariz., a town similarly carved up by miners and Chinese laborers who lived and traveled underground to avoid abuse by whites. He was planning to work on his doctorate in historical archaeology and noticed that Sonora was strikingly similar to Prescott at least underground.

"It's better known what they did in Prescott," Lundin said. "They constructed and lived underground."

When Arizona highway officials constructed a bypass near Prescott, Lundin said, they ran right into an underground joss house a Chinese place of worship filled with hundreds of opium bottles.

"There's lots of these underground workings in California that are unsafe," Lundin said.

As Batchelor's house proves, Sonora is no exception.

Tommyknockers under the church

Lundin's research in Sonora began when the rectory at St. James Episcopal Church the Red Church began to shift and sink into the ground.

The rectory, Lundin said, was "built in the '40s on loose workings, on a collapsed tunnel."

Church officials asked the Wondjina Institute to explore the possibility of moving the rectory hall to a nearby location.

Using high technology ground penetrating radar, radiometrics and low-frequency electromagnetics Lundin has begun to map the underground area around the church and has said that moving the hall will probably be feasible.

But he still has more work to do, combining all three technologies for a clearer picture of the underground workings.

"These are all aspects of remote sensing that archaeology is just starting to use to map man's use of the landscape," Lundin said. "These are all new things."

The resulting images show mine tunnels and shafts and where they have collapsed.

"There are mappable underground workings," Lundin said. "Some are collapsed, some are not. Some of them are 20 feet high."

Many of them are filled with water, and all are dangerous.

"When it rains here, where does the water go? In the old days, they'd pump the water out of the mines. Now it just accumulates in there," Lundin said. "They are dangerous, they're collapsed, they're full of water ? don't go in there."

The project led to a speech Lundin will give next year in Sacramento to the Society for California Archaeology entitled "Tommyknockers Under the Red Church."

A Gold Rush term, tommyknockers were the spirits and devils who made knocking noises on the walls of mines, terrifying miners by blowing out candles and generally wreaking havoc.

Concave pits

The maps piqued Lundin's curiosity, and he began a slow, outward spiral from the church, noting concave pits in the land, cracks across Washington Street and buckled sidewalk, all indicating old workings.

The small amount of research he did under Washington Street prompted him to invite Caltrans to do a similar study.

As Lundin pointed to where the sidewalk along Washington Street buckles and humps, a loaded logging truck rumbled by.

"We shouldn't be routing heavy traffic through downtown Sonora," he said. "Those wooden supports are going to collapse sometime. The stuff just rots."

Washington Street chasm

When the street collapsed into mine tunnels in the 1960s, it was during a heavy storm at night and no one was hurt.

"It was on a Saturday, storming hard, it stormed the night before, with lightning, and it blew out some transformers," remembered veteran Sonora City Councilman Ron Stearn, who worked at Mundorf's Mercantile at the time.

At five or six in the morning, Stern said, a truck carrying replacement transformers happened upon a Washington Street chasm that Stearn estimated at 7 feet wide and 20 feet across.

"The street just dropped down," he said. "They had trucks come and fill it up with muck."

The gash, which ran between Mundorf's now Creative Learning Center and Servente's tavern across the street was filled by noon and traffic was again on the move.

These are the kinds of stories Lundin is collecting from those he calls "informants," people who have witnessed first-hand the effects underground workings have had on Sonora.

Lundin is also looking for evidence of mineral rights or old maps that people might have stored away in basements or attics.

Using old maps he found at the University of California's Bancroft Library in Berkeley, Lundin is able to walk above mine workings and use modern technology to understand their current state.

"I'm standing right where the workings are," Lundin said from a shallow bowl in the ground where Red Church's youth center once stood.

The building was removed in September of 2002, when it started sinking.

Chilean miners

The workings were first dug by Chilean miner, who in in the 1850s shored up the tunnels with stulls, or heavy rounds of wood.

Following a rich placer vein, they extracted 50,000 ounces of gold, totaling $1 million at the time.

In the 1870s, James Divoll, who built the Sonora Opera Hall, acquired the mineral rights and started working what he called the Bonanza Mine.

"He staked the claims that are right under the Red Church," Lundin said. "Divoll, I think, found pockets where 900 pounds of gold were taken out."

The mines were lucrative until they were abandoned due to high water in 1902. The upper workings were re-opened in the 1930s, but only operated for a couple of years. The stulls still support some large tunnels, but if the wood rots or burns, they could collapse, disturbing everything built above them.

Lundin, who is also working on projects in Jamaica, the United Kingdom and the Marin County town of Bolinas where an underground ship might be a remnant from Sir Francis Drake's fleet wants to explore the Little Bonanza, the Last Chance and other Mother Lode mines.

Although he probably won't go into the old tunnels because too many are collapsed or dangerous, he hasn't completely abandoned the idea.

"I'd like to, if they're safe, with people who have actually been in there recently."

Contact Claire St. John at

Sierra Views is a weekly feature profiling various people and places of the Sierra foothills; every one and every place has a story. Have a profile suggestion? Call the editor at 532-7151 or 736-1234.