The Largest Mine in New England was in Cheshire. Who knew?
What lies beneath? That's what worries Cheshire resident Mary Vosburgh.
A good-sized chunk of her backyard is being swallowed up by something that has already gobbled up truckloads of fill, dozens of old tires, a few old automobiles and even a children's swing set. In 1978, it took a bite out of Sheridan Drive, a street perpendicular to Mary's, which collapsed 20 feet overnight, curb to curb. In 1994, it drank up a stream. So worried is Mary that she plans to fence off the sinking section of her already fenced yard. Otherwise, her inquisitive, hole-digging terrier, Kimba, may become the next morsel.
Welcome to Cheshire, home of New England's deepest underground mines. Beneath the residential neighborhoods of Peck Mountain and Jinny Hill is a honeycomb of abandoned mine shafts, prospecting pits, tunnels and partially dug veins of barite, an unusually heavy, soft, snow-white mineral that, when crushed, resembles powdered sugar. Mixed with the barite are fragments of maroon sandstone, coatings of agate-like quartz and the greenish-blue tinge of copper, all of which fill giant fractures that once steamed with geothermal fluids and rumbled with seismic activity. For more than 50 years (1813-78), Yankee laborers and an imported colony of more than 200 miners from Cornwall, England, worked underground like so many elves. In that dimly lit local version of Middle Earth, they used pickaxes to hammer out the soft, beautiful ore; chains to hoist it up through vertical shafts; narrow-gauge tramways to move it to mine portals; sledges to crush it; oxcarts to haul it west to the Farmington Canal; barges to float it to New Haven for processing; and railroads to ship it to New York City. There, the ore was used to thicken the white paint still covering so many early American homes.
Written descriptions, especially those by long-time mining superintendent J. Lanyon and a consultant from Germany, Hermann Credner, indicate that the deepest shafts extended more than 600 feet, and that more than four miles of passageways lie beneath the otherwise pleasant town of Cheshire. These astonishing estimates make sense when one takes a closer look at the miles of nearby stone walls, many of which were built using leftover blocks of the polychrome ore that weren't rich enough to break apart.
The Cheshire barite mines were abandoned long before the present era of mine safety and environmental regulation. Hence, the abandoned shafts and tunnels were never filled; their supporting timbers having long since rotted away. As the tunnels cave downward, the voids migrate upward, until they reach the surface and begin to swallow soil, one clump at a time, and surface streams that can now be heard (but not seen) trickling in the blackness. Water that entered the ground fresh seeps out somewhere else as mine drainage. Debris dumped in to fill the empty spaces slowly compacts and decomposes, reactivating the subsidence until more fill is needed, again and again.
The collapse is not completely random. Instead, it follows quasi-linear paths parallel to the mined-out veins and horizontal shafts below. One of these paths crosses an old basketball court in Mary's backyard, where the asphalt outlines a miniature rift valley 14 feet wide. Her neighbors tell of other strange tales: of sunken oak trees without visible roots; toppled cedars where surviving limbs became trunks; dank underground passageways complete with rotted door frames; a sequence of sinkholes opening like a zipper from east to west; random pits into which long poles can be inserted without touching bottom; an aboveground swimming pool built over a mine shaft, its water poised to flush down the drain should the earth decide to move abruptly.
Welcome to Cheshire, where town officials don't advertise their unique claim to fame. Mary grew up and went to public school in Cheshire, yet claims to have heard nothing about the town's colorful mining history in her social studies and science classes. After moving to Florida, she returned to buy a house on a lot that soon began to cave in. Rightfully, she wants to know why she wasn't informed about the potential for mine collapse by the town, the bank or the previous owner, especially since her lot lies on a line of sinkholes mapped by a now-defunct engineering consultant to the town. As a matter of public policy, Mary believes that everyone should be made aware of what is mostly an expensive annoyance, but one that is fully capable of swallowing an unsuspecting child.
What's needed is some sort of a ``homeland security'' act for Cheshire residents, one that would map out the abandoned mine workings, determine site-specific threats to safety and property, and put safeguards in place. Otherwise, the fates of residents will be left to chance encounters, to surface failures and drainage changes in places where people live and play, and where their underground utilities -- sewer, electricity, fuel lines -- are buried.
A good start would be to find the almost legendary map of the underground workings, which likely lies in someone's attic or engineering archive. Next would be a spelunking expedition to explore Cheshire's manmade caves.
There is a poignant irony in all this. During Mary's 11 years in Florida, she had reason to worry about sinkholes, a chronic and heavily regulated environmental problem in that soluble-limestone terrain. Moving back, she breathed a sigh of relief, knowing that she was returning to New England's ancient hard-rock terrain. Imagine her chagrin when sinkholes began to take her property down the drain. Imagine her outrage.
