Since it began operating in 1903, Danby Quarry has grown to become the largest underground marble quarry on the planet. Its tunnels, ramps, and vast caverns twist and turn to a depth of 1.5 miles, and its marble has been used in famous structures including the Jefferson Memorial and the U.S. Supreme Court building.
The quarry entrance into Dorset Mountain looks the same as it did a century ago, but while the square-cut mining shaft is the same entry shaft used in 1903, Danby Quarry has grown considerably since then.
Today, the quarry covers 25 acres, capable of producing up to 4,000 square feet of marble slabs per day, a total of roughly 200,000 cubic feet per year. The largest blocks removed from the quarry so far have weighed up to an impressive 93 tons.
The quarry encompasses various layers of marble with different characteristics, allowing the operator, Vermont Quarries Corporation, to extract 10 different types of marble.
Olympian Danby, for example, is quarried on the top floor, while Imperial and Eureka come from deeper inside.
The various types of marble have different veining, which determines the price. Royal Danby is the most common and therefore the most affordable. Imperial Danby, meanwhile, is the rarest and the most expensive.
According to atlasobscura