One hundred years ago the ground of the Black Hills cracked open and swallowed buildings...or so it seemed at Lead's Open Cut. The Open Cut is a man-made canyon hundreds of feet deep and 2000 feet across where once stood a solid mountain. It was created when 48 million tons of rocks were removed in search for gold.
The gold ore hauled up from the Open cut changed the map of Lead. As the gorge increased in size, Lead's business district retreated respectfully before it. North Mill Street, once the Main Street, disappeared block by block as the Cut grew ever bigger. The once five-block-long street no longer exists.
Even along lower main street the buildings and roadway would sometimes settle a foot or more. That's because timber props that held up underground tunnels would decay in three to five years. When they gave way it was only a matter of time before big areas collapsed. In one extreme case a pair of buildings fell away into an abandoned mine cavity, leaving a pit 60 feet deep.
Shops retreated up Main Street to the present business district, where "tirrea firma" provided to be firmer.
The Open Cut marks the only spot where Homestake Company's famous vein of gold reached the surface. But gone are the days Homestake could mine at or near the surface. Now deep tunnels are needed to follow the gold vein's sharp descent into the earth. North America's richest gold mine has shafts down to 8000 feet below the Black Hills. That's 3000 feet below either coast! And still they dig deeper.
The temperature of the rock at these depths is 134 degrees Fahrenheit. And every ton of rock yields a piece of gold only the size of a marble. Rock now taken from the tunnels is now replaced-a modern backfill method to prevent collapse.
10/01/03