Big Thunder Gold Mine

Useful Information

Location:	604 Blair Street, Keystone, SD 57751. (43.895041, -103.417232)
Open:	Mid-MAR to MAY Thu-Sun 10-16. APR daily 9-17. MAY daily 9-18. JUN to AUG daily 8-20. SEP daily 9-18. OCT daily 9-17. [2024]
Fee:	Adults USD 14.95, Children (6-12) USD 11.95, Children (0-5) free. [2024]
Classification:	Gold Mine
Light:	Incandescent
Dimension:
Guided tours:
Photography:	allowed
Accessibility:	yes
Bibliography:
Address:	Big Thunder Gold Mine, P.O. Box 45, Keystone, SD 57751, Tel: +1-605-666-4847.
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then. Please check rates and details directly with the companies in question if you need more recent info.

History

1892	W. B. Krupp and J. A. Engle, two German immigrant miners search for gold.

Geology

Description

Big Thunder Gold Mine is located in the Black Hills, an area with forested hills, which is actually most famous for Mount Rushmore, you know those huge heads of presidents. BUt the hills are quite interesting from the geological view. The center consists of crystalline rocks, which were uplifted. They are bordered by limestone which is karstified and has huge cave systems. But the geology also created deposits including some gold deposits. As a result there was a little gold rush in the 1890s. Much smaller than the Calfornia Gold Rush, or the Alaska Gold Rush. But nevertheless mines were opened and miners came looking for work and probably some luck.

Two German immigrant miners named W. B. Krupp and Julius A. Engle came to America independently. They actually met for the first time here in the Black Hills. The same language and some geological skills soon made them partners. The gold vein was named Lucky Boy vein, and it was already mined when they met at Keystone in 1892. They studied the direction and angle of the Lucky Boy orebody, in the hope to find another part on an available claim. Here at the Big Thunder property, they devised a plan to intercept the orebody by driving a tunnel into the hill. They used a drilling process called double jacking, where one miner held a steel drill bit while the second miner pounded it with a sledgehammer. Then they placed powder in the drill holes to blast the rock loose. They used a certain pattern to place the boreholes, which was called butterfly drill pattern. With its geometry and by blowing up from the inside to the outside, they blew out a cone of ore from the center and nevertheless maintained the outer walls’ reliability.

Around 1900, manual drilling was replaced by steam and compressed-air-driven drilling equipment. Water injected into the drill holes during the drilling to remove the rock chips increased the speed and reduced the dust in the air. In 1907, they finally reached the Lucky Boy vein about 100 m underground. But their dreams were crushed when they found that the vein had narrowed down and was not profitable any more.

But in 1909, the Columbia Mine opened on the adjacent property. They discovered a different vein, the Columbia vein, which ran parallel to the Lucky Boy vein. And it was profitable with over two ounces of gold per ton, with some rich pockets producing up to 10 ounces per ton. Krupp and Engle, reopend their mine in search of this second vein. They found it, but the vein had mostly pyrite, arsenopyrite, graphite and quartz, but little gold. Nevertheless, they removed the ore in a stope and processed it a nearby Tykoon Mill.

Mining ended for the first time due to World War I, the government issued L-208, an order to close mines not producing resources for the war. And gold was obviously not suitable to make weapons. Gold mining at Big Thunder Gold Mine ended in 1914. The few mines which reopened after the war, had the same problem in World War II, this second shutdown ended almost all gold mining in the Black Hills.

Big Thunder Gold Mine is one of the mines which were opened in the 1890s. It is located not far from Mount Rushmore. It offers an underground tour of historic mine tunnels, and there is a Mining Museum with the largest collection of equipment and artifacts from the Black Hills Gold Rush. They were collected from three different mines. There is a stamp mill, a bell crusher, jaw crusher, copper and Wilfrey tables, and ore bins, everything which was needed to process the ore. Mine trains, winches and elevator equipment were needed for transport of ore and miners. The blacksmith equipment was necessary to maintain the mining tools, The museum is a replica of the Tykoon Gold Mill, built in 1895 on the Big Thunder Gold Mine. And quite typical for the U.S.A., there is gold panning. It doesn't make sense because there was no placer mining in the Black Hills because there are no alluvial deposits, but it is important to fulfil expectations, even if they are abstruse.

The mine is located in Keystone. The mine passage is horizontal, so it's possible to visit with a wheelchair or a pram.