Inside the Sutro Tunnel:




The Comstock Lode was a rich mining development in Nevada.  There were many problems in locating, digging, and processing the ore-- one of these was an excess of geothermally heated underground water.  

"Floods in the mines were sudden and miners narrowly escaped being drowned by vast underground reservoirs that were unexpectedly tapped. Intrusion of scalding-hot water into the mines was a large problem, and the expense of water removal increased as depths increased."

http://en.wikipedia.org/wiki/Comstock_Lode

Adolph Sutro, a mining engineer, came up with the idea to dig a tunnel underneath the mountains to serve as a drain for the mines, as well as allow ventilation, and an alternate means to remove ore.  The mining companies, and the rich California banking interests that owned most of the mines, initially supported the idea, but changed their minds once they realized that Sutro would be threatening their monopoly of ore processing, transportation, and miner living quarters in Virginia City.  The Bank of California was especially hostile to the Sutro Tunnel.

http://en.wikipedia.org/wiki/Bank_of_California

Entrance to the Sutro Tunnel:




Sutro came up with the idea in 1860, and worked until 1869 to get the necessary funding from the East Coast and Europe, and fought political battles in Congress and the state legislature to get approval for his plans.

4 miles of tunnel was completed by July of 1878, too late to catch to heyday of economic boom times in Virginia City.  The tunnel accomplished what it was supposed to do, but by then, the mines had already been sunk deeper into the ground.  It was also neatly engineered-- when it reached the mines, the tunnel was only eighteen inches in deviation from its planned point of entry.  By 1879, Sutro left the company, selling his shares, and became a rich real estate owner in San Francisco, and later mayor of that city.

http://en.wikipedia.org/wiki/Sutro_Tunnel

Map of the Sutro Tunnel:




The tunnel still exists today, albeit in disrepair, and still drains water from the upper parts of the old mines of the Comstock Lode.

Sutro Tunnel in disrepair:




Further readings:

The Advantages and necessity of a deep drain tunnel for the great Comstock ledge

The Sutro Tunnel, Nevada History

The Sutro Tunnel Company, college research paper

Neat

Very cool! Thanks for posting.