The tunnel was built between 1851 and 1856. It was financed by Dr. Hillerscheidt and D. Albert. This original mining debris drainage tunnel was later purchased by North Bloomfield Gravel Mining Company and can still be seen today. If you plan to walk through this 557’ tunnel during the dry summer months, bring a flashlight and water shoes.
North Bloomfield Tunnel
To handle the needs of more gravel tailings and water volume the miners decided to build a bigger tunnel. In 1872 W. Hamilton Smith designed and began construction on the 7,878 foot North Bloomfield Tunnel.
This drainage tunnel, built 200’ below the Hiller Tunnel, was constructed to drain away the huge volume of rocks, gravel and mud washing out of the mining pit. It took the miners only a year and half to complete the tunnel. It was considered an engineering marvel, utilizing two crews in each shaft. Once miners reaching the bottom of the shaft the men would separate and work in opposite directions to connect with the crews working from the next shaft. There are 8 shafts leading to the bedrock below.
The tunnel has long since filled in with water and debris. It is no longer navigable, but you will see the tops of some of the air shafts as you walk down Humbug Trail.