Sutro Tunnel, the nearly four mile stretch from Dayton to Virginia City collapsed about 20 years ago, more than 100 years after it was built. Because of blockades of timber at one of the entrances, no one could go inside. But even if they could it wouldn't be safe.
Chris Pattison, the Project Manager with Friends of Sutro Tunnel said, "We don't know the condition of the inside of the tunnel. You send a person in there, and because of the air quality they could die just from methane gas, from carbon monoxide, carbon dioxide. Who knows what else. Timbers could fall. It's very dangerous in there for a human being."
So instead of sending people on a mission to explore the unknown, EROCK associates launched drones. The company was hired to investigate the historic mine and gather data.
The diameter of a drone they use is 14 inches, making it suitable to fit in tight spaces and capture video footage from inside the tunnel. The drones are also capable of going into the tunnel as far as 500 feet.
"The drone will go in there and surmise if the air quality is okay for humans and if the ground condition's are okay." said Eric Bennett, the owner of EORCK Associates, LLC.
Some drones have the ability to map spaces using LIDAR technology.
"It just captures a bunch of imagery that could be stitched together and put together with very high accuracy to show the conditions." said Bennett. "It doesn't need GPS. It doesn't need any connectivity to do its job. It's a drone that could fly by itself into confined spaces. It doesn't need light. It maps out the areas, and if it reaches the end, it comes back to you and brings you all that data."
The information collected will help Friends of Sutro Tunnel determine their next move in restoring the old mining site. The goal is to eventually open it and make it a tourist destination.
"We can have tourists and visitors, come out to our site tour the site, use it as an event location and eventually go into the tunnel itself and maybe eventually some day go from here to Virginia City again." said Pattison.
Even though the tunnel isn't open, the site leading to the mine is open for private tours. Historic structures are available for viewing, including a warehouse, machine shop, mule barn and wood shop.
Friends of Sutro Tunnel hopes to start clearing out the tunnel this year, however, they need donations to continue restoration efforts. It could cost more than $300,000.
To learn more about the Sutro Tunnel or donate click here.
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