By Dennis Cassinelli
Several times over the past few years, II have visited the town of Sutro and became the formal publicist for the Friends of Sutro Tunnel organization.
On my first visit to SUtro the Sutro Mill was still standing. It has sicce burned down. I have written several articles about the Sutro Tunnel, including the story about General Grant and President Hayes traveling through the Sutro tunnel and up the elevator yo visit Virginia City.
Sutro tunnel, north of Dayton collapsed about 20 years ago, more than 100 years after it was built. Because of blockades of collapsed timbers at the entrance, no one can go inside, but even if they could, it would not be safe. So now, instead of sending people on a mission to explore the unknown, EROCK Associates has launched drones to explore the inside of the tunnel. The company was hired to investigate the interior of the tunnel and gather data.
The diameter of the 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 capable of going into the tunnel as far as 500 feet.
“The drone will go in the tunnel and surmise if the air quality is safe for humans to breathe and if the ground conditions are okay” said Eric Bennet, the owner of EROCK 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 with very high accuracy to show the conditions” said Bennet. “It does not need any connectivity to do it’s job. It is a drone that could fly by itself into confined spaces above collapsed rubble. It does not need light. It maps out the areas, and if it reaches the end, it comes back to you and brings you all the data.
The information collected will help the Friends of Sutro Tunnel determine their next move in restoring the old mining site. Their goal is to eventually open it up and make it a tourist destination.
“We can can have tourists and visitors come out to tour the site, use it as an event location and eventually go into the tunnel itself and perhaps eventually go from the portal to Virginia City again” said Chris Pattison, Project Manager.
Even though the tunnel isn’t open, the site leading to the mine is open for private tours. Historic structures and artifacts are available for viewing, including a warehouse, machine shop, mule barn and wood shop.
This article is edited by Dayton Author and Historian, Dennis Cassinelli. You can order his books at a discount on his blog at  Just click on ”order books”