The Sutro Tunnel was completed from the valley near Dayton through nearly four miles, 20,589 feet, of solid rock to meet the Comstock mines approximately beneath the surface. Two drain laterals were dug, the north one 4,403 feet long and the south one 8,423 feet long. The tunnel was wide and high, inside the timbering. Drain flumes were sunk in the floor and over these were two tracks for horse carts. It required eight and a half years to reach the Lode. The tunnel drained up to 4,000,000 gallons daily.