The Nelson Tunnel, located in West Willow, was an engineering feat within the Creede Mining District. It linked the principal mines along the Amethyst Vein and turned their workings into a complex ore extraction system. The Tunnel should more accurately be named the Nelson-Wooster-Humphries Tunnel and connected the Bachlor, Last Chance, New York, Amethyst, and Park Regent Mines by 1902. In total the tunnel was 11,000 feet long! It was later connected to the Commodore No. 5 and was used by miners until the 1950’s. The rail line within the tunnel ran from the portal to the lower Willow Creek floodplain, south of Creede.
The Commodore Mine was also a network of underground workings linking the Commodore No. 1 mine and the Commodore No. 5. The entrepreneurs of this operation were in direct competition with the Nelson Tunnel operation. Mining began in 1892 and continued until 1972 and was the Creede Mining District’s longest and most extensive mine.
Since the first water sampling event in 1999, it has been recognized that the underground workings of the Amethyst Vein Complex, which discharge through the Nelson Tunnel at approximately 250-300 gpm, are the greatest contributors of heavy metals in the watershed. As the lowest tunnel with a portal, the Nelson acts as the recipient and discharge area for all surface and subsurface water entering the mine workings. The Nelson Tunnel adit accounts for 50% of the metal loading within the Willow Creek Watershed.
In 2005, a less-than-20- year flood set loose cribbing, waste rock and other debris down the West branch of Willow Creek from the Commodore/Nelson Tunnel area. The flood caused the destruction of a drainage channel designed to prevent the release of contaminants into West Willow Creek. These events prompted the USEPA listing of the site on the National Priorities List (NPL) in 2008. See photos of the flood below.
Since that time, the WCRC has worked with the USEPA, the Colorado Department of Public Health and Environment (CDPHE) and Colorado Division of Reclamation Mining and Safety (CDRMS) to investigate the workings of the Nelson Tunnel and divert West Willow Creek away from the Commodore Waste Rock Pile.
In December of 2000, the Willow Creek Reclamation Committee (WCRC) began underground investigations of the Amethyst Vein Complex, accessed through the Commodore 5 Level Tunnel, in the hopes of determining the source and hopefully a solution for the metal laden discharge at the Nelson Tunnel portal. The Amethyst Vein Complex encompasses the Nelson/Wooster/Humphries Tunnel, Amethyst Mine, Happy Thought Mine, Park Regent Mine, Commodore Mine and the Last Chance Mine. All of these mines are located along the Amethyst vein system, which is a north-south trending fault that is heavily mineralized. The Nelson/Wooster/Humphries Tunnel, which will be referred to as the Nelson Tunnel for convenience, appears to be the single largest discharge point to the surface for all water entering the Amethyst Vein Complex. The Nelson Tunnel drains into Willow Creek approximately ½ mile above the confluence with East Willow Creek. As shown by ongoing water quality characterizations of Willow Creek by the WCRC, the Nelson Tunnel drainage, averaging 250 gpm, remains the single largest heavy metals contributor to the watershed.
The Nelson Tunnel and Commodore 5 Tunnel were driven by competing mining interests to gain access to the rich silver deposits along the Amethyst Vein Complex. Eventually the Nelson Tunnel became the drainage tunnel for all subsurface water entering the mine workings. The Nelson Tunnel is located approximately 40 feet lower in elevation than the Commodore 5 tunnel at their respective entrances. Approximately 3 miles north of the entrances, the two mine entries converge near the Park Regent shaft. There are several intermediate connections including the Daylight Corner Winze, Javelin Shaft (winze), Berkshire Shaft (winze), Commodore Shaft (winze), No Name Winze, Last Chance Shaft, Amethyst Shaft, Del Monte Raise, Berkshire Shaft (winze), Happy Thought Shaft and Hospital Decline.
Because of the large cost to treat the mine drainage, the WCRC decided to investigate whether the source of the mine drainage can be intercepted before it enters the mine workings and/or whether the metals concentrations can be reduced through source controls.
During 2004 the WCRC initiated the process of pursuing the possibility of source controls on the Nelson Tunnel drainage with the Nelson Dewatering Pilot Project. If the pilot is successful, and the necessary funding for full dewatering is found, then the WCRC will be able to implement full dewatering in hopes of solving the Nelson water source. The source of water creating the Nelson drainage and its entry point into the mine remain the missing link in understanding and hopefully implementing a successful source control.
In 2005, work on the dewatering project (DALC) was successfully funded and implemented! You can view the DALC project in the video below. Additionally, the mine workings are currently being monitored for any maintenance and safety needs. Water levels are taken periodically to further establish long-term water trends within the mine. Water quality sampling within the mine should not be a priority unless new discrete inflows are discovered. Finally, additional work at the Commodore Mine should address the Nelson Portal flume and portal collapse, to ensure accurate flow measurements and alleviate portal blowout concerns. This coming year could prove to be an exciting time of discovery and progress within the Commodore Mine Complex!
2005 WILLOW CREEK FLOOD
In 2005, a less-than-20- year flood set loose cribbing, waste rock and other debris down the West branch of Willow Creek from the Commodore/Nelson Tunnel area. The flood caused the destruction of a drainage channel designed to prevent the release of contaminants into West Willow Creek. These events prompted the USEPA listing of the site on the National Priorities List (NPL) in 2008.
DEWATERING OF NELSON TUNNEL, AMETHYST MINE & LAST CHANCE MINE
DECEMBER 2006 – JUNE 2011
The Nelson Tunnel Pilot Dewatering and Amethyst, Last Chance Waste Pile Best Management Practices (DALC Project) was a complex project with a multitude of tasks. The Colorado Division of Reclamation, Mining and Safety (CDRMS) performed the dewatering pilot in 2007 and gained a better understanding of the hydrogeology within the mine complex, the water chemistry, and source of water. WCRC implemented BMPs for the Amethyst and Last Chance waste rock piles to reduce run-off, and build retaining walls to limit direct contact with West Willow Creek.