El Portal Barium Mine (AML), Mitigate Hazards
This project proposes to reduce hazards by more effectively limiting access through surface entrances, reducing hazards and mobility within the mine shafts, and communicating safety hazards to the public. This project proposes to mitigate hazards as follows:
(1) Replacement of the door: The solid steel door currently barring the main entrance to the mine (see file, El Portal Barium Mine Base Map and photo, El Portal Barium Mine Main Entrance) will be replaced with a bat-friendly steel gate. Approximate gate dimensions are 4' wide by 7' tall.
(2) Restoration of barrier fences: The five surface openings (see file, El Portal Mine Base Map) have vertical shafts that are currently surrounded by 6 ft. high chain link fences. These fences have been in place for nearly 50 years and are in poor to fair condition. This project proposes to repair these fences by reinstalling up to five old fence posts in concrete and replacing small sections of chain-link mesh with new mesh (color - flat black). A few small conifer trees and shrubs that grow near the fence will be removed, because they compromise the integrity of the post foundations and enable people to scale the fence more easily.
(3) Installation of external gates: Hinged steel gates (color - flat black) will be installed at surface openings #1 and #5 (see file, El Portal Mine Base Map) to block horizontal, "walk-in" access to the vertical shafts. These gates will be locked for security, designed to be bat friendly and to allow for emergency access if rescue is necessary. Approximate dimensions of gates are 4' wide by 4' tall.
(4) Installation of internal gates: Hinged steel gates (color - flat black) will be installed at two pre determined "pinch points" inside the mine to limit movement should anyone gain access. These gates will be locked for security, designed to be bat friendly and to allow for emergency access if rescue is necessary.
(5) Installation of grates: Fixed steel grates (color - flat black) will be installed over vertical pits at five locations within the mine (see file, El Portal Mine Base Map) to eliminate the risk of falling into the shafts.
(6) Installation of signage: A free-standing interpretive display will be installed near the main entrance to give a brief history of the mine and communicate safety hazards. Caution signs will be posted on fences and gates at up to ten locations at and around the mine site.
Initial funding to mitigate hazards and reduce risk is available through the American Recovery and Reinvestment Act of 2009 (ARRA).
Abandoned mine sites are often difficult and expensive places to work. Work crews will be instructed on how to minimize risk of injury while working at the site.
Subject matter experts from the Archeology & Anthropology, History Architecture & Landscapes (HAL), Wildlife, and Vegetation & Ecological Restoration (VER) branches of Resources Management and Science have been consulted in the development of this project. The project will be implemented following the National Park Service Plan to Minimize the Impacts of Physical Safety Hazard Mitigation Treatments at Abandoned Historic Mines.
The mine shafts provide habitat for several species of wildlife, most notably bats. Wildlife experts will continue to be consulted in the development of this project.
The objective of this project is to mitigate safety hazards at the El Portal Barium Mine, located within the boundary of the El Portal Administrative Site. The mine, in operation from 1910 to 1948, presents hazards of serious injury or death due to deep unobstructed shafts, accessibility of surface entrances, and proximity of the site to the Rancheria residential area. There is extensive evidence that people frequently enter the mine shafts in spite of current barriers.