Katherine Mine Site Main Shaft Stabilization

Lake Mead National Recreation Area » Katherine Mine Site Main Shaft Stabilization » Document List

The primary purpose of this project is to protect the visiting public from the hazards associated with the Katherine mine site. In recent years areas in the ground have begun to open up. A geotechnical firm conducted ground penetrating radar surveys to indicate any voids (underground mine workings) at the mine site. Several large void areas were discovered just under the rock surface; however more funds are required to perform a larger comprehensive site survey. The interim plan is to construct a fence around the mine site area to keep visitors safe from the void areas associated with this site.

Also on the site is a previously fenced area that contains an open shaft that accesses the main underground workings. This proposal also addresses stabilizing this shaft. The wooden support collar in the shaft opening is deteriorating and falling down into the shaft, creating unstable ground surrounding it. The dirt and rock supported by the collar is starting to collapse into the shaft, reducing the size of the shaft opening. The shaft opening needs be stabilized to maintain maximum opening size to accommodate the approximately 3,000 bats that use it to exit the underground mine workings. A new wooden support structure (collar) would be constructed in the shaft to stabilize the opening and surrounding area. Polyurethane Foam (PUF) would be used to fill in behind the collar for addition support and strength. Approximately, two feet of dirt would be backfilled on top of the PUF.