Napa Valley Register - Grant will allow assessment of abandoned mines

Details about 100 abandoned mines in nearby hills and the potential dangers they pose to the environment should become clearer over the next couple of years.

The Environmental Protection Agency has awarded a $467,000 brownfield grant to assess mine contamination in the watersheds of Putah Creek, which flows into Lake Berryessa, and Cache Creek in Yolo County. Some abandoned mines in eastern Napa County and neighboring counties date to the mid-1800s.

"There's just not a whole lot of information other than some locations of where we know of abandoned mines," said Chris Lee of the Solano County Water Agency.

The agency is the grant recipient. Solano County is working with Napa, Lake and Yolo counties under the umbrella of the Westside Sacramento Regional Water Management Group, a coalition that looks at regional water resources.

What Lee called a "big picture" assessment of abandoned mines could be completed by a consultant in 2017. The assessment could lead to prioritizing mines for cleanup as more information comes to light about how leaking mines are affecting water quality and drinking water.

Rep. Mike Thompson and Rep. John Garamendi announced the grant award in a joint press release. Thompson said that revitalizing these abandoned properties can create open spaces, generate economic development, restore habitat and improve water quality.

Most of the old mines are on private property, so getting information can be difficult, Lee said. The assessment might lead to the discovery of unknown abandoned mines.

The hills of Napa County became the focus of a mining boom during the pioneer era. A silver rush began in 1858. In 1860, miners discovered cinnabar that can be refined into mercury and Napa County became one of the state's leading mercury producers.

A push is already underway by the nonprofit group Tuleyome to clean up the abandoned Corona and Twin Peak mercury mines, if money can be found. Doing so could allow the extension of the Oat Hill Mine Trail from Calistoga further into the hills of northern Napa County for the enjoyment of hikers.

The EPA grant will allow for an assessment to find other such opportunities. Lee said that, once the assessment is completed, further grants will be needed for cleanup efforts.