Review of Samples of Tailings, Soils, and Stream Sediments Adjacent to and Downstream from the Ruth Mine, Inyo County, California

Introduction

The Ruth Mine and mill are located in the western Mojave Desert in Inyo County, California. The mill processed gold-silver (Au-Ag) ores mined from the Ruth Au-Ag deposit, which is adjacent to the mill site. The Ruth Au-Ag deposit is hosted in Mesozoic intrusive rocks and is similar to other Au-Ag deposits in the western Mojave Desert that are associated with Miocene volcanic centers that formed on a basement of Mesozoic granitic rocks. The volcanic rocks consist of silicic domes and associated flows, pyroclastic rocks, and subvolcanic intrusions that were emplaced into Mesozoic silicic intrusive rocks. The Ruth Mine is on Federal land managed by the U.S. Bureau of Land Management (BLM). Tailings from the mine have been eroded and transported downstream into Homewood Canyon and then into Searles Valley. The BLM provided recreational facilities at the mine site for day-use hikers and restored and maintained the original mine buildings in collaboration with local citizen groups for use by visitors. The BLM requested that the U.S. Geological Survey (USGS), in collaboration with Chapman University, measure arsenic (As) and other geochemical constituents in soils and tailings at the mine site and in stream sediments downstream from the mine in Homewood Canyon and in Searles Valley. The request was made because initial sampling of the site by BLM staff indicated high concentrations of As in tailings and soils adjacent to the Ruth Mine. This report summarizes data obtained from field sampling of mine tailings and soils adjacent to the Ruth Mine and stream sediments downstream from the mine on June 7, 2009. Our results permit a preliminary assessment of the sources of As and associated chemical constituents that could potentially impact humans and biota.

The following history of the Ruth Mine is summarized from Julihn and Horton (1937) and Briggs (2007). The Ruth Mine is in the Sherman Mining District, 12 miles north of Trona in Homewood Canyon, on the east side of the Argus Range (coordinates: 35°, 53’, 26.24” N, 117°, 24’, 32.18” W). Doug Graham and Smiley Jones discovered gold in the Canyon in 1899, and shortly after identifying the source, the Graham-Jones mine was formed. The mine operated under control of Jones and Graham until 1937 when they leased the mine to the Burton brothers. The Burton brothers renamed the mine the Ruth Mine in 1937 and upgraded the equipment to produce 70 tons of ore per day. Equipment included a 40-ton vat leaching cyanide mill. Nearby mines, including the Davenport Mine, also owned by the Burtons, transported ore to the Ruth Mill for processing. The mine operated until WWII when order L-208 shut down all gold mining in California. The camp became a ghost town nearly overnight. The Ruth Mine is in an unnamed ephemeral drainage in the Argus Range. Tailings from the mine have migrated downstream toward Searles Valley, to the northeast, during episodes of heavy rainfall. The area, located in the Basin and Range province, consists of short mountain ranges generally trending north-south, separated by valleys filled with quaternary deposits. Ore at the Ruth Mine consists of free gold associated with pyrite in iron-stained quartz stringers in a fissure in quartz monzonite bedrock. Bedrock of the surrounding area mostly is Mesozoic granite, with some Paleozoic marine sedimentary rocks and Pliocene and Pleistocene basalts and pyroclastic rocks. Quaternary alluvium covers much of the area of Homewood Canyon.

First posted April 29, 2011