Site Narrative

The Research Mercury Mine is situated in the Middletown Mining District near the headwaters of Dry Creek, a tributary of the Putah Creek watershed.  According to historical records the mine was located about 1870’s and was intermittently active up to the 1950s.  The mine workings which are mostly caved consists of a series of shafts, adits and underground mine workings.  This site and the upstream Chicago Mercury Mine may be contributing mercury-laden sediments to the drainage system which flows into the Putah Creek watershed.

Previous/Existing Assessments

The locations and condition of mine features were collected by the USGS technical team in 2001- 2003 when sediment sampling of retort tails and nearby soils were sampled..

Reclamation/Recommendations

Future remediation plans will entail capping excavation and consolidation of mercury calcine mill wastes.  A Removal Site Investigation (RSI) document has been compiled by an environmental contractor and has documented the release of mercury into the environment.  A pending Engineering Evaluation/Cost Analysis (EE/CA) document will likely propose several remediation alternatives or options, including capping and transport of a minor amount of tailings material.  The tailings capping proposal would minimize runoff into the adjacent wash during storm events as well as minimize air-borne transport of mercury into the adjacent soils and watershed.  The capped mill tailings would be recontoured with native soil and then reseeded with native plants.  A post-remediation monitoring and sampling program would be implemented to determine effectiveness of remediation efforts.  Removal of the remains of the Scott mercury retort furnace will also likely occur.

Estimated Costs

Sampling costs of water, sediment and biota samples downstream of the mine site were incurred as the result of the USGS technical team activities during 2001-2003.

Risks:  Water Quality, Mercury

Location:  Section 1, T10N, R8W, MDBM, Lake County, CA

Field Office:  Ukiah

Congressional District:  01

Collapsed mill site with relict retort below
caved adit and mine dump.