Empire Mine Collections Care
Empire Mine State Historic Park, located in Grass Valley, California, is the site of one of the oldest, deepest, and richest gold mines in the state. Opened in 1850 and closed in 1956, the mine produced approximately 5.8 million ounces of gold during its 100 years of operation. In 1974 the California State Parks purchase the Empire Mine surface for the creation of a state historic park. The park encompasses 856 acres of forested backcountry and includes many of the mine’s buildings, including the owner’s home, restored gardens, and the entrance to the 367 miles of abandoned and flooded mine shafts. The Empire Mine is on the National Register of Historic Places, a federal Historic District, and a California Historical Landmark.
EverGreene was contracted to perform conditions assessments on and implement comprehensive treatment plans for the Stamp Mill and nine 19th Century wrought and cast iron ore cars with their associated tracks on the property of the Empire Mine State Historic Park. Prior to beginning work, each piece was assessed and pre-treatment reports were created to outline conditions and treatment programs.
Stamp Mill
- Removed general soiling with solution of detergent and water agitated by soft natural bristle brushes. Loosen corrosion products were removed with waterjets at approximately 2,000 to 3,000 psi
- Applied tannic acid solution as a corrosion converter on the metal elements, and allowed to fully dry
- Applied two coats of a microcrystalline wax, buffed using cactus brushes and cotton rags
Iron Ore Cars & Tracks
- Removed deteriorated coating using a combination of solvent based paint strippers and steam
- Removed loosen corrosion products with waterjets at approximately 2,000 to 3,000 psi
- Applied a proprietary corrosion converter and allowed to fully dry
- Applied two coats of a microcrystalline wax, buffed using cactus brushes and cotton rags
- All loose components of the cars were reattached or secured using secure but reversible anchoring devices
