NPS Valgold Ore Processing Area
Restoration of the Valgold Ore Processing Area
History
The Valgold Ore Processing Area is located within the National Park Service’s (NPS) 1.6 million-acre Mojave National Preserve (MOJA or ‘the Preserve’) in San Bernardino County, California. The processing area is located on the eastern slope of the Ivanpah Mountains, in the northern section of the Preserve. Portions of the site were used for the mining and processing of silver and lead carbonate ore as early as the 1870’s. Valgold Mining Company (Valgold) acquired the mining claims in 1972. They constructed the Ore Processing Area and operated it until around 1991, utilizing the Ore Processing Area for acid leaching copper-rich waste rock from both the Bullion Mine and the New Trail Mine. Valgold abandoned the site in 1992. The Mojave National Preserve was established in 1994. Shortly afterwards, the Valgold Ore Processing Area became the first large-scale environmental clean-up in MOJA.
Mojave National Preserve (MOJA) in San Bernardino County, California
The Ore Processing Area was associated with both the Bullion Mine and the New Trail Mine. The Bullion Mine produced both silver and lead carbonate in the 1860’s and then yielded lead, copper, silver ore in 1916 and 1917. Mining activities then declined, and Bullion Mine became idle by 1930.
"New Trail Cabins"
The New Trail Mine included 28 claims and began operations in the early 1900s. There are also two cabins, referred to as the “New Trail Cabins” that are affiliated with the mine. The mine produced gold, silver, and copper between 1929-1950. Additional practices took place until 1951 and the mine became idle around 1953. The Ore Processing Area continued to be used after the abandonment of both the Bullion and the New Trail Mine.
Contamination
The Valgold Ore Processing Area is composed of three areas: the Ore Processing Area, the New Trail Magnesite Mine, and the two cabins area (affiliated with the New Trail Mine).
This image highlights mining features within the Valgold Ore Processing Area that required contamination and waste removal and restoration. These features included leach and plating vats, concrete pads, steel piping, ore piles, and more that are all associated with historical mining and ore processing activities.
Soil and waste rock sampling from a preliminary site inspection performed in 2001 and 2002 showed concentrations of metals, such as antimony, arsenic, cadmium, silver, mercury, copper, and zinc, that exceeded the criteria levels deemed safe for humans and wildlife. More susceptible wildlife included underground dwellers, such as the deer mouse. The levels of cadmium, copper and zinc were of particular concern for these types of native wildlife. A follow-up site inspection in 2005 and final inspection and remediation analysis in 2016 confirmed the action plans needed to restore the area.
Remediation
Photo of leach tank on site
The Department of the Interior (DOI) manages the Central Hazardous Materials Fund (CHF) to coordinate and support the clean-up efforts of environmental contamination sites across the country, to maintain healthy and sustainable public lands. The Department provided CHF funds to the NPS to assist in the remediation process of the Valgold Ore Processing Area.
Investigations into the contamination began in 2001 and continued until 2018 to identify contamination and evaluate the risk it poses to people and the environment. After investigations were completed, NPS prepared a removal action work plan to excavate soil contaminated with metals and dispose of these wastes at a certified, off-site landfill. The priorities of the remediation were the removal of waste debris, contaminated soil, ore-bearing rocks, and structures. This would restore the environment to its previous natural state, providing a safe habitat for native wildlife and plants as well as a place for visitors to enjoy.
Before contamination removal began, an interdisciplinary team was established to work together to ensure the highest care was given to both cultural and natural resources throughout the waste removal and restoration. The Regional Environmental Program Manager worked closely with MOJA to provide oversight and support. MOJA Physical Scientist organized and approved all on-site actions throughout both the removal and the restoration.
MOJA Vegetation Program team identified and helped transplant Joshua Trees, Mojave yuccas, and cacti that could be damaged during contamination removal to a safe location. MOJA Wildlife Biology Program identified all nearby desert tortoise burrows and surveyed for desert tortoise throughout the removal and restoration.
The Vegetation Program, Physical Scientist and Wildlife Biology Program routinely inspected vehicles and machinery to ensure all equipment was clean and free of mud that may contain invasive seeds.
NPS remediation activities excavated a total over 4,000 tons of waste and disposed the material safely in off-site landfills. Once contaminated soil and other waste was removed, NPS brought in clean backfill (from a local source) and recontoured the disturbed areas to match background conditions.
Restoration
After clean backfill soil, NPS prepared the site by recontouring the landscape.
Following the remediation activities at the site, NPS teams worked to restore the land back to its original condition. NPS restoration efforts included planting native Joshua Trees and hydroseeding various other native plants.
Once the Joshua Trees were planted, hydroseeding was completed. Two weeks after hydroseeding, the desert landscape can be seen quickly recovering.
Joshua trees transported to site
Hydroseeding in action (left), hydroseeding complete with joshua trees transplanted (middle), two weeks following the hydroseeding (right).
To protect the newly seeded landscape and delineate the restored area, the MOJA Physical Scientist, Botanist, and other dedicated MOJA employees built fences around restoration areas to facilitate plant growth.
The contamination removal and restoration of the site took place from September 2020 to March 2022. Overall, the planning took 20 years, and the removal of the contaminants took about 2 years.
These images show Valgold Ore Processing Area before (left) and after (right) the remediation and restoration.
The clean-up efforts at Valgold fostered partnerships between the community, federal and state agencies and land use considerations were a large part of the planning, remediation, and restoration processes. The National Park Service developed a community involvement plan (CIP) that included several MOJA Community Outreach meetings. The CIP helped promote valuable public participation, welcomed the community's feedback, and provided updates and details of the restoration of the site.
The Valgold Ore Processing Area is the largest abandoned mine area to be remediated on NPS land in the Mojave Desert. The successful restoration of the Valgold Ore Processing Area is due to the hard work of many involved in this committed NPS project and exemplifies how restoration can protect natural resources, the community, and wildlife habitats.
