Mining District Waste Removal

The Sulphur Creek Mining District, active mainly from 1880 to 1890, encompasses approximately 465 acres within the Sulphur Creek watershed in Colusa County, California. This area hosts six distinct mine sites, several of which sit directly adjacent to Sulphur Creek.
 
These sites contained a variety of materials including calcine tailings, waste rock, mercury-enriched soils, ore, miscellaneous waste piles, and remnants of mining equipment and structures. Homestake Mining Company enlisted our team for mine reclamation to excavate, haul, and deposit material into an on-site repository.
 
The primary goal was mine reclamation through permanent hazardous waste containment, thereby preventing migration into Sulphur Creek, and performing necessary environmental remediation and erosion control. Additionally, addressing groundwater remediation was crucial to prevent contamination from affecting the broader watershed.
 
The challenging terrain, with elevations ranging from 1,400 to 1,640 feet above sea level, presented significant hurdles for accessing and working on this heavy civil construction site. Compounding these challenges was the need to manage the proximity of a nearby hot spring, which required establishing an alternative route for equipment mobilization and demobilization.
 
We extensively planned to uphold our safety standards in all aspects of operation amid these environmental and logistical complexities.

To facilitate the project, we made substantial improvements to a two-mile-long access road. This included enhancing its infrastructure to accommodate heavy machinery such as a Komatsu PC 400 excavator and 4,000-gallon water trucks.

We also installed two rail car bridges using 20-ton cranes. Since the road’s entrance was connected to an active highway, we implemented strict traffic control measures approved by Caltrans.

The project team executed a comprehensive radio communication plan to manage heavy equipment traffic on the narrow, single-lane road. Additionally, we created a marker system to enable drivers to communicate their road locations via radio, enhancing safety and coordination.

Despite additional complexities, including navigating the bat breeding season and accommodating a nearby resort’s event schedule to limit disruptions, we maintained operational efficiency. We implemented strategies to minimize equipment mobilization and demobilization, thereby mitigating associated costs.

Moreover, we used an innovative, cost-effective sound barrier solution to address ecological concerns related to local bat habitats within the mine sites. This ensured effective erosion control measures were in place.

Groundwater remediation was another critical component of our solution. We implemented measures to prevent contaminated water from the site from leaching into the groundwater system, protecting the broader watershed from mercury and other hazardous materials.

The project’s successful execution resulted in excavating, hauling, and placing 17,000 cubic yards of hazardous waste within the designated on-site repository. This achievement included the permanent containment of mercury-containing hazardous mine waste, effectively safeguarding Sulphur Creek from potential contamination.

The improved access road not only facilitated safe and efficient equipment operations but also met rigorous Caltrans traffic control standards. The project’s radio communication plan was crucial in managing heavy equipment traffic seamlessly on the challenging terrain.

Additionally, our adaptive strategies during sensitive environmental periods showcased our commitment to sustainable practices and ecological stewardship. By incorporating effective erosion control measures, we enhanced the project’s overall success and mitigated environmental impact.

The groundwater remediation efforts ensured that hazardous substances did not infiltrate the water table, protecting the surrounding environment from long-term contamination. This comprehensive approach to mine reclamation has significantly contributed to the long-term safety and sustainability of the Sulphur Creek watershed.