Efficient Legacy Pit Dewatering for Closed Mining Operation in California.
Industry – Mining
Metal – Gold & Mercury
Location – Central California, United States
Product/Scope – 3 x Turn-key land-based evaporation systems with environmental management systems
Volume throughput – 4,800 GPM / 1,080 m3/hour
Evaporation efficiency – 30-40%
Application – Legacy pit dewatering
Brief
This case study details the successful implementation of a water management solution at a former gold and mercury mine in Central California, United States. The project involved the supply and commissioning of three turn-key land-based evaporation systems, each integrated with an environmental management system, to address water accumulation in legacy pits. The initiative enabled the facility to manage high water volumes, ensure regulatory compliance, and support mine closure.
Challenge
The mining operation faced environmental challenges due to excessive water accumulation in legacy pits, resulting from groundwater seepage and seasonal rainfall. This water posed risks to the safe closure of the site, creating a potential environmental hazard due to contamination from mercury-laden water. The facility required a high-capacity dewatering solution capable of handling substantial water throughput while maintaining regulatory compliance with environmental regulations. The solution also needed to be cost-effective and adaptable to varying environmental conditions.
Scope
The solution encompassed the supply and commissioning of three turn-key land-based evaporation systems, designed to process a total throughput of 4,800 gallons per minute (GPM), equivalent to 1,080 m³/hour. Each system was equipped with an Environmental Management System (EMS) for autonomous operation, adjusting to environmental parameters such as wind speed and direction. The scope included pumps, pipework, cable packages, and stainless filters, along with comprehensive commissioning, training, ongoing servicing, after-sales support, and troubleshooting to ensure reliable performance and integration with site operations.
Results
The deployed evaporation systems achieved a combined water flow rate of 4,800 GPM, equivalent to 6,912,000 gallons per day (25,920 m³/day). With an estimated evaporation efficiency of 30-40%, the systems removed between 2,073,600 and 2,764,800 gallons (to 10,368 m³) of water daily from the legacy pits. This high-capacity dewatering enabled the facility to maintain production schedules, reduce environmental risks associated with contaminated water, and support site rehabilitation objectives. The Environmental Management System ensured compliance with regulatory standards by autonomously adjusting operations based on site-specific environmental conditions, enhancing operational efficiency and sustainability.