Lining system supports upgrade at northern Nevada mine

AGRU collaborated with a Nevada mine’s stakeholders to supply more than 12.2 million square feet (1.1 million m²) of high-density polyethylene (HDPE) liner to help a mining operation expand its capacity. The project’s proximity to AGRU’s regional plant, the AGRU liner’s welding edges, and the flat-die extrusion manufacturing approach were all touted as benefits that have helped ensure a successful outcome for the project owner. 

Challenge

Modern mining operations rely on low-cost, high-efficiency technologies to keep the project profitable. Often, these mining operations utilize passive heap leaching to separate desired metals from crushed ores. Designing and implementing an effective heap leach pad requires careful planning and a robust and long-term design.

The mine described in this case study results from decades of iteration and improvements. The latest change saw the introduction of an HDPR crusher that supports year-round mining operations. The new crusher is expected to produce a finer product that facilitates cyanide heap leaching of silver and gold from ore, with an estimated 94% recovery for gold.

To achieve reliable, low-cost operations, both the heap leach pad and process pond required a durable and long-lasting containment system. Both would also need to be massive. And to further complicate matters, the expansion occurred during the global pandemic and a tumultuous time in the liner industry.

Solution

AGRU worked closely with the mine’s stakeholders to supply more than 12.2 million square feet (1.1 million m²) of HDPE liner for the leach pad and process pond despite industry shortages. AGRU manufactured 80 mil (2 mm) HDPE double-sided MicroSpike, with about 10.8 million square feet (1.0 million m²) going toward the new heap leach pad. AGRU also supplied about 600,000 square feet (55,700 m²) of 200 mil (5 mm) geonet for pond drainage as well as the geotextile specified for use under the riprap in the stormwater diversion channels and drainage outfall areas.

Because the existing heap leach pad was fast approaching capacity, the mine owners set an aggressive schedule for completing the new pad. The contractor and installers worked with large crews to accommodate the schedule and have consistently beat milestones, thanks in part to the AGRU liner having welding edges that helped streamline installation. MicroSpike also carries the benefit of being manufactured with highly consistent asperities that yield more reliable and predictable interface shear strength.

Outcome

The mine upgrade was completed on November 17, 2021. 

Project Highlights

Lining system supports upgrade at Northern Nevada mine

LOCATION: Northern Nevada 

GENERAL CONTRACTOR: High Mark

SUBCONTRACTOR: International Lining Technology

ENGINEER: NewFields

GEOSYNTHETIC PRODUCTS:

80 mil double-sided MicroSpike®

200 mil AGRU Geonet

AGRUTEX (AT101) 

GEOSYNTHETICS MANUFACTURER: AGRU America, Inc.