Water scarcity is the single greatest operational constraint facing mining companies in South America. Chile, Peru, and Argentina host some of the world’s largest copper, lithium, and gold operations — and nearly all of them sit in regions where annual evaporation vastly exceeds annual rainfall. When a 10-acre tailings pond or heap leach solution basin loses tens of millions of gallons per year to evaporation, the financial and regulatory consequences compound rapidly.
Modular floating covers offer a proven, field-tested solution. At AWTT, we have completed over 700 installations across 25 countries, deploying more than 20 million square feet of floating cover systems — including in the extreme UV, wind, altitude, and chemical conditions that define South American mining.
The Water Crisis in South American Mining
Chile produces nearly 30% of the world’s copper. Peru is the second-largest copper producer and a major gold and zinc exporter. Argentina’s lithium triangle holds some of the planet’s most valuable brine deposits. All three countries share a common problem: their most productive mining regions are among the driest places on Earth.
The Atacama Desert in northern Chile receives less than 15 mm of rainfall per year in many locations — effectively zero. Mining operations in the Atacama, the Peruvian coastal desert, and the Argentine Puna plateau routinely operate above 3,000 meters elevation, where thin atmosphere, intense solar radiation, and persistent wind accelerate evaporation far beyond what operators in temperate climates expect.
Regulatory pressure is tightening. Chile’s Water Code reforms and the establishment of the Superintendencia del Medio Ambiente (SMA) have increased enforcement of water extraction limits. Peru’s National Water Authority (ANA) has imposed stricter conditions on mining water permits, particularly in watersheds shared with agriculture and communities. In Argentina, provincial water authorities in Salta, Jujuy, and Catamarca are scrutinizing lithium brine extraction rates and their impact on local aquifers.
For mine operators, every gallon of water lost to evaporation is a gallon that must be replaced — at increasing cost and increasing regulatory difficulty.
Where Mines Lose Water
Evaporation losses in mining are not confined to a single point. Water escapes from multiple open-surface facilities across a typical mine site:
- Tailings storage facilities (TSFs): The largest surface area exposure at most mines. Conventional slurry tailings create expansive ponds that can span hundreds of acres. Even filtered tailings operations maintain supernatant water ponds that lose significant volume.
- Heap leach solution ponds: Pregnant leach solution (PLS), intermediate leach solution (ILS), and barren solution ponds hold chemically active water critical to metal recovery. Evaporation from these basins directly reduces process efficiency.
- Process water tanks and reservoirs: Make-up water reservoirs, raffinate ponds, and reclaim water basins all present open surfaces.
- Evaporation ponds: Some operations intentionally evaporate water to manage water balance — but uncontrolled evaporation from other facilities creates an unplanned deficit that these ponds cannot compensate for.
- Thickener overflow basins: Clarified water held in overflow basins before recirculation is exposed to the same atmospheric conditions as every other open surface on site.
The cumulative effect is substantial. A mine with 40 acres of combined open water surface in the Atacama can lose over 100 million gallons per year to evaporation alone. That volume often exceeds what the mine is permitted to extract from fresh sources.
Evaporation Rates in Arid and High-Altitude Regions
The numbers are stark. Annual evaporation rates across South American mining regions typically fall in these ranges:
| Region | Elevation | Annual Evaporation Rate | 10-Acre Annual Loss |
|---|---|---|---|
| Atacama Desert (Chile) | 2,000–4,500 m | 2,500–3,200+ mm (98–126 in) | 65–84 million gal |
| Peruvian Coastal Desert | Sea level–2,500 m | 1,800–2,500 mm (71–98 in) | 47–65 million gal |
| Argentine Puna / Lithium Triangle | 3,500–4,500 m | 2,200–3,000 mm (87–118 in) | 57–78 million gal |
| Central Chile (Copper Belt) | 1,500–3,500 m | 1,500–2,200 mm (59–87 in) | 39–57 million gal |
At the extreme end, Class A pan-equivalent evaporation in the Atacama exceeds 3,000 mm per year. Even applying a conservative pan coefficient of 0.7, free-water surface evaporation still exceeds 2,100 mm annually.
High altitude intensifies losses through multiple mechanisms: lower atmospheric pressure reduces the energy required to vaporize water, thinner air offers less resistance to vapor diffusion, and solar radiation intensity increases approximately 10–12% per 1,000 meters of elevation gain. Combined with persistent wind and extremely low humidity, these factors create evaporation rates that rival or exceed the hottest low-elevation deserts.
For context, a 10-acre uncovered pond in the Atacama losing 3,000 mm/year is giving up approximately 80 million gallons annually — enough to fill 120 Olympic swimming pools.
Challenges Unique to Mining Environments
Covering a mine’s water surfaces is not the same as covering a municipal reservoir. Mining sites present a combination of environmental and operational challenges that eliminate most conventional cover technologies:
Extreme UV radiation at altitude. Solar UV intensity at 4,000 meters is roughly 40% higher than at sea level. Standard plastics degrade rapidly under these conditions. Cover materials must resist UV-induced embrittlement over decades, not years.
High wind exposure. Open pit mines and tailings facilities in the Andes corridor are routinely subjected to sustained winds of 40–60 mph with gusts exceeding 80 mph. Any cover system that can be displaced by wind is not viable for mining.
Chemically aggressive water. Heap leach solutions operate at pH 1.5–2.5 (sulfuric acid leaching) or pH 10+ (cyanide leaching for gold). Tailings water contains dissolved heavy metals — copper, arsenic, molybdenum, selenium — at concentrations that corrode many materials. Raffinate ponds, PLS ponds, and acid mine drainage (AMD) channels all present aggressive chemical environments.
Large and irregular pond geometries. Tailings facilities are rarely uniform rectangles. They follow topography, expand over time, and change shape as deposition patterns shift. A cover system that requires precise dimensional fabrication or rigid structural support cannot adapt to these realities.
Remote locations with limited infrastructure. Many Andean mines are 4–8 hours from the nearest city, at elevations where heavy equipment operation is limited and labor availability is constrained. Installation methods that require cranes, divers, or specialized welding crews face severe logistical and cost penalties.
Seismic activity. Chile and Peru sit on the Pacific Ring of Fire. Tailings facilities must be designed to withstand significant seismic events. Any cover system anchored rigidly to embankments or berms introduces failure points during earthquakes.
Why Modular Floating Covers Work for Mining
Modular floating cover systems — individual interlocking units deployed directly onto the water surface — address every challenge listed above. This is why they have become the preferred evaporation control technology for mining operations in seismically active, chemically aggressive, high-altitude environments.
No anchoring required. Modular covers float freely on the water surface. They are not attached to embankments, berms, or structural anchors. During a seismic event, the covers move with the water rather than resisting it. There are no attachment points to fail, no tensioned cables to snap, and no rigid structures to crack. This is a decisive advantage over geomembrane covers in seismic zones.
Chemical-resistant HDPE construction. High-density polyethylene is chemically inert across the full range of mining water chemistry. AWTT’s covers operate reliably from pH 2 to pH 13, tolerating sulfuric acid leach solutions, cyanide-bearing process water, and high-TDS brine. HDPE does not corrode, does not leach plasticizers, and does not react with dissolved metals.
Tool-free installation in remote locations. Modular units are shipped flat or nested, then deployed by hand directly onto the water surface. No cranes, no welding, no specialized equipment. A small crew can cover an acre per day. For remote Andean mine sites where mobilizing heavy equipment costs tens of thousands of dollars per day, this logistical advantage translates directly to lower installed cost.
Adapts to irregular geometries. Individual modules conform to any pond shape — curved embankments, irregular shorelines, around instrumentation, inlet/outlet structures, and monitoring equipment. As a tailings pond expands, additional modules are simply added to the perimeter.
Minimal maintenance. Once deployed, modular covers require no tensioning, no pump systems, no ballast management, and no maintenance crew. They self-adjust to changing water levels, accommodate wave action, and tolerate debris without damage.
For a detailed comparison of modular systems versus traditional geomembrane covers, see our technical comparison guide.
Best AWTT Products for Mining Applications
AWTT manufactures three product lines specifically suited to the demands of mining environments. Product selection depends on wind exposure, required coverage, chemical conditions, and whether personnel access to the covered surface is needed.
Rhombo Hexoshield 66
The Rhombo Hexoshield 66 is AWTT’s heaviest-duty modular cover and the preferred choice for large tailings facilities and heap leach ponds in high-wind, high-altitude environments.
- Wind resistance: Rated to 130 mph — validated in open-exposure installations at altitude
- Buoyancy: 25 lb/ft² load capacity, sufficient to support personnel walking on the covered surface for inspection and sampling without auxiliary flotation
- Coverage: 99% surface coverage with interlocking hexagonal geometry
- UV stabilization: Formulated for extreme UV environments with a 25+ year service life
- Chemical resistance: Full HDPE construction, pH 2–13
The 25 lb/ft² buoyancy rating is particularly valuable for mining. Environmental monitoring protocols often require personnel to access tailings pond surfaces for sampling. The Rhombo Hexoshield 66 supports this without removing cover sections or deploying boats.
Hexprotect AQUA
The Hexprotect AQUA delivers comparable wind resistance (130+ mph) and 99% coverage in a lighter-weight profile suited to process water ponds, thickener overflow basins, and solution ponds where personnel access to the surface is not required.
- Wind resistance: 130+ mph
- Coverage: 99%
- Profile: Lower profile than Rhombo Hexoshield, reducing shipping volume for remote sites
- Chemical resistance: Full HDPE, pH 2–13
- Evaporation reduction: Up to 95%
For mines managing dozens of smaller process water basins, the Hexprotect AQUA provides the optimal balance of performance and deployed cost per square foot.
Armor Ball AQUA
The Armor Ball AQUA is a spherical floating cover unit best suited to moderate-wind basins, settling ponds, and water storage reservoirs where 91% coverage and up to 90% evaporation reduction meet operational requirements.
- Coverage: 91% (spherical geometry)
- Evaporation reduction: Up to 90%
- Deployment: Fastest installation of any AWTT product — pour from bulk containers directly onto the water surface
- Best for: Secondary process ponds, settling basins, and water storage where full wind resistance is not the primary design criterion
For complete product specifications, see the AWTT product catalog and technical data sheets.
Chemical Compatibility
HDPE is one of the most chemically resistant thermoplastics available. AWTT’s covers are manufactured from virgin high-density polyethylene with UV stabilizer packages engineered for long-term outdoor exposure.
Operating temperature range: -70 degrees F to +160 degrees F (-57 degrees C to +71 degrees C). This range covers every mining environment from high-altitude overnight freezing to direct equatorial solar exposure on dark surfaces.
Chemical resistance highlights relevant to mining:
- Sulfuric acid (all concentrations encountered in heap leaching)
- Hydrochloric acid
- Sodium hydroxide / caustic soda
- Sodium cyanide solutions (gold processing)
- Ferric chloride and ferric sulfate
- Dissolved copper, arsenic, molybdenum, selenium, and other heavy metals
- High-TDS brine (lithium extraction)
- Diesel, hydraulic fluid, and other incidental hydrocarbon contamination
HDPE does not absorb water, does not swell, does not become brittle in cold, and does not soften meaningfully at temperatures encountered in open-air mining. It is inert to biological activity — it will not support algae growth, biofilm formation, or microbial degradation.
Environmental Compliance and Regulatory Benefits
Mining operations face increasing regulatory scrutiny over water consumption, wildlife impacts, and contaminated water exposure. Modular floating covers contribute measurably to compliance in all three areas.
Water conservation targets. Chilean and Peruvian regulators increasingly require mines to demonstrate water efficiency measures as a condition of operating permits and environmental impact assessment (EIA) approvals. A floating cover that reduces evaporation by 90–98% is a documented, quantifiable water conservation measure that satisfies regulatory expectations.
Wildlife mortality reduction. Uncovered tailings ponds and process water basins attract migratory birds. Contact with cyanide-bearing, acidic, or heavy-metal-laden water is frequently lethal. Floating covers act as a physical bird deterrent — the covered surface eliminates the visual cue of open water and prevents landing. This addresses requirements under national wildlife protection laws and international frameworks such as the International Cyanide Management Code.
Reduced acid mine drainage exposure. Covering AMD collection ponds and channels reduces atmospheric oxygen contact with exposed sulfide-bearing water, slowing oxidation reactions that generate additional acidity. It also prevents rainfall dilution that can cause uncontrolled overflow events.
Dust and VOC suppression. In some mining processes, covered ponds reduce volatile emissions and wind-blown particulate from exposed tailings surfaces.
For operations pursuing ESG reporting, ISO 14001 certification, or compliance with the International Council on Mining and Metals (ICMM) performance expectations, floating covers provide documented, auditable environmental performance data.
ROI for Mining Operations
The return on investment for floating covers in South American mining is driven by three primary factors:
Water replacement cost. In the Atacama, delivered water can cost $5–$15 per cubic meter depending on source, transport distance, and treatment requirements. Desalinated seawater — increasingly the only permitted new water source for Chilean copper mines — costs $3–$8 per cubic meter at the coast, plus $2–$6 per cubic meter for pipeline transport to altitude. At these rates, a 10-acre covered pond saving 60+ million gallons per year represents $700,000 to $3,000,000+ in avoided annual water cost.
Regulatory compliance. A single water permit violation or EIA non-compliance finding can result in operational suspension, fines, and multi-year permitting delays. The cost of a floating cover system is a fraction of the cost of a single month of lost production at a major copper or gold operation.
Operational continuity during drought. South American mining regions are experiencing increasing drought frequency and severity. Mines that conserve process water through evaporation control maintain operational throughput during periods when water-constrained competitors must curtail production.
Most mining installations achieve full payback within 12–24 months. For operations paying desalinated water rates at altitude, payback can occur in under 12 months.
Use our ROI and savings calculators to model your specific site conditions.
AWTT’s Global Reach in Extreme Environments
AWTT has deployed floating cover systems across 25 countries and 700+ installations, totaling more than 20 million square feet of covered surface area. Our installations operate in every climate zone — from sub-arctic to equatorial, from sea level to high altitude, from freshwater reservoirs to the most chemically aggressive industrial process water.
This global experience means that when a mining engineer in Antofagasta, a lithium operator in Salta, or an environmental manager in Cajamarca evaluates floating covers, they are not looking at an unproven technology. They are looking at a system with decades of field performance data across the full range of environmental conditions that South American mining presents.
We provide site-specific engineering support, shipping logistics for remote locations, and installation guidance for crews working at altitude. Every project benefits from the cumulative knowledge of 700+ deployments worldwide.
Next Steps
If your operation is losing water to evaporation — whether from tailings facilities, heap leach ponds, process water basins, or any other open surface — the path forward is straightforward:
- Quantify your losses. Use our free evaporation and savings calculators with your site coordinates and pond dimensions.
- Review product options. Compare specifications across the full AWTT product line and download technical data sheets for your engineering team.
- Explore mining-specific solutions. Visit our mining industry page for case studies and application guidance.
- Contact our team. Request a consultation with an AWTT application engineer who understands South American mining conditions.
Water lost to evaporation is water that never reaches your process, never supports your production, and never satisfies your permit obligations. In the driest mining regions on Earth, that loss is no longer acceptable — and it is no longer necessary.