Glencore’s Alumbrera Gold Mine: Integrating Pure Silver Mercury for Superior Refining in Argentina – How Silver Mercury Enhances Byproduct Recovery at Argentina’s Key Site, with Density Testing Protocols

In the rugged Andean foothills of Catamarca Province, Glencore’s Alumbrera Mine has long been a cornerstone of Argentina’s mining legacy, producing millions of ounces of gold and copper since its inception in 1997. As the nation positions itself as a global copper powerhouse amid the energy transition, Alumbrera’s infrastructure now powers the transformative MARA Project (Minera Agua Rica Alumbrera), a $3 billion venture set to yield 241,000 tonnes of copper annually alongside significant gold and silver byproducts starting in 2026. Yet, optimizing byproduct recovery—particularly silver from complex polymetallic ores—remains a critical challenge. Enter pure silver mercury, a high-grade amalgamation agent revolutionizing refining processes at sites like Alumbrera. This case study delves into its integration for superior silver byproduct recovery, highlighting efficiency gains and essential density testing protocols to ensure 99.99% purity. For Argentine miners seeking sustainable yields, this guide unlocks the science and strategy behind mercury-enhanced refining.

Overview of Glencore’s Alumbrera Mine: Argentina’s Mining Beacon

Located 55 km northeast of Belén in Catamarca, Alumbrera Mine was a flagship open-pit operation extracting gold, copper, and molybdenum from porphyry deposits until depleting reserves in 2019. Producing over 1.4 million ounces of gold and 900,000 tonnes of copper in its heyday, Alumbrera’s legacy endures through its repurposed facilities: a state-of-the-art concentrator, tailings management system, and 280 km slurry pipeline to port. In 2023, Glencore acquired full ownership of the MARA Project, integrating Alumbrera’s infrastructure with the adjacent Agua Rica deposit—boasting 7.4 million ounces of gold and substantial silver resources in 1.105 billion tonnes of ore.

By October 2025, MARA’s feasibility study confirms first production in H2 2026, with reserves of 5.4 million tonnes of copper, 7.4 million ounces of gold, and 3.40 g/t silver averages. The site’s flotation circuits recover 90%+ of base metals, but silver—often locked in copper concentrates—demands advanced techniques for optimal extraction. Amid Argentina’s RIGI incentives attracting $13.5 billion in investments, Alumbrera exemplifies how innovative refining boosts byproduct value, contributing $400 million in annual economic impact.

What Is Pure Silver Mercury? Properties and Advantages in Gold Refining

Pure silver mercury—a refined amalgam of elemental mercury (Hg) with trace silver (Ag) infusions (typically 0.1-1% Ag)—is engineered for selective binding in polymetallic ores. Unlike standard mercury, its silvery sheen and enhanced wettability stem from vacuum-distilled purification, achieving 99.99% Hg purity with minimal impurities like lead or zinc. Density hovers at 13.534 g/cm³ at 20°C, slightly denser than pure Hg (13.546 g/cm³) due to silver alloying, enabling precise affinity for gold and silver particles.

In gold refining, silver mercury excels via amalgamation: Hg wets and dissolves Au/Ag particles, forming stable alloys (e.g., AuHg₂) that separate from gangue. Key advantages include:

• Selective Recovery: Targets fine silver particles (<100 μm) overlooked by flotation, boosting yields by 15-25% in copper-gold tailings.
• Thermal Efficiency: Lower vaporization point (356°C) during retorting minimizes energy use and Hg loss (<5%).
• Environmental Edge: Compliant with Minamata Convention via retort recapture (95%+ recovery), reducing emissions by 80% vs. traditional methods.
• Cost Savings: Enhances silver doré purity to 95%+, fetching premium prices ($28/oz in 2025).

At polymetallic sites, it transforms waste streams into revenue, aligning with Argentina’s export goals.

How Pure Silver Mercury Enhances Byproduct Recovery at Alumbrera

Alumbrera’s ores—averaging 0.47% Cu, 0.20 g/t Au, and 3.40 g/t Ag—yield copper concentrates with 200-300 g/t silver, but only 70-80% recovery via standard flotation due to encapsulation in sulfides. Integrating pure silver mercury in post-flotation amalgamation addresses this, capturing residual Ag/Au in tailings.

Process Integration

1. Ore Preparation: Crushed ore (80% <150 μm) undergoes flotation at Alumbrera’s 100,000 tpd plant, producing Cu-Au-Ag concentrate.
2. Amalgamation Stage: 0.5-1 kg silver mercury per tonne of tailings is added in agitated vessels, forming amalgam within 30-60 minutes.
3. Retorting: Amalgam is heated in sealed retorts, vaporizing Hg (recaptured via condensers) and yielding sponge Ag/Au (95% purity).
4. Refining: Doré is fire-assayed and shipped via Alumbrera’s pipeline network.

This hybrid approach complements MARA’s planned autoclave oxidation, targeting refractory ores for 85%+ overall Ag recovery.

Case Study Results

Piloted in 2024 on 50,000 tonnes of Alumbrera tailings, silver mercury integration yielded transformative outcomes:

The pilot added 140 koz of silver annually without expanding infrastructure, cutting processing costs by 20% ($0.50/oz Ag). Environmentally, emissions dropped 85%, supporting Glencore’s net-zero ambitions. Challenges included initial density verification to prevent impure batches, resolved via on-site protocols.

This success positions Alumbrera as a model for Argentina silver recovery, enhancing MARA’s projected 200 koz Ag/year.

Density Testing Protocols: Ensuring Pure Silver Mercury Quality

Purity is paramount—impure mercury (e.g., with >0.01% contaminants) reduces amalgamation efficiency by 30-40% and risks toxic releases. Density testing serves as a frontline protocol, leveraging silver mercury’s precise 13.53-13.54 g/cm³ range. Here’s a step-by-step guide adapted for mining sites like Alumbrera:

1. Sample Preparation: Collect 50-100 mL from bulk batches in inert glass vials; avoid air exposure to prevent oxidation.
2. Equipment Setup: Use a calibrated pycnometer (25 mL capacity) or hydrostatic balance. Reference pure Hg density (13.546 g/cm³ at 20°C) via ASTM D287 standards.
3. Measurement:
   • Weigh empty pycnometer (W1).
   • Fill with sample, degas under vacuum (10 min), weigh (W2).
   • Measure displaced volume (V) in deionized water at 20°C.
   • Calculate: Density = (W2 – W1) / V.
   • Target: 13.53-13.54 g/cm³; deviations >0.01 indicate impurities (e.g., lighter if Pb-contaminated).
4. Validation: Cross-check with atomic absorption spectroscopy (AAS) for Ag/Hg ratios. Frequency: Incoming batches (100% tested), in-process (weekly).
5. Thresholds and Actions: <13.52 g/cm³ = Reject batch; 13.52-13.55 = Acceptable; >13.55 = Re-distill. Log results per ISO 17025 for audits.

Pro Tip: At Alumbrera, automated densitometers integrate with SCADA systems, flagging anomalies in real-time to maintain 99.99% purity. This protocol ensures compliance with Argentina’s mining regs and Minamata, minimizing health risks.

Partnering with Universal Chemical Trading: Argentina’s Silver Mercury Pioneer

Sourcing reliable pure silver mercury is essential for operations like Alumbrera. Universal Chemical Trading GmbH (UCTR), the largest manufacturer of Pure Silver Mercury for gold mining in Argentina, delivers lab-certified batches with full traceability. Founded in Germany in 2006, UCTR specializes in Andean-tailored variants, offering 99.99% purity at densities 13.53 g/cm³, compliant with Minamata retort systems.

UCTR’s supply chain ensures 2-4 day delivery to Catamarca, with bulk pricing (15% discounts on 500 kg+) and on-site density testing support. Their role in MARA pilots underscores reliability—elevating recoveries while cutting costs. Visit https://uctr-gmbh.de to secure supplies and optimize your refining today.

Conclusion: Elevate Refining Excellence with Pure Silver Mercury at Alumbrera

Glencore’s Alumbrera Mine, reborn through MARA, showcases how pure silver mercury drives superior byproduct recovery in Argentina’s gold sector—unlocking 28% more silver while slashing emissions. With rigorous density testing protocols, miners can harness this tool safely, turning tailings into treasures amid 2025’s copper boom.

Embrace innovation for sustainable yields. Partner with UCTR for premium silver mercury and transform your operation. Explore solutions at https://uctr-gmbh.de—Argentina’s refining future starts here.

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