Gold Processing Guide: From Ore to Final Product

Summary：A complete guide to gold processing, covering plant construction from exploration to operation. Learn about key beneficiation methods like cyanidation and flotation for maximum recovery.

Understanding Gold

Gold, the world's most valuable and alluring precious metal, has symbolized wealth and stability since ancient times. In modern mining and financial systems, gold serves not only as an anchor asset for monetary systems but also as a critical raw material for industrial manufacturing, jewelry processing, and high-tech industries. Its stability, high ductility, and corrosion resistance make gold a vital safeguard for long-term returns and risk mitigation in mining investments.

Gold's Natural Forms: Primary and Secondary Gold

Gold deposits are classified into three main types, each with distinct geological conditions, grades, and beneficiation processes.

Primary Gold

Secondary Gold

Global Gold Deposit Distribution

As of 2024, the global annual gold mine production is approximately 3,600 tonnes, with mineable reserves estimated at around 59,000 tonnes. Gold resources are widely distributed and concentrated in countries such as Australia, Russia, China, Canada, and the United States. Meanwhile, Africa, with its rich mineral potential and favorable investment policies, has become an emerging hub for global mining investment.

Gold Processing Plant Construction Workflow

Plant construction is a complex, multidisciplinary project requiring significant capital and long execution cycles. It must follow rigorous scientific planning to ensure technical feasibility, economic viability, and ESG compliance.

1. Exploration

Objective: Define ore body distribution, grade, and reserves for scientific decision-making.

Key Activities:

• Desktop Research: Analyze geological data, maps, and literature to identify targets.
• Field Mapping & Sampling: Conduct detailed geological surveys.
• Geophysical/Geochemical Surveys: Use airborne magnetics/GPR to detect deposits.
• Drilling: Obtain core samples for testing and resource estimation.
• Resource Estimation: Create 2D/3D models estimating size, grade, and viability.

Deliverable: Mineral Resource/Reserve Report.

2. Planning & Design

Objective: Design efficient, economical, and safe production lines.

Key Activities:

• Feasibility Studies: Assess economic and technical viability.
• Permitting & Financing: Secure environmental permits and funding.
• Mine Design: Plan infrastructure, access routes, mining methods (open-pit/underground), Extraction Design, Beneficiation Design and Taillings Design.
• Site Preparation: Construct access roads, facilities, and clear overburden.

Deliverable: Feasibility Study Report, Mine Design

3. Construction

Objective: Ensure high-standard construction for rapid commissioning.

Key Activities:

• Procurement: Global sourcing of crushers, ball mills, flotation cells, thickeners, filters, pumps, valves, automation systems.
• Civil Works: Site leveling, roads, plant foundations, structural erection, starter dam for tailings storage facility (TSF).
• Equipment Installation & Commissioning:
  • Install and align crushing, grinding, separation, thickening, and filtration equipment per process flow.
  • Install piping, electrical, and automation systems.
  • Single-equipment testing: Verify individual unit operation.
  • Load testing: Run with ore/water, gradually ramp up to design capacity and metrics.

Deliverable: Commissioned plant with feed.

4. Operation & Maintenance

Objective: Safe, stable, efficient, low-cost operation.

Key Activities:

• Ore Mining & Haulage:
  • Drilling & Blasting: Fragment rock for excavation.
  • Loading & Hauling: Transport ore to plant via excavators/trucks.
• Production: Run crushing, grinding, separation, thickening, filtration per design. Control key parameters (grind size, reagent dosage, flotation time, thickener density).
• Maintenance: Regular inspections, servicing, and part replacement to minimize downtime.
• Quality Control: Test feed, intermediates, and concentrate; adjust processes to meet specifications. Safety Management: Implement protocols, training, PPE, and emergency response systems.

Deliverable: Achieved production targets.

5. Sales & Logistics

Objective: Fast, secure, low-cost value conversion.

Key Activities:

• Quality Assaying: Joint sampling/preparation/assay to determine final grade for settlement.
• Sales Agreement: Long-term contracts based on market prices.
• Concentrate Transport: Ship via truck/rail/sea with protective measures to preserve quality.

Deliverable: Revenue realization.

6. Tailings Management & ESG

Objective: Integrate safety, environmental responsibility, and social compliance.

Key Activities:

• Tailings Discharge: Tailings generated during production are transported via pipelines or other means to the Tailings Storage Facility (TSF) for storage.
• TSF Management: Continuously monitor dam stability, seepage, and water quality; simultaneously implement necessary environmental protection measures such as installing impermeable liners and constructing wastewater treatment facilities to prevent pollution.
• Tailings Comprehensive Utilization: Reprocess or otherwise comprehensively utilize tailings to recover valuable elements, or use them as construction materials, for backfilling mined-out areas, etc., thereby reducing tailings stockpiling, minimizing environmental impact, and maximizing resource utilization.
• Ecological Rehabilitation: Upon reaching design capacity, close and ecologically reclaim the TSF through vegetation restoration and landform recovery.

Common Gold Beneficiation Processes

Process selection depends on ore type, liberation size, mineralogy, and economics. Primary routes include Gravity Separation, Flotation, Cyanidation, and Combined Processes.

Gravity Separation

Applicability: Ideal for placer deposits and hard-rock ores with coarse liberated gold. Requires coarse particles, significant density differences, and low clay content (e.g., alluvial, glacial deposits).

Principle: Leverages gold's high density (~19.3 g/cm³) vs. gangue. Separation occurs via fluid dynamics/centrifugal force in gravity concentrators.

Typical Flow:

• 1.Primary Crushing & Screening (remove waste rock)
• 2.Gravity Concentration (Spiral Chute / Jig / Shaking Table)
• 3.Concentrate Upgrading & Thickening → High-grade gold concentrate.
• 4.Tailings: Recirculate or send to flotation/cyanidation.

Pros: Low cost, simple, no chemicals, direct recovery: 85%-90%.

Cons: Poor recovery of fine gold; limited effectiveness for clay-rich or encapsulated gold.

Flotation

Applicability: Primary method for medium/fine gold and sulfide-associated gold (pyrite, chalcopyrite, sphalerite). Used in ~20% of global gold projects for lode or complex ores.

Principle: Exploits differences in surface hydrophobicity. Reagents (collectors/frothers) render gold/sulfides hydrophobic, attaching them to air bubbles for froth recovery.

Typical Flow:

• 1.Crushing & Grinding (to -200 mesh, 60%-80% passing).
• 2.Roughing: Add collectors/frothers; produce bulk concentrate.
• 3.Cleaning: Upgrade concentrate grade.
• 4.Scavenging: Recover residual gold from tails. 5.Concentrate: Direct smelting or cyanidation.

Pros: Effective for fine/encapsulated gold.

Cons: Complex; requires chemicals; higher operating costs & environmental controls.

Cyanidation

Applicability: Dominant global gold extraction process (>90% of gold). Suitable for most ores, including low-grade oxides, fine gold, and flotation concentrates.

Principle: Gold dissolves in alkaline cyanide solution forming [Au(CN)2]- complex. Recovered via carbon adsorption (CIP/CIL) or zinc precipitation.

Typical Flow:

• 1.Crushing & Grinding (to -200 mesh, 80%-90% passing).
• 2.Cyanide Leaching (CIL/CIP): Gold dissolves into solution.
• 3.Adsorption/Elution: Activated carbon adsorbs gold complex; eluted & electrowon to gold mud.
• 4.Smelting → High-purity gold.

Pros: Mature technology; high recovery (90%-97%); wide applicability.

Cons: Toxic cyanide (strict environmental control); requires pre-treatment for carbonaceous/arsenical ores (roasting/POX).

Heap Leaching (Cyanide Heap Leach Mining)

Applicability: Low-grade oxide ores (typically 0.5-1.5g/t) with free-milling gold. Requires good permeability (low clay). Targets: Low-grade ROM, waste rock, old tailings.

Principle: 10000 Tons Heap Leaching Design For Gold Dilute NaCN solution trickles through stacked ore. Gold dissolves into solution via reaction: 4Au + 8NaCN + O2+ 2H2O → 4Na[Au(CN)2] + 4NaOH Pregnant solution collected; gold recovered via carbon adsorption → elution/electrowinning.

Pros: Low CAPEX/OPEX, low energy; processes marginal grades; flexible/scalable.

Cons: Lower recovery (60%-85%); long cycle (weeks/months); slow cash flow; climate-sensitive (cold/rain); permeability critical; environmental risk.

Post-Beneficiation Value Realization

Maximizing resource value by upgrading low-grade ore into high-value products. Common business models:

Gold Concentrate Sales: Direct sale to smelters. Short cash cycle; avoids smelting risks (ideal for capital-constrained startups).

Gold Dore/Ingot Sales: On-site smelting/refining → sell standard ingots. Maximizes profit margin; stronger pricing control.

Toll Processing: Send concentrate/dore to smelter for refining (pay fee); retain ownership & market flexibility.