EPC Turnkey Contract for a Gold Extraction Plant: Complete Solution for a 100-Metric-Ton-Per-Day CIP/CIL Mineral Processing Line

1. Crushing and Grinding

The raw ore undergoes coarse crushing in a jaw crusher, followed by medium and fine crushing in a cone crusher, and is then ground in a ball mill.For a 100-metric-ton-per-day operation, a single-stage grid-type ball mill paired with a spiral classifier or hydrocyclone is typically used to form a closed-circuit system; where the ore is highly hard or a finer grind size is required, a two-stage grinding process may be employed. Following the principle of “more crushing, less grinding,” the crushing stage handles the bulk of the work, while the grinding stage consumes less electricity.The grinding fineness is determined based on ore liberation tests.

2. Thickening and Dewatering

The ground ore is fed into a thickener for dewatering to increase the slurry concentration in preparation for leaching. The thickener overflow is returned to the grinding circuit or reused, while the underflow is sent to the leaching tank.

3. Leaching and Adsorption

CIL Process: Cyanide and lime are added to the leaching tank to adjust the pH (10–11), while activated carbon is simultaneously introduced, allowing leaching and adsorption to occur concurrently. Activated carbon is added in the final tank and moves forward in a countercurrent flow, coming into contact with the slurry in the opposite direction. Gold-loaded carbon is separated by screening in the first tank.

CIP Process: Leaching is carried out in a series of tanks. After leaching is complete, the slurry enters an adsorption tank where activated carbon is added; leaching and adsorption occur in separate tanks, allowing for a more thorough leaching time.

For a 100 metric tons per day scale, the number and volume of leaching and adsorption tanks are determined based on leaching time test data. The CIL process is compact with fewer tanks, while the CIP process ensures sufficient leaching time; the choice between the two depends on the ore\'s leaching rate.

4. Separation of Gold-Loaded Carbon and Desorption/Electrolysis

Gold-loaded carbon is separated from the slurry via a carbon separator screen or air lift and fed into the desorption system. Desorption at ambient temperature and pressure is suitable for conventional processing, while high-temperature, high-pressure desorption is more thorough and efficient. The precious metal solution obtained from desorption enters the electrolysis cell, where gold is deposited at the cathode as gold slime.

5. Gold Sludge Smelting

After acid washing, drying, and blending, the gold slime is fed into a gold smelting furnace for smelting, producing high-purity gold ingots.

6. Tailings Treatment

Leaching tailings are dewatered using a filter press; the tailings are either dry-stacked or treated in accordance with environmental regulations, while the lean solution is either recirculated into the system or sent for environmental treatment.

What GoldProcessingPlant Is Responsible For

1. Process Design and Technical Solutions: Analysis of ore characteristics, determination of processing flows, and reagent regimens; preparation of proposal documents including equipment selection and preliminary quotations.
2. Engineering Design and Drawings: Core design drawings such as site layout plans, equipment layout diagrams, and civil engineering condition drawings, along with a complete technical briefing.
3. Manufacturing of Core Equipment and Supply of Supporting Components: Manufacturing core equipment—such as crushing, grinding, leaching and adsorption, desorption and electrolysis, and smelting—in accordance with drawings; coordinating the supply of auxiliary materials such as pumps, piping, and electrical controls to ensure seamless integration between hardware and process.
4. On-Site Installation Technical Guidance: Dispatch engineers to the site to supervise equipment positioning, pipeline connections, and electrical and instrumentation installation, ensuring that construction crews follow the drawings precisely.
5. Integrated Commissioning and Personnel Training: Lead the commissioning of individual units and full-process integrated trial runs with water and feed materials; optimize grinding fineness, reagent regimens, and leaching parameters until standards are met and full production capacity is achieved; provide theoretical and hands-on training to the client\'s team.
6. After-Sales Service and Spare Parts Supply: We assume responsibility for equipment quality during the warranty period and provide long-term spare parts supply and process optimization recommendations.

Customer Responsibilities

1. Civil Engineering Construction: The client shall independently organize civil engineering construction in accordance with the civil engineering layout drawings provided by us (equipment foundations, loads, reserved openings, water and electrical connections, etc.). If complete architectural construction drawings involving plant structures, foundation reinforcement, etc., are required, these must be issued by a qualified local design institute.
2. Organization of Local Installation Workers: Specific installation tasks—such as equipment positioning, pipe welding, and cable laying—must be carried out by workers recruited locally by the customer. Our engineers will provide on-site guidance on installation procedures, while the customer is responsible for organizing the workforce to perform the work.
3. On-site Infrastructure: The client is responsible for ensuring “three utilities and one leveling” (water, electricity, and access roads; site grading) at the site, as well as preparing the water, electricity, and materials required for equipment hoisting and commissioning.
4. Local Compliance Procedures: The client is responsible for obtaining local approvals, including environmental, safety, and construction permits, at the project site. Environmental approvals for the cyanide process are particularly critical.

Process-First Approach, No One-Size-Fits-All Templates

Every 100 metric tons per day line is derived from the specific characteristics of the ore, rather than simply copying competitors\' blueprints. With over 20 years of experience in gold ore beneficiation process design and equipment manufacturing, we specialize in core processes such as CIP/CIL, flotation, gravity separation, and heap leaching, and excel at handling difficult-to-process ores and complex ore bodies.

In-House Equipment Manufacturing: Seamless Integration of Process and Hardware

Crushers, ball mills, leaching tanks, activated carbon adsorption systems, desorption electrolysis equipment, and gold smelting furnaces are all manufactured in-house. Process engineers and mechanical engineers collaborate as a single team, ensuring equipment is built strictly according to process drawings to avoid discrepancies such as “design drawings not matching equipment dimensions.”With two major manufacturing bases covering approximately 50,000 square meters, our annual production capacity exceeds 500 units. Our products are exported to more than 50 countries and regions, and we strictly adhere to the ISO 9001 quality management system; our products are CE-certified.

Unbroken EPC Chain of Responsibility

We provide comprehensive coordination of process design, equipment manufacturing, installation guidance, integrated commissioning, and personnel training, and take full responsibility for the final production targets. We do not shift blame to design institutes, equipment manufacturers, or construction teams when problems arise.

Global Project Experience

Projects span major gold-producing regions including Ghana, Mali, and Tanzania in Africa; Peru and Colombia in South America; Russia and Kazakhstan in Central Asia; and Southeast Asia, with processing capacities ranging from 30 to 5,000 metric tons per day. We are well-versed in international logistics, customs clearance procedures, and construction standards across different countries.In Africa, where power supply is unstable, we provide diesel generator sets; to address transportation difficulties during the rainy season, we stock up in advance; and when local workers have limited technical skills, we provide hands-on training.

Flexible Phased Implementation, No Mandatory Bundling

Clients may choose to conduct only mineral processing tests, purchase only process design and equipment selection plans, procure only equipment, or hire engineers for on-site commissioning; alternatively, they may opt for full-process EPC. Upfront payments for mineral processing tests and design fees can be fully offset against equipment costs when subsequent equipment or EPC contracts are signed.

Ongoing Technical Support

Commissioning and reaching full production capacity mark only the beginning of our partnership. We assume responsibility for equipment quality during the warranty period and, after the warranty expires, continue to supply spare parts, provide technical consultation, and offer process optimization recommendations.