Analytics in mining
From sampling to process optimization through precise particle analysis
Precise particle analyses help optimize grinding circuits, stabilize flotation processes, and reliably meet product specifications.
The economic processing of mineral resources depends significantly on precise analytical methods. Particle size distribution, fines content, and particle shape influence key process steps such as crushing, classification, flotation, pelletizing, and dewatering. Even minor deviations can affect energy consumption, throughput, metal recovery, and product quality. Therefore, reliable analytical methods have become an indispensable tool for process optimization, quality control, and the economical operation of modern mineral processing plants.
By enabling targeted control of crushing, classification, and flotation processes, precise particle analysis helps reduce energy consumption, raw material losses, and resource usage throughout the entire processing chain.
Representative sampling as the basis for reliable results
The quality of any analysis depends entirely on the quality of the sample. Even the most advanced analytical instruments cannot provide meaningful results if the sample is not representative of the material being analyzed.
In mining, heterogeneous ore streams, varying moisture contents, and highly variable particle sizes make representative sampling particularly challenging. Segregation effects during material transport, fluctuations in ore grade, and uneven moisture distribution can lead to significant measurement errors. Standardized sampling procedures therefore form the foundation of any reliable process monitoring system.
Sample preparation: the key to data quality
After sampling, the material must be prepared for laboratory analysis. The objective is to produce an analysis-ready laboratory sample from what is often several kilograms of source material without altering the actual particle composition.
Drying
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Many raw materials are extracted or transported with residual moisture. Prior to analysis, the sample often needs to be gently dried to reduce agglomeration and ensure reproducible results. At the same time, temperatures must not be so high that they alter the material properties.
Size reduction
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Coarse ores or rock samples are frequently reduced to a suitable particle size using jaw crushers, roll crushers, or laboratory mills. Care must be taken to avoid generating artificial fines that could distort the subsequent analysis.
Sample division
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Since the original sample often weighs several kilograms, while only a few grams may be required for analysis, a multi-stage sample division process is used. Riffle splitters or rotary sample dividers ensure that the sample composition remains representative even after mass reduction.
Particle analysis as a process control tool
Only after proper sample preparation is the actual particle analysis performed. Particle size distribution influences nearly all critical mineral processing operations:
• Degree of liberation of valuable minerals
• Efficiency of hydrocyclones and classifiers
• Flotation performance
• Pelletizing behavior of concentrates
• Dewatering efficiency
• Compliance with product specifications
The analysis of fine and ultra-fine fractions is particularly important, as even minor changes can have substantial effects on downstream processes.
Mining Industry Brochure
The right sieving technology for different mining applications
Particle analysis requirements in mining are highly diverse. While monitoring crushing and classification processes often involves large sample volumes and coarser particle sizes, ore concentrates, coal dust, and industrial minerals require highly accurate analyses in the fine particle range.
NEXOPART offers various solutions that can be selected according to material properties, particle size, and sample volume.
EML analytical sieve shakers for dry and wet sieving
The EML analytical sieve shakers are based on the principle of vibratory sieving and enable both sample preparation and particle size determination of dry and wet bulk materials. The electromagnetic drive generates a three-dimensional throwing motion that allows every particle the opportunity to pass through a sieve aperture and be separated according to its size.
The EML product line includes three models for different sample volumes and sieve diameters:
- EML 200 for analytical sieves from 50 mm to 200 mm or 203 mm in diameter
- EML 315 for analytical sieves from 200 mm to 315 mm in diameter
- EML 450 for analytical sieves from 400 mm to 450 mm in diameter
This allows selection of the most suitable solution depending on sample volume, particle size range, and laboratory requirements.
For mining laboratories, EML analytical sieve shakers are particularly suitable for:
- Monitoring crushing and grinding processes
- Analysis of ore, sand, and gravel samples
- Monitoring classification processes
- Quality control of aggregates
- Wet sieving of moist or difficult-to-disperse materials
- Routine testing in laboratories and production environments
The three-dimensional motion ensures high sieving performance and reproducible results across a wide particle size range. With the availability of the EML 200, EML 315, and EML 450, both small laboratory samples and larger sample quantities can be analyzed efficiently. This makes the EML series a versatile solution for particle analysis throughout the entire mining process chain, from incoming material inspection and process monitoring to final product quality assurance.
UWL 400 for heavy bulk materials and large sample volumes
When dealing with coarse materials or high sample volumes, conventional laboratory sieve shakers often reach their limits. This is where the UWL 400 comes into play.
As NEXOPART’s largest and most powerful 3D analytical sieve shaker, it is specifically designed for heavy dry bulk materials with a feed capacity of up to 20 kg.
Typical applications include:
- Control sieving of crushed products
- Analysis of primary and secondary crusher products
- Monitoring feed particle sizes for grinding circuits
- Particle size determination of aggregates
- Process control in quarry and open-pit mining operations
By processing large sample quantities, the reliability of analytical results can be significantly improved, especially for inhomogeneous raw materials.
Air jet sieving for fine and ultra-fine particles
While vibratory sieve shakers excel in coarser particle fractions, fine powders present unique analytical challenges. Iron ore concentrates, coal dust, limestone powders, phosphate powders, and industrial minerals often have a tendency to agglomerate.
For these applications, air jet sieving was developed. The NEXOPART e200 LS combines a rotating slotted nozzle with adjustable vacuum pressure. This breaks up agglomerates and efficiently transports fine particles through the test sieve. The air jet sieve is suitable for analyses from 20 µm to 4 mm and, with an optional adapter, down to 5 µm. It operates with adjustable vacuum pressures from 1,500 to 5,000 Pa and airflow rates from 70 to 130 m³/h. RFID-based sieve recognition and automatic vacuum control also ensure a high level of measurement reproducibility.
Air jet sieving compared to alternative methods
Conventional vibratory sieving is ideal for coarser materials and routine analyses over a broad particle size range. However, with fine and cohesive powders, agglomeration and sieve blinding can reduce separation efficiency.
Laser diffraction methods provide rapid results and can detect extremely small particles. However, they are based on optical models and calculate equivalent particle diameters. Many mining product specifications, in contrast, are based on actual sieve residues at defined cut points such as 45 µm, 63 µm, or 75 µm.
Air jet sieving bridges this gap by enabling the physical and reproducible determination of such fine fractions.
Practical mining applications
Optimization of grinding circuits
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In iron ore, copper, and gold processing plants, comminution is one of the most energy-intensive process steps.
Regular monitoring of the fraction below 45 µm allows early identification of overgrinding or undergrinding:
- Excessive fines content → unnecessarily high energy consumption and increased wear
- Insufficient fines content → inadequate mineral liberation and reduced recovery
The analytical results support optimization of mill speed, grinding media loading, and classification parameters.
Since grinding is among the most energy-intensive processes in mineral processing, optimized grinding parameters can also reduce specific energy consumption and contribute to more resource-efficient plant operation.
Monitoring hydrocyclones and classification systems
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The efficiency of hydrocyclones depends directly on the particle size distribution of feed and overflow materials. Regular sieve analyses enable monitoring of defined fine and coarse fractions and support optimization of separation efficiency.
Stabilization of flotation processes
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Particle size distribution has a major influence on flotation behavior.
Particles that are too coarse are often not completely liberated, while ultra-fine particles may not readily attach to air bubbles. Therefore, analysis of feed, concentrates, and tailings provides valuable information for stabilizing metal recovery and product quality.
Quality control of industrial minerals
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For products such as calcium carbonate, kaolin, talc, or quartz flour, product specifications are often defined by specific sieve residues. Precise particle analyses support reliable batch release and compliance with customer-specific quality requirements.
Added value for modern mining laboratories
Modern mining laboratories require a range of analytical technologies to cover the full spectrum of mineral resources. With the EML analytical sieve shakers, the UWL 400, and the e200 LS air jet sieve, NEXOPART offers solutions for coarse, medium, fine, and ultra-fine particle fractions.
Key benefits include:
- Reproducible analytical results
- Standardized testing procedures
- Flexible use for dry and wet materials
- Analysis of large sample quantities up to 20 kg
- Precise fine particle analyses down to 5 µm
- Digital data acquisition and documentation
- Easy integration into existing laboratory workflows
