HERZOG Mining offers complete solutions for sample preparation in the mining industry and is one of the world’s leading suppliers of laboratory systems e.g. for the iron ore, gold, copper, phosphate and other industries.



HERZOG systems are optimized for the control of all production steps in the mining industry and are used for the analysis of geological, concentration and flotation samples. They are scalable according to the customer’s needs and are implemented as manual or fully automatic laboratories.

DetailsTo sample preparation

Quality control for mining industry

The mining industry, like many other natural resource sectors, requires a large-scale use of automation at various levels and degrees.  Although automation is quite advanced in drilling, hauling and process control, there is still a large potential to automate processes within the laboratories.  Virtually most future ore reserves are linked to lower grades, harder and deeper ores, complex mineralogy, and rising cost associated with water, power, sustainability, larger plants and other challenges.  High capacity, 24/7 automated labs are critical for early and continuous, large-scale geo-metallurgical profiling of new ore bodies.  This, in turn, is a priority requirement for avoiding costly delays in start- or ramp-up.  For existing operations, the change to automation can optimize mining, ore routing, comminution, flotation, leaching, and contribute to lower operating costs and higher recoveries.

As ore routing, processing and optimal final products are inevitably governed by fast, high-quality, high-throughput, and 24/7 analytical data, state-of-the-art automated laboratory facilities constitute the center of cost-effective plant operations.  As such, lab automation (via upgrading of existing facilities, expansions, modular lab segments, new installations or central laboratories) is an imperative priority for competitive mining in the near future.      


HERZOG’s Automation Team can provide you with a tailored concept and layout suitable for a specific mine site, multiple different mines or a central laboratory serving an entire mining region.  In addition, HERZOG can design your laboratory needs in an underground operation. HERZOG Automation Technology covers your entire mine and plant requirements in regard to sample preparation and interfacing with analysis:

  • Exploration & Mine Geology (drill core, drill cuttings, blast holes, bulk ore samples)
  • Geo-Metallurgy (mineralogical, chemical, metallurgical samples)
  • Plant & Process (mill feeds, flotation products, leach feeds/residues, slags, mattes, cathodes)
  • Environmental (soil, overburden, AMD samples, others)

Laboratories for the mining industry

HERZOG is looking back on longstanding and worldwide activities in the mining industry. In recent decades we have successfully installed numerous large and smaller automations. We are proud to be the partner of the leading mining and engineering companies. This cooperation helps us to constantly improve our technology for better fulfillment of our customers’ needs.

HERZOG has delivered some of the most innovative and extensive  laboratory systems worldwide such as:

  • The largest automation project in the world to Anglo Platinum (South Africa)
  • The largest robotic sample preparation in the world for copper to Freeport-McMoRan (USA)
  • The largest fully automated iron ore laboratory in the world to BHP Billiton (Australia)

    HERZOG has recourse to large expertise in the mining industry. Our experienced team is composed of mechanical and software engineers as well as geologists and chemists. Furthermore, HERZOG has a close strategic cooperation with IMP, a company with longstanding experience and expertise in the mining industry and operations in Australia, South Africa, Canada, USA and Brazil. Since 20 years HERZOG and IMP have successfully managed more than 100 large-scale mining projects.

    Iron ore laboratories

    HERZOG Mining offers fully automated sample preparation and analysis facility for many hundred samples per day. The fully automated systems are designed to process geochemical mining and pit control samples, metallurgical control samples as well as geochemical exploration samples. Depending on application, different sample preparation steps can be integrated in the laboratory.

    In automatic laboratories, large dry samples of up to 15 kg are entered into the system. Sample drying and automatic moisture determination can also take place within the lab using convection ovens. Usually, samples are then crushed and then split to smaller aliquots before being pulverizing to 90% passing 106µm. Pulverized samples are dosed into a vial as part of the analysis which includes 4 point LOI and the fusion of glass beads for XRF elemental determination. As an alternative, fine grinding and pelletizing of samples produce very acceptable quality analytical data especially for ores with high hematite composition.

    Once the samples have entered the system, all of the processes described above are fully automated. Therefore, human intervention errors commonly associated with manual or non-integrated geochemical laboratories are eliminated. The robotics carry out repetitive tasks with absolute precision, while the HERZOG sample preparation equipment automatically prepares the samples for analysis. Robotic preparation systems delivers the geochemical sample determination and quantification tools to provide the production site with real time information for process control decision making.

    HERZOG also offers manual equipment for each single preparation step. Furthermore, compact automatic equipment is available like, e.g., the HP- BTM for crushing, splitting and pulverizing.

    Port laboratories for the mining industry

    HERZOG delivers complete laboratories for ship loading and unloading. We are taking care that the design of the laboratory is compliant with the client's latest site-specific requirements, safety standards and regulations. The port laboratories meet quality standards to ensure product quality and is compliant with requirements of ISO3082. Equipment and control system are designed to guarantee highest safety, easy maintenance, maximum availability, rapid turnaround times, and traceability of all activities. 

    Our systems are designed for completing the following tasks:

    • Sample Receipt, Weighing, Labelling and Tracking
    • Sample division
    • Drying
    • Moisture determination
    • Sieve analysis
    • Crushing
    • Splitting
    • Compositing
    • Pulverizing

      The port laboratories are designed for both time-based and mass-based sampling regime. The time-based regime results in a shorter duration between samples, meaning that the equipment is placed under additional load when compared to a traditional mass-based sampling method. In case of time-based sampling, manually processing this volume of sample would be logistically impossible, with 40 kg samples arriving every 90 seconds in a worst case scenario.

      Increments arriving in the laboratory are processed through various stages of accumulation, splitting, crushing, pulverizing to achieve representative samples for the chemical analysis of the loaded product. At the same time, moisture content and particle size distribution are determined. The complete process is fully automated with a minimum time requirement to allow quickest possible analysis reporting. The port lab has sufficient magazine capacity to store increments, aliquots and accumulations.

      Various designs are available according to the procedural and architectonic demands of our customers. Exemplary configurations are one or two robot circuits or linear robot cells with one or two robots moving on a track. The arrangement of the robot and associated equipment allows maintaining each piece of equipment in a safe manner. The robot remains operational due to special machine guards and “Safe Move” mode.

      Copper mining laboratories

      As the reliability and availability of analytical data is primarily contingent on Sampling and Sample Preparation, automating the sample preparation laboratories (“the bucking rooms”), will provide a copper mining operation with significant improvements.  Automation of sample preparation for chemical analysis can include virtually all mine and process materials including drill core, blast holes, bulk ore, process products, slags, sludge’s and other residues. Barcoded or RFID-tagged samples can be subjected to automated:

        • Moisture determination
        • Filtration & drying
        • Crushing, pulverizing
        • Screening, blending/splitting,
        • Ultrafine grinding, tablet pressing
        • Dosing, bagging, assay pulp transport
        • Cathode Analysis.

        One of the major economic and technical benefits of automated sample preparation is the capability to process substantially larger samples (10-15 kg/sample) at high-throughput rates.  Since sample size and higher sample frequency are major factors in better ore representation, automation also enables production support labs to generate statistically more robust data.

        In addition to chemical Labs, the HERZOG Mining automation can be linked to:

        • High-throughput XRD and FT-NIR Mineralogy Labs
        • Automated Fire Assaying
        • Support of Automated Mineral Analyzer Labs (such as TIMA-X, QEMSCAN, MLA, Others) with auto-sizing, splitting, drying, potting, curing and transport to Auto Polishing.

          Flotation laboratories

          HERZOG has developed special technologies for the sample preparation of different slurry types

          Froth flotation is a standard procedure for the separation of a large range of sulfides, carbonates and oxides before further refinement. It is a frequent process stage for the recovery of copper- and lead-bearing material but also for a variety of other ore applications. It is also widely used for phosphate extraction including different types of ores like apatit- staffelite (collophanite). EFlotation requires a steady process control for a successful beneficiation. For this purpose, HERZOG provides fully automatic sample preparation equipment covering slurry transport, slurry drying, sample splitting, fine grinding and pelletizing into steel rings or production of fused beads. The results of this process are chemical composition and grain size distribution and can be used for at-line-analysis or calibration of online- analysis methods.

          The sample material includes three different sample types retained from different locations important for the flotation processes. The sample types are following:

          • Feed
          • Concentrates
          • Tailings.

          HERZOG provides solutions for the pneumatic transport of slurries from the flotation plant to the laboratory. Usually, a secondary vesin cutter splits a sample, which flows to the slurry sending station while the surplus is returned to the process. The slurry is sent to the laboratory station where it is split down to a volume of 1.2- 1.8 l. After each transport cycle, the whole piping system is cleaned by water avoiding any form of cross contamination.

          After transportation of the slurry sample into the laboratory, the material is dewatered by using the HERZOG filter press system. In the filter dryers, the water is pressed out by means of compressed air. A multifilamentic fabric that is especially adapted to the material properties of the sludge is used as filter textile. This system also makes use of self-reinforcing filter effects supporting the filtering of small particles and detachment of the filter cake. The filter presses are available for manual or automatic operation. Residual moisture of approximately 10% evaporates during controlled drying in either microwave systems or air circulation ovens. After drying, the sample is further processed by pulverizing, pelletizing, fusion, grain sizing etc.

          Usually, the dry sample is further split into aliquots for pulverizing, pelletizing and spectroscopic analysis, composition of average sample, as well as grain sizing. Avoiding contamination between the mill feed and the technology tailing samples proved to be the most complex step of sample preparation. However, using a blind sample between each pulverizing step or sand cleaning usually prohibits contamination.


          Sample preparation



          Herzog crushers are designed for the coarse crushing and pre-crushing of sample material. The analytical fineness required for a subsequent spectroscopic examination is normally achieved with the aid of a disk vibration mill.

          Jaw Crusher HSC 550

          Herzog jaw crushers are designed as jaw crushers equipped with one movable and one fixed breaking jaw. This involves pressing the material to be crushed through the moving jaw and against the fixed jaw and crushing it through the application of pressure and impacts. The moving jaw is moved by an eccentric shaft and is thereby forced into an elliptical movement pattern that crushes the material and moves it downwards. If the grain size is smaller than the width of the bottom gap, the crushed material drops into the collecting container. Using no-rebound funnels prevents material from escaping out of the crushing chamber. IN some automatic machines we also integrate double rocker crushers.
          Depending on the material being crushed, the jaw crushers can be supplied with crushing jaws made of different materials. One characteristic of jaws made of manganese steel is that they harden further over time with increased use. Stainless steel is recommended when the formation of rust can be expected due to feed material. Tungsten carbide jaws are particularly hard resistant to wear. Their service life is long even when used on hard materials.

          With the cone crusher, the crushing occurs in the gap between the crusher jacket and the crusher cone. This gap opens and closes circumferentially as a result of the eccentric tumbling motion of the crusher cone. The advantage of the cone crusher is that the material is crushed continuously by pressure and friction. There is no alternating working stroke and no-load stroke as occurs with the jaw crusher.
          The HP-CM/AUT is a crusher especially designed for automotive catalyst. Entire monoliths can be crushed down to a particle size suitable for fine grinding. The crushed material is captured in a special container (3 l), which can be easily removed by the operator. The material loss is reduced to a minimum and cleaning of the crusher is achieved by compressed air.


          Grinding and pressing is a time-saving and cost-saving sample preparation procedure that is used in the analysis of many inorganic and organic materials. Using powdered samples not only allows the chemical composition to be determined, it also permits the use of X-ray diffraction methods (e.g. cement, salts) for some applications in order to determine the mineral content.

          Prior to pressing, the material must be finely ground in order to guarantee sufficient homogeneity. HERZOG offers a wide variety of disk vibration mills in different sizes and configurations for the grinding of sample material. Very hard materials (e.g. silicon carbide) can also be ground down to a grain size that is sufficiently fine to guarantee a high-quality analysis. Along with the program parameters, the attainable fineness is also dependent on the following factors:

          • Material
          • Input quantity
          • Grinfing aids used
          • Grain size when out in

              Generally, a grain size that permits an analysis is obtained after about 60 seconds in the case of most materials. If milling is performed for longer, agglomerations and material accumulations occur in the grinding vessel in the case of specific materials.

              Pulverizing of coarse-grained Material to fine powder, suitable for analysis with RFA, diffractometry and others.


              To perform the analysis by means of RFA, it is often necessary for the sample material to be ground to a grain size of < 75 µm. The grinding vessels must be made from wear-resistant materials in order to guarantee sufficient abrasion resistance. This applies particularly when the sample contains very hard mineral phases and has abrasive properties (e.g. clinker, silicon carbide, etc.).

              Grinding vessels

              This means that during grinding, there is inevitably abrasion of the used grinding stones and of the grinding vessel. Depending on the application, the grinding vessel should be suitably hard and should have a chemical composition that does not contain any elements that are of analytical interest. Different grinding vessels are available in order to prevent the entry of elements that are relevant to the analysis.

              The automatic mills are especially suitable for preparing precious metal bearing materials because the machine offers various cleaning options to avoid cross contamination. Three cleaning features namely compressed air, sand cleaning and wet cleaning allow a sufficient material removal. Using the different cleaning functions, cross contamination can be reduced to a low ppm-level. Furthermore, spoon sampling during the material input provides the possibility to pre-contaminate the grinding with the following sample. The final particle size after ± 30 seconds of milling is commonly 90% below 50µm. Grinding vessel, ring and puck have to be made from chrome steel in order to avoid line overlapping by elements introduced by the grinding stones.


              Grinding and pelletizing of sample material for XRF and XRD spectroscopy is an established procedure not only within the primary extractive industry but many industrial processes. HERZOG offers a wide range of different equipment from manual machines to fully automatic laboratory solutions.
              For sample pelletizing HERZOG provides manual and automatic machines. For manual applications with small or medium sample loads following models are available: TP20, TP20E, TP40, TP 40/2d, TP60, TP60/2d, HTP40, HTP60. All standard pelletizing procedures can be completed using manual pellet presses. The sample material is filled in manually. Dependending on the used model the pressure is generated manually or by an electrical hydraulic unit.
              The automatic pellet presses HP-MP, HP-P, HP-PA, HP-PD6 are automatically dosing the ground material into the press tool. After pressing excess material and dust is removed from the steel ring. In the HP-P a second press tool can be used as option to avoid cross contamination between two divergent material types.  The ready pellet can be automatically transported to the analyzer. Following analysis the ring is automatically cleaned and stored in a ring magazine.
              The HP- PD6 is a special pellet press for pelletizing of samples for diffractometry analysis. Few grams of sample material is pelletized into a ring using very low pressure. For stabilizing the material within the ring an aluminium button is inserted using a special backloading procedure.

              Depending on the analytical requirements, it is possible to choose between four standard pressing methods:

              Free pressing

              Free pressing is the lowest-cost pressing method because no consumables are required. Precise dosing of the sample material is also not required.

              2- component pressing

              Pressing of 2 components requires an additional work step, but also offers the possibility of preparing small sample quantities for analysis. The refill magazine (e.g. boric acid, Boreox) is dosed and pre-pressed in an initial work step. A special pressing tool cover is used for this. The actual sample material is then pressed into the prepared matrix in a second pressing step. 

              Pressing in aluminium cups

              For pressing in aluminium cups, the plunger should have a suitable venting groove in order to prevent compression of gases in the plunger. Aluminium cups are available in various diameters. Aluminium cups have the advantage that no significant costs are incurred if the samples are to be archived. Nevertheless, aluminium cups offer no guarantee with regard to eruptions occurring on the edges.

              Pressing in steel rings

              Using steel rings offers far-reaching advantages over the other pressing methods with regard to use in automated sample preparation systems. Using steel rings reduces the risk of contamination in the spectrometer by preventing eruptions on the sample edge. However, high costs are incurred if the re-useable rings must be archived. Two rings types are available for pressing in steel rings (Ø 40 mm & Ø 51 mm).

              Cleaning steel rings

              A three-stage brush system can be used to clean used steel rings after the analysis. This can be used with both manual and automatic presses. On manual presses, it is placed manually into the ring and is then removed manually. In automated pressing, the cleaning runs entirely without the operator's intervention. The empty rings are then automatically stored in the internal magazine.

              Almost no additional binding agents for, e.g., catalyst material are necessary to achieve a high quality pressed pellet with a smooth surface. Cleaning of the automatic press is commonly done by means of compressed air. If cleaning by air is not sufficient, a Mylar foil can be used to cover the pressing tool. The pressed pellets can be prepared by using the automatic pelletizing press HP-PA, which can be connected with the pulverizer HP-MA in a linear automation. This allows batch processing of up to 100 samples with a minimum work load.

              Representative splitting

              Representative sampling of secondary raw materials is an important prerequisite to ensure a reliable physical and chemical analysis and in the end lot value determination. After the primary sampling, size-reduction has to be undertaken in such a way that the final aliquot presented to the analytical laboratory displays the lot as much as possible 100 %. The relative sampling variation (RSV) of the sub-sampling to realize the size reduction should be less than 5 %. The prospective RSV has to be determine for each new application with an at least 5-folded simple replication experiment to ensure a full conformity to a representative operation. Representative splitting is of particular importance in PGM recycling but also many other material and commodities sectors like, e.g., mining, food, pharma, secondary raw materials, and agricultural products.


              Fusion process

              Fusion is an extremely efficient method of sample preparation for various analysis methods such as X-ray fluorescence, ICP and AA. The term fusion normally covers the mixing of a sample with a fusion agent, fusing the mixture and pouring in the form of a glass bead or dissolving in an acid solution.
              Fusion is the best method when standards or sample material do not have a consistent matrix. This is normally the case with exploration, environmental and geological samples including mining material, minerals, clay, ores, dusts and waste materials. It is also often used with mixing materials such as cement, catalysts and electronic materials.

              Improving the analysis results

              Preparation with the aid of the fusion process results in a significant improvement in analytical accuracy. There are various reasons for this.
              Firstly, samples that have an identical chemical composition can differ from each other in terms of mineralogy and particle size. This alone can result in different counting rates in the analysis instrument. The fusion process eliminates these factors and thereby increases measuring accuracy.
              Secondly, dilution occurs in fusion through the addition of a fusion agent. This leads to a reduction in the interaction between the elements being analysed and a reduction in the so-called matrix effect.
              Thirdly, fusion makes it significantly easier to perform a calibration. On the one hand it is possible to produce perfect matrix-matched standards for a large number of materials. On the other hand, synthetic standards can be used if no referenced standards are available. Accordingly, synthetic standards can be produced for almost any material without the complex regression analyses for creating calibration curves.

              Avoiding errors

              Fusion is an extremely important part of material analysis by way of X-ray fluorescence, ICP and AA. Fusion is an excellent method for avoiding errors that can have a negative influence on the accuracy of the corresponding measuring method. Fusion is also the simplest and most reliable method for preventing errors arising from inhomogeneous particle distribution, mineralogical effects and insufficient surface quality.

              Improving the sample solution

              Fusion can easily dissolve oxidic samples that are difficult to prepare with the aid of acidulation. Conventional acidulation of resistant material such as silicates aluminium, zirconium etc. takes a long time and often only results in incomplete dissolving. However, complete sample dissolving is an extremely important factor for improving the accuracy and reliability of analysis results.

              Perfectly suited to fluorescence analysis

              The fusion process produces a glass bead that is perfect for X-ray fluorescence instruments. The glass bead has the optimum dimensions, displays excellent homogeneity and has a flat surface.

              Time saving

              A typical fusion process seldom takes longer than ten minutes. In contrast, acidulation takes hours before a satisfactory result can be obtained.


              Fusion is a reliable sample preparation process that requires no harmful acids and reagents. Special safety measures are therefore not necessary. The fusion process is especially safe when it is done with apparatus that has automatic sample handling, fusing and pouring of the melt.

              Fusion process

              The most common method is borate fusion. This involves fusing a sample with an excess of lithium borate and in the form of  a glass bead with a flat surface. During the fusion process, the sample's material phases are converted into glass-like borate, which results in a homogeneous fusion bead that is perfectly suited to X-ray fluorescence analysis.
              The finely ground sample material is first mixed in a crucible with a borate fusion agent (usually lithium), consisting of 95% platinum and 5% gold. The crucible is then heated to temperatures in excess of 1000°C until the sample is dissolved in the fusion agent. Movement of the melt during the fusion process improves the homogenisation of the material still further. A wetting agent (bromide, iodide, fluorine) can be added in order to support the separation of the melted material from the wall of the platinum.
              Borate fusion of escrap or catalyst recycaltes in a Pt-crucible is complicated as Pt, Pd and Rh, which are contained in the sample, will alloy with the crucible wall. Nevertheless, the application of fused bead method can improve the accuracy of analysis by the factor 5. Therefore, it should be checked from case to case if fusion is applicable.