Orway specialises in designing comminution circuits, developing comminution testwork programs, circuit audits and optimisations.
Our expertise encompasses a range of comminution processes through crushing, HPGR, AG & SAG mills, rod & ball mills, and other novel comminution unit processes, both wet and dry.
Orway has also undertaken numerous studies on fine grinding to determine specific energy and equipment selection. Industry and research studies of fine grinding techniques and the influence of grinding media have aided the honing of our in-house design techniques. Given this comprehensive understanding of the technologies, Orway can expertly assist clients in making sense of the selection and utilisation of fine grinding technology.
Scrubber design is another area of Orway's comminution expertise. Ore scrubbing can potentially add enormous value to minerals projects by liberating valuable minerals from waste gangue and other deleterious minerals to allow beneficiation and upgrading of the feed to downstream processing. Orway has gained extensive knowledge in the interpretation and application of batch and pilot plant scrubbing testwork across various projects and commodities. An understanding of sampling requirements and scale-up from testwork to full size is crucial to allow the accurate design of the scrubber dimensions, determination of power requirements and identification of operating envelopes.
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Over 150 comminution circuits have been successfully installed based on Orway designs.
Orway has developed accurate and proven methods for comminution circuit design and selection throughout more than 40 years of operations. Our modelling techniques utilise ore characteristic testwork to select the circuit configuration, generate mass balances and size major equipment. Simulation of mine schedules or the life-of-mine blend is then used to refine designs.
The results are used to produce an engineering design brief to assist the development of detailed engineering and capital and operating costs. The design brief includes circuit description, process flow diagrams with mass balance, major equipment specifications, consumable estimates and commentary on the circuit design, including specification of essential functional requirements and control recommendations.
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Orway audits and optimises comminution circuits worldwide. This process can be via desktop review or may involve a site visit. Circuit optimisation includes analyses of circuit performance, a review of production data, control philosophies and will often involve grinding circuit surveys and plant trials.
Specialist in-house tools benchmark the performance of unit processes to identify potential constraints and bottlenecks. Poor control practices are identified and remedied to stabilise and optimise the operating circuit.
Desktop studies using mass balances and models produced from production data or circuit surveys are then used to quantify the effectiveness of recommended changes to the circuit.
Based on the site visit findings and preliminary audit results, considerable improvements in plant performance can often be obtained through recommended changes to the operating control philosophy and the training of plant staff. Our consultants have wide-ranging experience in working with in-house teams to improve their understanding and knowledge via onsite coaching.
In addition to the traditional optimisation approach, Orway also works with clients on continual improvement of comminution circuits using our exclusive offering of the MillROC service.
MillROC (Mill Remote Optimisation Consulting & Coaching) monitors and models processing plants to ensure optimal performance. MillROC is a unique service offered by our joint venture subsidiary OrwayIQ to facilitate continual optimisation of mineral processing plants, proactively optimising performance to minimise opportunity loss.
The data analysis and parallel modelling (including machine learning) provide optimisation feedback to the operations team to ensure the circuit runs efficiently and maximises throughput at all times. This facilitates continual operation improvement in terms of throughput, stability, efficiency and equipment life. Optimisation projects are identified, site implementation encouraged and supported, and the results analysed to determine the impact. This process also allows for the continuous improvement of the skills and experience of the onsite team, continuity during staff changes and an auditable record of progress, all without the need for on-the-ground consulting, which may be impractical or cost prohibitive.
Orway has optimised more than 200 comminution circuits worldwide and regularly achieves improvements above 10%. This can include increased circuit capacity, efficiency, and reduced maintenance costs (liner and media consumption), leading to reduced energy consumption and CO2 footprint per metal unit produced.
The Orway survey database contains 610 surveys on 163 comminution circuits worldwide.
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Orway's experience and a solid practical understanding of the circuit and equipment, supported by our best practice modelling techniques, enable us to provide credible and realistic solutions to design and processing challenges.
The Orway team is expertly trained in using in-house proprietary software for flowsheet design developed over the Company's decades of operation. In-house software has been calibrated and honed, utilising the Company's sizeable industrial database of operating plant performance on sites worldwide.
As well as Orway's proprietary software, the team specialises in using other comminution circuit modelling packages, including JK SimMet, Bruno, LIMN and PlantDesigner.
Ore characterisation testwork, combined with detailed modelling, forms an integral part of a process design or circuit optimisation. Orway's power-based modelling approach and JK SimMet, which uses a breakage rate model methodology, are complementary systems that provide two separate methods with comparative results to ensure greater confidence in the design basis.
The Orway models are regularly recalibrated using operational data from optimisations. This provides valuable feedback about the accuracy of the models for various circuit configurations and ore types. Modelling results are also regularly benchmarked against results in the Orway database to validate and provide clients with confidence in the recommendations and deliverables.
More detail about our comminution modelling approach can be accessed by viewing Orway’s technical paper on "OMC Power Based Comminution Calculations for Design".
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Orway specialises in developing testwork programs for comminution circuit design and capacity modelling.
The process involves working with project geologists and applying their knowledge and insights to develop a lithological, spatial and mining schedule sample-selection program that best aligns with onsite needs.
Orway's standard philosophy for comminution testwork is that samples should represent the orebody in terms of:
Geographical spacing as seen on a plan view of the pits
Lithology to include all the ore types of significance
The weathering-state of the major lithologies (oxide, transition and fresh ore tested separately)
Depth profile (samples showing hardness at varying depths, often best represented on the long sections of the holes)
The inclusion of alterations within the same lithology where the ore is visually different in physical characteristic
As the study level increases, the spatial sampling for analysis should increase to better represent the orebody in terms of:
Scoping / Concept Level: Test the main lithologies only
Prefeasibility Level: Test all lithologies that make up more than 10% of the ore body. Variability testwork specified for DFS level study may occur at this time if the project is to be fast-tracked for development
Feasibility Level (DFS / BFS): Test variability samples and fill in any gaps identified in the PFS to increase confidence in the design and reduce project risk
The number of variability samples depends on the project size and can be anywhere from 10 to 200.
If ore handling is a potential problem (e.g. extremely clayey material), specific TUNRA-type testwork can be considered.
Dependent on the sample source (whole rock, PQ, NQ or HQ core, half or quarter core samples), a testwork program is developed to characterise the comminution properties of the ore and assess variability.
Orway's extensive database contains information collated from more than 40 years of testwork, surveys and circuit performance data, providing credible guidance on the most appropriate circuit for a given ore. The results also provide input to Orway's power-based and JK SimMet modelling for major equipment selection.
The Orway database comprises testwork on more than 15,000 tested samples from close to 750 projects covering over 90 countries.