Sensor-based ore sorting is one of the most powerful pre-concentration technologies available to the mining industry - capable of rejecting waste before it enters the processing plant, reducing energy consumption, cutting water use, extending mine life and unlocking ore bodies that would otherwise be uneconomic.
But ore sorting only delivers on that potential when the evaluation is done correctly: when the right ore characterisation underpins the right sensor selection, when sortability testing is structured to answer the questions that matter at each project phase and when operating machines are calibrated and maintained against standards that reflect the actual ore being sorted.
ROKKSTA provides the technical services and equipment that make ore sorting decisions defensible. We work across the full ore sorting evaluation and operational workflow - from initial characterisation and feasibility testing through to equipment performance audits, calibration standard development and laboratory test equipment. Our methodology is structured around your project's technical objectives and our findings are grounded in measured data - giving you the clarity to make confident, well-supported decisions.
- Why Ore Sorting Evaluations Go Wrong
Ore sorting has delivered transformational results in some mining operations and disappointing results in others. The difference is rarely in the technology itself - it is almost always in how the evaluation was structured.
The most common failure pattern is straightforward: an operation moves quickly from limited test results to an equipment decision, receives encouraging trial numbers and commits - only to find that real-world performance falls short of what the trial suggested. The ore body turns out to be more variable than the test sample. The sensor chosen was the one that happened to be tested, not the one best aligned with the ore. Calibration standards verify that the sensor functions, but not that it is accurate for the specific ore. And there is no quantified baseline against which to measure performance or detect drift over time.
The root cause is a methodological one: when an ore sorting evaluation is designed around equipment availability rather than material behaviour, the most important questions - which sensor is genuinely best aligned with this ore, what is the theoretical performance limit, how representative is the test sample - go unanswered.
ROKKSTA was founded to close this gap. We design ore sorting evaluations that are structured around the material and the project. We interpret results against quantified baselines. We separate what the ore can intrinsically do from what a given machine actually delivers. And when an existing ore sorting installation is underperforming, we diagnose precisely why.
- Technical Rigour. Your Project First.
Confidence in an ore sorting decision comes from one thing: evidence that is grounded in your material and tested against a quantified baseline. That principle governs everything ROKKSTA does.
Every service we provide is delivered according to a transparent, documented methodology - not a black-box process. When sortability testing shows that a different sensor technology would outperform the one originally expected, we show you the data behind that conclusion. When an equipment audit reveals that calibration drift is costing recovery, we quantify the loss and specify the correction.
When a feasibility evaluation shows that ore sorting is not yet justified at the current project stage, we report that clearly - because a defensible "not yet" is worth more to your project than an unsupported "yes".
What this means for your project
• Sensor selection is driven by your ore's physics - by the contrast that actually distinguishes ore from waste at the particle scale
• Test programme design reflects your project's technical objectives and decision points
• Audit findings are reported against a measured performance baseline, with full traceability
• Calibration standards are specified around your ore body, not around a generic instrument specification
• Every conclusion is supported by data you can see, interrogate and carry forward into your own study documentation
ROKKSTA was established in Cologne, Germany, and works with mining operations and project teams across Europe, Africa, the Americas and Australia. Our founding team brings more than three decades of international experience in sensor-based ore sorting - spanning technical leadership, operations and applied research, supported by published peer-reviewed work in the field.
- A Structured Path From Evaluation to Performance
Ore sorting projects that succeed share a common characteristic: technical confidence builds progressively, and each decision is supported by evidence appropriate to the project stage. ROKKSTA's services are designed around this principle.
Scoping - Intrinsic sortability assessment using available ore characterisation or assay data. Establishes whether ore sorting is technically plausible for your material and justifies structured further evaluation. Minimum investment, maximum risk reduction at the earliest decision point.
Pre-Feasibility - Full sortability testing programme: intrinsic grade–recovery modelling, sensor principle selection, amenability testing (including bench-scale XRT testing on the ROKKSTA test rig), and dynamic trials with a representative reference sample set. Outputs a preliminary ore sorting mass balance and cost estimate, closing the technical gaps needed to shortlist ore sorting as a process option.
Feasibility - Bulk ore sorting trials on representative material, validated against the pre-feasibility baselines. Outputs a ROM-representative mass balance and ore sorting performance dataset for bankable cost estimation and final process design.
Operations - Equipment audits, calibration standard development and maintenance, threshold re-optimisation, and targeted amenability testing as the ore body evolves. Keeps operating ore sorting systems performing at their potential throughout mine life.
- Proven Expertise Across Commodities and Applications
From pre-concentration of low-grade sulphide ores to waste rejection ahead of heap leach, from diamond recovery to battery mineral beneficiation, ROKKSTA's ore sorting services cover a broad range of commodities and processing objectives.
Sensor-based ore sorting is applicable wherever meaningful compositional, mineralogical or physical contrast exists between valuable and waste fractions at the particle scale - and establishing whether that contrast exists and whether it is practically exploitable, is exactly what we do.
Commodities We Work With
• Calcite & Dolomite
• Chromite Ore
• Coal
• Copper Ore
• Diamonds
• Fluorspar
• Gold Ore
• Iron Ore
• Lead, Zinc & Silver Ore
• Limestone
• Lithium / Spodumene Ore • Magnesite
• Manganese Ore
• Nickel Ore
• Phosphate Ore
• Platinum Group Metals
• Quartz
• Tin & Tungsten Ore
Unit Process Applications
• Particle Sorting
• Bulk Sorting
• Pre-concentration
• Final Recovery
• Waste Rejection
• Contaminant Removal
• Grade Control
- Research-Backed. Operationally Grounded.
ROKKSTA's methodology is not based on proprietary correlations or unverified rules of thumb. Our ore sorting evaluation framework draws on published research, validated physical models and direct operational experience across active sorting installations. ROKKSTA contributes to the advancement of the field through peer-reviewed conference publications and the development of transparent, physically grounded methodologies for ore sorting performance prediction and upscaling.
Our work on single-particle performance prediction - methods for upscaling bench-scale test results to full-machine ore sorting performance with quantified confidence bounds - is designed to give mining projects the same level of analytical rigour for ore sorting that established semi-empirical tools already provide for flotation, comminution and gravity separation.
For ore sorting to take its rightful place as a standard pre-concentration option in mineral processing flow sheets, the industry needs robust technical infrastructure: characterisation standards, validated upscaling methods, accessible engineering tools and evaluation frameworks built on transparent science. Building that infrastructure is central to what ROKKSTA does.
- Get in Touch With ROKKSTA
Ready to optimise your ore sorting process? Our team of experts is here to provide tailored solutions and independent insights.
