Comminution is the reduction of solid materials from large to smaller particle sizes by crushing, grinding or milling. As the need to reduce particle size increases, so the energy consumption increases exponentially.
Comminution accounts for approximately five percent of the total global power consumption and generates similar levels of green house gas emissions. In a typical mining operation comminution circuits may account for over 50% of its power consumption, with power accounting for around 10% of operating costs and grinding consumables (media) accounting for up to 30% of operating costs. In cement production, grinding accounts for nearly 90% of their operating power cost.
Energy efficient crushing technology currently extends down to around the 1-10 mm particle size, below which energy intensive mostly wet attrition and grinding circuits are used to achieve fine grind sizes below 100 microns. The GRolls™ uses both shear and compressive forces to break particles to further extend energy efficient crushing down to product sizes below 100 microns.
The annual global METS comminution market in tertiary and quaternary applications for which the GRolls™ will penetrate is over AUD$2B. The mining sector accounts for around 56% of that global market sales, followed by the cement sector at around 23%.
CBSM has identified four areas for market penetration by the GRolls™ over the next 5 years, being the shift from wet to dry mining processes, grinding of supplementary cementitious materials for the cement industry, wet regrind (quaternary) circuits and the growing market for waste recycling/processing. A small but influential market which the GRolls™ can also penetrate is laboratory and field/exploration testing equipment for research and resource evaluations.
Mine operators are seeking continual capital and operating cost reductions to stay competitive, increasing power efficiencies from their comminution circuits and lower water demands to meet stricter regulatory requirements, higher environmental sustainability and community expectation levels. Mining operations are also becoming more remote as global resources are exhausted, with new lower grade mining operations generally having limited access to water and infrastructure.
The ability to undertake mineral processing using dry circuits reduces the amount of water needed for processing and concentration, which could lead to the elimination of tailings storage facilities that cover large surface areas and reduce the risk of catastrophic failures. Dry processing reduces power consumption, eliminates the need for media and may also improve mineral recovery rates, all providing significant improvements to profitability of future mining operations.
Comparison of wet vs dry mining processing costs
CBSM’s GRolls™ technology may be applied directly for fine-crushing for a range of mineral commodities, including critical minerals. The GRolls™ can be part of a primary flowsheet, mineral by-product recovery from waste streams or reprocessing of tailings. Operated dry, the potential to replace more than one comminution stage and reduce water and energy consumption, is significant. Replacing wet re-grind with wet “re-crush” prior to cleaning circuits engenders further energy savings.
The GRolls™ could provide an economic sustainable solution to tailings reprocessing as it can also be operated wet for reprocessing old tailings at their in situ moisture content, removing the requirement for drying prior to re-processing.
The GRolls™ can provide energy and water savings and enabling dry mining processing unit operations. Coupling GRolls™ with other new unit operations, such as coarse/fine mineral flotation, brings greater efficiencies and further reductions in footprint. The resulting benefits of much reduced or eliminated wet tailings cannot be overestimated. At smaller scale, such as for low tonnage process streams, drill site applications and container modules, power requirements using renewable energy sources becomes attractive.
The GRolls™ could be used to augment existing wet or dry process equipment, including wet regrind circuits, providing additional power and cost savings by reducing the recirculation loads on existing circuits. Mobile GRolls™ units could also be used to assess and pre-process satellite deposits or be part of in-pit crushing & conveying (IPCC) units.
These features are significant and commercialisation of the GRolls™ could facilitate the unlocking of previously un-economic mineral resources.
The cement industry is one of the largest green house gas emission industries and is striving to provide more sustainable products by using increasing amounts of supplementary cementitious materials (SCM’s) and other additives to reduce cement contents. Grinding of clinker and SCM’s such as slags and fly ashes incurs very high power consumption.
The GRolls™ can dry crush limestone clinker, slags and fly ash to minus 40 micron sizes at a lower power consumption than VRM’s. The GRolls™ is also able to crush moist or wet feed material such as fly ash tailings for reprocessing.
The reprocessing of waste materials, including E-Waste, is a growing industry, and energy efficient comminution is sought as part of processing and adding value to bulk waster materials. The GRolls™ is able to process wet or dry materials and produce consistent crushed products which enhances the process of separation and winning valuable commodities. Energy and cost efficient crushing may also be used to process waste such as recycled glass and concrete into reusable materials to further enhance the communities push for sustainable circular economy products.
Our Alpha GRolls™ unit is a laboratory scale unit that can process up to 1tph of minus 20mm dry or wet feed material. The unit is suitable for laboratories and research organisations that require size reduction of materials as part of mineral studies, with the GRolls™ providing a very close match to operating processing crushing results.
The laboratory scale GRolls™ is also suitable for trailer mounting such that it could be taken to exploration or mine sites and process bulk samples to produce a product during feasibility studies for further laboratory testing. The crushing will provide a large homogeneous sample suitable for subsampling and testing required for the specific mineral resource during feasibility studies.