Compression of particles to a fixed final gap is the mode of application of stresses in many crushing devices. Understanding and modeling this particle fracture process is indispensable for comminution operations. The present work is based on detailed compression tests conducted with five different ores to which different deformation ratios are applied to characterize their size-dependent fracture energy distribution and progeny size distribution. An energy-based model is proposed to describe single-particle breakage by compression based on three modes, which define whether the particle is classified for breakage (classification function), the likelihood that the classified particle is sufficiently nipped to break (breakage probability), and the extent of breakage the particle will undergo (breakage distribution). Expressions that allow the calculation of the energy absorbed by the particle in both primary and secondary breakage are proposed by explicitly accounting for particle thickness, stiffness, and the fixed applied final gap. Model verification is demonstrated, with the model predicting the breakage response and energy consumption for single-particle compression experiments performed on a bench-scale with all materials investigated. The validation of the model is shown by accurately predicting, without any fitting, the progeny size distribution and overall energy consumption of compression using fixed gaps and breakage in a double roll crusher.

Fehrite (MgCu₄(SO₄)₂(OH)₆·6H₂O) from the Casualidad mine (Sierra de Alhamilla, Almería, Spain) was described in 2021 as a new member of the ktenasite group. This secondary sulphate had been previously found in the Les Ferreres mine (Rocabruna, Ripollès, Catalonia, Spain) in 2012 and was reported by amateur collectors as a potential new mineral. The available samples, however, still lack a formal characterization. The aim of the present work is to investigate the fehrite from Les Farreres, which contains light green to bluish-green aggregates of very elongated tabular crystals of the mineral, typically forming parallel to radial acicular clusters. It occurs in association with brochantite, devilline, gypsum, and minor connellite, among others. SEM–EDS, Raman spectroscopy, and X-ray diffraction (XRD) data confirm that these crystals correspond to fehrite with the empirical formula Mg₀.₇₇Cu₃.₃₉Zn₀.₆₁S₂.₀₈O₈(OH)₆·nH₂O on the basis of 20 O atoms per formula unit, consistent with Mg dominance at one of the cation sites, Cu at the two other sites, and Zn in substitution of both Mg and Cu cations. The refined monoclinic unit-cell parameters (s.g. P2₁/c) are a = 5.626 Å, b = 6.137 Å, c = 23.861 Å, β = 95.21°, and V = 820.5 ų, which closely match the published data for the type material. The paragenesis of fehrite from Les Ferreres is also discussed and compared to that of the type locality.

The Tamdroust copper deposit, located in the Bou Azzer–El Graara inlier (central Anti-Atlas, Morocco), is hosted in Lower Cambrian carbonate–siliciclastic formations. Copper mineralization is structurally controlled by an N110°–N150° fault system and occurs mainly within greenish siltstones and dolostones deposited in a shallow marine platform setting influenced by terrigenous deposits. Two mineralization styles are recognized: disseminated sulfides in host rocks and vein–veinlet stockworks along fracture corridors. Three paragenetic ore stages are distinguished: (1) early disseminated and veinlet-type bornite–chalcopyrite–pyrite associated with quartz–calcite; (2) hydrothermal enrichment along fault zones marked by the replacement of bornite by chalcocite, together with digenite and covellite; and (3) supergene weathering producing native copper and secondary carbonates (malachite, azurite, tenorite). Sulfur isotope data (δ³⁴S ≈ +10.2‰) indicate a dominant contribution from thermochemical reduction of evaporitic sulfates. Carbon and oxygen isotopes in calcite (δ¹³C = –3.6 to –2.6‰ VPDB; δ¹⁸O = –15.8 to –15.2‰ VPDB) suggest hydrothermal fluids at moderate temperatures (~150–160°C) derived from mixed meteoric–basinal brines. The spatial distribution of mineralization reflects redox-controlled precipitation at the interface between oxidized hematite-rich red beds and reducing green siltstones and carbonates. These results support a model of epigenetic, stratabound copper mineralization formed during Hercynian tectonic reactivation of Cambrian carbonate–evaporite sequences. The Tamdroust deposit shares strong similarities with Jbel N’Zourk and Jbel Laassal, providing a predictive analog for regional exploration targeting redox interfaces and structurally focused brine pathways.

We studied the specific effects of NaCl, KCl, MgCl₂ and CaCl₂ on the ability of sodium dodecyl sulfate (SDS) to inhibit the coalescence of the bubbles in water and to make foam. We related our observations with the thermodynamic data about the activities of the salts and water using the model of Pitzer for each particular salt. Moreover, we measured the surface tension of each particular foaming solution, which allowed us to calculate the adsoprtion parameters of SDS in the presence of the different salts. All these allowed us to look at our main experimental data from different perspectives. As we have expected, the addition of each one of the salts to the aqueous solution of SDS significantly decreased its critical coalescence concentration (CCC). Yet their effects on the ability of SDS to make foam were various. For example, NaCl significantly increases the foaming ability of SDS, while KCl acts as foam suppressor. MgCl₂ boosts the ability of SDS to make foam, while CaCl₂ appears to be foam suppressor. Sodium (Na) and Potassium (K) belong to the 1A group of the Mendeleev’s periodic table, while magnesium (Mg) and calcium (Ca) belong to the 2A group. Sodium (Na) is a foam booster, while potassium (K) is a foam suppressor. Magnesium (Mg) is a foam booster while calcium (Ca) is a foam suppressor. The two pairs of chemical elements have identical electronic configurations in their last electronic layers. The only difference between them is in the radii of their atoms. This difference draws difference in their ionization potentials, polarizabilities, hydration numbers and all related thermodynamic parameters. We developed a detailed analysis, thus drawing the conclusion that the larger counter-ions act as flocculants of the surfactants, thus becoming foam suppressors, while the smaller ions act as foam boosters.

In seeking to improve efficiency in the mine to mill process, mining companies are incorporating ore processing variables during ore planning and scheduling stages to improve decision making. Therefore, the accurate modelling of these ore processing variables has become more critical.

This case study presents a D-vine copula modelling process applied to predict recovery (Rec) from three geometallurgical variables, that is, Bond Work index test (BWi), resistance to abrasion and breakage index (A*b), and semi-autogenous grinding (SAG) power index test (Spi), using a dataset consisting of 775 diamond drill core samples of the four geometallurgical variables from the Tarkwa Mine in Ghana. The distributions of the four variables were used to create a geometallurgical model to predict values of Rec based on SPI, BWi, and A*b using a 10-D version of copula-based quantile functions, which can be integrated in the mine planning and scheduling process. The module produced an average predicted recovery of 89.26% compared to an observed average recovery of 88.64%. A mean absolute error of 4.41 was obtained indicating an acceptable module performance considering the observed recovery values, which suggests that the model's predictions closely align with the observed values.

This modelling framework enables the creation of a geometallurgical block model that not only improves the prediction of metallurgical variables but also significantly improves the integration of geological and metallurgical information, thereby optimizing processing outputs, project revenue, and cash flows for mining companies.

Located 30 km southeast of the Tagragra d’Akka inlier, Jbel Addana forms part of the Ordovician Jbel Bani chain within the Paleozoic cover of the Moroccan Anti-Atlas. The area is composed of weakly metamorphosed Upper Ordovician detrital units, mainly quartzites, shales, and sandstones. Metallogenically, it corresponds to a mining district comprising several mineralized zones, among which the Central Plateau represents the largest deposit. Lithostratigraphically, the sequence includes interbedded sandstones, shales, and quartzites of the Rouid-Aïssa Formation, overlain by the Upper Ktaoua shales and capped by Second Bani quartzites. Geological mapping focused on lithostratigraphic architecture and structural features controlling mineralization. Petrographic, metallographic, and Scanning Electron Microscopy (SEM) analyses were conducted to identify mineral assemblages and alteration stages. Electron-microprobe analyses were performed to determine the chemical composition of ore bodies. Structural data were processed using Win-Tensor software to reconstruct the paleostress responsible for fracture formation and ore emplacement.

Mapping revealed that competent units of the Rouid-Aïssa Formation preferentially host mineralization. Ore bodies occur as N110°E–N130°E vertical subparallel veins with regular spacing, carrying lead and copper mineralization. Metallographic and Scanning Electron Microscopy (SEM) observations indicate two main paragenetic stages: (1) a hydrothermal stage marked by quartz, galena, chalcocite, stromeyerite calcite, and siderite; and (2) a supergene stage characterized by anglesite, cerussite, covellite, malachite, smithsonite, and iron oxides. Microprobe analyses show that galena contains minor gold and bismuth (88.77 wt.% Pb, 12.48 wt.% S, 0.76 wt.% Bi, 0.72 wt.% Au) with a structural formula of Pb1.04Bi0.01Au0.01S0.94.

Structural analysis indicates that mineralization is hosted by a dense network of regularly spaced joints. Win-Tensor results show that these fractures were opened under a sub-vertical σ1 stress controlled by the Hercynian uplift of Precambrian basement blocks. This stress regime promoted fracture opening along the anticline hinge, enabling hydrothermal fluid circulation and ore deposition.

This work is a mineralogical study of fluorite samples (colourless, yellow and purple) from the mining districts of Villabona-Arlós and Caravia-Berbes (Asturias, Spain). It integrates data from UV fluorescence microscopy, SEM-EDS, fs-LA-ICP-TOFMS and fluid inclusions. Different growth stages were identified, some with abundant fluid and solid inclusions, and, in yellow fluorites, yellow bands alternated with colourless bands. UV fluorescence microscopy revealed growth bands with emissions of varying intensity and colour. SEM-EDS identified growth bands with inclusions of barite and celestine crystals, rich in aqueous fluid inclusions containing the same trapped minerals. In one fluorite crystal, an innermost colourless zone contained primary H₂O–NaCl–CaCl₂ fluid inclusions with trapped barite/celestite. Surrounding this zone was a yellow band full of tiny barite/celestite inclusions and an external colourless band hosting H₂O–NaCl fluid inclusions and sulphides. This growth zoning supports a fluid‑mixing process previously proposed by other authors. Such mixing induced a local transition from oxidizing to reducing conditions, facilitating the shift from sulphate to sulphide precipitation. Trace and ultra-trace element analyses by fs-LA-ICP-TOFMS were performed in the fluorite growth bands. The designed analytical conditions (15 μm spot size, 3-3.5 J/cm² fluence, 5 s of background and 5 s measurement, Ca as internal standard, NIST610 and 612 as external standards) show the REE distribution at a single crystal level. The REE patterns have an enrichment in the MREE, a positive yttrium (Y) anomaly and a LREE impoverishment. Yellow growth bands have higher REE and yttrium concentrations compared to colourless bands and violet fluorites. The bands with higher UV fluorescence intensity are those with higher concentrations of REE and Y. The results confirm that fluorites from the Villabona-Arlós district contain more ΣREE than those from the Berbes District. These results are consistent with bulk-sample chemical analyses reported by other authors (Sanchez et al., 2010).

Between 2020 and 2050, global tailing generation is projected to reach 300 Gt. When poorly managed, mine tailings pose significant environmental and safety risks, contributing to more than 2,650 recorded deaths since 1915. Despite this, the mining industry continues to rely heavily on reactive waste strategies—repurposing and reuse—rather than preventing tailings at the source. Ore-sand, a by-product derived from mineral processing, offers a preventative pathway. This opportunity stems from the realisation that most mineral waste originates from discarding dominant minerals—particularly silicates—that could instead be mined as fit-for-purpose by-products. Ore-sand has demonstrated strong technical feasibility as a substitute for natural sand, the world’s second-most consumed resource. An estimated 50 billion tonnes of natural sand are extracted annually from rivers and coasts, with environmental and social consequences particularly severe for communities in coastal regions. Successful implementations already exist. Vale’s Brucutu iron ore mine produces around 2 Mt of ore-sand per year, while Newmont’s Cadia copper–gold mine has demonstrated the viability of coarser ore-sand production using HydroFloat technology. However, despite these promising examples, no comprehensive method currently exists to estimate ore-sand resources, reserves, and recoverable quantities as a by-product, nor to align these estimates with application-specific and market-driven requirements such as particle size distribution, shape, elemental and mineralogical composition. In this study, we present the first framework for estimating ore-sand resources, reserves, and recoveries across different sand applications. We evaluate key factors influencing ore-sand generation, including primary commodity production, mineral processing circuits and technologies, market-based performance criteria, and market absorption. This framework provides a crucial foundation for understanding the true valorisation potential of ore-sand, including the volume of tailings that can be avoided, the degree to which natural sand extraction can be offset, and the extent to which ore-sand can meet the technical requirements of various sand applications.

Emerging frontiers in mineral science emphasize the need for sustainable, low-impact materials that leverage waste resources while delivering functional performance for advanced applications. In this study, agro-industrial waste—specifically rice husk ash combined with excess aluminum sulfate—was transformed into synthetic alkali feldspar particles through a rapid sol–gel process. The resulting powder exhibited an optimal chemical composition of 59.33% SiO₂, 16.42% Al₂O₃, and 7.12% alkali oxides, confirming its successful conversion into a synthetic feldspathic mineral. The product also displayed a high lightness value (L* ≈ 100), indicating a bright white chroma suitable for reflective and thermal management coatings. X-ray diffraction patterns further verified the presence of albite, orthoclase, quartz, and thenardite phases, demonstrating the formation of mixed alkali feldspar and associated phases.

To assess its application potential, the synthesized alkali feldspar was incorporated into a paint matrix and applied to a glass substrate. At a low particle concentration of 1.59%, the coating reduced thermal conductivity to 1.03 W/m·K, whereas a higher particle concentration of 7.90% increased conductivity to 1.68 W/m·K relative to the control substrate of 1.07 W/m·K. Optical microscopy confirmed well-dispersed particles within the coating layer, suggesting favorable compatibility and dispersion behavior.

Overall, the findings highlight waste-derived alkali feldspar as a tunable, sustainable mineral resource with promising applications in energy-efficient coatings, reflective surfaces, and thermally adaptive construction materials—aligning with innovative future opportunities in material resource development.

Advancements in materials development continue to drive innovations in sustainable and resource-efficient construction materials. Coconut shell ash (CSA), a byproduct of using coconut shells as fuel in industries, is a good resource to utilize because of its abundance. This study explores the potential of waste-derived coconut shell ash (CSA) as a material resource-based micro-filler for concrete, aligning with emerging frontiers in waste resource utilization. CSA was incorporated at 10% by volume as a partial sand replacement to evaluate its influence on the physical, mechanical, and thermal performance of the composite. Comprehensive chemical, mineralogical, and morphological analyses were conducted on both CSA and CSA-modified concrete.

Results show that CSA addition slightly reduced concrete density from 1.813 to 1.760 g/cm³ and increased apparent porosity and water absorption to 1.77% and 7.68%, respectively. Mechanical performance decreased moderately, with flexural strength declining from 4.60 MPa to 4.02 MPa and compressive strength from 6.76 MPa to 6.04 MPa. Thermal conductivity, on the other hand, increased from 0.451 to 0.490 W/mK, attributed to the intrinsic porous microstructure of CSA, as shown in Figure 1.

Overall, CSA incorporation significantly influences the physical and thermomechanical behavior of concrete. While the mechanical properties slightly decrease, the findings highlight the potential of CSA as a viable waste-derived resource for developing greener, low-impact construction materials, contributing to breakthrough directions in sustainable material/mineral engineering.