ABSTRACT Blasting performance is influenced by rock fragmentation, seismic vibrations, and breakout profiles, which are traditionally assessed using empirical methods and field trials due to the lack of a unified blastability framework. This study presents an operational implementation of enhanced signature tests combining Single-hole blastablity indexing and traditional signature hole tests to systematically quantify burden-dependent blasting conditions and requirements. The method addresses key parameters such as specific charge, fragmentation, and vibration attenuation, combining empirical field measurements with analytical and computational tools. Two enhanced signature hole tests, four conventional signature shots, and two large-scale production blasts were conducted at a limestone quarry in Montreal Canada. Results demonstrate how enhanced tests can derive site-specific relationships between burden, energy input, and blast outcomes, enabling improved prediction of blast efficiency and fragmentation. This work establishes a consistent procedural framework for blastability indexing, supporting more reliable, scalable, and data-driven blast design practices across varying geological conditions.

ABSTRACT To prepare for the electrification of a haul truck operation in a Canadian underground environment, battery swapping and fast charging were virtually compared for an eight-truck fleet, considering productivity, durability, fleet logistics, and total power requirements. A haul truck with a 42-t capacity was simulated. Duty cycles prescribed battery activity, consisting of stationary, driving, and recharging phases. A thermally coupled equivalent circuit model and battery degradation model were used. A parametric study considered fast charging versus pack swapping, pack capacity, route distances, and battery-to-truck ratios for swapping, producing complex output. For durability, larger pack sizes, lower charging power, short routes, and high battery ratios increased battery lifetimes. Energy consumption ranged from 12 to 23 kWh/km. Swapping required from 5% to 27% less energy per km compared to fast charging. For fast charging, one battery lasted from 1.5 to 4 years to 60% state of health, while for swap scenarios, two batteries lasted from 1.5 to 7 years. Compared to diesel, electric trucks had 90% productivity but required less than one-third of the energy. The tracking of battery health in a comprehensive fleet context for two electrification modalities is entirely novel. A deeper techno-economic assessment is a next step.

ABSTRACT This research examined the plant of an anonymous aggregate production company, hereafter called Quarry X, focusing on how to reduce failures and improve crushing efficiency. The plant has faced unplanned downtime and decreased production capacity, necessitating an assessment and proactive maintenance strategy. Key performance indicators were calculated, revealing an efficiency of 43.9%, a production availability of 61% (and therefore downtime of 39%), and mean time between failures of approximately 10 hours. This result highlighted ore, equipment, and maintenance issues as the main causes. Using Bruno simulation software, we devised solutions, such as replacing the pan feeder with a grizzly feeder, to increase capacity and enhance efficiency, ultimately boosting Quarry X’s production and industry competitiveness.

ABSTRACT This study evaluated the optimization of open-pit design at a nickel mining site. Two sales schemes were assessed: direct nickel ore sales and processed ferronickel sales. The Lerchs-Grossman algorithm was implemented. Technical and economic parameters, stripping ratio, selling price, and mining costs were used to evaluate the net value and reserve distribution. The ore sales scheme yielded 2.4 times more reserves than the ferronickel scheme; however, the ferronickel scheme produced a net value that was 1.9 times higher, as the ferronickel scheme had a higher nickel (Ni) content.

ABSTRACT This study aimed to determine the current state of gold (Au) prospectivity and the characteristics of gold panned from the Osu area in southwestern Nigeria. Soil, heavy mineral samples, and gold nuggets were collected from artisanal mining pits. Heavy mineral samples were analyzed using scanning electron microscopy (SEM). Trace elemental composition of soil samples was determined using inductively coupled plasma-mass spectrometry. The morphological, mineralogical, and micro-chemical characteristics of gold grains were determined using TESCAN integrated mineral analysis. SEM revealed that the heavy minerals associated with the gold are sub-rounded to sub-angular ilmenite, baddeleyite, quartz, zircon, and staurolite. The Au concentration from the pits ranged 0.1–40.5 ppb, with higher concentrations of 33.3–40.5 ppb observed around 12–15 m and 12.3 ppb around 10–13 m. The Au nuggets varied 10–900 µm and were elongated and sub-angular to rounded, which implies that they were close to their source. The Au grains were composed of 88.3–100% Au and 0–11.7% silver, with ilmenite-rutile, cassiterite, columbite, kaolinite, monazite, chamosite, and iron oxide as accessory minerals. Gold exploration in soils around Osu should target depths of 10–15 m, which are associated with anomalous gold concentrations in this study.

ABSTRACT To date, multiple methods, including experimental and numerical approaches, have been proposed to address the behavior of a tunnel colliding with a dip-slip fault. However, the potential of artificial intelligence techniques remains largely untapped for evaluating tunnel behavior. In this study, three predictive models were applied to forecast fault displacement and tunnel fragility: multilayer perceptron (MLP), self-organizing map (SOM), and nondominated sorting genetic algorithm (NSGA). The MLP model excelled in predicting displacement associated with dip-slip faults (R 2 = 0.99), suggesting an extremely high level of forecast accuracy. Additionally, SOM analysis revealed that the behavior of continuous tunnels in response to varying angles of normal faults is more complex than that observed with reverse faults. Notably, lowering the height-to-diameter ratio (h/D) and decreasing the fault angle below 70° dramatically increased tunnel fragility, adversely impacting its performance. Furthermore, the findings from NSGA indicate that dip-slip faults with angles 50–63° coupled with low overburden heights (3.5–6 m) pose a serious and substantial risk to the stability of thick, continuous tunnels.

ABSTRACT The use of battery electric vehicles (BEVs) over diesel-powered machines as mobile production equipment in underground mines provides improved working conditions due to the elimination of diesel exhaust gases and diesel particulate matter, reduced heat output, and lower noise level. Another benefitis the reduction of vehicle energy consumption due to the higher efficiency of electric motors over diesel engines. Electric vehicles and equivalent diesel-powered machines have been presumed to consume energy at a ratio of 1:3 based on diesel engine (33%) and electric motor (95%) efficiencies. However, engine-to-motor efficiency is only one of the drivetrain components needing to be considered. Field trials were carried out at several underground mines in the European Union and Canada to quantify the actual BEV-to-diesel energy consumption ratio. These trials show the observed energy consumption ratio to be considerably lower than the hypothetical ratio, varying between 1:6 and 1:4 for near-horizontal grades and between 1:9 and 1:7 for inclined grades. This paper discusses causes of the difference, including the influence of regenerative braking, as well as presents a preliminary assessment of equipment heat output.

ABSTRACT Cobalt (Co) is a critical metal key to a successful global energy transition. The Democratic Republic of the Congo (DRC) contains more than 50% of the world’s Co reserves, positioning it as a leading source, with an estimated market share of 76% in 2023. However, a non-negligible share of the DRC’s Co originates from artisanal and small-scale mining (ASM), which is highly criticized due to serious ethical and environmental concerns; these concerns negatively impact the perception of DRC mineral extraction. The U.S. Department of Labor has therefore blacklisted DRC Co. This embargo on Co will prevent the DRC from realizing its ambition of using the profits from the exploitation of mineral resources to expand socioeconomic development. This article describes DRC ASM, examines the role it could play in addressing the challenges of the nation’s socioeconomic development, and suggests a procedure to improve the applicability of mining laws and regulations.

ABSTRACT New dynamic models of overwind arresting and crash beam impact of the conveyances of a multi-rope friction winder are developed. These models treat the descending head ropes as axial components with distributed mass and stiffness. Using explicit analytical solutions derived for the crash beam impact model, an example case is analyzed. Compared to a previous model by Greenway that treated the descending ropes as rigid bodies, this analysis predicts significantly lower head rope tensions on both the ascending and descending sides of the winder drum for crash beam impact. The predictions of the new overwind arresting model are compared to two previous models by Hamilton and Greenway for the same example winder. While some variation in the results is apparent, the numerical values are all similar. On the other hand, the time histories of the new model show better correlation with Hamilton’s numerical simulation than with the rigid rope model of Greenway. A wave propagation effect is evident in the new model output as well as in Hamilton’s method. This and the use of a model for a constant force arrestor demonstrate the importance of modeling the flexibility of the descending head ropes—particularly for deep shafts.

ABSTRACT Reaching an informed decision about optimal drill-hole spacing (DHS) is an essential task in geostatistics that adds value to mining projects. The optimal DHS is sensitive to many factors, including inherent geologic characteristics of the deposit, mining and operational parameters or constraints, economic factors, the purpose of the mineral resource estimation, and the metric to be optimized. Final estimates at the grade control (GC) stage of mining are meant to maximize the correct classification of mineable volumes. When considering dedicated GC drilling, DHS optimization for profit balances the cost of estimation uncertainty and the cost of drilling. The drilling amount is optimal when drilling less would incur large estimation costs and drilling more would incur large drilling costs. We developed a DHS framework for regularly spaced drilling aimed at maximizing profit in GC. Each of the steps are described in detail, including sequential Gaussian simulations, resampling, estimation, transfer function customization, mineable limits definition, and final profit calculation. The DHS framework is demonstrated on a realistic data set, followed by a sensitivity analysis to relevant factors. This work establishes a conceptual foundation and provides practical details for developing DHS optimization for final estimates in mining operations with dedicated drilling systems.