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By Mirjana Boskovic

LKAB’s Kiirunavaara Mine is a sublevel caving iron-ore mine located above the polar circle in northern Sweden. The mine has been proclaimed seismically active since 2008 after a magnitude 3 seismic event, according to Swedish National Seismic Network (SNSN). At that time the Kiruna Mine did not have mine-wide seismic system. Since then, the Kiruna Mine experienced several damaging seismic events of which the largest one on the May 18, 2020. The magnitude, based on the moment tensor inversion results on data from the SNSN as well as seismic stations in Finland and Norway, is estimated to 4.2 ± 0.2 moment magnitude. The seismic event on the May 18, 2020 was located in the middle of the one of the productions areas and caused the major damage in the mine, damaging several kilometres of drifts on six mining levels, some of them beyond the practical repair. These damages affected four of ten production areas on several levels, some more some less. Luckily, no person got injured from the seismic event and the very long aftershock series. An important part in the whole process after the seismic event was information flow and decision-making process. It was very important to keep workers and community informed as that contributed transparency of decision-making and decreased the speculations. Resuming the production in the damaged areas in the safe manner, very soon become main focus for the mine management. It was obvious that not only rehabilitation of the areas is needed to resume the production. It was A MUST to understand the factors behind the seismic event and its mechanism to be able to avoid same situation and prevent seismic event of similar size. Mine engineers had to think outside the box to find the solutions to ‘rescue’ every drift that they could to be able to make good enough base for continued mining of the area. The paper describes actions taken in a very complex process of recovering the area that we from the beginning thought need to be abandon. Seismological analyses of the event on May 18, 2020 and past activity in the area, damage mapping, detailed studies of structures and geology, numerical modelling as well as engineering judgement were used as base for all our decisions how to proceed in attempt to restore mining of the area heavily damaged by 4.2 moment magnitude seismic event, in a safe way.

Apr 26, 2022

By J. D. Miller, C. L. Lin

From mine to mill, the 3D characterization of particles ranging in size from meters to micrometers is now possible. A brief review of X-ray tomography for mineral processing is given with recent advances considered, such as high-speed scanning and image analysis procedures to describe important particle properties, including size, shape and composition. Considering these new 3D characterization tools, applications in mineral processing are discussed for high-resolution X-ray microtomography (HRXMT) laboratory analysis of particles ranging from 20 mm to 5 μm, with a voxel resolution of about 1 μm, including (1) multiphase particle characterization by HRXMT and comparison with scanning electron microscopy (SEM), (2) particle damage state as a result of blasting/comminution, (3) liberation characterization to describe expected separation efficiency, (4) exposed grain surface area analysis to explain the flotation of locked particles, and (5) floc size, shape and water content for polymer-induced flocculation. Finally, applications in mineral processing for plant-site analysis using high-speed X-ray computed tomography (HSXCT) are examined, including, for example, coal washability analysis, the analysis of crusher plant products, and the analysis of pebble phosphate products from central Florida. Scanning rates on the order of 1 kg/min for particle sizes ranging from 150 mm to 1 mm are possible, with a voxel resolution of about 100 μm. For coarse particles smaller than 5 to 10 mm, high scanning rates of more than 300 t/h may be possible at a voxel resolution of about 1 mm.

By E. -R. Niinikoski, M. A. Islam, H. Mischo, G. Barakos, J. Joutsenvaara, G. Meissner

European Union's transition to a low-carbon and digital economy highly depends on securing the strategic autonomy of the Critical Raw Materials (CRMs) supply chain. This paper introduces a European Commission-funded research and innovation action, AGEMERA, which aims to create detailed geological and people's concerns maps to unlock the CRMs potential in Europe. Furthermore, the project will develop educational packages for schools and universities, publish online CRM-related games and news flashes, and arrange public events to ensure a basis for socially accepted and sustainable exploration and mining of CRMs in Europe. 1. IntroductionCritical Raw Materials (CRMs), crucial for shifting to a low-carbon and digital economy, should focus on maintaining Europe's overall supply-demand balance (Birol, 2022). Therefore, to proactively address the surge in demand and ensure the strategic autonomy of European industrial supply chains, the exploration and extraction of CRMs must be scaled out across the continent. Moreover, mobilizing Europe's domestic potential is vital for the EU to become more resilient and to establish open strategic autonomy as the demand for CRMs continues to increase quickly on a global scale (European Commission, 2021). Base metal extraction and mining have a long history in Europe. Nevertheless, CRMs mining projects have shown less success, although these have a lot of potential (Guzik et al., 2021). The main barriers are a lack of investment in mining and exploration, complicated and drawn-out national permitting processes, and low levels of public support (European Commission, 2020). It is necessary to have a vast amount of knowledge and intelligence about CRM's potential and market impact. Novel non-invasive geophysical survey techniques that enable sustainable exploration must be created and used to enhance mineral system models of ore deposits incorporating CRMs. The minerals policy framework significantly influences the mining industry's performance, stability, and sustainability. However, the EU Member States' mineral policy frameworks differ significantly (MINLEX, 2017). In addition, the Fraser Institute Annual Survey of Mining Companies offers concrete information on how managers and executives of mining companies view key policy areas that impact mining activities in the jurisdiction in which they operate or are familiar (Jackson & Green, 2015).

Feb 1, 2023

By Jose A. Gomez, Javad Sattarvand

Failures of tailings dams have been happening lately. Due to the lack of laws on particular design criteria and stability requirements related monitoring during construction and maintenance, they are thought to be more fragile than hydraulic dams. Monitoring the dam is therefore necessary to understand its current condition and guarantee its safety. The physical condition of the dam could be evaluated with the early identification of seepage. Additionally, due to their adaptability and capacity for high-resolution data collecting, UAVs are an excellent choice for efficiently covering the tailings dam site. UAVs may capture high-quality photos when equipped with a high-resolution RGB camera, thermal sensors, or multispectral sensors. When these sensors are paired with image processing and machine learning algorithms, the result is a reliable estimate of the dam condition.

Jun 25, 2023

By Yongjun Peng, Yufan Mu

Pyrite depression in the flotation of copper ores is difficult due to the activation of Cu2+ ions on pyrite surface. In this study, the radical chain reaction involving the redox cycling of Cu(I/II) induced by sodium metabisulphite (MBS) was exploited to selectively depress the flotation of copper-activated pyrite at pH 8.0. Electrochemical measurements revealed that the presence of Cu2+ and O2 was essential to the formation of SO•− 5 through sulphite oxidation, the main entity to convert the activating species Cu(I)S on pyrite to Cu(II)-hydroxide/sulphate, causing deactivation of pyrite. The depression role ofMBS on pyrite flotation was closely associated with the type of grinding media which affected the electrochemical conditions of flotation. When forged steel was used as the grinding media, a high dosage of MBS was required to depress pyrite, but a low dosage of MBS could almost completely depressed pyrite when high chrome steel grinding media was used. This is because high chrome steel produced a stronger oxidation condition with a higher amount of Cu2+ and O2 which promoted the formation of SO•− 5

Jan 26, 2021

By C. J. Slaughter, S. P. Harteis, L. L. Chasko, D. W. Alexander

The Department of Health and Human Services (HHS), National Institute for Occupational Safety and Health (NIOSH), Office of Mine Safety and Health Research (OMSHR), with the assistance of cooperating underground mining operations and state agencies, has conducted research exploring devices and technologies that could be used to assist miners navigating through smoke and dust resulting from a fire or explosion. Recent events in mines confirm that smoke and dust can enter and contaminate mine escapeways, creating an atmosphere with severely reduced visibility. This reduced visibility results in substantially increased escape times, possible disorientation or confusion, and increased stress levels, and may prevent evacuation altogether. Tools or devices that assist miners in navigating through smoke-filled areas void of lifelines could make the difference in successful escape from the mine. This paper presents the results of OMSHR research to identify and evaluate tools and devices that could provide meaningful information to evacuating miners in areas with limited visibility and without the benefit of a lifeline.

Jan 1, 2011

By Dong Yang, Jicai Han, Xiaoshuang Guo, Tichang Sun, Zhengyao Li

Straw charcoal was used as a novel reductant in the co-reduction roasting of laterite ore and red mud. The influence of the reductant dosages, co-reduction temperature, and co-reduction time were investigated. Results showed that a powdered ferronickel product of 1.81wt.% nickel and 81.40wt.% iron was obtained under straw charcoal dosage of 15wt.% and roasted at 1250 °C for 80 min. The corresponding recovery of nickel and total iron were 97.21wt.% and 98.87wt.%, respectively. The performance of straw charcoal was also compared to that by the conventional coke reductant. Results showed that ferronickel particles using straw charcoal were larger in size than coke, mainly due to the lower S (0.14wt.%) and ash content (3.80wt.%), which could not hinder the agglomeration of the ferronickel grains, and lower melting point that producing liquid phase and promoting ferronickel particles growth. In addition, the gasification reactivity of straw charcoal is better than that of coke, which is beneficial to the iron oxide reduction and the recovery of iron. To conclude, straw charcoal is a promising reductant for the co-reduction of laterite ore and red mud in coal-deficient areas.

Aug 12, 2021

By C. R. DeGennaro, Yongjun Zhang, J. Bickson, J. L. Carr, Chenming Zhou, J. R. Srednicki, B. Lambie, M. Girman, J. A. Galanko

Between 2005 and 2021, surface mining haul trucks were involved in 54 fatal incidents in the United States [1]. Collision warning and avoidance systems (CXS) can help haul truck operators navigate their route safely. The evaluation of CXS object detection performance for surface mining haul trucks relies on the positional accuracy of the ground truth instrument. As part of a holistic approach, researchers from the National Institute for Occupational Safety and Health (NIOSH) characterized the accuracy of a global navigation satellite system (GNSS) that serves as the ground truth instrument to determine object position and velocity in CXS object detection performance testing. We used precision surveying equipment to establish ground truth points for comparison with GNSS data collected for static positional measurements and reduced-scale straightline vehicle dynamic tests. We conducted these tests with real-time kinematics (RTK) and then satellite-based augmentation systems (SBAS). For the dynamic tests, we measured a distance error of 1.34 m (4.40 ft) using RTK and 1.50 m (4.92 ft) using an SBAS. This research will provide CXS manufacturers and CXS researchers a basis for evaluating the positional accuracy of CXS. Note that we did not evaluate any CXS in this experiment.

Feb 1, 2024

By Erik Klohn

The El Soldado copper deposit occurs in volcanic rocks of alkaline affinity of Lower Cretaceous age. The orebodies are discordant and show strong structural and lithological control. The mineralizing event was accompanied by hydro- thermal alteration expressed as carbonatization, silicification, and chloritization. Individual orebodies contain bornite-chalcopyrite cores which are surrounded by haloes dominated by chalcopyrite and pyrite respectively. The sulfur isotope composition of copper sulfides strongly suggests the sulfur is of magmatic origin. Fluid inclusion studies show the mineralizing fluid to be a highly saline NaC1-CaC12, brine. No evidence of boiling was found. The deposit is most likely of epigenetic origin. Hydrothermal fluids were produced during crystallization of a sodium rich trachytic magma during the waning stages of an episode of alkaline magmatic activity. Similar copper deposits along the Chilean Coastal Range may also be associated with alkaline host rocks.

Jan 1, 1986

By Neha Shukla, Nikhil Dhawan

The current study examines the extraction of rare-earth elements from trichromatic phosphor of discarded tube lights via baking processes. The Y2O3: Eu3+ (YOX) and BaMgAl10O17: Eu2+ (BAM) phases completely decomposed during acid and alkali baking with > 90% Eu and Y extraction. Prior, selective acid leaching of the YOX phase enhanced the acid baking process at a lower temperature (< 230 ℃). Feed acid baking showed a maximum 87% Tb, 36% La, and 17% Ce extraction at 500 °C, 0.5 h, 1 ml/g H2SO4, and alkali baking yielded 16.1% Tb, 86% La, and 73% Ce at 300 ℃, 0.5 h, 50 wt.% NaOH. The acid baking of the acid-leached phosphor yielded 72% Tb, 95% La, 63% Ce, ~ 95% Y, and Eu extraction at 300 °C, 0.5 h, 1.05 mL/g H2SO4. Lower Tb extraction during the acid baking of acid-leached phosphor can be attributed to the formation of Ba3Tb( PO4)3 and BaTbO3 phases. Insoluble Si3Tb5 phase formation and partial decomposition of CeMgAl11O19: Tb3+ (CMAT) phase in the alkali baking route leads to lower Tb extraction. The acid baking process is suitable for extracting Tb, Eu, and Y, whereas the alkali baking process is suitable for La and Ce. The thermal analysis of phosphor and flux interaction depicts that alkali baking is less energy-intensive than acid baking. In comparison, the one-step acid baking process and the two-step alkali baking process yielded desirable extraction results (87% Tb, total RE (rare earth) 78.5% and 50.4% Tb, total RE 59.3%). The product yield in the acid and alkali baking route of feed, acid-leach phosphor is 36%, 29%, and 39%, 28.2%, respectively, with ~ 98% mixed rare-earth oxide purity.

May 5, 2022

By Emre Karakaya, Niyazi Bilim

Boreholes are used for many purposes in mining operations, petroleum engineering, and construction works. Numerous factors affect the performance of drilling equipment. Researchers continue to work on the variable drilling parameters that can be adjusted in order to reach more efficient drilling operations. Penetration rate is an essential indicator in drillability analysis and estimating. This parameter is of great importance in mining projects. There are almost no models that can estimate the penetration rate for core drilling operations. Under the abovementioned circumstances, this paper focuses on developing models that allow estimating the penetration rate based on rock material properties. During the conduct of this study, drilling experiments under 11 different pressure forces were performed on 8 different rock units, and the equations which estimated the penetration rate depending on the physico-mechanical properties of the rock samples were derived. Experiments were carried out under different pressure forces to investigate the effect of the pressure force on the derived estimation models. The obtained results allowed deriving equations that ensured estimating the penetration rate based on the physico-mechanical properties of the rocks and the applied pressure force. Using these equations, the penetration rate in core drilling operations can be estimated.

Sep 30, 2020

By T. M. Yegulalp

A new explanation of the scale dependency of the strength properties of rock is presented based on the theory of extremes. A review of past work on specimen size strength relationship is followed by an introduction to the fundamentals of the underlying theory of extremes and its relationship to the scale effect on the statistical properties of the strength distribution. It is shown that the weakest link theory is directly related to extremal statistics and properties of strength distributions of rock can be derived as a function of the specimen size. Three sets of Brazilian test data are used to demonstrate the use of this approach.

Jan 1, 1992

By Rambabu Pothina, MELO EDUARDO PIMENTA DE, Rajive Ganguli

 The mining industry is home to a mass of sensor-generated data that are critical to real-time and long-term optimization. This heavy reliance on sensor data has resulted in an undesirable development. The industry is reluctant to verify the accuracy of sensors as it would mean shutting down important processes. Sensors are typically calibrated once a year, if at all. Errors in sensors go undetected until the next calibration or until errors are so gross as to be obvious

By Peter Zhang, Todd Minoski, Gabriel Esterhuizen, Jack Trackemas, Berk Tulu, Morgan Sears

Longwall mining is a highly productive and efficient coal mining method used in the USA. During longwall retreating, the belt entry must be maintained stable, and any roof fall in the belt entry would jeopardize mine safety and substantially interrupt the continuous production of coal in the longwall face. Past experience of longwall mining has shown that belt entry stability was the greatest challenge in longwall ground control, and the occurrence of roof falls in belt entries was largely associated with high horizontal stress. To properly support the roof in the belt entry, it is important to understand how longwall-induced horizontal stress changes affect roof stability in belt entries and to strategically install supplementary support to prevent any potential roof falls. Researchers from the National Institute for Occupational Safety and Health (NIOSH) performed horizontal stress measurements in the immediate roof of the belt entries for two Pittsburgh seam longwall panels oriented unfavorably to high horizontal stress. Hollow inclusion cells (HICells) were installed in the immediate roof at the intersection in each of the belt entries, and stress changes were monitored as the longwall face was approaching and passing the intersection. Numerical models were set up to calculate the longwall-induced horizontal stress changes in the roof at the monitoring sites. With the verified model, investigations were made of how horizontal stress is concentrated and relieved in the belt entry roof near the face under different panel orientations. Both measurements and modeling results showed that high horizontal stress is concentrated in the roof in the belt entry within about 15 m outby the face when a longwall panel is unfavorably oriented to the major horizontal stress. The study demonstrated that longwall-induced differential horizontal stress can be used as an indication of the degree of horizontal stress concentration. Roof support strategies are discussed on how to maintain the stability of belt entry under high horizontal stress concentration.

Jun 14, 2022

By Abegail Endraca, Allan Sebastian, Andrew Raine, Allan Patdu

The project involves the construction of a new aqueduct tunnel by an Earth Pressure Balance TBM tunnel for the Novaliches-Balara Aqueduct No 4 (NBAQ4) project in Metro Manila. It comprises a 7.3 km long and 3.1 m internal diameter tunnel that can deliver up to 1,000 MLD of raw water and the tunnel passes under urban residential and urban populated areas adjacent to and along Commonwealth Avenue. A new reservoir intake structure was constructed in the La Mesa reservoir by a cofferdam and the TBM breakthrough connected the reservoir to the outlet surge shaft structure and the downstream pipe network system connecting to the Balara Water Treatment Plant. The TBM incorporated a double articulated head configuration to allow tight 80 m radius curves to navigate some of the difficult alignment considerations. The alignment passed very close to some existing foundations for MRT7 and needed to clear several tight curves to remain within government land ownership. The project excavated through the local Guadalupe weak rock formations and there was minimal ground movements observed as a result of the work.

Jun 13, 2023

By Dennis K. Mortensen

The warm southwestern desert of Arizona is an ideal location for ASARCO&apos;s new Sacaton Unit. The climate of this arid region played a major role in the design considerations of the Unit&apos;s crushing and concentrating facilities. Low yearly rainfall and relatively high yearly temperatures are a combination that was taken advantage of when designing the surface facilities. The plantsite, located due west of the mine pit, is in an area originally covered with sparse desert vegetation, underlain to an average depth of 125 feet by desert alluvium. The entire plantsite area slopes gently to the southwest at approximately 1%. Ground conditions at the plantsite area were not acceptable for construction due to the collapsability of the wetted soil when under loaded conditions, Overburden from the pit area was used to form the foundation for the entire plantsite. This waste material, entirely devoid of rock, was placed and compacted to an elevation approximately 20 feet above the desert floor. Elevating the plantsite by filling with waste material not only provided an adequate construction foundation but also eliminated the possibility of flooding from run-off in the surrounding desert areas.

Jan 1, 1974

By K. L. Ludeke

For many reasons it appears that deep-rooted, perennial shrubs offer potential for improved stabilization and provide maintenance-free vegetative cover to harsh sites where perennial grasses have not been successful. The very fact that a drought-adapted shrub has a massive root system that can use moisture from a greater volume of mineral waste soil materials suggests that long-range arid environment resource development may be greatly enhanced by utilization of desirable forage shrubs. An effort is underway to assemble information and plant materials of promising species from many arid regions of the world. Surprisingly, many of the better plants for arid sites are quite high in protein content, and with proper management, breeding, and selection may prove to be very desirable livestock feed. Advancements in arid-land solid waste stabilization hold favorable promise for many industries that mine and mill in arid regions for effective reclamation of disturbed areas. Particularly exciting is the possibility of establishment of high density maintenance-free vegetative cover of climax vegetation that reclaims the disturbed area back to its original land use. Because of high shrub productivity, stabilization potential, nutritional quality, and reclamation success, greater use should be made of shrubs in disturbed land reclamation associated with mining and milling operations in harsh arid environments.

Jan 1, 1984

By A. Bascetin

Materials produced in quarries have been used for different intentions such as concrete and cement raw material, asphalt and embankment aggregates, railway ballast. Especially in cement manufacturing, the chemical composition and the uniformity of the raw materials play a strategic role in the economy and quality of the cement process. Therefore, it is necessary to achieve uniformity and desired chemical composition and maintain these at all production stages according to the type of cement produced. To achieve this goal the production planning and pit design play an essential role. This paper briefly outlines the production optimization of cement raw materials in a quarry in Istanbul western part of Turkey. For the purpose it was used the 3D ore body modeling and the geostatistical techniques. The variation of chemical components (%CaO, %Al2O3, %Fe2O3 etc.) and quality control parametres (LSF, SR, AR and etc.) obtained from the quarry were determined. Then the values of unknown chemical components and quality control parameters in the ore body were estimated using Kriging which is one of the geostatistical interpolation methods. The open pit design was also created by specifying wall slopes and taking into consideration of the grade distributions of the benches. The most important revolution in the paper is investigating the effects of the block dimensions in block modelling which is important for reserve estimation. The other important point in the study is using the different range values in variogram analysis for determination optimal reserve estimation. n this study, the effects of two parametres on reserve and waste amount estimation were determined according to CaO% distribution. The study was pointed out that the changing of the two parameters are very important for the optimal mine planning and environmental considerations.

Jan 1, 2010

By Eduardo Pimenta de Melo, Rambabu Pothina, Rajive Ganguli

Sensors are everywhere in the mining industry, with sensor information being used to monitor and operate processes. Therefore, when sensor information is wrong, economic losses can occur. Unfortunately, sensor errors are usually not detected till they become large. This is problematic as most calibrate their sensors no more than once a year (Beamex, n.d.). Using principles of data mining, where all relevant information is tapped to glean hidden information, Pothina [8] designed an algorithm to detect errors in temperature sensors in gold stripping circuit in Pogo mine, Alaska. This paper continued his work by analyzing the behavior of the algorithm on baseline data and testing the algorithm in new data and under more rigorous conditions. It also made a change to the algorithm. The modified algorithm performed very well in the new data. It also worked well under the new error conditions. Three types of errors were seeded, a fixed additive error (+ 2%), a fixed subtractive error (− 2%), and a noisy, normally distributed error, with a mean value of + 2%. Artificially seeded errors were detected within about 20 gold stripping cycles. Inherent bias in operation impacted algorithm performance by increasing the number of cycles needed to detect errors. This paper reinforced Pothina’s [8] conclusion that when data mining approach is used, sensor errors can be detected even when they are pretty low. Significant economic losses can thus be minimized.

By Gordon C. ‘Bud’ Presley

The pumice and pumicite review arrived too late for the June issue. Estimated domestic production of pumice and pumicite in 1992 was up compared with 1991, according to US Bureau of Mines statistics. The Bureau estimate of domestic production of 400 kt (440,000 st) for 1991 turned out to be 401 kt (442,000 st) of actual production, the lowest since 1989. In 1992, the estimated the value of pumice and pumicite sold or used in the United States was $11.6 million, up only $200,000 from the 1991 value. There was an increase in the mine, or mill, average price from the five-year low of $11.44/t ($10.37/st) in 1986 to $26.42/t ($23.96/st) in 1992. Estimated tonnage produced in 1992 was 439 kt (484,000 st). Apparent domestic consumption was 642 kt (707,000 st), up 135 kt (149,000 st) from 1991. Imports for consumption were estimated to be 215 kt (237,000 st) last year. Domestic production supplied 68% of the demand in 1992, with net imports supplying the remaining 32%. This compares with domestic production sup¬plying 53% and net imports supplying 47% of the apparent consumption in 1988. Exports were about 900 t/a (1000 stpy) for the period 1984 to 1988. In 1989, exports rose sevenfold to 7 kt (7700 st) and to 20 kt (22,000 st) in 1990. The Bureau of Mines reported that the amount of pumice and pumicite exported in 1992 was 12 kt (13,200 st). It is assumed that these exports were from the Pacific Coast because imports, mainly from Greece, continued to be a market factor on the East Coast and the Gulf Coast States in the United States.

Jan 1, 1993