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By Fahimeh Dehghani, Louis Ackah, Tathagata Ghosh, Justin Godbold, Jia Liu, Meisam Peiravi, Manoj Mohanty, Azam Baharlouei

Primary economical deposits of rare-earth elements (REEs) are exhausting all over the world, and it has become necessary to find new sources and methods for their extraction. In addition, increasing the application of REEs in modern technological society has increased its demand globally. One of the important movements to compensate for the future shortages of critical metals is the recovery of REEs from recyclable materials. This paper presents a review of the classification and extraction methods, as well as general applications of REEs with emphasis on secondary sources such as coal and coal byproducts, iron ore tailings, apatite, and phosphate byproducts. An overview of the current state of knowledge on the various methods of REE beneficiation and extraction is covered. These methods include physical separation, as well as hydrometallurgical and bio-hydrometallurgical techniques. The application of these REE extraction techniques for enhanced recovery has been driven primarily by the unique industrial application of these important elements. This paper further explores the existing and potential environmental challenges associated with REE extraction. The authors have presented a wide array of literature, in-depth discussion of the subject, and a succinct summary of processes and relevant case studies.

Sep 23, 2020

By Jacob Petersen, Jon J. Kellar, Samuel Kessinger, Kiran Green

Belle Fourche Shale was processed and characterized for use as a clay-based ceramic. The shale was wet sieved to produce particles that were ± 150 μm. X-ray diffraction (XRD) revealed that the -150 μm material was enriched in clay content compared to the unprocessed materials, whereas the oversize material was enriched in quartz compared to the undersize sample. Particle size analysis was performed on the—150 μm sample, which showed that the median particle size was around 10 μm. Scanning electron microscopic (SEM) analysis further confirmed the small plate size, which appeared to be primarily layered clay particles. Next, the -150 μm particles were rolled into a green body, dried at room temperature, and fired at 998°C. The fired piece was analyzed by XRD and contained 6 wt% hematite, 55% quartz, 19% microcline, and various other minor amounts of minerals. When fired at 1152 ℃, mullite was found with increasing hematite compared to the 998 ℃ firing. A multi-spectral analyzer was used to quantify the color change of the 998 ℃ fired (orange) to the 1152 ℃ fired (red) samples. Micro-computed tomography (Micro-CT) of the unfired body exhibited very few large pores, while the piece fired at 998°C also exhibited few and small pores, the overall porosity of the fired body increased. Microhardness data, obtained from the aforementioned samples, resulted in Vickers Hardness (HV1.0) values of 70.8 HV1.0 (998 ℃) and 485.7 HV1.0 (1152 ℃). Three-point bend testing was performed, giving an average strength of 23 MPa on pieces fired at 998 ℃. The average bending strength of the samples fired at 1152 ℃, was 55 MPa.

Sep 26, 2023

By Chiranjibi Santi, Amit Kumar Gorai, VIVEK KUMAR HIMANSHU

Air overpressure (AOp) and peak particle velocity (PPV) are the most undesirable effects of blasting in mines. It is an urgent need to design a predictor model for AOp and PPV for universal applications to minimize environmental effects and damages that occur due to blasting. The present study attempts to design an artificial neural network (ANN) model for the prediction of AOp and PPV in different conditions. In this study, the blast design parameters (number of holes, depth of the blast hole, stemming length, spacing, burden, distance of vibration monitoring location from the blast site, charge weight per delay) of two active mines (coal and iron ore) are considered in four different conditions for training and testing of the model for the prediction of AOp and PPV. The model was trained and tested in four different combinations of data (trained using data of one mine and tested using data of another mine, trained and tested using data of coal mine, trained and tested using data of an iron ore mine, trained and tested using combined data of both the mines) for examining the applicability in different conditions. The results indicate that R2 values are ranged from 0.886 to 0.908 and 0.8728 to 0.8959, respectively, in the prediction of PPV and AOp. A comparative study of the performances of the developed model with the other empirical model is also demonstrated. For this, the site constants of different empirical models were estimated individually for both the mines. The study results indicated that the ANN model performs much better than all the empirical models. It can be inferred from the results that blast vibration cannot be accurately predicted only from charge per delay and distance from the blast hole. The ANN model was considered many other factors and thus can predict the vibration level more accurately.

Jul 30, 2021

By S. R. Titley

Results of regional analyses of precious metal habits in Arizona ores lead to interpretations of a fundamental ore control related to geographic location that corresponds with crustal contrasts. Measurements of isotopic and trace element characteristics of Laramide ore-related intrusions lead to interpretations of crustal derivation of apparent ore-related magmas. Interpreted regionally, the numerous kinds of Laramide ores, which include porphyry copper deposits of this southern cordilleran region appear to be phenomena of a specific crustal lithology characterized by a basement of Proterozoic turbidites and (an interpreted) lower crust of amphibolite. This association with a specific basement terrane may be extended in principle from the United states into Mexico where faulted offsets of this basement are similarly favorable to formation of Laramide porphyry ores -to the exclusion of adjacent terranes. Whereas plate tectonic mechanisms may have triggered evolution of these ores, it is hypothesized here that crustal setting and crustal composition are more profound influences of metallogenesis.

Jan 1, 1992

By Serhat Özdemir, Derya Öz Aksoy, Pınar Aytar Çelik, Ahmet Çabuk, Sabiha Koca, Hüseyin Koca

In carbonate flotation, oleate has been used for many years as a collector in industrial scale. Compared to sulfide minerals, the flotation of carbonate minerals requires more collector consumption and has lower yield and selectivity. It has been previously shown that surfactin provides higher yields in smaller amounts than oleate in the bioflotation of calcite as one of the carbonate minerals. In this study, the usability of surfactin as a flotation collector for magnesite was investigated. For this purpose, the adsorption of surfactin on the magnesite surface was inspected with analyses such as FTIR, SEM–EDS, contact angle, and zeta potential measurements. In addition, the effect of surfactin on the surface tension of water was also revealed. The same analyses were also performed for oleate as a reference point. All flotation experiments were performed without optimizing with both collectors. FTIR results showed that the surfactin, like oleate, was chemically adsorbed on the magnesite surface. Surface tension analyses showed that the surface tension of water decreased to approximately 32 N m− 1 at 10− 4 M oleate concentration, and this value decreased to below 25 N m− 1 at the same surfactin concentration. According to contact angle measurement results, the contact angle of magnesite was 85° after the surfactin adsorption of 2 × 10− 4 M concentration, while this value remained at 46° for oleate. Finally, according to flotation experiments, high temperatures and high collector dosages are necessary for acceptable flotation recovery with oleate, yet surfactin can produce the desired result at ambient temperatures and lower collector amounts.

Dec 13, 2022

By Gary D. Aho

The United States on a daily basis no consumes about 15MM barrels (2.38 x 106m3) of oil; 5MM (0.79 x 106 m3) of this is imported. This compares tai a daily consumption of 18MM (2.86 x 106 m3) in 1980 when we imported 8MM (1.27 x 106 m3). We are producing the 10MM barrels (1.59 x 106 m3 ) of conventional oil at home from what amounts to just 2% of our domestic energy reserves. Nearly 90% of our total domestic energy reserves occurs in solid forms such as coal, oil shale, and tar sands; this is more than enough to meet our needs for the next 100 years. Worldwide, oil shale is second only to coal as a potential source of energy and the U.S. has approximately one-half of the world oil shale reserves which average over 25 gallons per ton (10.43 x 10-2 L/kg). Since the United States has immense oil shale resources, including some of the richest in the world, and since oil shale produces a superior transportation fuel, it would seem logical that the U.S. would be prudently developing this domestic resource. Unfortunately, despite over 50 years of research and a number of false starts, there is not a commercial shale oil industry in place today. There are a number of recurring roadblocks which have hindered private industry's efforts to develop oil shale and we will look at some of these.

Jan 1, 1983

By D. J. Gurtler

On January I, 1988, Chino Mines Company initiated the use of a system of economic splits for all materials encountered in mining. All mined material is evaluated as mill ore, solvent extraction-electrowinning plant feed and non-ore material to determine its disposition. Post-implementation studies indicate that a significant increase in financial returns on material mined was realized when compared with the copper cut-off grade previously in use.

Jan 1, 1990

By W. B. Collingwood, D. Misra, T. Ghosh, S. Bandopadhyay

Understanding the variability of sulfur and calorific value in coal seams is critical to planning mining operations and marketing the mined coal. In this study, statistical and geostatistical techniques were used to explore the underlying spatial trends present in a large coal deposit. Eight prediction models for the sulfur content of the coal seam were developed. Six of the models were created using geostatistical techniques, while the remaining two models were created using other techniques. The performance of each model was examined by conducting cross validation exercises. The results of the study showed that very pronounced trends and anisotropies were present in the sample data, which had to be accounted for in the modeling. The study found that a cokriging model using sulfur and ash is the best prediction model for predicting sulfur content in this coal reserve.

Jan 1, 2014

By W. L. Josey

The Stibnite Project is an open pit/cyanide heap leach gold property located in the Yellow Pine mining district of central Idaho. The gold ore is in an oxidized zone of an epithermal deposit which is associated with a fault system related to Tertiary igneous activity of the region. The faults transect a roof pendant of metamorphosed sediments within crystalline rocks of the Idaho Batholith. Seasonal mining is at a rate of 3900 mt/d (4300 st/d) of ore with a 2:l waste to ore ratio. Gold and silver are recovered through a process of cyanidation, carbon adsorption and desorption, and electrowinning. Disposal of the leached ore requires chlorination of the residual cyanide.

Jan 1, 1984

"Cast blasting is the primary means of overburden displacement in a surface coal mine. It serves two purposes; fragmenting the rock and throwing it directly to its spoil pile using explosive energy. Increased throw minimizes costs by reducing the amount of material that needs to be rehandled. Prior studies have shown that by only changing blasthole timing with the same blast design, fragmentation and throw alter. It is necessary in cast blasting to optimize both fragmentation and throw, since larger fragments will require more wasted energy to throw the same distance. In an operating mine in Georgia, an optimum interhole delay for fragmentation has been found by studying timings from 0 millisecond (ms) to 45 ms. Instantaneous timing between holes increased the throw by more than 31 m (100 ft), but fragmentation was poor. Shock and detonation wave collision is a potential reason for this increased throw.Explosives are utilized extensively by the mining industry in order to break rock, as either ore or overburden, for hauling, loading and crushing. An effective production blast strives to achieve optimum rock fragmentation in order to increase the efficiency and reduce the costs of those downstream operations, while simultaneously meeting environmental regulations. The goal of blasting with respect to fragmentation is, according to Hettinger (2015), “to decrease the average particle size of the fragmented rock without overly increasing fines or, in other words, improve fragmentation.”Additionally, the distance the rock is transported by the explosive energy from the blast, also known as throw, can increase efficiency by reducing the amount of material that is rehandled by mine equipment. The primary situation in which this is desirable is the cast blasting of overburden across the narrow pit of a surface coal mine. A key variable in a blast design pattern that can be manipulated to optimize both fragmentation and throw is delay timing between detonations. The invention and increased utilization of electronic detonators have allowed for precise delay timings to be used between rows, holes and even multiple primers within the same hole. These recent developments in the blasting community have also provided an opportunity to investigate whether or not the mechanism of shock or detonation wave collisions caused by short timing delays are responsible for any increased fragmentation or throw. This experiment attempts to demonstrate if an increase in throw can be achieved while maintaining optimum fragmentation."

Jan 6, 2017

By Greg Colzani, Emily Thompson

The 3RPORT Project, includes a 5-mile tunnel excavated by a 19-foot diameter slurry Tunnel Boring Machine below the city of Fort Wayne, IN. The Geotechnical Baseline Report (GBR) indicated vuggy to massive argillaceous dolomite within the tunnel alignment. During excavation of the first reach, the TBM encountered zones of cohesive clay and sandstone presented in full face and mixed face conditions. The occurrence of Sandstone was not a “Baselined Condition” described in the GBR for this reach of the alignment. This paper will discuss the methodology to investigate, mitigate and evaluate the DSC impacts on TBM performance.

Dec 1, 2022

By William I. Weisman

Natural sodium sulfate is obtained from both brines and solid deposits. The brines almost always contain other salts with sodium chloride predominating. They may be obtained from surface occurrences, such as Great Salt Lake or from shallow subterranean deposits. Althought many sodium sulfate minerals are known to exist, only three are of commercial significance. These are thenardite, the anhydrous salt; mirabilite, the decahydrate; and glauberite, the double salt of sodium and calcium sulfate. The reader is referred to Weisman (1983) for details on mineralogy and geology of sodium sulfate minerals. Sodium sulfate deposits, either in the form of brine or solid minerals, are found in many parts of the world. Natural sources, by far, provide the primary supply of commercial grades in Canada, Mexico, Spain, and probably in the U.S.S.R., Chile, Argentina, and Turkey. In the United States, production of natural material and synthetic (including by-product) are about equal in volume and have been for many years.

Jan 1, 1984

By N. Chow

The recovery of manganese from lower-grade resources has been studied for a number of years. Of key importance in prior work was the discovery that higher-valent manganese can be readily leached with sulfurous acid. This eliminates the need for high-temperature reduction roasting that is conventionally used in processing high-grade material. High-temperature roasting is energy intensive, emits a large amount of carbon dioxide and would not be economical for processing lower grade material. While the prior work provides important information for extracting manganese from lower-grade resources, the production of unwanted byproducts and high water and energy usage has limited its commercial use. This paper describes the results from laboratory work that demonstrate solutions to problems that to this point have precluded commercial development. Preliminary mass and energy balances show that a significant opportunity exists in producing manganese with this hydrometallurgical scheme in a low-cost, environmentally friendly manner. The emphasis of the work is on low water use, low overall energy use and economic destruction of unwanted byproducts.

Feb 1, 2012

By Adeyemi Adesina, Subhabrata Mishra, Syed Mohammed Mustakim, Malaya Kumar Jena, Shaswat Kumar Das

Utilization of low-grade manganese ore adopting the carbothermic reduction roasting process is a proven method to produce high-grade manganese ore. To minimize industrial waste and protect the environment, gas cleaning plant sludge (GCPS), which is a solid waste from steel industries, was employed as a reductant to perform the reduction roasting process. The optimum conditions to carry out reduction roasting of the low-grade manganese ore were found to be: a roasting temperature of 950 °C, a residence time of 2 h, 40% GCPS as reductant, and magnetic separation at 5000 G for a manganese ore size of –10 mm. A lowgrade manganese ore comprising Mn grade 31.27% and Fe grade 19.78% having a Mn/Fe ratio of 1.58 containing a high silica content of 26.48% was used for the carbothermic reduction roasting having mineral phases of pyrolusite (MnO2) and hematite (Fe2O3) as found from XRD. The gangue minerals were separated during the magnetic separation, and the upgraded product was obtained, which reached a maximum value of TMn 49.5% with RMn 76.55% and TFe 62.19% with RFe 42.51%. In the study, activated charcoal (AC) was also taken as a reductant for comparative analysis; the experimental results revealed that GPCS performed better than that of the AC, showing potential to be used as a reductant in metallurgical industries. However, the resultedMn/Fe ratio was very low for the reduced sample; therefore, it can be used for smelting along with high-grade manganese ores as a feed.

Mar 5, 2021

By A. L. Slaughter

A mineral deposit has been discovered and explored sufficiently to establish the presence of ore in ?commercially marketable quantities," This is the point at which exploration ends and development begins, Of course, when the presence of commercially marketable quantities of ore are thought to be present the deposit had to be evaluated before this decision could be reached. If, on the other hand, it was thought that commercially marketable quantities of ore are not present, either more exploration has to be done or the project must be abandoned. It is this decision with which this paper is concerned, more particularly, the influencing factors behind this decision. The final question to be answered is: what profit can my company reasonably expect to make by developing this property and putting it into production? The answer must be expressed as a figure for final profit per ton, money which can be used to pay dividends or to build up cash reserves. Some acquisition cost has probably been paid and the exploration cost incurred at the time of decision, (abandonment or development). In addition to returning these acquisition and exploration costs, the deposit must pay development, mining, milling, capital expense of new plants and equipment, taxes, and various other related costs.

Jan 1, 1958

By Laura Suarez, Jörgen Kajberg, Pär Jonsén

In recent years, slag, a residue from pyrometallurgical processes, has become more attractive in circular economy frameworks to increase the efficient use of resources throughout the life cycle of steel products and help in the reduction of carbon emissions. Its applicability is strongly dependent on the particle size, and therefore, the optimization of breaking processes should be approached by increasing the knowledge of the dynamics of slag to promote fracture. Increasing the knowledge on themechanical response ofmanganese slag opens up the potential for the development of cost-effective numerical models, e.g., constitutive models based on inverse engineering calibration frameworks or digital twins. In this study, rate-dependent tests of manganese slag have been performed using a split Hopkinson pressure bar device for testing its dynamic mechanical response. In order to obtain information about the crack initiation and fracture process, 2D ultra-high speed imaging was implemented with a sampling frequency of 663,200 fps for diametrically loaded specimens. Full-field deformation measurements using digital image correlation (DIC) techniques showed a staggered fracture process where failure points on mechanical response curves vary due to the internal events happening in the material. Localized frictional occurrences and inertial effects acting inside the pre-cracked matrix have a strong effect on the global mechanical response, and therefore, a great variability of strengths was obtained.

Nov 3, 2023

By Alexander N. Winchell

"Location. The copper mines of Michigan are all in the northern part of that state on the Keweenaw Peninsula, which extends from the (Michigan) mainland for about seventy miles northeasterly toward the middle of Lake Superior. The mines occur in a belt or zone occupying the central portion of the peninsula from end to end.. The most productive mines for many years past have been those located not far from the city of Houghton in' the central part of the zone, in a section extending about ten miles southwest of Houghton and fifteen miles northeast. The most important mines in order of location, from the northeast to south¬west, are the following: Mohawk, Ahmeek, Allouez, North Kearsarge, Wolverine, South Kearsarge, Centennial, Calumet. and Hecla, Osceola, Franklin, Quincy, Hancock, Isle Royale, Superior, Baltic, Trimountain, and Champion. The first three named are in Keweenaw county and all of the others are in Houghton county. Still farther to the southwest are the Lake, Mass, Adventure, Michigan, Victoria, and White Pine mines. These are in Ontonagon county.History. The exploitation of these copper mines extends back into prehistoric times. There is little evidence that the American Indians carried on mining operations in this region in the period shortly before the advent of white men, but there is abundant evidence that the ancestors of the Indians, •or some earlier inhabitants of the region, carried on primitive mining operations. For example, Mr. S. O. Knapp, Agent of the Minne¬sota Mining Company, in the winter of 1847-48, made the first discovery of prehistoric mining. This event is described as follows by Foster and Whitney :"

Jan 1, 1920

By Giovanni Barla

This paper examines the application of gelatin mixture models to the study of factors such as gravity effects, tectonic and residual stresses, anisotropy, physical nonlinearity, time-dependent behavior of the rock mass and connectedness of the geologic space. The calibration technique of gelatin mixtures, proposed by Richards and Mark in 1966, is applied to the particular problem considered. Similitude relationships between model and prototype are discussed with reference to the constitutive equations describing the physical behavior of the rock mass. The interaction between two openings in a linearly elastic medium, under conditions of plane strain, is used as an illustrative example, with the view of describing the history of stress and deformation changes on the rock medium and lining around a slusher drift while undercuts are made in block caving.

Jan 1, 1968

By Hernan Fernandez, Khalid Saif F S Al- Khayareen, Volkan Salepciler, Jacek B. Stypulkowski

Wakrah and Wukair Drainage Tunnel, WWDT is 13 km long with a 4.5 m ID sewer water tunnel about 50 to 60 m below ground surface. Integral to the project are several adits with provisions for future connections as well as four work shafts, four intermediate access shafts, ancillary hydraulic structures, and an Odor Control Facility. The shaft depths range from 50 to 60 m. The project is constructed in aggressive ground with aggressive ground water. The construction activities require years of pumping and disposal of the ground water during tunneling operations as well as construction of permanent structures in shafts. Grouting of the corrosive rock mass in corrosive groundwater for the WWDT has been described in detail.

Jun 23, 2024

By A. D. Hammond

Vanadium is a transition metal, ductile, silver-gray metal. It is harder than most metals and steels and it has a good resistance to corrosion, it is stable against alkalis, sulfuric and hydrochloric acids. Vanadium is oxidized in air about 660 °C, although an oxide layer forms even at room temperature. The chemistry of vanadium is noteworthy for the accessibility of the four adjacent oxidation states 2-5. In aqueous solution the colors are lilac V2+, green V3+, blue VO2+ and, at high pH, yellow VO42-. Considered to be as abundant as zinc, metallic vanadium is not found in nature, but it is known to exist in about 65 different minerals. Economically significant examples include patronite (VS4), vanadinite (Pb5(VO4)3Cl), associated to the uranium mineral carnotite (K2(UO2)2(VO4)2?3H2O) and in a vanadium mica called, roscoelite K(V3+,Al,Mg)[(Si,Al)4O10](OH)2. Other important vanadium ore oxides are montroseite (V,Fe)O(OH) and corvusite (Na,Ca,K)V8O2.4H2O. Much of the world's vanadium mine production comes from magnetite-hosted deposit and to a lesser extent, in sedimentary-hosted sandstone. Vanadium is also present in bauxite and in fossil fuel deposits such as crude oil, coal, oil shale and tar sands. In crude oil, concentrations up to 1,200 ppm have been reported. A significant vanadium production comes from the processing of petroleum residues, fly ash and recycling spent catalysts. In 2011, metallurgical applications accounted for 93% of the use of vanadium. Here, an alloy called ferrovanadium is utilized to strengthen steel to be used as rebar in the construction industry, in the manufacturing of axles, crankshafts, gears and chassis in the automotive and transportation industries and in the manufacturing of high-speed tools. In the aerospace industry, vanadium is utilized as a titanium alloy in the manufacturing of airframes and jet engines. The reason for the wide use of vanadium as alloy is its high strength-to-weight ratio, the highest of any engineered material on earth. The major non-metallurgical use of vanadium is in the production of catalysts for the chemical industry. The most commercially important compound is vanadium pentoxide (V2O5), which is used as catalyst in the production of sulfuric acid.

Feb 23, 2014