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By T. Gupta, T. Ghosh

Rare earth elements (REEs) and their compounds are essential in a multitude of mundane and sophisticated applications such as renewable energy technologies, catalysts, medicine, and defense applications. The global supply deficit could be attributed to the destabilization of REE market that has, as a result, incentivized indigenous production of REEs. Cost-effective and environmentally benign opportunities are being explored for the production of REEs from non-conventional mineral sources including coal and coal by-products to stabilize the supply chain. Coal from Healy coal mine and Wishbone Hill deposits in Alaska have been quantified for REEs and were found to possess elevated total REE concentrations as compared to world average levels (60– 70 ppm). The objective of the study was to concentrate the REEs in the froth phase by froth-flotation of the fine size fraction (< 75 μm). A Box-Behnken design of experiment was employed to ascertain the main and interaction effects of operational parameters on response variable by analyzing 3D response surfaces. Experiments were carried out to maximize REE recovery and concentration by modeling and optimization of three operating variables (frother dosage, pulp density (% solids), and collector dosage). Based on the results, the optimum flotation conditions for maximum recovery at an elevated concentration of REEs in the froth fraction was obtained at 4.2% solids and 32.7 ppm of frother dosage for Healy sample and 10% solids and 37.9 ppm of frother dosage for Wishbone Hill coal sample. The quadratic relationship between the input and response variable was found to be independent of collector dosage suggesting good surface hydrophobicity and floatability of the two coal samples.

By R. Berton, M. Walden, S. Melberg, N. Rocco

Recent tailings dam failures around the globe have influenced many mining industry regulators to reassess their requirements for the numerical modelling of tailings dam failures. This type or forward modelling is associated with overarching uncertainties as the model cannot be calibrated against a physical result. Dam breach analyses that meet the requirements of current industry standards and guidance typically begin with identification of credible failure modes and selection of appropriate topographic data set to represent the study area. The breach parameters and the volume of tailings released are then determined using available methodologies and empirical relationships. Subsequently, when the breach hydrograph is developed and the hydrology of stream networks are complete, the runout simulation is implemented. Due to the uncertainty involved in the process, sensitivity analyses are recommended to quantify variations in model inputs on the inundation extent and the flow characteristics. This paper outlines some common methodologies utilized for development of dam breach models, summarizes associated uncertainties with these methodologies and inputs, and provides guidance on how sensitivity analyses can address a wide array of uncertainties inherent in tailings breach analyses. This paper provides an understanding of how selecting appropriate breach parameters can result in reasonably conservative inundation extents consistent with the identified credible failure modes.

Mar 2, 2022

By J. Ye

A comprehensive flotation study has been carried out on a Chinese fluorspar ore using the packed flotation column developed at Michigan Technological University. The results are compared with that of a conventional mechanical flotation method on the same feedstocks. Key factors controlling flotation performance of both methods are evaluated based upon a simple statistic design. The flotation concentrate produced in one stage of the packed column has 4-S% higher recovery and much lower silica impurity content than that produced by up to six stages when a conventional mechanical cell is used. The results also show that the packed column flotation process is particularly suitable for recovery of finer fluorspar particles.

Jan 1, 1992

By Rosario Lunar, Jesús Martínez-Frías, Egidio Marino, Trinidad Torres, Jose E. Ortiz, Juan A. Martín-Rubí, Luis Somoza, Ricardo León, Teresa Medialdea, Javier González

Seamounts, submarine banks, volcanoes and undercurrent channels are prominent geomorphic features that have become an important target for minerals research and exploration with the goal of future exploitation. Polymetallic ferromanganese deposits are common types of mineralization on these settings. Co-rich ferromanganese crusts are important as potential resources of Mn and Co, but also Ti, Ni, Tl, REEs, PGEs, and other metals. Many seamounts and channels along the Atlantic Spanish continental margin are known to hold mineral deposits but are poorly studied. This work presents and briefly describes the most recent activities of the Spanish Geological Survey (IGME) on exploration and investigation of ferromanganese deposits along the Atlantic Spanish continental margin. Different submarine areas from the northwestern margin of the Iberian Peninsula to the west off Canary Islands have been surveyed by geophysical, sampling and underwater observations from 89 to 4000 m water depth. The mineral deposits cover a large diversity of submarine geological and geomorphical features: mud volcanoes and diapirs related to hydrocarbon seeps, seamounts associated with hot spot volcanism, hydrothermal vents in active magmatic volcanoes, structural basement highs and banks or contourite channels. Considering the collected dataset, we present the preliminary results of the study of these mineral deposits, including ferromanganese nodules and crusts and phosphate pavements and nodules, which can be considered as potential sources of raw materials.

Sep 1, 2014

By H. Kellerwessel

This paper refers to the new crushing and grinding process, which was invented by Professor Schönert (Ref.1), Clausthal, Germy (author of one of the papers presented at this meeting). The process is known as high pressure particle bed comminution or interparticle crushing. Several papers by Professor Schonert and his coworkers and by specialists of the companies producing the necessary equipment under license agreements already described fundamentals of the process, the equipment used, results of lab size and large scale tests and finally the first results of truly commercial operations (Ref .2 to 11). Therefore it should be sufficient to summarize the main facts here: - To a bed of bulk material a pressure of more than 50 MPa is applied. Comminution is achieved mainly by the pressure which one particle transfers to the other and not by squeezing single particles between the working surfaces of some crusher or grinding media.

Jan 1, 1987

By Gary B. Glass

In 1997, 92.3% or 235.7 Mt (259.8 million st) of coal produced in Wyoming came from the Wyodak coal zone in the eastern Powder River coalfield. The mined portions of the zone consist of one to three beds of coal with an aggregate thickness between 15 and 33.5 m (50 and 110 ft). The thickest expression is 61 m (200 ft). The delivered coal from this zone averages 0.33% sulfur, 5.12% ash and 19.98 MJ/kg (8,590 Btu/lb.). This coal zone occurs at or near the top of the Paleocene Fort Union Formation, which is overlain by the Eocene Wasatch Formation. There is also production from two coalbeds in the lower portion of the Wasatch at the southern end of the basin. Production of coalbed methane derived from the Wyodak coal zone is currently an estimated 289 Mm3/a (10.2 billion cu ft/year). This production is occurring west and downdip from the coal mines and is increasing each year.

Jan 1, 1998

By P. J. Bethell

In the froth flotation process the detrimental effect of slimes on the froth flotability of valuable minerals has long been known.1 Work by Aplan2 on the froth flotation of coal has shown that the presence of clay slimes causes loss in flotation selectivity, and recovery of combustibles. Obviously then the presence of clay slimes to any great extent in the froth cell feed in a coal preparation plant is undesirable. This problem is exacerbated in plants treating raw 600 um (28#) by zero material due to the variation in flotation with size. The net effect of this phenomenon in a bank of cells treating raw minus 600 µm (28#) material s that by the time adequate flotation of the coarsest size fractions has occurred the finer sizes are already producing undesirable high ash material, which often leads to unacceptable overall quality. Reduction in aeration rate and/or chemical addition to combat this, further decreases the flotation rate of the coarsest fraction leading to heavy losses of coarse low ash coal to the tailings. The above mentioned characteristics formed a key aspect of the fine coal circuitry design at Elk Run Coal Company in Sylvester, WV. The plant was designed to produce compliance steam coal (less than 1.20 lbs. S02/million b.t.u.) Desliming ahead of the froth flotation was included, as the slimes in the plant feed were clay rich, had very high ash levels, and low potential recovery. Lab testwork had also shown that poor selectivity would be expected if raw minus 600 um (28#) material was froth floated.

Jan 1, 1986

By Arthur B. Johnson

Potassium, is one of the three basic plant nutrients along with nitrogen and phosphorus. There is no substitute for potassium compounds in agriculture; they are essential to maintain and expand food production. Potash is found throughout the world in both soluble and insoluble forms. It is only the soluble forms that are economically attractive to process, primarily chlorides and sulfates, with potassium chloride by far the most important potash salt. Sylvinite ore, a mechanical mixture of sylvite (KCl) and halite (NaCl), is a natural mineral of potassium. This ore is found in commercial quantities in the Permian sin region near Carlsbad, New Mexico. Vast tonnages of high-grade de, low-clay-content ores have been mined and concentrated during the past 40 years; however, these deposits are rapidly being depleted leaving high-clay, low-grade ore reserves of over 135 million tons. These ores, containing 13 to 22 percent K20 and 3 to 8 percent clay slimes; cannot be effectively processed by current commercial flotation methods. The present concentration processes for potash minerals in Carlsbad relate mainly to ores containing 1 percent or less of clay-slimes with a K20 content of 20 to 25 percent to yield products to meet the requirements of the agriculture market, namely, 95 percent KC1 equivalent to 60 percent K20. Discoveries of potash ore in Saskatchewan, Canada, have shifted the emphasis on expansion outside the United States. Presently, the American companies are looking to Canada for future growth, expenditures, and expansion. Four of the seven companies operating near Carlsbad are produces of Canadian potash despite the large investment sons required for shaft sinking and milling installations.

Jan 1, 1970

By H. H. Murray

Abstract. World reserves of bauxite are abundant. Domestic reserves are limited and as a consequence the United States must rely on foreign suppliers for over 90 percent of its bauxite. Nationalization of many bauxite mining operations, levying of higher taxes, increased production and transportation costs, and attempts to create a uniform market price combined to place the United States in a vulnerable position. Alumina from kaolin, alunite, anorthosite, and oil shale have-been-or are being evaluated. World bauxite reserves are increasing and attempts to establish a uniform price have failed; therefore, it may be many years before domestic non-bauxite sources of alumina can compete with imported foreign bauxite.

Jan 1, 1980

By R. J. Mirville

Flocculation is an important step in the treatment of coal preparation waste waters. The effects of polymer charge and molecular weight and solution pH and ionic strength on the adsorption and flocculation characteristics of a series of polymeric flocculants on some typical waste water constituents have been studied experimentally. The results indicate that the nature and extent of flocculation are strongly system-dependent. For the case of coal, both adsorption and flocculation behavior can be correlated with the polymer conformation in solution. For the mineral constituents, on the other hand, adsorption and flocculation depend also on the surface properties of the solid.

Jan 1, 1979

By Rajat Gangrade, Haotian Zheng, Jarrett Smith, Daniele Nebbia, Mike Mooney

The application of artificial intelligence (AI) to improve tunnel boring machine (TBM) operations requires a significant amount of information to train robust performance prediction models, e.g., for tunneling-induced settlement, productivity, tool wear, etc. This paper presents the AI framework applied to the North-East Boundary Tunnel (NEBT), the largest component of the Clean Rivers Project in Washington, DC. The paper focuses on required elements for real-time AI use to estimate tunneling-induced ground and building deformation and cutter tool wear. Keys to the framework include defining the necessary quantities of data required as well as the process of windowed training, validation and model testing. To date, the models developed for ground deformation and tool wear show satisfactory performance when compared to observed field observations during tunneling.

Jun 13, 2021

By A. Porvali, V. Agarwal, M. Lundström

Hydrometallurgical recovery of rare earth elements (REE) from NiMH battery waste can be performed using sulfuric acid leaching followed by selective precipitation as double salt (REENa(SO4)2•H2O) by adding Na2SO4 as a precipitating agent. The formed double salts can be treated further with NaOH solution to form REE hydroxides. This study focuses on metamodeling of a simulated flowsheet with design of experiments (DOE). Based on literature survey, a process flowsheet was developed using HSC Sim software. The created flowsheet focuses on circulation of solution containing Na+, K+, SO42- ions and impurities liberated in the NaOH treatment of double salt precipitate. The effect of seven parameters (P1-P7) on seven responses (R1-R7) were modeled using central composite design (CCD). INTRODUCTION Nickel metal hydride (NiMH) battery waste can be considered as an urban mineral due to the presence of valuable metals like: Ni, Co and rare earth elements (REE) (Larsson et al., 2013). In NiMH battery waste leaching experiments, sulfuric acid has often been employed as a lixiviant (Pietrelli et al., 2002,Zhang et al., 1999,Rodrigues and Mansur, 2010,Porvali et al., 2018). The key advantages of sulfuric acid are its stability and cost-effectiveness compared to other mineral acids such as HCl and HNO3. However, the usage of sulfuric acid in NiMH battery waste leaching poses simultaneous challenges and advantages. Limited REE solubility can be taken as benefit when recovering REEs double sulfates after solid-liquid separation. However, sodium and potassium hydroxide, present in electrolyte residues in the battery waste, can cause in-situ precipitation already during leaching due to limited solubility, thus decreasing the total REE recovery (Porvali et al., 2018). However, this problem can be circumvented by washing the electrolyte residues off the raw materials. Subsequently, the REEs may be precipitated in bulk as a mixed double salt out from the solution at very low pH with minimal co-precipitation of Ni and other metals. This relatively easy separation method can be extremely advantageous in the case of such a complex solution matrix with relatively high REE concentrations (conc.). Once REEs have been precipitated as double sulfates as per eq. (1) (Porvali et al., 2018), the resulting double salt precipitate lacks applications without further treatment. Direct thermal treatment would generate sulfur dioxide emissions and likely require high temperatures in order to transform double sulfates into REE oxides. Furthermore, the precipitate contains Na ions, which would need to be removed by chemical treatment from the calcined REE product. In the context of circularity of raw materials, it can be taken of a remarkable benefit if the sodium and sulfur present in the double salt could be reused instead of wasting them into the side streams. To that end, in this simulation study, the double salts are converted by dissolution and precipitation to hydroxides which are readily treatable, e.g. with total dissolution and solvent extraction, for further purification (Abreu and Morais, 2010):

Jan 1, 2019

By W. Hu

Gravity concentration has been the main method for tin ore beneficiation, based on the significant difference of density between cassiterite and gangue in the tin ore. However, with the exhaustion of rich and coarse reserves, the proportion of tin distribution in slime be-comes as high as 50 to 70% and has a size range of -19 urn. In some sulfide tin ore, most of the tin is of the minus 10-urn size fraction, and thus slime processing has gained importance in tin ore processing. Some innovations are being developed, such as the centrifugal cone separator, belt concentrator, slime table, B-M separator, and slime flotation. Direct flotation with tolyl arsonic acid has been practiced with success.

Jan 1, 1989

By YUSONG MIAO, DI WU, XIANRONG YAN, YIPING ZHANG, JIE LIN, KEBIN LI

Rock fragmentation has been a concern in hard-rock mining for the mining industry. Rock fragmentation distribution is an important index to measure the blasting effect. It not only affects the cost of drilling and blasting, but also affects the efficiency of subsequent operations, such as loading, transportation and secondary crushing.

By Billy W. Parks

This paper reports on the first 2 years in operation of a special-purpose coal handling rig which provides blending, temperature reduction, and continuous, automatic mechanical sampling as part of midstream barge to ship coal transfers. Briefly reviewing some of the characteristics of coal handling peculiar to midstream transfers, the paper discusses how the most beneficial aspects of midstreaming were enhanced through the design of this blending and sampling rig.

Jan 1, 1986

By Peter I. Brooker

The semi-variogram, the basic tool of geostatistical estimation procedures, must itself be estimated from the available data. From a numerically simulated two dimensional deposit, with known variability expressed through its semi-variogram, the standard arithmetic mean estimator is used to calculate experimental semi-variograms. These are determined on a series of data sets obtained from the deposit with various sampling grids which cover different areas of the deposit and which have a wide range of available data. The orders of discrepancies between estimated and theoretical semi-variograms are determined in this idealized situation; and this provides a basis against which to assess experimental semi- variograms made on field data.

Jan 1, 1982

By Jerry F. Fountain

Variations in ore grade, mineralogy, and copper pricing structures over the life of the Inspiration mine have mandated many modifications to the treatment methods to maximize process economics. In the 1970&apos;s, copper prices generally declined, while inflation, wages, and interest rates increased. A metallurgical treatment route had to be developed for this continuing economic climate which would be capable of minimizing labor, energy, and capital cost requirements. After many years of development, the patented "Ferric Cure" process was introduced to satisfy these requirements. This dump leach process for treatment of mixed oxide/sulfide ore includes: strict mineralogical control of ore placed for leaching, controlled leach pad construction, solution saturation and curing of the pads with higher acid concentrations, and, finally, rinsing of the cured pads for removal of dissolved copper. Leach solutions, high in sulfuric acid during the cure application and low in sulfuric acid during the rinse, contain sufficient ferric iron to enhance the leaching of chalcocitic sulfide minerals.

Jan 1, 1983

By Georgios Bartzas, Vasiliki Karmali, Konstantinos Komnitsas, Anna Kritikaki, Dimitra Vathi, Stylianos Tampouris, Arne Peys

Large volumes of slags, with varying mineralogical and geochemical characteristics, are produced annually by the ferrous and nonferrous metallurgical industry. Most of them are considered as potential secondary resources and may be valorized, following the principles of circular economy, for the recovery of critical elements, including energy transition metals. Apart from the economic benefits, valorization of slags may contribute to the competitiveness of the metal industry and the conservation of natural resources. Valorization also results in minimization of environmental impacts on soils and waters in slag disposal areas, due to the prevention of solubilization and subsequent migration of potentially hazardous elements. The present study utilizes ferronickel (FeNi) slag for the production of alkali-activated materials. The effects of the main experimental parameters, including sodium hydroxide (NaOH) molarity, silica/sodium oxide (SiO2 /Na2O) molar ratio in the activating solution, precuring and curing time, curing temperature and aging period on several properties of the final products, are assessed.

Apr 1, 2025

By Paul R. Thomas

This paper addresses two issues affecting the international ferrochromium market as they pertain to the changing pattern of U. S. chromium import dependency. These issues are 1) the long-term ferrochromium production cost differential between the United States and the Republic of South Africa and 2) the ability of Zimbabwe to expand ferrochromium production and exportation. This paper draws upon the data and analyses of a recent Bureau of Mines Minerals availability Program appraisal that evaluated the international availability of chromium in the form of chromite and ferrochromium from 10 market economy countries. South African ferrochromium producers are shown to have a long-term production cost advantage over U.S. producers of $0.03 to $0.04 per pound of contained chromium, in 1981 dollars. Zimbabwean ferrochromium production and exportation are expected to increase in the future. Major expansions of production capacity will be dependent upon alleviating potentially serious constraints in electric power, rail, and port facilities. In the long term, ferrochromium production costs in Zimbabwe are expected to increase faster than the rate of inflation, because as chromite mining from the podiform resources in Zimbabwe decreases, production from the Great Dyke resources will increase.

Jan 1, 1984

By L. A. Readdy

Defining classes of ore using geostatistical methods that match historical classifications has presented problems in the past. A simplistic and practical approach to this problem is presented. An example of the approach is presented using a porphyry type system as a case study. The technique described uses area of drill hole influence and known conditions from similar deposits, or the production history of the deposit being studied. It provides a practical bridging mechanism for defining the class of ore on a block-by-block basis using .the error of estimation value developed during kreiging. The approach provides a filtering method that refocuses attention on the adequacy of drill hole spacing.

Jan 1, 1985