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By Alvaro Lucio

The continuous increase of the fuel oil price compelled CV3D to look for an alternative fuel. Charcoal was selected as the alternative energy source. This paper justifies its selection, describes charcoal properties, the methods for using charcoal in the pelletizing and shows the results of the in-plant tests.

Jan 1, 1982

By Rongjie Kong, Shiwei Wang, Guomin Wei

Owing to the selective oxidation and uneven combustion that occur on the surface of carbon anode, some carbon particles detach and form carbon residue, which is defined as spent anode slag (SAS). The highly graphitized and toxic impurities such as fluorite ( CaF2), corundum (α-Al2O3), and cryolite ( NaAl11O17) are crucial components of SAS resource but are difficult to separate from graphite. This study developed a method of using water-soluble (emulsified) kerosene to separate the carbon particles from the toxic impurities in the SAS resource. The flotation purification approach of utilizing conventional kerosene was experimentally investigated and compared with that of using water-soluble kerosene. The results showed that with the use of emulsified kerosene, the maximum combustible matter recovery of the carbon particles was 89.86% while that of using traditional kerosene was 80.30%. The emulsified kerosene was comprehensively examined by various instruments to clarify its adsorption mechanism on the carbon particle surfaces. Because of the superior dispersibility of emulsified kerosene, it effectively envelops carbon particles with a smooth surface, oxygen-containing functional groups, and hydrophilic C–F bonds, thereby increasing the surface hydrophobicity and flotation responses of targeted carbon particles.

Feb 6, 2024

By V. I. Lakshmanan

Crystalline Flake Graphite is a strategic mineral. Since 1954 nearly all North American consumption has been imported from offshore. The Bouthillier Project in Quebec, Canada, is Orrwell Energy's bid to enter the market. Milling of flake graphite is considered easy, yet more problems have been encountered in flowsheet and plant design than in most other minerals. A fresh approach to existing technology was taken, giving results that are highly satisfactory. The key to graphite liberation without flake deterioration is found to be in autogenous grinding. In addition to producing marketable coarse graphite by such autogenous grinding, flotation and tabling, super purity fines can be produced using repeated regrinding, elutriation and flotation. This paper discusses the design of a 500 TPD plant based upon the results obtained from bench and pilot plant studies.

Jan 1, 1984

By R. B. Crookston

This paper presents the status and mining method chosen by each of the active underground oil shale projects in the united States today. Potential improvements in equipment and methods on the near-term horizon are discussed. The problems and potentials that lie in the long-term future of oil shale mining are examined in light of the demands which must be met by this developing technology.

Jan 1, 1981

By Mark A. White

Arch Mineral has developed several computer programs that aid the surface mine planning function. These programs are utilized to perform long term projections for various area or semi-area stripping operations. The program generated reports include yardage, tonnage, quality and ratio information for the user-specified time periods. The projections are used to anticipate the annual budget, to compare alternative mine plans and to analyze acquisition candidates. The programs are user friendly, fast and accurate. Geological Grid File Two data files must be set-up and used in conjunction with the mine planning programs. These are a geological data file and a general input file.

Jan 1, 1984

By M. S. Frasad

The State of Minnesota is interested in stimulating the development of clay resources and recently supported a two year project to collect data on geological, mineralogical, processing, economic and environmental aspects of such potential developments. This paper presents the .various process options adopted on the bulk samples collected from the Minnesota River Valley area which is a primary deposit and contains a major silica fraction. A standard test flowsheet involving degritting, dispersion, HGMS, and cycloning was developed and for some samples yielded an acceptable filler grade product. Secondary streams containing relatively high grade kaolin but of coarse size were also obtained. Improvement in particle size distribution and in physical properties related to paper product specifications (brightness, viscosity) were obtained by size reduction processes. Market and economic considerations for kaolin consumption in the upper Midwest are analyzed. Current markets for paper grade kaolin in Minnesota were briefly discussed.

Jan 1, 1990

By B. J. Arnold, F. F. Aplan

Prior laboratory work has demonstrated that much of the fine ash forming minerals entering a flotation froth are there as a result of water carryover- from the bulk contents of the flotation cell (Arnold and Aplan, 1986a). Using a bank of four 8.5 m3 (300 cu ft) Wemco flotation cells cleaning a well-liberated Lower Kittanning seam coal, test results show that the sulfur and ash content of the froth is directly related to the water content of the froth (or inversely related to the percent solids in the froth). Reagent changes that result in a watery froth produce a higher ash content in the froth. A direct comparison of laboratory and plant results show that the standard laboratory flotation test produces a product higher in sulfur and ash than that produced in the plant. Caution should be exercised when extrapolating laboratory test results to the plant situation. A method of estimating coal flotation product quality in the plant based on laboratory tests is given.

Jan 1, 1991

By R. P. Schneider

The Chino mine, concentrator, and smelter are located in Grant County in Southwestern New Mexico. Chino Mines Company is a partnership two-thirds owned and operated by Kennecott Santa Fe Corp., and one-third owned by MC Minerals Corp. (Mitsubishi) of Japan. The Chino Ore Body The Chino ore body is a widely varied deposit of rock types and contains intrusive stocks and sediments. The stocks contain chalcocite in a matrix of quartz, mica, and feldspar. Much of the feldspar is altered to clay. Some of these stocks are enriched with native copper. The sediments contain chalcopyrite associated with gangue minerals including magnetite, pyrite, garnet chlorite, and epidote. The contact of the stock and sediment is heavily altered to chlorite and clay. The stock ores contain economic quantities of molybdenite. The operating work index of Chino ore varies from 5 to 20 kwh/ton and averages 8.5 kwh/ton. The ore head to the concentrator averaged 0.81% copper and 0.010% molybdenum. Fifteen percent of the total copper head exists as nonsulfide mineralization.

Jan 1, 1985

By P. J. Arps

Cyanide (CN) is used to recover gold from its ores in many locations worldwide. In spite of the established history of gold mining in Alaska, modern cyanidation methods have been used at only one location, the Ryan Lode Mine at Ester Dome, near Fairbanks. Ore was processed by heap leaching between 1987 and 1989, when permitting issues caused operations to be terminated. Those issues have since been resolved, and plans to reopen the mine are currently being discussed. Plans are also proceeding to develop several other ore deposits in the state, all of which include the use of cyanide for gold recovery [6]. Since tailings and effluent water produced from these mines will require treatment, it is important to develop detoxification methods suitable for the Arctic and sub-Arctic conditions found in Alaska. Several methods exist for removing cyanide from mining wastewater. However, most industrial users prefer chemical treatment systems, and typically use sodium hypochlorite, hydrogen peroxide, or sulfur dioxide/air/copper to oxidize free and complexed cyanides [9]. Biological treatment has been used successfully at two sites in the United States [30,32] and field tested at several others [20,27,28]. In addition, one mine uses "natural processes", which include natural oxidation, photodegradation, and degradation by naturally occurring bacteria [33].

Jan 1, 1994

By M. N. Herrera

The bioleaching of mineral sulfide pulps in a bench-scale rotating drum reactor has been studied. The reactor includes horizontal paddles in the inner wall for lifting of the mineral pulp. The performance of the reactor was tested in the bioleaching of a refractory pyritic gold concentrate in the presence of pure Thiobacillus ferrooxidans strain (ATCC 19859). The concentrate was efficiently bioleached at 50% pulp density with the drum operating at 0.5 -1.0 rpm Attempts of bioleaching the concentrate at the same pulp density in conventional stirred reactor showed severe inhibition of bacterial activity. The results demonstrated that the drum reactor allows to operate at much higher pulp densities than the conventional stirred tank reactor. This behavior is explained in terms of an improvement of the bacterial activity due to a better control of the attrition of the mineral particles.

Jan 1, 1997

By H. R. Manouchehri

The responses of calcite, feldspar, and quartz minerals In a laboratory free fall electrostatic separator, before and after tribocharging with stainless steel, PVC, and copper plates, have been investigated. The effect of H3BO3 and BaCl2 chemicals pre-treatment on the electrical properties of the minerals is examined. The changes in the electrical properties are discussed with the determined charge, dielectric constant, and electrical conductivity of the mineral samples. Electrical properties of the minerals and their responses to the electrical field during separation, after tribocharging and chemical pre-treatment, are explored for the need to characterize the electrical behaviour of the minerals.

Jan 1, 1998

By N. W. Johnson

Two analysis tools which have been applied to problems in industrial Flotation processses are the application of kinetics and detailed mineralogical or liberation data, both on a size-by-size basis. The paper describes practical examples of the application of kinetics to examination of the entrainment recovery mechanism, the retardation of valuable minerals at the commencement of flotation sections and the resolution of problems related to valuable species with reduced rate constants at the end of sections. Examples of the usefulness of size-by-size liberation data for monthly composite samples of products from a concentrator are also described.

Jan 1, 1985

By William F. Stowasser

The United States has traditionally been the world's largest producer and net exporter of phosphate rock and related fertilizer products with the exception of rock exports from Morocco. In recent years, however, U.S. producers have faced increasing competition from operations in foreign countries, leaving the future position of the U.S. phosphate .industry as a leader in the world markets somewhat less certain. This paper will review the U.S. phosphate rock industry in relation to its known demonstrated reserves, its historical and present production and export levels, and its future mining potential. The paper will include an analysis of the availability of phosphate rock in the United States represented by cost-tonnage relationships. The U.S. phosphate rock industry has for decades provided raw materials at reasonable costs to the phosphate fertilizer industry, and the fertilizer products have been made available to both domestic and international markets. Natural soils normally contain low quantities of phosphorus, and cultivation exhausts the available phosphorus through the removal of harvested products. Yields diminish, and it becomes necessary to apply phosphorus to the soil in an amount at least sufficient to compensate for removal. Raising the level of phosphorus also permits nitrogen and potash fertilizer nutrients to be effective and sustain the high crop yields necessary to support increasing food demands. In only a few areas of the world are soils, climate, rainfall, and low-cost phosphate fertilizer available to assure high agricultural yields in successive years. One of these areas is the central United States and south central Canada. By contrast, in the Soviet Union, the weather conditions in farming areas frequently cause crops to either bake or drown in the field. To attempt to counter the effect of weather on production, the U.S.S.R. has increased use of fertilizer and equipment in recent years. The effect of fertilizer on various crops has been documented, and in all cases, improvements in yield and plant development were noted, as was the ability of fertilizer to mitigate the effects of unfavorable climatic conditions. Phosphate resources can be classified as either identified or undiscovered. In the identified classification, we are principally concerned with demonstrated phosphate resources, or those that have been measured or indicated. In the southeastern United States, the phosphate mining areas of Florida and the Carolinas have been explored and drilled extensively in attempts to locate new deposits. The exploration programs indicate that another Florida Bone Valley Formation or North Carolina Pamlico River Deposit is unlikely to be discovered in the southeastern U.S. coastal plain. Phosphate rock deposits of commercial interest in the western United States are located in Montana, western Wyoming, northern Utah, and southeastern Idaho. The deposits are in the Permian Phosphoria Formation with most of the mining activity occurring in Idaho. Although substantial demonstrated resources have been identified, recovery costs and the field's isolation from markets have restricted growth of the industry in the west. The phosphate rock deposits in Tennessee are well known, and it is estimated that about 29 million metric tons1 are potentially recoverable. Undiscovered deposits of brown rock in Tennessee would likely be quite small.

Jan 1, 1985

By L. A. Baker

The presence of goethite in a hematite ore has been shown to strongly affect the time of heating to the firing temperature. The investigation of spalling of single pellets and of packed beds has enabled free water and goethite spalling to be identified as separate phenomena. In addition, it has been shown that even for an 18 inch deep bed of green balls the free water and goethite drying periods can be considered separately. Based on this observation, a method of predicting production rate and hood temperature profile is presented. The method required knowledge of the ore goethite content, ore grind and the green pellet bulk density. Laboratory results were found to be in good agreement with actual plant practice and have led to improved process performance.

Jan 1, 1972

By O. F. Brown

Excavation and loading are primary operations in the surface mine production chain, constituting a significant component of production costs. This makes excavation and loading important cost centers that need to be improved to lower production costs. Optimizing the design and use of excavators will improve energy efficiency in earthmoving operations, and this requires a thorough understanding of the soil-tool interaction process. Modeling the interaction process accurately is the key to this optimization. Experimental and analytical methods have provided limited information on the behavior of soils during excavation. Finite element (Fe) analysis of soil-cutting blade interaction produces some advantages over experimental and analytical methods. However, the soil constitutive equations used in most of the available Fe analyses fail to adequately model the plastic behavior of the soil. This work uses Fe modeling to study the behavior of formation-cutting blade interactions in dozer excavation. The formation is modeled as a nonlinear elastoplastic material using the modified cam-clay (mCC) model. The model accounts for soil-tool interface friction, and progressive and continuous cutting at the blade tip. The results provide soil forces, a progressive developed failure zone and soil displacement fields. The sensitivity analysis of changes in blade angle on cutting force shows that the cutting force increases with increasing blade angle. The cutting depth of the blade had a similar effect on blade cutting force. Increasing the depth of cut increases the required cutting force. Increasing the coefficient of friction at the soil blade interface increases the blade cutting force. Reducing the coefficient of friction at the soil blade interface from 0.3 to 0.05 reduces the cutting force by 22.3%. The percentage represents the maximum potential savings in blade cutting force. This research initiative advances the frontiers of soil-tool interactions during excavations to expand the limited knowledge in this critical area.

Jan 1, 2012

By Yoginder P. Chugh

Physical mine modeling and computer simulation techniques were used to conduct technical feasibility and economic analyses of selected pit configurations for surface mining a single coal seam dipping at about 15 percent to a maximum depth of 150 feet. The pit orientations along the dip (dipline), strike (strikeline) and along an apparent dip were studied. Physical models of each pit configuration were prepared first to delineate potential operational problem areas, and also to furnish a data base-for the computer simulation models. A dragline micro- simulation model (Fluor), a shovel/truck simulation model and a cost analysis model were used to conduct the study. Sensitivity analyses were conducted on variables such as the pit width, block length, and angle of dip. The productivity (Cu.yds/hour) of the mining equipment (dragline or stripping shovel) under each set of conditions was used to optimize the pit configuration. Both block length and panel width were found to significantly affect the dragline productivity larger size trucks were preferable to smaller size trucks in the pit configuration along an apparent dip. The cost analysis results showed that the pit configuration along the seam dip was more economical than the pit along the strike or along an apparent dip.

Jan 1, 1984

By G. I. Mathieu

Research and development studies were carried out at the Canada Centre for Mineral and Energy Technology to produce a synthetic forsterite sand from asbestos tailings for Les Sables Olimag Inc. The National Research Council of Canada also supported and collaborated to the project. Theoretically, the technological approach consists of a heat at over 1300°C; however, the process without additive would result in the production of an enstatite-rich product (MgSiO3) having a fusion temperature less than 1600°C. The purpose was to foster the formation of forsterite (Mg2SiO4), a more refractory compound. The fabrication of the forsterite product requires pre-agglomeration of serpentine-MgO with a binder, which is stable at high temperature, to prevent the loss of the powdered magnesium oxide as dust in the kiln off gases and to maintain the mixture homogeneous during the process. Characterization of the end products with respect to mineral composition and thermal resistance are described. The synthetic forsterite in sand form was tested with success under a bath of liquid steel maintained at 1700°C for up to two hours. The advantages of the new sand and its potential applications will be reviewed.

Jan 1, 1992

By M. Bai

The influence of mining on the hydro-geomechanical environment is greatly constrained by alternating mining geometries. The limiting magnitudes of surface subsidence and groundwater flow over the mining area, as a result of geometry changes, can be reasonably predicted through a coupled finite-element model introduced in this paper. Verification of the model has been tested using real and conceptual case studies which reveal that changes in strata conductivities are strongly related to the strata deformation induced by mining. The greatest modification of hydraulic conductivities occurs within the caving or severely fractured zones. The study indicates that narrowing the panel face width will substantially reduce both the intensity and extent of mining damage to the overlying strata, limit surface subsidence and constrain the change in hydraulic conductivity to a reduced scale and smaller extent, particularly as mining depth increases.

Jan 1, 1993

By Bradley S. Van Gosen, Anjana K. Shah, George M. Bedinger, Donald I. Bleiwas, Karl J. Ellefsen

"Ancient and modern coastal deposits of heavy mineral sands (HMS) are the principal source of several heavy industrial minerals, with mining and processing operations on every continent except Antarctica. For example, HMS deposits are the main source of titanium feedstock for the titanium dioxide (TiO2) pigments industry, obtained from the minerals ilmenite (Fe2+TiO3), rutile (TiO2) and leucoxene (an alteration product of ilmenite). HMS deposits are also the principal source of zircon (ZrSiO4), from which zirconium dioxide (ZrO2) is obtained for uses mostly in refractory products. Sometimes monazite [(Ce,La,Nd,Th) PO4] is recovered as a byproduct mineral, sought for its rare earth elements, and thorium (Ault and others, 2016; Sengupta and Van Gosen, 2016; Van Gosen and Tulsidas, 2016).HMS are sediments containing dense (heavy) minerals that accumulate with sand, silt and clay in coastal environments, locally forming economic concentrations of the heavy minerals (Fig. 1). Economic (mined) HMS deposits include Holocene sediments on modern coasts, such as examples in India and Brazil, as well as coastal deposits formed by transgressions and regressions of the seas during intervals in the Quaternary, Tertiary and Cretaceous, such as in Australia and the southeastern United States. Economic deposits typically contain heavy-mineral concentrations of at least two percent. Individual heavy minerals are commonly defined as minerals with a specific gravity greater than approximately 2.9 g/cm3. These minerals are generally resistant to chemical weathering and physical degradation and thus survive well in fluvial and coastal environments. Heavy minerals in coastal HMS deposits may include, in order of general abundance, ilmenite, leucoxene, rutile, magnetite, zircon, staurolite, kyanite, sillimanite, tourmaline, garnet, epidote, hornblende, spinel, iron oxides, sulfides, anatase, monazite, cassiterite and xenotime. Of these, ilmenite, leucoxene, rutile and zircon are the primary economic minerals. Garnet, monazite, cassiterite and xenotime are occasionally recovered as byproducts. The heavy minerals as a suite typically make up no more than 15 weight percent of a deposit and usually much less. Quartz and clay minerals form the bulk of the sediment. The geology of HMS deposits and examples of significant districts are summarized in Van Gosen and others (2014) and Hou and Keeling (2016)."

Oct 1, 2016

By Yuemin Zhao, Wenxuan Liu, Maoming Fan, Zhanyuan Long

"Coal is mainly composed of energy-producing elements carbon and hydrogen. In addition to these elements, coal usually contains many other valuable elements, including iron, aluminum, silicon, rare earth elements, lithium, gallium, germanium, vanadium, uranium, titanium, scandium and phosphorus. These coalassociated elements are significantly enriched in coal combustion byproduct fly ash because the majority of the main components, carbon and hydrogen elements, being removed. Table 1 provides the chemical composition range of the main element oxides in 12 Chinese fly ash samples collected from coal power plants located in Northeast China, Northwest China, Southwest China and Southeast China. It can be seen from Table 1 that the major mineral components of different ashes are similar, but the bulk chemistry of different fly ashes may vary due to the changes of ratios of the mineral components in different coals. The major mineral components in various Chinese coal combustion fly ash are silicates, iron oxides and unburned carbon.Chinese coal fly ash usually contains about 5 to 15 percent of unburned carbon, which are generally chars with irregular shapes and wide particle size distribution. In addition to unburned carbon, XRD analysis of four Chinese fly ash samples from Liaoning, Shanxi, Guizhou and Shandong provinces indicates that the fly ash samples are composed of minerals such as quartz (SiO2), mullite (3Al2O3.2SiO2 or 2Al2O3.SiO2), hematite (Fe2O3), maghemite (gamma form of hematite, ?-Fe2O3) and magnetite (Fe3O4). The mullite and quartz particles are usually present as spherical particles because they are formed by melting clays, feldspars, quartz, calcite and other common minerals in coal during coal combustion. The silicate particles have usually entrapped gas to yield hollow spherical particles because their lower melting point facilitates gas entrapment.The iron oxides are usually spherical also. The magnetite (Fe3O4) is derived from pyrite (FeS2), hematite (Fe2O3), siderite (FeCO3) and limonite (2Fe2O3.3H2O) in the coal. Maghemite (?-Fe2O3) is formed by dehydration of the mineral hydrohematite (?-FeO(OH)) and/or oxidation of magnetite (Fe3O4) during coal combustion. Maghemite (?-Fe2O3) and magnetite (Fe3O4) are strongly magnetic, so they are recovered from Chinese coal fly ash and widely used for coal processing in China (Fan et al., 2005, 2000)."

Jan 3, 2018