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By Gary L. Hundley

The Bureau of Mines has devised and demonstrated an ammoniacal sulfate leach process for recovering nickel and cobalt from low-grade domestic laterites. Solvent extraction of cobalt, one of the process steps, requires the reduction of hexammine complexes of C03+ to C02+ in an ammo-niacal leach solution. Previously, reduction was accomplished using cobalt metal shot in a column. This report presents experimental results and an economic evaluation comparing two alternate techniques with the shot column: (1) an electrolytic reduction cell with an extended surface area cathode and (2) direct electrowinning from purified leach solution using a cell with a fluid bed cathode. The second alternative eliminates the conventional solvent extraction-electrowinning steps. The costs of the three methods, based on the requirements of a pro-posed commercial-sized plant, including all unit operations, were deter-mined by the Bureau's process evaluation group. The operating costs for the shot column, $1.19/kg Co, and for electrolytic reduction, $1.20/kg, are essentially the same, but the cost of direct electrowinning, $3.77/ kg Co, would eliminate this method as a practical alternative. The cap-ital cost of approximately $14.4 million for reduction in a shot column is much higher than the approximately $4.4 million for electroreduction.

Jan 1, 1985

By L. C. S. Dharmasiri, S. M. Shin, A. Senaputra, J. S. Sohn, K. H. Park, J. Avraamides

Reducing agents can be applied to leach metal values from natural and secondary resources such as laterite ores and deep sea manganese nodules and recycled materials such as spent batteries / catalysts which contain high-valent metal oxides of manganese, cobalt and iron. Selective leaching of some metals can be achieved by selecting conditions to control the saturated solubility and dissolution rates of metals from oxides or mixed metal/oxide matrices. The leaching results are rationalized on the basis of chemical species, Eh-pH diagrams and heterogeneous kinetic models. The role of reducing agents such as hydrogen peroxide, sulfur dioxide and iron(II) sulphate, in acid, alkali and in the presence of complexing ligands such as ammonia for the improvement of the leaching of metal oxides and metals is discussed. Previous studies on acid leaching of metals from nickel laterites, manganese nodules and spent catalysts/batteries in the absence or presence of reducing agents show that the rate controlling step involves the diffusion of protons through a thickening product layer on the particle being leached. It is shown that the leaching of nickel and cobalt from manganese nodules and zinc-carbon batteries in ammoniacal sulphur dioxide solutions also obey shrinking core kinetics.

Jan 1, 2014

By Paul R. Dingess, Edward H. Hare, Douglas C. Brockie

Mining in the Tri-State district of Missouri, Kansas, and Oklahoma has been nearly continuous from about 1848 until the present day, although the major activity was from about 1880 to 1955. The district, which has produced over $2 billion in zinc and lead concentrates, ranks as one of the greatest mining districts in the world. Unlike other Mississippi Valleytype deposits in the United States, which occur in Cambrian and Ordovician limestones and dolomites, the Tri-State district ores occur in Mississippian limestones containing abundant chert. Zinc is 5 to 6 times more abundant than lead. In the Picher Field, the principal sub-district which has accounted for 61 percent of the total district production, most of the ore has been mined from the single horizon, M bed. Most ore bodies, other than those of the "Sheet Ground" or blanket-type, are in large, essentially flat-lying breccia zones and have a definite mineral zonal pattern. An irregular, generally elongated central dolomitic core is surrounded progressively outward by the main ore run, the jasperoid zone, the muddy or shaly and bouldery zone, the sparry calcite limestone zone, and the fossiliferous, dominantly crinoidal, limestone zone. Some of the zones may be absent or nearly so and may overlap to some extent with an adjacent zone. Although the district has been studied by many authors, much controversy still exists about such items as genesis, paragenesis, and time of emplacement. These subjects are discussed in the paper.

Jan 1, 1968

By Mark I. Copeland

Bureau of Mines researchers investigated the combined effect of copper and tin additions on the mechanical properties of hot-rolled steels. Wrought steels containing 0.2 wt-pct C and up to 0.2 and 1.0 wt-pct Sn and Cu, respectively, were made and evaluated by conducting tensile and impact tests and electron-beam microprobe and electron microscopy examination. Tin additions did not significantly affect the tensile properties of steel at different copper contents in the hot-rolled condition. Tin lowered the copper content at which strengthening by copper precipitation normally starts, 0.8 wt-pct, and decreased the strength of steel aged at 1,022° F (550° C). The most adverse effect of tin was lowering the notch toughness of steels at most copper contents.

Jan 1, 1976

By J. E. Geier

This Bureau of Mines report reviews hypotheses for the mechanism by which water jets reduce the specific energy of cutting for drag bits. Several of these hypotheses are shown to be inconsistent with published evidence and new observations. The notion of a limiting cutting speed, above which water jets would be incapable of rendering assistance, is shown to be improbable. The hypothesis that seems most plausible is that specific energy reductions are mainly due to the erosion of crushed materials from in front of the bit. This hypothesis leads to a prediction that, for a given rock type and jet-bit configuration at a constant depth of cut, the reduction in bit forces should be a function of dM/dx, the jet energy spent per unit length of cut. This dependence upon dW/dx is shown to be consistent with other workers? results.

Jan 1, 1987

By Agnes Y. Lee

The Bureau of Mines has developed an effective hydrometallurgical method to recover high-purity Pb metal and elemental S from concentrates. This low-temperature process eliminates S gases and Pb emissions, in contrast to the current high-temperature smelting technology. The method consists of (1) oxidative leaching with H202, Pb02, and waste fluosilicic acid at 95° C to produce a solution of PbSiF6 and a residue containing elemental S, (2) electrowinning the PbSiF6 solution at 35° C to produce 99.99 pct Pb metal and H2SiF6, and (3) solvent extraction to recover S, leaving a residue containing Cu, Ag, and other metal values. Spent electrolyte was recycled repeatedly, with impurity buildup controlled by controlling the leach parameters.

Jan 1, 1986

By B. T. Wykoff

This paper describes an important function of mining in Southeast Missouri. The practice is a necessary procedure to prevent disintegration of the pillars. Although the technique is peculiar to this district, it might have application in other mines using room and pillar method. CONSIDERING the subject alone, this paper would cover only a mechanical treatise of pillar roping. Because the St. Joseph Lead Co. originated the practice, it is proper to give a short introduction to the company. It is also proper to describe pillars and discuss their purpose to justify expending large sums of money to preserve them after the surrounding area has been thoroughly mined. Because the St. Joseph Lead Co. originated the practice of back pinning with wedge bolts, patch plates and channel irons, and the pouring of substitute pillars of concrete, these too, are mentioned. The Southeast Missouri Division of the St. Joseph Lead Co. is the largest lead producer in the United States. About 95 pct of the present producing mines are in St. Francois County, which begins 60 miles south of St. Louis. The entire lead ore production of this county, at the present time, is mined and milled by this company, treatment plant capacity being about 22,000 tons per day. This area is also the oldest, lead having been mined at Mine La Motte, in Madison County, in 1723. Estimated production of all the various companies that have mined here is about 7,000,000 short tons of pig lead. Method of Mining The lead occurs in the ore as galena. Galena is found either in the form of disseminated or solid streaks, of varying thickness. Ore stratum is the Bonne Terre dolomite, which is about 350 ft thick, but almost all the ore is in the lower 100 ft. Ore is mined by room and pillar method in open stopes. These stopes vary in height from 7 ft to 200 ft, depending on the thickness of the pay ore in that spot. Back, or roof, is supported entirely by pillars. In a majority of stopes, after the loose scales are mined down, the back has remained solid for many years (fig. 1). Under ideal conditions pillars are spaced to form an equilateral triangle and are as small and as far apart as the height of the stope and the character of the back will permit. They vary in diameter from 10 ft to 50 ft and are from 18 ft to 50 ft apart, measured from the outer edges. In general, the pillars are approximately 12 ft in diameter, and 25 ft apart. The spacing is very uncertain because of the vagaries of the ore trend, the desire to better support breaks in the back, and the attempt to spot out the thinner ore by not placing one in the core of the ore body. Use of Structural Steel Channels In stopes where the back is bad because the overlying formations are thin with wet, weak and shaly

Jan 1, 1951

By B. T. Wykoff

This paper describes an important function of mining in Southeast Missouri. The practice is a necessary procedure to prevent disintegration of the pillars. Although the technique is peculiar to this district, it might have application in other mines using room and pillar method. CONSIDERING the subject alone, this paper would cover only a mechanical treatise of pillar roping. Because the St. Joseph Lead Co. originated the practice, it is proper to give a short introduction to the company. It is also proper to describe pillars and discuss their purpose to justify expending large sums of money to preserve them after the surrounding area has been thoroughly mined. Because the St. Joseph Lead Co. originated the practice of back pinning with wedge bolts, patch plates and channel irons, and the pouring of substitute pillars of concrete, these too, are mentioned. The Southeast Missouri Division of the St. Joseph Lead Co. is the largest lead producer in the United States. About 95 pct of the present producing mines are in St. Francois County, which begins 60 miles south of St. Louis. The entire lead ore production of this county, at the present time, is mined and milled by this company, treatment plant capacity being about 22,000 tons per day. This area is also the oldest, lead having been mined at Mine La Motte, in Madison County, in 1723. Estimated production of all the various companies that have mined here is about 7,000,000 short tons of pig lead. Method of Mining The lead occurs in the ore as galena. Galena is found either in the form of disseminated or solid streaks, of varying thickness. Ore stratum is the Bonne Terre dolomite, which is about 350 ft thick, but almost all the ore is in the lower 100 ft. Ore is mined by room and pillar method in open stopes. These stopes vary in height from 7 ft to 200 ft, depending on the thickness of the pay ore in that spot. Back, or roof, is supported entirely by pillars. In a majority of stopes, after the loose scales are mined down, the back has remained solid for many years (fig. 1). Under ideal conditions pillars are spaced to form an equilateral triangle and are as small and as far apart as the height of the stope and the character of the back will permit. They vary in diameter from 10 ft to 50 ft and are from 18 ft to 50 ft apart, measured from the outer edges. In general, the pillars are approximately 12 ft in diameter, and 25 ft apart. The spacing is very uncertain because of the vagaries of the ore trend, the desire to better support breaks in the back, and the attempt to spot out the thinner ore by not placing one in the core of the ore body. Use of Structural Steel Channels In stopes where the back is bad because the overlying formations are thin with wet, weak and shaly

Jan 1, 1951

By Rui Mao, Ke-Xin Nao, Jian-Liang Zhang, Xiang-Nan Xu, Meng-Fang Wei

"In this research, fundamental characteristics of dust and sludge containing iron from the dusting system of sintering process, blast furnace, oxygen converter and rolling process in steel enterprise were studied by chemical analysis, X-ray diffraction analysis, optical microscope analysis, scanning electron microscopy analysis, particle size analysis and other analysis means. Development direction of resource utilization for dust and sludge containing iron from steel enterprise was put forward on the basis of above study.IntroductionDust and sludge containing iron for steel enterprise mainly come from the dusting system of sintering process, pelletizing process, blast furnace, oxygen converter, rolling process and other related process. Iron content of dust and sludge is between 30% and 70%, and they also contain certain content of carbon, calcium oxide, magnesium oxide and harmful elements [1-3]. Output of dust and sludge is determined by raw materials conditions, technological processes, equipment configuration and management level. Dust output in sintering process accounts for about 2% to 3% of the sinter production, while dust and sludge from iron making and steel making process respectively take up 3% to 4% of hot metal and crude steel production, and the solid waste from rolling process accounts for about 0.8% to 1.5% of the output of rolled products [4,5]. Dust and sludge contains Fe, CaO, MgO, C and other valuable resources, it will not only result in the waste of resources, but also cause serious pollution to environment ifthe dust and sludge are not recycled. China's crude steel production in 2012 is about 700 million tons and output of dust and sludge containing iron is nearly 60 million tons, so, it is of great significance to have a resource recycling for dust and sludge containing iron from steel enterprise."

Jan 1, 2014

By R. Castro, R. Gómez, F. Betancourt, M. Moncada

In block cave mining, rock fragmentation is a key parameter that influences the production level design and mine planning. Fragmentation occurs mainly by natural breakage during the caving process and in the draw column. The breakage that occurs within the column is known as secondary fragmentation. Secondary fragmentation has been successfully described using the block caving comminution model, which replicates the fragmentation mechanics between particles under drawn and vertical loads in a draw column. This model is based on a kinetic and population balance approach, in which non-normalized and normalized assumptions can be used depending on material and comminution system behaviour. In this paper, the non-normalized and normalized approaches are applied and compared to laboratory data to determine which assumption should be used for secondary breakage in block caving. Approaches are compared graphically, with the mean square error and the Fisher test with a false-rejection probability of 0.05. Based on a statistical analysis, the results show that the normalized model can be applied to all the rock types tested.

Nov 1, 2021

By H Turrer, M Badawi, R Belissont, Y Foucaud, E Kleiderer, L Southavy, J Mesquita, Y Basselin

The Mont Reed iron ore deposit, owned by ArcelorMittal, is situated approximately 140 km southwest of the Mont-Wright mine in the southern region of the Labrador Trough, Canada. Acquired by Québec Cartier Mining (QCM) in the 1960s, the Mont Reed mining property has remained unexploited due to the complex nature of the ore in the area. However, during the last years ArcelorMittal’s R&D team has been dedicated to developing a process to beneficiate the Mont Reed ore and produce high-quality pellet feed suitable for direct reduction furnaces. Extensive research revealed that achieving a good liberation degree of particles required grinding the material below 75 μm (P80 of 53 μm). To find the most effective technology for this task, a detailed comparison between ball mill and vertical stirred mill grinding was conducted. Both grinding technologies underwent detailed testing in bench-scale experiments. The ground products were comprehensively characterised, including size distribution analysis and chemical analysis per size fraction. Additionally, liberation analysis was performed using an automated scanning electron microscope (SEM). To determine the grinding specific energy, a method previously developed at Samarco (Brazil) for fine grinding of iron ores was employed. Furthermore, magnetic separation and flotation tests were conducted on the ground products. After a thorough evaluation of all the results, it was observed that both ball mill and vertical stirred mill grinding produced samples with similar physical characteristics. However, the vertical mill demonstrated higher efficiency in grinding the material. To conclude the study, an economic evaluation was conducted for both options considering various factors. Overall, ArcelorMittal’s R&D team’s dedicated efforts have brought them closer to unlocking the potential of the Mont Reed ore deposit and paving the way for its future utilisation to the production of high-quality pellet feed.

Sep 18, 2023

By Gilbert M. Farrior

The electrical resistivity the coefficient of electrical resistivity the Hall coefficient, and the absolute thermoelectric power were determined in this Bureau of Mines investigation for nine compositions of the TiB2-CrB2 sub-system. The numerical values of the electrical resistivity and the thermo-electric power were greater for the intermediate compositions than for the end members. The absolute values of the Hall coefficients and the coefficients of electrical resistivity were less for the intermediate compositions than for the end members. The electrical resistivities and Hall coefficients were about the order of magnitude of most metals--from 34 to 202 microhm-cm and from about 0 to -23.3 X 10-4 cuP/coulomb. The thermoelectric power was somewhat greater than that of most metals--up to 15.6 microvolts per 0 C.

Jan 1, 1965

By Y Peng, D Wannas

In the fine particle flotation technologies being developed today the fine hydrophilic (gangue) particles are usually well dispersed. These highly dispersed fine particles can be recovered into the flotation froth product by mechanical entrainment. Flocculation of hydrophilic particles caused by polymer depressants could potentially reduce the mechanical entrainment of these particles. This paper reports testwork completed on fine particles of several solids, iron oxide, hydroxylapatite, galena and sphalerite, as well as on a relatively coarse quartz sample (-75+38 ¦m). Dodecylamine was used as a collector for the quartz, and several dispersants and polymer depressants, including sodium silicate, sodium metaphosphate, zinc sulfate, potassium dichromate, corn starch, corn dextrin and carboxymethyl celluloses (with molecular weights of both 700 000 and 80 000) were used as flotation modifiers. The major part of the testwork involved flotation tests in a 200 ml flotation column. Both water and solid recoveries were recorded. The degree of flocculation and dispersion was determined by settling tests in 250 ml graduated cylinders. It was observed that flocculation of the fine hydrophilic particles significantly reduced their mechanical entrainment, while dispersion severely aggravated it. Thus, in the flotation separation of artificial mixtures of the -75+38 ¦m quartz and fine iron oxide or hydroxylapatite, polymer depressants that caused flocculation were found to perform better than the ones that did not cause flocculation.

Jan 1, 2005

By Robin P. Gardner

The mechanistic approach to comminution consisting of incorporating particulate breakage functions into a suitable population balance equation has been developed by a number of researchers over the past decade or so. (1) To date this approach has been developed and demonstrated primarily for batch-operated, laboratory or small-scale ball mills. However, since industrial mills are mostly quite large and operated in the continuous mode; suitable population balance models and methods for obtaining the necessary breakage and other model parameters must be developed. This paper describes and investigates a radioisotope tracer technique for this purpose, Population balance models previously developed(2,3) are adapted for this study.

Jan 1, 1974

By M. H. Chetrick

An important factor in the design and operation of a lignite-gasification plant is knowledge of the thermal requirements. These not only vary with different-size plants but also with the operating conditions for a plant of given capacity. Thermal data have been collected since 1945 from a commercial-scale lignite-gasification pilot plant operated by the Bureau of Mines at Grand Forks, N. Dak. The description and operation of this plant and a study of the gas-composition data have already been described in previous reports (1, 2, 3, 4, 5).2) / This investigation was made to review the thermal data taken in tests and to correlate them in terms of the fraction of undecomposed steam and the H2:CO ratio.

Jan 1, 1953

By Alexander May

This report describes a new method of weighing based upon observing the apparent weight of an object ill two separate pure gases. The method is presented in terms of experimental data which prove its soundness, but does not attempt to show the maximum accuracy possible with this technique. The new method incorporates the underlying principle that the apparent weight of an object is a linear function of the density of the atmosphere in which the object is weighed. The coefficients of this linear function are the true mass and volume of the object. From this functional relationship the true mass and volume of the object may be determined.

Jan 1, 1970

Carbon injection into metallurgical slag is important in electric arc furnace (EAF) steelmaking for foamy slag practices and in nonferrous slag cleaning operations. The current publication presents kinetic data for coal injection into EAF slag to understand the interaction between injected carbon and metallurgical slag. Coal particles were injected into EAF slag and the kinetics were followed by gas and slag analysis. The results were analyzed, in terms of fundamental rate equations for each possible reaction step, as a function of temperature and slag composition.

Jan 1, 2003

By L. Allan White

Instrumental analysis is an indispensable tool to many phases of research on rare-earth metals and their compounds; therefore, the development of new and improved instrumental techniques is essential. This report describes an emission spectrometric analytical method using direct-current carbon-arc excitation of various rare-earth-oxide mixtures. Lanthanum oxide serves the dual purpose of an internal standard and a constant major constituent. The versatility of the method was demonstrated by three different applications: (a) Analysis of complex rare-earth concentrates; (b) determination of impurities in high-purity rare-earth oxides; and (c) detection of rare-earth elements in other types of matrices, such as those resulting from beneficiation of rare-earth ores. The average error of analysis in the concentration range of 0.2 to 10.0 percent was 14.6 percent for a group of complex synthetic mixtures of rare-earth oxides. An average error of analysis in the concentration range of 0.05 to 0.50 percent was 21 percent for a group of high-purity rare-earth oxides.

Jan 1, 1959

By Krishna P. Sinha

An investigation was made to determine the creep behavior of oil shale at elevated temperatures. During the first phase of the investigation, work done on creep behavior of geologic materials was reviewed and triaxial creep tests on oil shale were planned. Tests at temperatures up to 250°C and axial stress up to 3000 psi were conducted at no confinement and at confining pressures equal to 1/3 and 2/3 of axial stress. Wide variations in the elastic properties as well as creep characteristics are exhibited. Creep deformation is more pronounced at elevated temperature but no definite quantitative remarks can be made regarding effect of grade of oil shale due to wide scatter and limited number of data paints. Primary creep can be described by a power law. Secondary creep seems to be an experimental function of deviatoric stress. Teritary creep was not observed within the test duration (24 hours in most tests).

Jan 1, 1983

By Howard S. Avery

The wear resistance of an alloy in heavy mill liner sections may be quite different from that of the same alloy in small balls and other light sections. This fact was established by means of a well standardized laboratory test that was validated for ball mill service. The salient properties of mill liner alloys, including austenitic manganese steels, medium alloy hardenable steels, and abrasion resistance cast irons are described, critically compared, and quantitatively ranked in terms of mill liner service. Where they are tough enough the high-chromium and other martensitic cast irons (e.g. Ni-Hard) promise maximum economy, but their section sensitivity is a limitation. To overcome this an extensive research program studied over a hundred experimental alloys, ranking them for heavy section abrasion resistance by means of the laboratory test. Computer analysis of the results provided a parabolic formula in terms of composition, the apexes of the parabolas providing optimum wear resistance. From the extensive family of parabolas one apex was selected for intensive study in experimental liners, pilot plant production, development of quality controls, and finally full scale production. This is a 19% chromium iron critically alloyed with nickel and molybdenum and hardened by heat treatment. It has excellent resistance to various types of abrasion, but its chief advantage is in heavy mill liner sections, where it has about 25% better abrasion resistance than the best of the quality controlled chilled Ni-Hards. It is also tougher. After production problems were solved, a number of ball and rod mill tests were arranged on a guaranteed performance basis. Two of these, representing about 138,000 pounds of mill liner castings, have recently confirmed in service the superiority that was predicted by the laboratory tests.

Jan 1, 1969