Search Documents

[University of Alaska College, Alaska Mining Society TOM CHRISTENSON, President MARY ANN KISER, Secretary H. G. WILCOX, Faculty Sponsor WM. FACKLER, Counselor University of California Berkeley, California Mining Association JOHN W. COOK, President LORETTA A. RICHTER, Secretary W. S. WEEKS, Faculty Sponsor]

Jan 1, 1946

By Russell L. Dahl

In a continuing effort to improve plant efficiency, United States Steel's Atlantic City Ore Operations completed the rubber lining of its balling drums in late 1982. This resulted in benefits of reduced bentonite consumption, reduced maintenance costs, improved production rates, and lower power consumption. These advantages far outweigh the disadvantages of increased oversize production and increased surging on the roll screen sizing devices. Certain operating characteristics and variables are discussed herein.

Jan 1, 1983

By Cayo Soto

Mining activity is important for the development of humanity. This development must be understood from the Academy where it allows showing alternatives for the industry performance. Likewise, these mining companies need to improve their results. Historically, a few years ago the application of the ESG (Environmental, Social and Governance) criterion was verified, which is positioned as a factor/regulator in the design of the performance of industries in general. ESG as an integral part of the concept of sustainability serves as a tool to conceive mining without conflicts and with a reputation based on trust in the interrelation of the university, industry and society. Therefore, the academy must strive for new knowledge in a way that allows it to continue in the virtuous circle of constantly feeding it. In this context, the best mining practices are implemented in constant questioning of their activities. The scientific essence of the industry supported by the academy developed in an operational dynamic is addressed. Finally, the objective of this research work is to interrelate 3 variables: ESG, Academia, and the Mining Industry, where the transition of knowledge and the role of each variable in relation to each one can be understood. This allows for an additional understanding of mining in the future with new mental attention.

Feb 1, 2025

By PAITIP THIRAVETYAN, KANJANA KUDPENG

The aim of this study is to compare amino acids and organic acids in the extraction of gold from silicate ore. Amino acids were found to have higher efficiency of gold extraction than organic acids at the same acid concentration, which is likely due to amino acids having both carboxylic and amine groups in their structure, while organic acids only have carboxylic groups. Five amino acids (glycine, aspartic acid, glutamic acid, lysine and tryptophan) and seven organic acids (citric, malic, tataric, fumaric, oxalic, succinic and ascorbic acids) were selected to investigate gold extraction efficiency. Aspartic acid was found to have greater capacity to extract gold than succinic acid. The optimal gold to aspartic acid molar ratio was 1:6, and low concentrations of aspartic acid extracted 35 to 42 percent of gold from silicate ore within 15 days. Further studies are needed to increase gold leaching and reduce incubation time. The results imply that aspartic acid can be used as an alternative reagent to traditional methods for extracting gold from ore. This method is nontoxic to humans, is environmentally friendly and can have real applications.

By Andrew B. Cecala, Emily J. Haas, Jay F. Colinet

Researchers from the U.S. National Institute for Occupational Health and Safety (NIOSH) studied the impact of an unregulated dust control technology (the Helmet-CAM) and a regulated dust control technology (the continuous personal dust monitor) within a sociotechnical system (STS) framework to mitigate respirable dust sources. The results address how to best incorporate the overarching principles of meta-design STS during the technology integration process. Specifically, quantitative and qualitative data show that a prominent focus on the social factors within an STS framework could help reduce organizational unpredictability and may improve communication within the system to help reduce technology adoption time.

By Chen-Luh Lin, Jan D. Miller, Sindhoora Puvvada

Most of the future phosphate resources in Florida, which accounts for 70  percent of production in the United States, are contaminated with too much dolomite that is difficult to remove with existing industrial practices. The low-grade ore quality coupled with increased phosphate demand is of concern to the Florida phosphate industry. In order to resolve the dolomite issue, various beneficiation technologies were designed and evaluated, but none have been sufficiently successful [1]. 

By A. A. El-Midany, R. M. Farag, A. M. Salem, S. E. El-Mofty

Bentonite is one of the main players in the stability of drilling mud. Its particle size and particle size distribution significantly affect drilling mud’s rheological properties. Although the Specifications for Drilling Fluids Materials report on Oil Companies Material Association (OCMA)-grade bentonite states that the API recommended powder having 2.5 percent mass fraction as the maximum value of residue of diameter greater than 75 μm, there is no other information on the specific size distribution for API bentonite. It was found that API bentonite has a specific size distribution with specific mixing weights. It is important to investigate why that mixture represents the optimum properties of drilling mud and how each individual size fraction has a specific function in the mixture. To clarify the effect of individual size as well as the collective effect of the size distribution, API bentonite was classified into different size fractions, with each tested separately for controlling properties such as filtration loss, plastic viscosity, gel strength, cake thickness and packing density.

By Alejandro Gutiérrez, David Ahues, Paola Merino, Felipe González

The semiautogenous grinding (SAG) mill is one of the most important pieces of equipment in the comminution of materials. Its objective is to reduce the size of the ore until the ore can be released and continue on its transformation process. Although it is a simple process that involves impact, abrasion and attrition, its energy consumption is extremely high and inefficient, with no more of 17 percent of the energy supplied going toward size reduction. This gives rise to an important challenge because any improvement generates great economic benefits.

By Eti Purwaningsih, Widi Astuti, Erik Prasetyo

Increasing demand for high-grade manganese (Mn) ore has led to the practice of selective mining, which produced low-grade Mn ore as waste and in the long term could lead to environmental pollution. Research had been carried out to extract Mn from low-grade ore, which mostly exists as black Mn(IV) oxide (MnO2). Most extraction methods involved the reduction of insoluble MnO2 to soluble Mn2+ in acidic media. Metals other than Mn are also transferred to the pregnant leach solution (PLS) during the leaching process, especially iron (Fe). Due to high Mn concentration in PLS, precipitation is considered the best method to isolate Mn from PLS compared with solvent extraction and ion exchange/absorption. However, due to unselective leaching, the presence of Fe in the PLS makes the Mn separation and purification difficult. Therefore, in this research, the parameters affecting the selectivity of Mn over Fe in leaching process were investigated.

By G. W. Grove, G. L. FreAS

One of the chief hazards in mining bituminous coal is the accumulation of coal dust in the mines . When coal dust is thrown into suspension , it can be ignited and exploded by electricity through short -circuiting of mining machinery and trolley wires , or by arcs and sparks . The Bureau of Mines has endeavored to assist the coal -mining industry in preventing disasters from this cause by urging that all bituminous -coal mines be rock -dusted . As it has been difficult to convince some mining men of the danger of ignition of coal dust and of the effectiveness of rock dusting in preventing widespread explosions , a small , portable , coal -dust - explosion gallery has been designed to demonstrate the explosibility of bituminouscoal dust . Such galleries are furnished to Bureau engineers , inspectors , and safety instructors to illustrate visually and impressively the Bureau's accident -prevention educational work on the causes and prevention of dust explosions in bituminous -coal mines .

Jun 1, 1949

By G. Heiken

On the Earth's Moon, obvious hazards to humans and machines are created by extreme temperature fluctuations, low gravity, and the virtual absence of any atmosphere. The most important other environmental factor is ionizing radiation. Less obvious environmental hazards that must be considered before establishing a manned presence on the lunar surface are the hazards from micrometeoroid bombardment, the nuisance of electro-statically-charged lunar dust, and an alien visual environment without familiar clues. Before man can establish lunar bases and lunar mining operations, and continue the exploration of that planet, we must develop a means of mitigating these hazards.

Jan 1, 1991

By T. I. . I. Sibbald, D. E. Jiricka

The Goldfields area on the north shore of Lake Athabasca , was active in the thirties and early fortie . In 1934, Tom Box discovered gold mineralization in quartz veins in pyritized 'granite' at the ite of what wa to become the Box Mine of the Consolidated Mining and Smelting Company of Canada Ltd . In the rush of activity that followed numerou other gold occurrences were found. the most significant of the e being the Athona and Frontier prospects which underwent underground development bur did not reach production. Probable reserve identified to date in the Box and Athona deposits amount to some 3.5 million ton grading an average 0.ITT oz gold/ton . Some 10 to 15 million tons of lower grade, po ible reserve are also reported at the Box. From 1939 to 1942, the mine produced, from underground , 64,066 ounces of gold from ore grading 0.0452 oz gold/ton at a cost of between $1.5 and $2.0 a ton. The Goldfield area is underlain by upracrustal rock intruded by mafic bodies and invaded by ·granite'. The upracru tal . thought to be of Lower Proterozoic age are characterized by a helf-type ucce ion metamorpho ed under lowermiddle amphibolire facie conditions into quartzites, quartz-mica chi ts. dolomitic marbles, diop idic calc-silicates and cordierite-anthophyllite-biotite schi t . Amphibolites of presumed igneou origin form concordant to subconcordant units up to a few ten of metre thick in the upracrustals and occur as le regular masses in the 'g ranite·. Compositionally they vary from gabbroic to granodioritic. with the more mafic varieties being most common. Granitic rocks exhibiting a variety of textural , structural and compositional characteristics underlie most of the area. Four main units are recognized: foliated (older) 'granite', 'leucogranite', feldspar augen 'granite· and pyritic mine 'granite', however, in geological mapping the e are somewhat arbitrarily differentiated due to transitional relationships and admixture of types. Although there is no unambiguous age data available for the e 'granite ' adjacent northshore 'granite' of geologically similar age yield Rb-Sr isochron dates around 2000 Ma. The area is characterized by two major deformation events of which the earliest gave rise to the dominant regional foliation and to rare minor and outcrop scale folds. This foliation which in general parallels compositional layering is folded into the major Goldfields syncline, whose axis plunges weakly to moderately outh. Related open minor folds have subvertical axial surfaces which are locally paralleled by a weakly defined schistosity. Most rock display a pronounced rodding fabric, coaxial with second fold axes and apparently the product of this deformation event. However, a note of caution is introduced into this interpretation, as the rodding fabric is also parallel to first fold axe .

Jan 1, 1986

By Clayton Vernon Deutsch, Marcel Antônio Arcari Bassani, João Felipe Coimbra Leite Costa, Vanessa Cerqueira Koppe, Pedro Henrique Alves Campos

Traditional linear approaches oversimplify the complexities of ore blending. Adopting nonlinear blending models in mining and mineral processing is critical to enhancing prediction accuracy and allowing optimization regarding nonadditive variables, such as metallurgical recovery. This study implements a simulated annealing algorithm in short-term mine planning that seeks to optimize the metal recovery by considering how to blend the ore in the mine better. Two nonlinear metallurgical recovery models are used as inputs to the algorithm to represent synergistic and antagonistic blending. The results of the case study demonstrate that the optimized schedule exhibits improvements in both blending behaviors when contrasted with conventional linear-based scheduling plans.

Jan 1, 2025

By Jaeheon Lee, Junmo Ahn, Jiajia Wu

To reduce the environmental footprint of hydrometallurgical processing of black mass from spent lithium-ion batteries (LIBs), a green leaching system based on glycine and sodium metabisulfite (Gly-SMS) was proposed. The leaching study demonstrated that the highest cobalt and lithium recoveries of 100 percent and 99.8 percent were achieved under optimal conditions. The leaching mechanism revealed that the dissolution of LiCoO2 in the Gly-SMS solution followed the shrinking core model. The apparent activation energies for cobalt and lithium were determined as 48.05 and 41.51 kJ/mol, respectively, indicating a surface chemical reaction controlling mechanism. The leachate was then processed by an acidification- precipitation technique with oxalic acid as the precipitant to remove cobalt. Glycine complexes with metal ions by zwitterionic ligand and recycles in the leaching-precipitation circuit, reducing the reagent cost. Compared to other studies, this leaching system has near-neutral operating conditions and is cost-effective, making it an economically viable alternative for treating cathode materials from spent LIBs.

Dec 1, 2024

By Jorge A. S. Tenório, Pedro F. A. Prado, Denise C. R. Espinosa

There has been an increasing push to develop environmentally sound recycling processes of electronic waste (WEEE), including end-of-life photovoltaic modules, to reclaim materials such as silver which is both valuable and pollutant to human health and wildlife. However, process sustainability and economic feasibility of PV panels recycling is strongly tied to the materials separation step, which currently presents challenges due to use of high temperature treatments and strongly acidic solutions. A method using an easily accessible solvent — isopropanol— dissolved the silicone-based encapsulant of crystalline silicon PV modules in 2 days at room temperature, separating the module into semiconductor wafer, glass, ribbon and backsheet.

Mar 1, 2017

By Onuralp Yucel, Ahmet Turan, K. Can Candeger

Exothermic riser sleeves are important tools to increase solidification duration, particularly for iron-steel casting. Increasing the time to solidus improved casting product quality by minimizing cavities. Therefore, process costs were significantly reduced. In comparison with the use of unsleeved risers, exothermic riser sleeves retain up to 30–35% of the heat and increase the duration to solidus by nearly 50%. Exothermic riser sleeves are a mixture of metallothermic-based exothermic and insulating materials that are manufactured in different sizes and shapes. Various suppliers produce these sleeves in different compositions. However, the designers must clearly understand the thermochemical and thermophysical properties. The purpose of the present study was to experimentally determine the effects of varying experimental parameters such as reaction duration, flammability and temperature change etc. on selected exothermic sleeves. The results were compared with thermodynamical simulations which were performed using the contents and the corresponding thermophysical properties of exothermic sleeves.

Mar 1, 2018

By C. Hakan Gür

Optimization and control of the microstructure is important for improving the properties of steel components. Development of non-destructive techniques for microstructure characterization is a critical task. Magnetic Barkhausen Noise (MBN) technique is a promising and challenging non-destructive technique fo automated evaluation of microstructures in steel components in a fast and reliable manner. This paper presents the results of MBN measurements for microstructure characterization of the quenched and tempered steels.

Mar 1, 2017

By W. P. Sykes

IN CONNECTION with a study of tungsten steels, Honda and Murakami1 reported an investigation of the system iron-tungsten. This report included a tentative equilibrium diagram, photomicrographs of various alloys in the series, and qualitative measurements of hardness and magnetic properties. The present investigation originally had as its object the study of the hardness and tensile properties of a series of carbon-free iron-tungsten alloys. But, as the work progressed it became evident that the system possessed other features of interest, so the scope of the investigation was enlarged. MATERIALS The iron powder used in preparing the alloys was obtained as follows: Iron oxalate was precipitated from a ferrous-sulfate solution by the addition of a solution of oxalic acid. This oxalate, after thorough washing, was ignited to iron oxide, which after reduction in hydrogen at about 1000° C. yielded iron powder containing but about 0.2 per cent. iron oxide and about 0.005 percent. carbon. Tungsten metal in the form of powder, such as is used in the manufacture of filaments for incandescent lamps, was the other constituent. This material analyzed 99.8 per cent. tungsten and contained no carbon, The metal powders, in the desired proportions, were mixed by tumbling and formed, under pressure of 20 tons per sq. in., into rods 3/8 by 3/8 by 10 in. To form the alloys without contamination, sections of the pressed rods were placed on alundum slabs and heated in an alundum tube wound with a tungsten resistor and packed in heat-insulating material. While the resistor was heated, a stream of hydrogen was continually passed through both the tube and the case containing it. The tungsten winding on the tube, as well as the material heated within the tube, was thus protected from oxidation. Such a furnace will operate constantly

Jan 2, 1926

By Robert Archer

IT is now well known that the structure of aluminum-silicon alloys can be refined in a rather remarkable manner, with consequent improvement of physical properties, by certain treatments applied to the molten metal shortly before casting. The differences between the treated and the untreated alloys are so marked that special terms are used to distinguish them, the untreated alloys being referred to as "normal" and the treated alloys as "modified." The first practical method of accomplishing this result was that of A. Pacz,1 which consists in treating the molten metal with a, salt flux of which the, active ingredient is sodium fluoride. The result can also be brought about, and in a more economical manner, by the addition of small quantities of metallic sodium (or potassium) to the molten alloy shortly before casting.2 The action of the Pacz flux evidently consists essentially in the production of free sodium by the reaction of sodium fluoride with aluminum. The changing of a normal alloy to a modified alloy is referred to as "modification' and any process for accomplishing this result is a "modifying" process. Modified aluminum-silicon alloys were introduced several years ago, and it has been demonstrated both in the laboratory and in commercial practice that it is no simple matter to produce castings having the maximum or nearly the maximum properties which under favorable circumstances can be obtained. The alloys are rather sensitive to small changes in chemical composition, and the modifying process must be carried out in a very particular manner to obtain the best results. Extensive experimental work has been carried out in the laboratories of the Aluminum Company of America with the object of determining the conditions that must be observed to make these alloys of the greatest possible

Jan 2, 1926

By George H. Roseveare

Early flotation dealt primarily with the bulk concentration of sulphide minerals or the separation of one sulphide from another and was referred to as oil flotation because oils and fats were used as reagents. The separation or concentration of one nonmetallic mineral from another developed later with the use of fatty acids. Fatty acids are organic acids present usually as glycerides in tall oil and oils of fish, peanut, cottenseed, soya beans and ethers of veg¬etable and animal origin. Some, of these oils and their derivatives were used by the Phoenicians as early as 600 B.C. in making soap, and the use of such reagents in mineral dressing is referred to as "soap flotation". The first use of oleic acid for the recovery of minerals was the early agglomeration process.' The coarse particles of ore, from 1/16 to 1/4 inch diameter, were coated with large amounts of soap or oil and after screaming from the gangue were recovered by screening, hydraulic or table classification. In 1886, a patent was issued to Mrs. Carrie Everson in which the essential feature was the constituted commingling of pulverized ore, fat or an oil, either animal, mineral, or vegetable, for the purpose of effecting .a. union of the free metal or metallic portion of the ore with such admixed material whereby the same may be changed in subsequent separation of quartz or other rock therefrom by washing or other suitable means. The patent mentions the use of red, cotton seed, caster, sperm and linseed oils, In the early use of collectors the amount of oil for froth flotation was often 2 to 6 per cent by weight of the ore rather than pounds per ton.

Jan 1, 1959