Search Documents

By J. D. Miller, C. L. Lin, J. Dong

Nano clay mineral particles such as kaolinite — with primary particles typically smaller than 2 μm in size — can cause significant problems in flotation processes and tailings disposal, including the processing of Florida phosphate rock and Canadian oil sands. In this study, the consolidated state of flocculated kaolinite sediment was examined, and high-resolution X-ray microtomography (HRXMT) was applied to describe the structure of the consolidated sediment. Using this tomographic information, the complex geometry of the channel network structure for the consolidated flocs was established for the first time. With the establishment of the experimental channel network structure, permeabilities were estimated by flow simulation using the Lattice Boltzmann method. Results for kaolinite sediment with and without polymer are compared and discussed. Results for flocculated kaolinite sediment in a gravitational field are also presented and discussed. The results show that as polymer dosage increases, the permeability of flocculated kaolinite sediment increases, and as suspension pH increases, the permeability of flocculated kaolinite sediment decreases.

By K. J. Kruger

Aluminium alloys have gained popularity in many industries due to their high strength and low weight. One shortcoming of aluminium alloys is their poor resistance to abrasion and erosion wear compared to materials such as stainless steels. In this project, aluminium alloy 2014 (AA2014) was coated with a 1.5 mm thick laser-deposited layer composed of silicon, copper, and aluminium with the aim of increasing the wear resistance. The amount of silicon, copper, and aluminium added to each sample was determined by a mixtures model. It was discovered that the Al-Cu system is very sensitive to silicon additions and that wear resistance depends on the primary phase to solidify as well as on the final phase distribution. Two primary phases were identified; alpha aluminium and theta intermetallic. It was observed that the clad layer increases both the hardness and wear resistance of AA2014, and that the material solidifying as primary alpha aluminium displayed a lower hardness but higher wear resistance than the samples containing primary theta phase. All clad layers performed better in terms of wear resistance than the unclad samples. The knowledge gained and principles used in this project could be applied to many other aluminium alloys.

Jan 1, 2014

By S. K. Sharma

The Bureau of Mines has investigated the fundamentals of the flocculation process. The objective of this study was to determine the effects of various physico-chemical parameters such as shear rate, polymer dosage, and polymer concentration on floc growth and to determine the applicability of a model in predicting polymer flocculation behavior. A rapid in-line particle size analyzer was used to follow the progress of both the floc growth and the breakage as a function of time. A genetic algorithm (GA) was used to determine the unknown parameters in the model and to fit a curve to the experimental data. Results show that the model, using GA as a tool to determine the unknown parameters, reproduces the experimental data with only reasonable accuracy and was relatively insensitive to the parameters. Results of the flocculation study showed that increases in polymer dosage had greater effect on the time required to reach the maximum floc size than on the floc size itself. It was also determined that, given all the aforementioned parameters, the degree of slurry mixing during the flocculation process had the greatest bearing on the floc growth.

Jan 1, 1993

By Hui-gang Wang, Mei Zhang, Min Guo

Metal-doped Ni–Zn ferrite with spinel structure was directly synthesized from treated zinc-containing electric arc furnace dust (Zn-containing EAFD) by solid state reaction method, realizing the transformation of Zn-containing EAFD from solid waste to high value-added material. A certain mass of NiCl26H2O was added to the treated Zn-containing EAFD before calcination. Then the effects of the mass ratio of treated Zn-containing EAFD to NiCl26H2O (RTZE/N, g g−1) and calcination temperature on the synthesis and magnetic properties of as-synthesized samples were systematically investigated by X-ray Diffraction, Raman Spectroscopy and Physical Property Measurement System. It is indicated that RTZE/N and calcination temperature had important influences on the synthesis of single-phase spinel ferrite and their magnetic properties. Pure metal-doped Ni–Zn ferrite, which exhibited good magnetic properties of higher saturation magnetization (Ms, 60.5 emu g−1) and lower coercivity (Hc, 49.8 Oe), was obtained when the calcination temperature was controlled at 1100 °C for 2 h with RTZE/N of 1:0.9.

Mar 1, 2017

By Dorothy M. Richardson

The Bureau of Mines has participated in the American Petroleum Institute Research Project 48A (API-RP48A) program on the Separation and Identification of Sulfur Compounds in Crude Petroleum. The lack of reference compounds or infrared spectral data has made difficult the identification of individual sulfur compounds boiling above 140° C. The recent acquisition of 24 alkylthiophnnes has made possible a limited study of this important class of sulfur compounds. The infrared spectra of 2-monoalkylthiophenes and 2,5-dialkylthiophenes for the 2 to 15p range are reported. Correlations for determining the 2-alkyl and 2,5-dialkyl substituted thiophenes are derived from this information. The 2-alkylthiophenes show a unique pattern in the 5.50 to 6.54 region, while the 2,5-dialkylthiophenes show a distinctive pattern in the 5.6µ to 6.7µ region. A skeletal vibration occurs in the 9.5 to 10.0µ region for all of the thiophenes investigated. These data will aid the infrared spectroscopist in the identification of compounds of the type reported.

Jan 1, 1961

By R. Horn

The financial performance of the mining industry, measured by return on equity and capital employed, has been inadequate for many years. Consequently, mining companies are not valued highly by stock markets. Among the more important causes for the decline in the sector are the conservative working practices and reluctance to adapt to change or to develop new technology, although some relatively recent developments such as SX-EW copper and heap leach gold have made a significant impact on the cost base of these metals. The subsidiary business of metals exploration suffers from the same problems as the rest of the industry. The rate of discovery of ore deposits has been falling over many years and since the late 1990s, there has been a sharp reduction in global exploration activity that, if it continues, will further reduce the global supply of new ore reserves. New technological developments, particularly in geophysics and different operational practices may help reverse this trend. Statistical methods for evaluating the risk of ore reserve estimates will also improve the economic return on new mining ventures. The science of ore geology has potential to reduce exploration risk, but modern ore genetic theory has not contributed greatly to recent discoveries. The junior exploration market has almost ceased, but a new style of technically specialized efficient small exploration company has emerged which, in alliances with major companies, may be the vehicle for future global exploration. Exploration in virgin terrains has a higher risk discounted potential for the discovery of very large orebodies than that in known mining districts but mining companies have little financial incentive for this high risk exploration because of the very long lead time to production. Alliances of two or more companies reduce the risk in both the exploration for and development of major new mining projects. If new orebodies are not found, then metal prices will inevitably rise in the long term. Governments of industrial countries, particularly those with a significant mining industry such as Canada, should therefore provide assistance to exploration in order to maintain their existing industry and prevent a metals shortage from developing in the future with its consequent impact on the world economy and increased environmental damage as large lowgrade orebodies are developed to supply an expanding market.

Jan 1, 2002

By J. Sadaki, G. Dodbiba, S. Murakami, T. Fujita, S. Matsuo, H. Ono, K. Okaya

Printed circuit boards (PCBs) from discarded personal computer (PC) and household appliances were crushed by mechanical crushing or water explosion to remove mounted parts. More parts were stripped from PCB for PC composed of epoxy resin than from PCB for household appliance composed of phenol resin. In an attempt to raise the copper grade of PCB by removing other components, a carbonization treatment was investigated. The crushed PCB without surface-mounted parts was carbonized under a nitrogen atmosphere at 1073K. After screening, the char was classified by size into oversized pieces, undersized pieces and powder. The copper foil and glass fiber pieces were liberated and collected in undersized fraction. The copper foil was liberated easily from glass fiber by stamping treatment. On the other hand, tantalum capacitors were collected from mounted parts. The tantalum-sintered bodies were separated from molded resins by heat treatment at 723 to 773K in air atmosphere and screening of 0.5mm. Silica was removed and 70% of tantalum grade was obtained after more than 823K heating and separation.

Jan 1, 2011

By J. D. Doll

MSHA has promulgated a rule to limit the exposure of underground metal/nonmetal miners to diesel particulate matter (DPM). In May 2008, the final personal exposure limit will be lowered to 160 µg/m3 total carbon. To comply with this rule, mine operators are implementing a variety of control technologies. In this study two types of control technologies (ventilation and cabs) which are being implemented in limestone mines were investigated. Two stone mines in this study use large diameter propeller fans for main mine ventilation and direct the air to the faces using auxiliary fans, stoppings, and long pillars while bypassing the old mine workings. NIOSH measured for sub-micrometer elemental carbon (EC) using SKC DPM cassettes (analyzed using NIOSH 5040) and a near real time instrument. With the present ventilation and the number and type of vehicles used, the concentration of EC from DPM at the working areas was at or below 400 µg/m3 for both mines and about 166 µg/m3 and 251 µg/m3 at the returns. The real time data showed that the ventilation was reaching the working areas and effectively diluting the DPM. Environmental cabs were also used to reduce DPM exposures in three underground limestone mines. Using NIOSH method 5040 and near real time EC instrumentation, NIOSH sampled inside and outside of a loader cab at one of these limestone mines to determine the effectiveness of the cab. The cab was found to be over 90% effective in removing DPM as long as the cab system was properly maintained, and doors and windows were closed.

Jan 1, 2009

By V. J. McSweeney

This paper is directed at interested parties outside the Beach Sand Industry : the scope is quite broad. The geomorphology described is a successful working hypothesis which guided the author during prospecting and pegging campaigns : the author is not an expert in this field. The test data used in the text, for illustrative purposes, is original and may constitute a contribution to the state of the art. The operation- al and design philosophy embodied in the text is personal and describes the author's methods : all practising exponents would differ in some degree amongst themselves on these subjects. In this paper, no criticism of any existing operation or brand of equipment is intended and names are used to maintain a real contact with the subject matter. The author believes that the operational and design techniques evolved in the Beach Sand Industry under continual duress, have a wider application in the mining industry. This glimpse of the Industry is intended to enhance the respect for the present and past members. Space does not permit individual acknowledgements.

Jan 1, 1982

By Lloyd M. Kniffin

[This paper is one of series being prepared by the United States Bureau of Mines on mining methods, practices, and costs in the various mining districts of the United States. It describes the mine of the Hanover Bessemer Iron & Copper Co. at Fierro, Grant County, N. M., which is the only operating iron mine in the southwestern part of the United States. This mine is in a district noted for the great variety of ores that it produces. Within a small area, as shown is Figure 1, there are noteworthy deposits of nearly all the common metals. The ore occurs in lenticular masses dipping at about 50°. An underhand stoping method has been developed that requires but a very small amount of handling of ore. As the ore is very irregular in iron content and also in the distribution of the impurities--chiefly sulphur, silica, and magnesia--a method has to be used that will permit selective mining and will also allow ore and waste to be taken out separately as conditions change. A magnetic cobbing plant raises the grade of the ore shipped about 10 per cent.]

Jan 1, 1930

By E. P. Youngman

This paper is one of a series of digests of foreign mining legislation and court decisions that is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the mining laws of British Honduras has been prepared from the best available information in Washington and is released subject to amplification or correction, if necessary, by United States foreign-service officers. INTRODUCTION The mining law governing all mineral substances other than oil is ordinance No. 7 of 1927 (Minerals Ordinance, 1927), passed by the Legislative Council on March 25, 1927. The accompanying regulations, No. 3 of 1932 (General Minerals Regulations, 1932), made under the authority of section 66 of the minerals ordinance, were made by the Governor in Council on December 23, 1931.

Jan 1, 1934

By R. W. Ballmer

Bingham Canyon lies in the heart of the Oquirrh Mountains, 25 miles southwest of Salt Lake City, Utah. In it is located the world's largest open-pit copper mine, owned and operated by the Utah Copper Division of Kennecott Copper Corporation. From the beginning of open pit mining operations in 1906 until 1963, the pit haulage, or materials transportation, was primarily by rail. In 1963, phase-in of a truck haulage system in the upper two-thirds of the pit was begun. The details of that conversion, its associated problems and the resulting pit operation have been covered in an earlier paper.1 The purpose of this paper is to discuss various factors for consideration in transportation system selection, and to discuss some of the alternatives considered prior to making the change from rail haulage to truck haulage for a portion of Bingham Canyon.

Jan 1, 1968

By R Shaw, T T. Neidel, C Adams

Sampling equipment manufacturers endeavour to ensure that the mechanical equipment installed in sampling systems are designed and manufactured to adhere to the requirements of the International Organization for Standardization (ISO) or other standards relevant to the application. The mechanical parameters necessary to achieve these standards can be well controlled and requirements such as constant speed can be met through good mechanical design and engineering. However, when the equipment is installed and put into operation, the ISO compliance of the system is out of the hands of the equipment manufacturer and handed to the operator, who may be a generalist control system integrator.Making a sampling system perform according to standards, and being able to monitor and report on compliance require that the sampling system knowledge and the control integration is combined and applied in an integrated approach. Using a dedicated library of control routines developed for sampling can change a system from having compliant equipment to being a compliant system. The library has to include monitoring of relevant parameters and control and reporting on sampling parameters.CITATION:Neidel, T T, Adams, C and Shaw, R, 2014. Control and monitoring of International Organization for Standardization compliance for industrial sampling systems, in Proceedings Sampling 2014 , pp 121–126 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By C. J. McKee

A gold-silver-lead-zinc deposit at Montana Tunnels, Jefferson County, Montana is located in a diatreme of middle Eocene age (45 to 50 m.y.). Sulfide minerals within the diatreme occur as disseminations, veinlets, and locally as breccia matrix. Principal sulfide minerals are pyrite, sphalerite, and galena. The diatreme is a matrix-rich quartz latitic breccia with a fine grained rather soft matrix and heterolithic clasts. The ore deposit contains approximately 50 million tons of ore at a grade of 0.025 oz/ton Au, 0.5 oz/ton Ag, 0.25 % Pb, and 0.65 % Zn. Mining is by open pit methods. The original process flowsheet included flotation and cyanide leaching. Problems with the leaching circuit led to a change to the straight flotation process which is presently in use. To maintain a reason-ably uniform feed material, blending of ore is required for grades of four metals as well as for ore hardness and oxidation.

Jan 1, 1988

By W. E. Wells

This report describes experimental investigations made in the batchwise retorting of Colorado oil shale. Three heat-carrying mediums were used -hot shale gas, superheated steam, and hot flue gas. Using hot Shale gas for retorting, the several variables studied were retort-inlet-gas temperature, gas velocity through the shale bed, shale particle size, and grade of shale. In studying the effect of any one of these variables on oil yield, as and operability, the other variables were maintained essentially constant. Oil yields decreased with increasing in-let-gas temperature and increasing shale-particle size, and oil yield increased with increasing grade of Shale up to 50 gallons of oil per ton of shale, beyond which the process was inoperable because of swelling and caking of the shale during retorting. Changes in gas velocity had little effect on oil yield. Gas yield increased with increasing inlet-gas temperature, gas velocity, particle size, and shale grade. Oil yields of 100 percent of Fischer assay and from 1,600 to 1,800 cubic feet of 300-B.t.u. gas per ton of shale were obtained. Two runs only were made using superheated steam. Oil yields averaged 97 percent of Fischer assay, and gas yields averaged 4,00o cubic feet per ton of shale. Retorting with a hot flue gas produced from combustion in the shale bed, as in the N-T-U process, gave excellent yields using closely sized shale with recycling of flue gas. An excess of fine shale in the charge resulted in channeling and low oil yields. Using no recycle gas, good yields were obtained that tended to decrease with increasing air rate, and the retorting rate increased with increasing air rate over the range studied. Coking was not found serious with 30-gallon shale at the air rates used.

Jan 1, 1952

By Dan Michaelsen, Warwick Stewart

"PT Kaltim Prima Coal (KPC) is a large-scale truck and shovel operation mining thermal-coal in East Kalimantan, Indonesia. The operation produces 15 million tonnes of coal and mines over 120 million bank cubic metres of overburden annually. Approximately 35 percent of the waste rock is classified as potentially acid forming. Acid drainage must therefore be managed to prevent acid formation from spoil dumps and mined-out areas.KPC aims to prevent acid production in dumps by covering potentially acid forming spoils with materials identified as non acid-forming. The covers, built to engineering standards, minimise the flux of oxygen and water to pyritic spoils, thereby controlling the oxidation reaction, and reducing ARD discharge to negligible rates. Cover designs and cover materials vary according to stability, materials availability, equipment availability, and cost effectiveness. A modified field net acid generation (NAG) test procedure has been developed at KPC to identify and segregate overburden geochemical types. This paper discusses the ARD management strategies and operational procedures adopted by KPC to manage potentially acid forming waste rock. The development and field application of the NAG procedure at KPC is presented in a companion paper. Analytical"

Jan 1, 1999

By Livia Mara Candido

As reservas de minério de ferro, apresentam tendências de menores teores de Fe, tornando maior a necessidade da redução da fração granulométrica inferior a 150µm, o que torna o processo viável tecnicamente por meio concentração. O método mais comum utilizado é a concentração através da flotação. Flotação é uma técnica de separação baseada na afinidade das espécies minerais com as moléculas de água. Na flotação reversa de minério de ferro, utilizam-se agentes que reforçam o caráter hidrofílico das partículas de Ferro, chamados de depressores. O mais comumente utilizado é o amido de milho em forma de solução, gelatinizado com a adição de soda cáustica. Dentro desse contexto e afim de aumentar o poder de gelatinização do depressor, foram realizados através do planejamento fatorial estatístico, ensaios de flotação em bancada, com diferentes concentrações iniciais e finais de amido de milho presente na solução e ainda a relação de amido/soda para avaliar o impacto sobre a recuperação metalúrgica da flotação, concluindo-se que recuperação metálica foram fortemente influenciados pela concentração inicial da solução de amido.

Oct 30, 2017

By Harry Teicher

The subject of Specialty Silica Products could encompass a broad range of materials, some of which would be familiar to members of the Society of Mining Engineers. With the concurrence of your chairman, I have chosen to limit my remarks to synthetic materials, not including such siliceous materials as diatomaceous earth, asbestos, quartz and clays. For purposes of discussion, I have classified Specialty Silica Products into two groups -- powders and liquids -- which I will discuss in that order and which are categorized in Figure 1. The synthetic silica powders are amorphous to x-rays and are manufactured by various processes resulting in products of a wide range of physical and chemical properties, as well as functional performance and applications. Applications or functional properties are generally dependent upon such physical properties as micron-sized particles exhibiting large surface areas per unit weight and low apparent bulk density. Their presence in various systems modify surface properties. As summarized in Figure 2, they act as viscosity modifiers, flow conditioning agents, anti-slip agents, anti-blocking agents, flatting agents in surface coatings, reinforcing agents in polymers such as silicone rubber and numerous other applications. Although the various types of silicas exhibit various levels of functional performance in these end uses, they are not usually equally effective as direct replacements and I will briefly discuss the various types of materials.

Jan 1, 1974

By Y Xie, L O’Connor, S C. Dominy

"Sheeted vein gold deposits are characterised by multiple subparallel veins and free milling gold. In situ heterogeneity of mineralisation results in grade and process parameter variability, which will increase project risk. Measured variability is often enhanced by poorly designed sampling and test work protocols. Protocols that are optimised within the framework of the theory of sampling to suit the ore type, together with quality assurance/quality control systems, will reduce variability and provide fit-for-purpose results. The geometallurgical approach requires spatially distributed samples within a deposit to support variability modelling. Diverse attributes from core logging, mineralogical/textural determination and small-scale tests are used to measure variability. This contribution emphasises early stage geometallurgical intervention during project development. It presents a discussion of representative sampling in the context of the theory of sampling. A case study presents a protocol that exemplifies how data can be gained from a well-designed and planned program to support a resource estimate and prefeasibility study.CITATION:Dominy, S C, O’Connor, L and Xie, Y, 2016. Sampling and Test Work Protocol Development for Geometallurgical Characterisation of a Sheeted Vein Gold Deposit, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 97–112 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By J. D. Ramsdell

The purpose of this investigation was to determine the effects of the impurities, oxygen, nitrogen, carbon, and iron (in low percentages) on the mechanical properties of electrolytic titanium. The strength and hardness of binary Ti-O, Ti-N, and Ti-C alloys are linear functions of alloy content in the composition range investigated. Compared to oxygen and carbon, nitro-gen is the most effective strengthener and hardener, followed by oxygen, then carbon. When the carbon concentration is above 0.10 percent, carbides are present, and strength and hardness are relatively unchanged. For equivalent hardness levels, Ti-Fe alloys are stronger than binary titanium alloys containing oxygen, nitrogen, or carbon. However, the strengthening is related to the presence of transformed beta in the structure.

Jan 1, 1960