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By D. C. Foguel, J. L. R. Bravo

For several years, Caraiba Metais S.A. (CMSA) had to stock the arsenic sludge generated from the electrolyte purification process of its tankhouse. The amount stocked · reached approximately 3,500 tonnes, as the effects of its recycling during the smelting process and consequently in the sulfuric acid plant were unknown. Besides, it had as limiting factors the high content of arsenic in the copper concentrates supplied by foreign countries as well as the reduced capacity of the tankhouse's purification plant. The choice for selling the mentioned residue, which generally contains more than 50% of Cu, was attractive, but the environmental policies and regulations had not allowed this option. Other alternatives, such as the production of bicupric arsenic by means of a solvent extraction process or arsenic trioxide, were considered but the economic feasibility was not attractive due to the absence of a domestic market and a poor international market. After a study of the arsenic partition in the metallurgical process, it was verified that the residue could be recycled without causing any operational problems or damage to the environment. To make this possible, the capacity of the purification plant was increased and the way of removing the arsenic sludge from the cells was modified from manual to mechanical, therefore avoiding the direct contact of the workers with this poisonous substance. Moreover, procedures for recycling in the smelter were established and tolerance limits were set for both the smelter and the sulfuric acid plant. The main amount of arsenic to be recycled is released with the smelting furnace off-gas, which is washed during the purification stage of the sulfuric acid plant. The acid water, rich in arsenic, is then treated in the waste plant and the arsenic, in its stabilized condition, is confined in an appropriate area.

Jan 1, 2000

By K. V. Raj, C. A. Berry, A. T. Weakley, A. L. Miller, P. R. Griffiths, D. A. Parks

Diesel particulate matter (DPM) has been classified as a carcinogen to humans by the International Agency for Research on Cancer. As a result of its potential carcinogenic nature, DPM exposure is regulated by the Mine Safety and Health Administration. Currently, diesel emissions in the workplace are monitored by collecting the aerosol onto filters, which are then sent to a laboratory for thermal-optical analysis using the NIOSH method 5040. This process can take days or even weeks, and workers can potentially be exposed to excessive levels of DPM before the problem is identified. Moreover, the delay involved in getting the loaded filter to the lab inevitably means the loss of some of the more volatile organic carbon. To remedy this delay, researchers from the National Institute for Occupational Safety and Health are seeking to develop a field-portable, real-time method for measuring elemental and organic carbons in DPM aerosols. In the current study, the use of mid-infrared spectrometry was investigated. It is believed that mid-infrared spectroscopy is more suitable for use in a real-time field-portable device than thermo-optical analysis methods. This article presents a method for measuring organic carbon (OC) and elemental carbon (EC) in DPM for a broad range of OC/EC ratios. The method has been successfully applied to laboratory-generated and mine samples.

By O. Terichow

A pendulum sclerometer designed by the Bureau of Mines is described. Its method of operation is given, along with the results of tests made on representative mineral samples of Mohs' hardness scale to determine the applicability of the device for research on rock testing. The sclerometer hardness values obtained from the tests indicated that reproducibility and accuracy were good. A quantitative comparison of the pendulum hardness values with microhardness and surface energy values published by other investigators showed good agreement on minerals with Mohs' hardness numbers of 2 to 9.

Jan 1, 1967

By Zhihe Dou, Yan Li, Qiuyue Zhao, Guozhi Lv, Yan Liu, Hongliang Zhao

"Abstract: How to reduce carbon dioxide emissions has become a vexing problem, meanwhile, there exist high energy consumption and low efficiency problems in the existing CO2 capture and storage technologies. For CO2 comprehensive Utilization, this paper researches a new technology of absorbing the CO2 emission with high alkaline calcium or high alkaline wastewater sludge mineralization of calcium and invent a core device for multi-level jet carbonation. The industrial test has been carried out in China Xinyu slag Engineering Co., Ltd. The wastewater flow is 150m3/h in the pilot scale. The prepared calcium carbonate has a whiteness greater than 90%, particle size less than 150nm. The mineralization of aluminum exhaust with waste carbide indicates that the CO2 absorption rate is greater than 99.0%, CO2 concentration in the exhaust gas is lower than 0.08%, the purity of mineralized calcium carbonate is greater than 99.0% and particle size is less than 100 nm.InstructionAccording to the statistic data from IEA (2009), the carbon dioxide discharge from fossil fuel consumption in China has exceeded it in the US by the year of 2007, China, has become the largest emitter of carbon dioxide all over the world. Meanwhile, the economic scale is still on an increasing trend in the next 50-100 years, leading to a continuous increment in carbon dioxide discharge. According to the international energy agency forecasts, the energy-relative CO2 discharge in China will rise to 11,615 million tons, 91.3% higher than it in 2007. In the year of 2012, the CO2 gross discharge has reached 10,000 million tons, obviously higher than the predicted value. It is a tremendous task to reduce the emission. Non-ferrous metals industry is one of the largest emitters of carbon dioxide among the industrial circle, the whole industry might discharge a huge amount of carbon dioxide (over 600 million tons), in which the electrolytic aluminum industry is the largest energy consuming industry and CO2 emitter. At present, the CO2 discharge has focused by the whole world due to the environmental problems it causes; meanwhile, supplement of new carbon source is needed due to the exhausting oil and coal resources, so that various countries in the world are attaching importance of the recycle and purification of CO2. Many countries are studying on the cyclic utilization of carbon dioxide. Gas CO2 is mainly applied in chemical, pharmaceutical raw materials, beverage filling agent, refrigerant, inert medium, solvents, pressure source, the welding protective gas, antioxidant and fire extinguishing agent, etc. Solid CO2 is mainly applied in penicillin production, fish, cream, ice cream and other food storage and transportation at low temperature, etc. nowadays, such methods as absorption method, membrane separation, adsorption, etc. are widely used to recycle CO2, with such problems as high investment cost and technical constraints etc."

Jan 1, 2014

By R. A. Pallanch

IN his recent paper, "The Controversial Art of Flotation," (Mining Technology, March, 1944) E. H. Rose states that "flotation is a science in so many variables that only art can blend them." This statement is apt. It contains meat. In other words, a valid scientific reason is behind every flotative effect. Some of these reasons we understand, but much the greater number of them still escape us. This does not prevent us from "going places," as familiarity and experience with the problems result in an increasingly intelligent and artful handling of these effects. Hypotheses are built up by the individuals concerned to explain certain happenings. Many of these hypotheses have to be abandoned when placed under the glaring scrutiny of actual trial. A few survive the severest of tests, come through unscathed, and are elevated to the rank of theories, something susceptible of certain chemical and physical explanation, under the conditions of the particular plant concerned. If these theories continue to hold water under all the variations existing in most milling plants, they gradually become accepted as facts in the minds of the plant operators. But-and here is a big BUT-these so-called facts may fall down completely in another plant working under an entirely different set of conditions. In other words, each plant tends gradually to build up its own facts, which may or may not be facts at another operation.

Jan 1, 1945

By Wilfredo Serrano

El presente artículo describe la historia, características, especificaciones, ventajas de la máquina WS Morococha de gran volumen. Dicha máquina fue diseñada en 1966 en el asiento minero de Morococha y es utilizada para concentrar minerales por el método de flotación de forma económica. Entre las principales ventajas tenemos: gran volumen y capacidad por unidad, bajo costo de inversión y mantenimiento, la operación es independiente en cada máquina, su alto radio de concentración permite obtener rougher concentrados limpios directos y que en las paradas no se pierden el volumen del mineral retenido y el punto se descarga en la parte superior. De forma que esta máquina concentradora de minerales por flotación de concepción y desafíos mejorados, desarrolla mayor eficiencia y selectividad.

Mar 1, 1976

By Raja V. Ramani, Wilson Miola

"The potential health effects of quartz-bearing airborne dust in mine and mill atmospheres point to the need for the quantification of quartz content in the source material for determining the source-sink relationships and for choosing applicable control measures. While a standard method exists from a regulatory point of view for the sampling of coal mine atmospheres for determining (i) respirable dust concentrations and (ii) the amount of quartz in the samples, there is no generally accepted standard method for quartz analysis in bulk samples of coal and host rocks. Generally, the bulk sample is reduced to a powder for producing quartz analysis samples. Extensive controls arc necessary to ensure representativeness of the analysis samples when these are very minute fractions of the bulk samples. Since the amount of analysis sample is not limited, alternative methods for quartz analysis may also be tried. It is, however, necessary to adopt a procedure which will satisfy several statistical requirements to guarantee representativeness of the quartz analysis samples.In this paper, the important factors in the preparation of quartz analysis samples from the host rocks and bulk samples are discussed. The method developed to prepare the analysis samples is outlined. The results of application of the procedures are presented. The procedure developed for quartz analysis sample preparation is based on sound statistical foundations. The procedure has been validated for reproducibility and homogeneity.The current methods used for quartz analysis in powders are the P-7 infrared spectrometry and quantitative X-Ray Diffraction (XRD). Both have similar restrictions concerning the sample characteristics and operational problems, which arc intrinsic to radiation beams, device geometry, mechanics and controls of the radiation behavior. Although improvements can be made in the spectrometers and diffractometers, some of the most important steps are the procedures for analysis sample preparation from bulk samples and for calibration of the instruments. The sample preparation process is often referred to as one of grinding and sizing the bulk sample to generate the powder for the scanning devices. The particle sizes are referred to and their influence emphasized but the representativeness of the sample is assumed. Assuring sample representativeness during the sample preparation procedures is critical.For the sampling of airborne respirable dust in coal mines, the collection devices, the collection procedures and the analysis procedures are defined. This is not true for bulk samples where weights must be reduced thousands of times to generate the analysis samples for the scanning devices. The specifications to be developed may include bulk sample amount, sample reduction procedures, sample particle size distribution and sample amounts. However, the common problem of insufficient sample amount which is often encountered with mine airborne dust samples need not exist for bulk samples. Further, the same bulk sample can yield analysis samples for several experiments. The latter, of course, requires sample homogeneity.Three concepts are important in the selection of any procedure for sample preparation and analysis. These arc accuracy, reproducibility and representativeness. The adopted procedure has to guarantee a homogeneous sample representative of the population, a defined level of accuracy and reproducibility. Important statistical concepts are embedded in these requirements, particularly with respect to estimation and dispersion errors. Accuracy and reproducibility are totally different though not independent concepts. Estimation is related to accuracy and the true value. Dispersion is related to reproducibility and is measured by the classical statistical standard deviation of the distribution of a series of measurements or analysis performed over the same lot or analysis sample. The dispersion variance (or dispersion error) does not tell a"

Mar 1, 1992

By M. B. Royer

Sulfur is present in many ores and other raw materials that are used in the production of metals and alloys of industrial importance. Its presence, especially in ferrous-metal products, generally is undesirable because of its detrimental effect during processing and upon various physical properties of the finished metal. Therefore, various methods are resorted to for elimination of the element to some specified maximum final content. Such removal or elimination of sulfur is designated as desulfurization.

Jan 1, 1948

By Paul H. Miller

After passage by the Congress, Public Law 95-87, the "Surface Mining Control and Reclamation Act of 1977" was signed by President Carter on August 3, 1977. This law, in its simplest form, was intended to control the environmental effects of surface coal mining and to ensure that mined land is restored to a condition equivalent to that prior to mining. Immediately after the signing, the wheels of government bureaucracy began turning to establish a new federal agency -the Office of Surface Mining Reclamation and Enforcement or OSM -in the Interior Department that would implement the provisions of the Act. Since this took time and because the Congress had not yet provided funding for OSM, a special task force was assembled within the Interior Department to begin the task of writing interim regulations to implement the Act. With respect to the use of explosives, the Act specified that a blasting plan be included in the application for a mining permit. The blasting plan will outline the procedures an operator will use to meet specified environmental protection performance standards. The performance standards established by the Act require explosives to be used only in accordance with existing state and federal laws and regulations and with regulations to be promulgated by the regulatory authority. The regulatory authority was defined as either a state agency operating under an approved state program or the OSM operating under a federal program. As a minimum, it was specified that the regulations should include provisions to require that: 1) a blasting schedule be published in a local newspaper and be mailed to local governments and to all residents living within 1/2 mile of the blasting site . 2) daily notice be given to residents in the area prior to blasting. 3) blast reports be prepared that are maintained for three years and available on request to the public. 4) blasts be designed to prevent injury to persons, damage to property outside the permit area, adverse impacts on underground mines and adverse effects on ground or surface water channels or availability outside the permit area. 5) upon request of residents or property owners within 1/2 mile of the permit area, preblast surveys shall

Jan 1, 1978

By Jerry G. Craig

The Bureau of Mines has developed a computerized oil and gas well data retrieval system from studies of the waterflood potential of a producing reservoir. This system stores pertinent information about each well completed in a reservoir and facilitates selection and manipulation of large volumes of data. Use of the system enables reservoir information to be supplied rapidly, accurately, and at less expense.

Jan 1, 1971

By Zhibao Li, Lanmu Zeng

The behavior of dicalcium silicate in NaOH-NaAl(OH)4-Na2CO3 solution is of significance for controlling the silica level in the production of alumina via the sintering process. Dicalcium silicate samples were obtained through a twostep approach: coprecipitation of calcium and silicate from CaCl2-Na2SiO3-NaOH solutions; and calcination of the hydrated precursor at 1200°C for 4 hours. The optimization of the synthesis parameters including temperature, solution concentrations and aging time was also investigated. Xray diffraction (XRD) and chemical analysis show that the calcined solids include dicalcium silicate with trace amounts of wollastonite. The solubility of the synthesized dicalcium silicate in HCl, NaOH, mixed NaOH-NaAl(OH)4 and NaOH-NaAl(OH)4-Na2CO3 solutions was determined. It was found that the solubility increases with increasing HCl and NaOH concentration. The effect of temperature on the solubility in HCl solutions is limited, but the solubility decreases with increasing temperature in NaOH solutions. The solubility of dicalcium silicate in NaOH-NaAl(OH)4 and NaOH-NaAl(OH)4-Na2CO3 solutions was shown to increase with increased temperature, Al(OH)3 and Na2CO3 concentration. The BromleyZemaitis model for the aqueous electrolyte system was selected to predict the solubility of dicalcium silicate. The model’s predictions yielded certain success compared with experimental solubility data.

Jan 1, 2014

By Wen-Ming Chien

Keywords: AN-KN Phase Transition, Lattice Parameters of AN-KN, X-ray Diffraction The lattice parameters of the low and high temperature phase of KNO3-rich (in NH4NO3) solid solutions have been determined by the X-ray diffraction method. The low temperature single KNO3 phase (KN II) are from 92%-100% KNO3 in NH4NO3 composition range and from room temperature to 393 K showing in X-ray diffraction patterns. The high temperature KNO3 phase (KN I) showed very broad composition range between 20% to 100% KNO3. The lattice parameters of KNO3-rich (KN II and KN I) solid solutions have been calculated at different temperature range. The volumes of orthorhombic KN II phase decrease from 0.3208(3) to 0.3195(3) nm³ at the room temperature as the compositions increase from 95% to 100% KNO3. The lattice constants of the hexagonal KN I phase show that there is no significant change in a-direction when the temperature increases. Details X-ray results and lattice expansion equations during heating will be presented.

Jan 1, 2005

By Joseph Indeck, Seokbin Lim, Andrew Thompson

In the design of explosively driven penetration devices, understanding the impact conditions between the explosively propelled penetrator and the target is one of the most important steps in optimizing the performance of the device. These impact conditions are especially prevalent when a shaped charge jet impacts concrete, which is not an ideal target material. The specific impact conditions, including but not limited to the impact angle and jet properties, create a great deal of variability that affects the performance and penetration of the shaped charge. The large amount of impurities and voids in concrete, along with its heterogeneous nature and the general strength characteristics, make concrete a non-ideal material for shaped charge jet penetration. These material characteristics lead to a highly non-linear deformation behavior of the concrete target during a hyper-velocity impact.

Jan 1, 2011

By S Pradhan, A Kuras, R Mahajan

This paper describes the design of the precast concrete segmental lining for the 13.1 m internal diameter and 450 mm thick, 2.4 km long mainline tunnels for the Waterview Connection project in Auckland for the New Zealand Transport Agency.The design and detailing of this segmental lining presented some noteworthy challenges, including an alignment that has sections of low cover in soft ground. Key points of interest are that this precast segmental lining is the largest to ever include steel fibres as the primary method of reinforcement and the lining includes cams on circumferential joints to control ring deformation.The paper describes some of the key design decisions that were made in a collaborative manner with the construction team, tunnel boring machine manufacturer, segment manufacturer and the designers.CITATION:Mahajan, R, Kuras, A and Pradhan, S, 2014. Design of segmental lining for Waterview Project, Auckland, New?Zealand, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 289–294 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By S. Klerkx, R Battulwar, J Valencia, J Sattarvand, E Emami, M. Soleymani Shishvan

A new technology for energy distribution optimization, supported by NIOSH.

Feb 1, 2020

By Elgin D. Bell

Within the next, year or two, Western Canada should overtake Mexico and France. to become the worlds second largest producer of elemental sulphur, surpassed only by the United States, By 1965, it should produce about 25% of the world's total elemental production and, about 10% of sulphur produced in all forms. In 1952 Alberta had but one small sulphur recovery plant. By 1962, it had fifteen plants with a total designed capacity of almost 6,000 long tons of sulphur per day and actual production of almost one million long tons per year. This decade of dynamic growth was the result of Alberta's rapidly developing natural gas industry. More particularly it was the result of approval in 1960 to export natural gas in large volumes into the United States. Prior approval to export gas from Alberta to eastern Canada and relatively modest volumes to the U. S. had resulted in the construction of several plants but none were of the scale required to serve the U. S. market.

Jan 1, 1963

By David S. Yang, Osamu Taki

The innovative Soil-Cement Mixing Wall Technique, developed independently in Japan, consists of mixing in-place soils with cement grout using multi-axis augers and mixing paddles to construct overlapping soil-cement columns. The applications of overlapped soil-cement columns include cutoff walls for groundwater control and structural diaphragm walls for excavation support. The special features of this technique include water tightness, versatile strength design, and efficient installation in subsurface materials varying from clayey soils to cobbles or soft rocks. Through the introduction of two recent subway projects in Japan, this paper presents the design parameters, construction procedure, quality control and performance of soil-cement wall for excavation support and groundwater control.

Jan 1, 1989

By E. Suárez, V. Rivasplata

El proyecto Piel Canela está ubicado en los distritos de San Luis y San Bernandino en la provincia de San Pablo dentro de la región Cajamarca. La geología muestra unidades volcánicas del Paleógeno (Paleoceno – Eoceno/Oligoceno) las cuales se presentan deformadas. El basamento en el área de estudio está representado por secuencias de depósitos volcanoclásticos gris verdosos intercalados con flujos de lava, de manera concordante ocurre sobreyaciendo a esta unidad una secuencia de flujos piroclásticos de pómez y cenizas con intercalaciones de flujos de lava compactos. Además se observan en las partes más altas flujos piroclásticos de composición dacítica rica en cristales con coloraciones gris blanquecinas.

May 1, 2008

By W. E. Coxe

In 1857 the Philadelphia and Reading Railroad Company, whose main line extended from Philadelphia to Pottsville, Pennsylvania, with branches into the coal regions of Schuylliill County, made a contract with the Fairmount Rolling Mill, at Philadelphia, for the rerolling of some four thousand tons of iron rails. The essential features of the agreement were that the old rails should be piled with puddled iron and rolled into flats for the rail pile, which latter was • to be of a section seven inches square, and after being heated, and reduced, by rolling, to a bloom of a section about fire inches by six inches, was to be reheated, before being finished into the rail of the T pattern, four inches high, weighing sixty-four pounds per yard. Great care was exercised in the execution of this contract, and the rails being distributed over all parts of the road, gave general satisfaction by their excellent wear. Five years afterward, the principal proprietor and manager of the Fairmount Rolling Mill was elected President of the Reading Railroad, and very many of the rails made under his supervision were still in use in the tracks of the company, of which he had just assumed the management. His first efforts were, therefore, directed to the procuring of more rails of the same quality wherewith to replace those worn out. Here he encountered some trouble, makers refusing to bid because of the details in the specification, the required reheating being the objectionable feature, for which it was generally intimated they would not be sufficiently remunerated for the increased labor, extra coal consumed, and the changes necessary from the established methods of working. Most of the new rails were, therefore, bought, and the old rails rerolled without regard to any particulars as to the manner of piling, heating, etc., each manufacturer furnishing what he deemed the best article possible for the money. As a consequence, rails of all imaginable grades were placed in the tracks, some giving out in six

By W. E. C. Coxe

IN 1857 the Philadelphia and Reading Railroad Company, whose main line extended from Philadelphia to Pottsville, Pennsylvania, with branches into the coal regions of Schuylkill County, made a contract with the Fairmount Rolling Mill, at Philadelphia, for the rerolling of some four thousand tons of iron rails. The essential features of the agreement were that the old rails should be piled with puddled iron and rolled into flats for the rail pile, which latter was to be of a section seven inches square, and after being heated, and reduced, by rolling, to a bloom of a section about five inches by six inches, was to be reheated, before being finished into the rail of the T pattern, four inches high, weighing sixty-four pounds per yard. Great care was exercised in the execution of this contract, and the rails being distributed over all parts of the road, gave general satis¬faction by their excellent wear. Five years afterward, the principal proprietor and manager of the Fairmount Rolling Mill was elected President of the Reading Railroad, and very many of the rails made under his supervision were still in use in the tracks of the company, of which he had just assumed the management. His first efforts were, therefore, directed to the procuring of more rails of the same quality wherewith to replace those worn out. Here he encountered some trouble, makers refusing to bid because of the details in the specification, the required reheating being the objectionable feature, for which it was generally intimated they would not be sufficiently remunerated for the increased labor, extra coal consumed, and the changes necessary from the established methods of working. Most of the new rails were, therefore, bought, and the old rails rerolled without regard to any particulars as to the manner of piling, heating, etc., each manufacturer furnishing what he deemed the best article possible for the money. As a consequence, rails of all imaginable grades were placed in the tracks, some giving out in six

Jan 1, 1877