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Commercial explosives range from pure emulsions to pure ANFO, with blends of these providing interesting alternatives: energy is often adjusted through addition of aluminium, or the control of density. The energy rating of explosives is derived chiefly from detonation codes, which are used to derive expressions for the internal energy change of the detonation products as they do work under expansion. While all codes used for this purpose work on the basis of Ideal detonation, it is common knowledge that commercial explosives operate in the Non-Ideal domain, which affects the mode of energy delivery to the environment. However, since Ideality represents the foundation from which actual performance evolves, it is valuable to examine the intrinsic energy release of a formulation before attempting to understand the influence of Non-Ideality. In examining the Ideal pressure profile of fundamental formulations, remarkable correlation has been found with field performance, and this increases understanding of the influence of various formulation modifications, especially in regard to the stage at which energy is released, and the effect on rockbreaking. This work has emphasised the value of attempting to understand and define better the non-ideal detonation process.

Jan 1, 2001

By Hugo E. Camargo, Amanda S. Azman, Brian Kim

Repeated noise exposure and occupational hearing loss are common health problems across industries and especially within the mining industry. Large mechanized processes, blasting, grinding, drilling, and work that is often in close quarters put many miners at an increased risk of noise overexposure. In stone, sand, and gravel mining, noise is generated from a variety of sources, depending on the type of ore being mined as well as the final consumer product provided by that mine. Depending on the source of noise generation, different strategies to reduce and avoid that noise should be implemented. The National Institute for Occupational Safety and Health (NIOSH) has evaluated the noise profile at three operational surface stone, sand, and gravel mines. A-weighted sound level meter data as well as phase array beamforming data were collected throughout the mines in areas with high noise exposure or high personnel foot or vehicle traffic. Sound level meter data collected on a grid pattern was used to develop sound profiles of the working areas. These sound contour maps as well as phase array beamforming plots were provided to the mines as well as guidance to modify work areas or personnel traffic to reduce noise exposure.

Jan 6, 2022

By Charles M. Hauptman

The Karst asbestos deposit, discovered seventy years ago, is 32 miles south of Bozeman in southwestern Montana. The deposit is about one-half mile west of the Gallatin River which flows in a deep V-shaped valley flanked on either side by rugged mountains. The Madison range is west of the river and the Gallatin range lies to the east. A busy all-weather highway, U.S. No. 191, follows the river and is the major north-south route between Bozeman and the Gallatin valley to the north and Idaho and the west entrance of Yellowstone National Park to the south. The asbestos deposit is a large body of serpentinized peridotite in which anthophy11ite.occurs, both as distinct veins and as a disseminated mineral in the peridotite mass. The known exposures of the asbestos-bearing rock occur on a steen south slope at an "elevation of about 7000 feet, an elevation 'which is about 1200 feet above the Gallatin River. Over the years, a number of small companies have attempted to exploit the Karst asbestos deposit without continuing success. The present operator, Galaxy Mining Corporation, has attempted a systematic approach to the problem by utilizing geologic and engineering surveys to determine the economic and technical feasibility of a mine and plant to produce a finished asbestos pro-duct. The results of this work indicate a high probability of success for the project. However the company now faces that dilel1lJllB so common to the non-metallic mineral business; that is, whether to continue a research program of further mineralogical and technological studies in conjunction with detailed market surveys or to rely on the work done to date and embark on a pilot progril1n

Jan 1, 1971

By C. J. Johnson, C. J. Bise

"IntroductionCoal extraction by continuous miners (CM) is currently the most common underground method in the US industry and accounts for slightly more than two-thirds of the nation· s deep mining production (National Coal Association, 1987). Even if longwall mining should become more commonplace, it can proceed only af1er ventilation and access entries have been driven by CMs. Since an area of concern continues to be the effects of the dust generated on the health of mineworkers, this paper discusses the relationship between the elemental composition of mining-generated airborne dust sampled from the immediate ventilation return of a CM and laboratory-generated dust derived from channel samples taken from the mines.There are several potential contributions of this type of study to the coal mining industry. First after more fundamental knowledge of the causes of Coal Worker's Pneumoconiosis (CWP) is learned, the laboratory-generated respirable dust could be used to identify a potentially hazardous coal seam. Also, this study could possibly aid in understanding the fundamental causes of CWP by producing mining-simulated samples of coal dust that could be used in epidemiological studies.Further, assuming that there is no difference in the elemental composition of a drill-core sample and a channel sample from the same location a mining company could predict anew mine's respirable dust elemental composition In the immediate ventilation return by using exploratory drill core samples of the roof ,coal, and floor rock to prepare the laboratory dust. Ventilation engineers could then use engineering design and control measures during premine planning to reduce the incidence and severity of CWP by better ventilating the potentially hazardous coal seam. If this proper planning prevented any future changes to the ventilation equipment and mine design, much time and money could be saved.Scope of workTo investigate the variability of the chemical characteristics of respirable dust, airborne dust samples from eight underground coal mines located in the eastern and mid western United States were collected with eight-stage Sierra Model 298 Marple cascade impactors, as well as 25 channel samples of mined material. Each channel sample was removed from the middle of the coal face before mining occurred. Sampling of the mining-generated dust was conducted by Lee ( 1986) by sampling the entire working sections, primarily for characterization purposes, to obtain information on the locational variability of dust characteristics. Research performed for this study used the elemental analyses of the mining-generated dusts he sampled in the immediate ventilation returns of CMs."

Jan 1, 1989

By T. -W. Hong, Y. Son, S. -J. Hong, D. Choi

The characteristics of indium-tin-oxide (ITO) nanoparticles recovered from TFT-LCD panel scraps were investigated. The ITO was separated from TFT-LCD panel scraps by dissolving the color filter layer located between the ITO layer and the glass substrate. The solution was filtered to separate the ITO from the color filter component, and the filtered ITO was dissolved in the acid solution. ITO nanoparticles were then precipitated with ammonium hydroxide and organic dispersing agent, followed by heat-treatment at 600 °C. HRTEM, EDX and XRD analyses revealed that the 20 nm sized particle were composed of 90 % In and 10 % Sn, and were well crystallized to in the (222) preferred orientation.

Jan 1, 2014

By J. N. Van der Merwe

"The probability of survival of coal pillars is a more rational indicator of stability than the safety factor. Over time, pillars undergo reduction in size by progressive scaling of the sidewalls. The probability of survival is therefore not constant but reduces over time. The rate of scaling can be quantified, and the reduction of the probability of survival as a function of time can therefore also be quantified. The paper describes the link between the factor of safety, probability of survival, and reduction of the probability of survival. Using the safety factor, probability of survival, and the time at which the probability of survival will reduce to 50% is proposed as a more rational method of evaluating pillar stability than the safety factor alone.IntroductionCoal pillar strength has long been the subject of research in South Africa and several other coal-producing countries. However, it began receiving serious attention only after the Coalbrook disaster in 1960. The most important outcomes of the initial investigations were the groundbreaking research by Salamon and Munro (1967) that resulted in the well-known power formula for pillar strength, and the work by Bieniawski (1969) that resulted in a linear formula for strength. The former approach was based on empirical back-analysis of failed and stable pillar cases, and the latter on in situ strength tests on large specimens.The Salamon and Munro (1967) formula has been widely used in South Africa and even adapted for application to hard rock pillars by researchers such as Hedley and Grant (1972).At the time of the initial work by Salamon and Munro, there were only 27 failed pillar cases suitable for analysis. It was not possible at the time to determine site- or seam-specific strength, and the result was a general formula for use in all seams in all mining districts. Since that time pillars have continued to fail and the database continued to grow – as of 2013, there were 85 cases in the database. Using the additional data, there have been a number of re-evaluations of the strength formula and it has also become possible to differentiate between the different mining seams and areas."

Jan 1, 2016

By A K. Raina, V M. S R Murthy

Rock mass response in blasting is an important element to determine the performance of a blast along with its other outcomes. The near-field monitoring for rock mass response analysis is vital for determining the behaviour of a blast; however, due to costly and cumbersome methods involved in such measurements the subject has received scant attention so far and the publications on this account are perfunctory in nature. This paper presents a non-destructive method to monitor the blast-induced pressure in the rock mass at a distance from a blasthole. The methodology of monitoring and a few examples of actual field monitoring are detailed in this paper. The responses of the rock in the near-field of a blasthole under dynamic loading have been documented to predict fragmentation and throw. The proposed method has also been used in limited cases earlier by the author to predict flyrock using a semi-empirical method and trajectory equation. The pros and cons of the method are discussed while throwing light on the actual response and the prediction of fragmentation and throw of blasted rock.CITATION:Raina, A K and Murthy, V M S R, 2015. Measurement of blast-induced pressure in bench blasting and deciphering explosive performance through rock mass response analysis – a methodology, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 501–508 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By Longjiang Li, Mao Jiang, Zhihui Shen, Guizhou University, Yin Pan

This paper aims to study the influence and action mechanism of collector Y-89 on the flotation of auriferous pyrite. The measurement to identify adsorption quantity, IR and XPS spectrum analysis and flotation experiment made on the pure mineral were conducted. The research results show that when the dosage of MIBC is 20 mg/L, and pH of 8, the dosage of Y-89 over 60 mg/L, the pyrite recovery rate is greater than 80%.And when the dosage of Y-89is 60 mg/L, dosage of MIBC 20 mg/L, the pH in a wider range (pH=4~9), the recovery is greater than 75%. When the pH is above 10, the pyrite is depressed and its recovery rate is found to be dramatically dropping. Adsorption quantity measurement also shows that the strong alkaline conditions inhibit the adsorption of Y-89 on the surface of auriferous pyrite. IR measurement indicates that chemisorption of Y-89 occurs on the surface of auriferous pyrite. XPS spectrum analysis indicates that without adding Y-89, oxidation reaction occurs on the surface of pyrite. But when Y-89 is added, the chemical environment of Fe on the surface of pyrite has changed. Such findings indicate that with Y-89, chemisorption occurs on the surface of auriferous pyrite.

Jan 1, 2014

By Godofredo Torreblanca

El presente trabajo identifica, inventaria y estima los montos de inversión de los “peligros históricos” que conforman los “pasivos de seguridad” en la unidad de producción Morococha, -en tanto, representan las mayores causas ocultas de los incidentes /accidente, de forma que priorizan el nivel de riesgo que representan para tomar las medidas preventivas y crear un sistema de gestión de seguridad. De otro lado, los pasivos se han codificado para facilitar su administración y seguimiento, en aspectos relacionados con posibles fallas en el diseño de las instalaciones, peligros por antigüedad de equipos y herramientas, peligros por infraestructura minera defectuosa, y todo aquello que pueda representar un riesgo para los trabajadores (labores con secciones reducidas, tajeos sin chimeneas de ventilación, equipos defectuosos o inadecuados, instalaciones inadecuadas, instalaciones eléctricas sub estándares, etc.).

Sep 14, 2009

By William Y. Warren

Messrs. Thomas & Cross, having leased from the Akron Cement Company from twelve to fifteen acres of abandoned cement-tunnels and chambers, for the purpose of propagating mushrooms for the market, commenced operations about a year ago, and are now beginning to furnish mushrooms in quantities to the local markets of Buffalo and Rochester. The quarries, or, more properly, the mines, of the Cement Company are located at Akron, Erie County, PIT. Y. The cement-rock occurs in a stratum about 71/2 to 8 feet in thickness, which is overlain by from 1.5 to 25 feet of limestone and flint-rock. There is a gentle rise from the opening of the tunnel inwards, giving a natural drainage and leaving the chambers comparatively dry. The roof is good and is supported by pillars and heavy timbers. The mushroom-beds are located about 300 feet from the opening of the tunnel, and are made in the form of mounds about 3 feet by 12 feet, at the base, and 24 feet high, giving to the chambers the appearance of a subterranean graveyard. Many experiments have been made to determine the best form for the beds, and the mound

Jan 1, 1889

By Víctor Barrientos

El presente texto describe una de las formas de liderazgo en el manejo de información de las empresas a través de la técnica de Barrientos y cómo su metodología fue aplicada para el mejoramiento de la información del mantenimiento en una mina a cielo abierto. Para ello, se revisa la gestión de activos, estrategias del cambio y el liderazgo situacional con el objetivo de que alcancen el mayor nivel de desarrollo frente a una meta específica.

Oct 1, 2016

By J. M. Rapkoch

In late October 1996, an acid plant at a major U.S. copper smelter was faced with unexpected and rapidly increasing pressure drop across the gas cooling tower in the acid plant, indicating a build-up on the packing. This threatened to halt operations if not resolved. Earlier that month, a smaller vessel in the acid plant was found to be completely plugged with lead sulfate. It was feared that a similar fate awaited the gas cooling tower unless the scale build-up was stopped. Although lead sulfate is present in most copper smelter acid plants, this accumulation was unusually severe. An investigation was launched to find the source of the lead, determine how lead is transported to the gas cooling tower, recommend operating practices to prevent such severe scaling, and seek ways to recycle the lead value in the scale covered polypropylene packing. Late in the investigation it was learned that the lead originated from an improperly executed recycling program.

Jan 1, 2000

Reduce the number of accidents caused by slips and falls from large mining equipment. Approach A powered lift was developed that provides operators with a safer way of getting on and off large machines. How It Works The powered step is designed to lift personnel and materials to working levels on large machines. It eliminates hazardous blind steps and makes it unnecessary to climb on irregular surfaces made slippery by mud, ice, snow, and accumulations of grease. The step is powered by a self-contained electric/hydraulic unit which is connected to a vehicle's auxiliary power supply. When in the "down" position, the step rests about 15 inches above ground level. When the power unit is activated with an electrical switch located on the step, a Single cylinder attached between two lifting arms smoothly lifts the step. In conjunction with the lifting motion, a linkage and bearing arrangement on the mounting end of the lift arms causes the step to rotate towards the machine, so that the step moves in an arc from ground to platform level. When the machine Is operating, the step is automatically locked in the "up" position, protecting it against any damaging contact with obstructions. The step is lowered by activating a pressure release solenoid. An in-line orifice controls downward speed and prevents free fall. On most machines, additional control switches are conveniently located at ground level and in the operator's cab. Visual alarms and machine interlocks are provided where necessary to prevent machine operation when the step is In the "down" position. The powered step can be easily adapted to any type or model of large machinery.

Jan 1, 1981

By L. W. Page

PrEvious to the introduction of the motor vehicle the broken stone or macadam' road met the conditions of rural horse-drawn traffic better than any other type of road, but under fast motor traffic it has been proved to be quite unsatisfactory, and necessitates high maintenance charges. Such a road depends for its success upon the fact that the rock dust fills the voids between the stones and acts as a cement or binder. Under ideal conditions it should be constructed of rock so suited to the volume and character of horse traffic that only enough fine dust is worn from the stones of which the road is composed to take the place of that carried off by wind and rain; and when these conditions are met, the fine dust resulting from the wear of traffic forms with the stone a smooth, impervious shell, shedding the surface water and protecting the foundation. With increase in the number and speed of motor vehicles, however, it was soon found that the cost of maintenance also increased, until at the present day highway engineers consider the old method of constructing and maintaining broken-stone roads increasingly inadequate, and are introducing every known type of binding material other than rock dust to cement the stone together. Among the most prominent types of products in use are those produced from our various petroleums. That the value of modern methods of road preservation was appreciated in this country much earlier than we have been accustomed to believe is demonstrated by the recent revival of an old patent which was granted to one John Martineau, of Elbridge, N. Y., in 1834. Petroleum had, of course, not been discovered at that time, but he claims as his invention and improvement "The application of tar, turpentine, or any of that class of tenacious, cohesive substances, reduced before use to a fluid state, and that state used as a cement, to apply to, and combine with sand, gravel, pebbles, and pulverized stone, such as is used for a Mc-Adam road, or cobble stone, the interstices of coarser material being in all cases filled,'as well as may be, with sand and gravel and cemented with tar or turpentine, to form the wearing face or surface of streets,

Jan 1, 1915

By P. A. Peach, W. H. Gross

The modern economic geologist in Canada is well equipped to apply geological, geochemical or geophysical techniques in the exploration for ore. Recently, great advances have been made in geophysics and geochemistry, and a large number of new orebodies have been discovered by these methods. An attempt is made in this paper to show that there has also been a considerable advancement in geological knowledge and that the most effective application of geophysics and geochemistry often occurs in areas already considered geologically favourable for the occurrence of ore. Ali exploration methods sooner or later suffer from diminishing returns. Therefore, as time goes on, one can expect to see the application of some of the more subtle or refined geological techniques that are presently being developed.

Jan 1, 1967

By K. Abe

Onahama Smelter has two green-charge reverberatory furnaces and the annual smelting capacity is 600 thousand tons copper concentrate. In addition to the concentrate, various kind of industrial wastes has been processed and utilized. First, the brick waste from converter is ground and used as raw material of castable for repairing the copper melt launders. Second, the slag containing calcium-sulfide from other foundry is fed to the reverberatory furnaces. Calcium sulfide is oxidized to CaO. The melting rate of concentrate is accelenlled and the slag loss is decreased. Third, the tip tire made of waste car tire is charged into the reverberatory furnaces as fuel. The steam of waste heat boiler for turbine generators has been increased so as to decrease the electricity cost. Fourth, the sulfur accretion from other chemical plant is blended into the copper concentrate and the sulfur is recovered as the gypsum for sale. Fifth, the processed waste oil has been utilized in the copper concentrate dryer by which the smelting capacity was increased effectively. Consequently, Onahama smelter contributes to the society by processing the wastes to the harmless slag and utilizing them as fuel through the copper smelting.

Jan 1, 1996

By B. Friedrich, A. Birich

Gold has been a metal of special importance for mankind for several thousand years. Its outstanding chemical resistance is an important property of this noble metal, but becomes a disadvantage when it comes to gold recovery. The established processes are based on highly aggressive and toxic reagents. Different alternative leaching reagents with a significantly lower toxicity proved to be promising alternatives in the last decades. Major research activities in this field focused on gold ores, so that leaching of secondary resources were not described sufficiently. Based on literature research and extensive experimental investigations, a reagent assessment was conducted for hydrometallurgical gold recovery from electronic waste. It was found that besides thiourea and halides, thiosulfate in particular represents an alternative of major relevance. A variety of different electronic waste (e-waste) specimens were investigated to identify suitable leaching conditions. As a result, an almost complete and selective gold recovery in less than 48 hours from different electronic waste types and components was achieved by thiosulfate leaching. Within the experiments conducted, it was found that the leaching behaviour of cyanide alternative lixiviants differ strongly from leaching of primary ores. Keywords: Gold leaching, cyanide alternative, thiosulfate, electronic waste

Jan 1, 2020

By AIME AIME

FEW men are better known in fuel engineering circles in the Middle West than the present Chairman of the Coal Division of the A.I.M.E. - Julian Elnathan Tobey. Now vice-president in charge of engineering of Appalachian Coals Inc., of Cincinnati, he has served that pioneer regional marketing agency since Aug. 1, 1934, when he became manager of its engineering department. His duties have included field promotion work in the interest of use of the agency's coals from eastern Kentucky and Tennessee, south western Virginia, and southern West Virginia in new plants of all types. He has been especially interested in certain industries which have shown an alarming tendency to change to natural gas or hydroelectric power; also in the development and practical application of small stokers and other mechanical equipment.

Jan 1, 1941

By Sábata Marla Reis Durães Oliveira

Este trabalho tem como objetivo o uso de modelos termodinâmicos da literatura e termodinâmica computacional no estudo de dessulfuração de ferro-gusa através de misturas CaO-Fluorita e CaO-Sodalita. As experiências foram realizadas com a adição de diferentes misturas destes sistemas em ferro-gusa a uma temperatura de 1400°C. Os resultados dos testes foram analisados e comparados com os obtidos pelos modelos termodinâmicos da literatura e o software de termodinâmica computacional ThermoCalc. Através dos modelos da literatura foram calculados basicidade óptica, capacidade de sulfeto (Cs) e partição de enxofre (Ls). Pelo software ThermoCalc foram calculados o teor de enxofre de equilíbrio no metal, fases sólidas, e a quantidade de líquido em cada uma das misturas dessulfurantes utilizadas no processo a uma temperatura de 1.400ºC. O ThermoCalc mostrou-se mais preciso que os modelo da literatura na análise da capacidade de dessulfuração das misturas utilizadas neste trabalho.

Aug 16, 2017

By A. K. Stagg

Toxic substances in On solutions can retard biological leaching of copper sulfide dump ores. On solutions were analyzed for metals, organics, and chloride, and showed inhibitory concentrations of aluminum, manganese, and chloride. Inhibition of bacterial activity by the solid fraction of On solution, with and without the organic constituents, was evaluated. Toxicity to bacterial species was evaluated by monitoring bacterial numbers, pH, Eh, and rates of iron oxidation. The On solution solids were toxic at 50 -60% of their field concentration. Most of the toxicity of the On solution was due to the organic fraction. Different SX reagents show varying degrees of inhibition of T. ferrooxidans. Bacterial inhibitory effects of carriers and lixiviants used in the SX plant should be determined so that entrained SX reagents do not retard biological dump leach systems. The reagents used should be the most cost effective and the least toxic.

Jan 1, 1994