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By J. Wagner, P. Eger

Although lifetime estimates for sulfate reduction based on total substrate carbon typically range from 20 to 30 years, field and laboratory experiments showed that rates of sulfate reduction decreased over time as readily available organic material was consumed. When the rate of acid input exceeded the rate of sulfate reduction, alkalinity was removed from the substrate, pH decreased and metals increased. Output pH increased from 4 to over 6 after the system was shut down for several weeks and the rate of acid input was reduced. Successful long term treatment requires a design based on the input pH and the long-term organic decomposition rate.

Jan 1, 2001

By Robert A. Jankowski, J. Drew Potts

In this U.S. Bureau of Mines study, four underground respirable dust surveys were conducted to determine factors affecting belt entry dust levels and how using belt air to ventilate work areas affected dust exposures. Belt entry dust levels on the surveyed longwall and continuous miner sections averaged 0.59 and 0.26 mg/m3, respectively. The stageloader-crusher contributed an additional 0.5 to 0.9 mg/m3 of dust to belt air, while the feeder-breaker contributed 0 to 0.2 mg/m3 of dust. A 1,000-ft increase in belt entry length or a 200- to 500-st-per-shift increase in production resulted in roughly a 0.1-mg/m3 increase in dust. Using the belt entry as an intake entry on the continuous miner section appeared to reduce dust levels by 0.1 to 0.3 mg/m3 during cutting. Belt air was not used to ventilate the face on the longwall section.

Jan 1, 1992

By Timothy M. Bruner, William J. Maloney

Faced with rapid growth that strained their current water supply capabilities, the Somerset Water Service in Somerset, KY decided to construct a new intake structure on the shore of Lake Cumberland. With an existing intake structure within 200', very hard limestone geology with calcite geodes, and lake level fluctuations as high as 50 ' ,this project posed many challenges. The following paper discusses how mechanical excavation techniques were used to overcome these obstacles.

Jan 1, 2001

By Chand F

The silver deposits of Rockvale near Armidale, N.S.W., occur in fissure veins in epi-Permian granite. The ore is fine grained, mineralogically complex, and contains twenty-seven different minerals including eleven silver minerals. The ore is characterized by a unique multiple unmixing from a sphalerite solvent. The following minerals have exsolved from solid solution in sphalerite: pyrrhotite, chalcopyrite, cubanite I, cubanite II (chalcopyrrhotite), valleriite, "brown" stannite, "olive" stannite, argentian tetrahedrite, pyrargyrite, and an unknown grey-white mineral. Several of these minerals derive from a second-stage unmixing, the immediate solvents of which are the products of earlier exsolutions.INTRODUCTIONSmall silver-rich base metal deposits occur at several localities near Armidale in the New England district of New South Wales. Chief among these are the Tulloch Mine and the Rockvale Mine at Rockvale, 27 miles SE. of Armidale, and the Tait's Gulley deposits some 15 miles NE. of Armidale.At Rockvale (Kenny, 1928), irregular lenses of lode material, principally quartz and calcite, occur along a zone of shearing in biotite granite and altered sediments. The orebodies had a maximum width of 6 ft but averaged 2 ft 6 in. The largest lens was 150 ft long and 50 ft high. The Rockvale deposits were worked for both arsenic and silver; 2,897 tons of arsenic were produced but no figures are available forsilver.Little is known of the Tait's Gulley deposits which occur in folded arenites containing small but rich veins of pyrargyrite with base metal sulphides.The sediments in these localities are possibly Silurian.

Jan 1, 1962

By C. G. Anderson

Today, with a stringent economic and environmental climate prevailing in the copper business, there is increased interest in evaluating new processing alternatives for production. Hydrometallurgical pressure oxidation of copper concentrates is one of the more viable approaches and several technological candidates have emerged. Of these, an overlooked but, ironically the first industrially proven methodology, utilized nitrogen species catalyzation in the oxidizing pressure leach system to produce copper via SX/EW. Given its many inherent process advantages, this may prove to be a feasible process alternative for the future. In this paper, the history of the system and its application to copper concentrates and ores will be outlined. In particular, a novel methodology for effective recovery of precious metals from chalcopyrite concentrates will be discussed. Finally, the perceived economics of chalcopyrite concentrate treatment with this unique industrially proven process will be delineated.

Jan 1, 2001

By F. F. Peng

The raw-coal feeding system and the upward medium current flow in a dense-medium vessel (DMV) are, in addition to the residence time of particles in the separator, important factors for efficient coarse particle separation. The feed material from a raw coal screen and/or pre-wet screen merge with the major volume of circulating medium as push medium, guided by an adjustable submergence baffle plate deep fed into the separator for effective separation. The remaining volume of the circulating medium enters from the purge and drain hoppers at the bottom of the DMV. This generates a gentle upward medium current flow in the separator, which prevents dense medium stratification/settling and merges as part of the push medium. A two-dimensional, two-phase model developed using computational fluid dynamics (CFD) is used to describe the flow pattern and evaluate the function of the dip plate for understanding the mechanisms of particle separation in the separator. The particle movement in the DMV is also tracked to investigate the major operating parameters affecting the separation performance of the DMV. The simulation results of the DMV separation performance are validated by in-plant test data.

Jan 1, 2007

A Novel Diagnosis and Evaluation Procedure for Flotation Plants

Sep 13, 2010

By I. Matsunaga, K. Aoki, W. -j. Jung

Blasting is widely used in mining and basic construction because of its speed and economy to destroy the rocks. Blasting has the advantages of reduced excavation costs and shorted construction time when compared to the use of heavy machinery for excavation and cutting such as that with a tunnel boring machine. There are numerous problems with blasting, including the noise, vibration and fly rock. So it is necessary to accurately evaluate fracture mechanics of rocks on the dynamic loading condition to control the fracture process of the blasting. The tests using Hopkinson's effect for the dynamic condition using the precise detonators were performed for various strain rates on three different kinds of rocks. In the tests using Hopkinson's effect for the dynamic condition, the high-speed camera was used to observe the fracture process of the test sample rocks. As the results of experiments there was an increase in the tensile strength of rock with an increase in the strain rate for three kinds of rock on the dynamic loading. The tensile strength of rocks with high porosity on the water saturation condition was decreased on the both static and dynamic condition. It is clear that the strain rate and water saturation were influenced to the tensile strength of the rocks.

Jan 1, 2003

By E. H. Burroughs

HISTORICAL REFERENCES OCCURRENCE-GEOLOGY AND ORIGIN. 4. ARNOLD, RALPH. Conservation of the oil and gas resources of the Americas, Econ. Geol., vol. 11, Apr.-May, 1916, pp. 203-222; June, 1916, pp. 299-326; Proc. 2nd Pan American Sci. Cong., 1915-1916, vol. 3, Conservation of natural resources, pp. 207-237. Shows occurrence of oll, and status and possibilities of oil Industry in each country. Discusses briefly ways in which oll reserves may be conserved. 5. RUTIS, A. A. Petroleum known since remote times. Oil and Gas Jour., vol. 15, Nov. 2, 1916, pp. 33, 37. Gives historical reférences to the use of petroleum from Bible times to its discovery In America. See also Nos. 3, 257, 202, 337, 1843.

Jan 1, 1919

By T. Iwanowski

Stress wave measurements and calculations are often used to make a safe determination of the bearing capacity and the integrity of driven piles. Some applications to the restoration of old buildings in the Old Town of Stockholm are referred to and especially analyses of measurements combined with simulations are discussed here.

Jan 1, 1991

The phenomena of nature cannot present themselves to any thinking wild without claiming from it some solution. The earth, as it has often been observed, is laid out like a well ordered cabinet, presenting to us, in measure, some means of judging how the laws of nature and the essential properties of matter have worked out all we see before us. "That there have been depositions of strata gradually laid down aud stocked with the remains of the living objects, vegetable and animal, that flourished when they were being imposed, is an universally acknowledged fact. It speaks of a constantly maintained series of operations whereby the globe has been brought to its present condition, and which are ever advancing it to stages that are still before it. That immeasurable ages have been consumed in effecting these developments is also conceded. We witness the very graduated rate of the existing advances and can see that the past action must have been conducted in the same slow deliberate manner. There are many questions, however, upon which inquirers are not agreed, hence they are still within the domains of fair discussion.What has led to those great climatic changes whereby the same portions of the earth have had at various times climates that were glacial, temperate, and tropical? What causes the constant contortions and dislocations of strata and the upheaval and depression of land levels, and that there is a tendency to alternation in the parallel areas undergoing opposite kinds of movement as if the sinking of one area balanced the rIsing of another? What is the reason that the centres of volcanic action are continually shifting, and that the line of greatest activity is always upon the rising areas? That portions of the earth have been subjected to intense alid long continued volcanic action, and again to long periods of repose, and that the periods of activity and repose are·recurrent at long intervals of time? What the mountain chains of the world are in broadly parallel bands? What has caused the stratified rocks to be tilted from their original?

By Christopher Mark

Sixty years ago, underground coal mining was the most hazardous job in the United States. Roof falls were a big part of the problem. They killed about 100 miners every year, more than all other causes put together. Fast forward half a century to 2016, which is the first year ever with zero roof fall fatalities. Just three miners were killed by roof falls during the following 6 years. How was this historic goal achieved? This paper starts with a modern analysis of the causes of the roof fall fatalities in 1968. Then it follows the reductions over time by category, using snapshots of the fatalities occurring in subsequent decades. Along the way, it evaluates the influence of the regulatory environment, changing mining methods, and better ground control technology. The paper shows that in 1968, more than half of roof fall fatalities at large mines were attributable to an inadequate safety culture. The immediate effect of the 1969 Coal Mine Health and Safety Act was to reduce the riskiest activities, like needlessly going under unsupported roof. Other hazards, like large roof falls, required technological developments before they were brought under control. Roof control plans, which the U.S. Bureau of Mines had been advocating since the 1920s, played a significant role throughout the process.

Jul 1, 2023

By W. R. Crane

Mining of the red iron ores of the Birmingham district, Alabama, has _gone on energetically for the past 50 years and has created a large iron and steel manufacturing center, the only important one in the South. The district produces about 10 per cent of all the iron ore mined in the United States and 80 per cent of the Alabama output is red ore ; moreover 43 of the 419 blast furnaces of the country are in the district tributary to Birmingham and produce 7 per cent of the pig-iron output. The rapid growth of the district has been made possible by investigations that have led to radical changes in furnace practice; studies of methods by which the low-grade, highsilica ores may be treated by concentration 1 will give still greater impetus to development. The· mode of occurrence of the ore has made mining practice comparatively simple, but with the rapid extension of the workings underground and the disturbed condition of the ore bed some distance from the outcrop, conditions tend to become more difficult. Stoping, handling, support, drainage, and ventilation are all affected, sometimes favorably and sometimes adversely, by the extended workings and increased depth of cover. Should beneficiatioil make available the high-silica ores of the lower bench of the Big Seam, mining practice must necessarily be adapted to the new conditions and will be rendered more difficult as the weight of cover increases at long distances from the outcrop. The support of workings will require more attention as the weight of cover increases, and the efficient and economical operation of the mines will depend largely upon improvements in mining and handling the ore.

Jan 1, 1927

By José Porras

El presente trabajo señala el proceso de optimización en la mina a través del área de Tecnología de la Información, superintendencias y las áreas directas de las operaciones. En ese sentido, durante el diagnóstico de todos lo procesos levantados como geología, planeamiento mina, operaciones mina, mantenimiento, logística, control de gastos, se determinó mejorar las oportunidades que generen valor, como las oportunidades de control y reducción de costos, gastos, y su relación con los resultados obtenidos en su ejercicio.

Sep 9, 2007

Taking the Presidential chair of the Australasian Institute of Mining Engineers, my first duty is to thank you for the high honour and position you have conferred on me. A position entailing the highest compliment the Institute could bestow on any of its members, and one which I feel my inability to properly fulfil, inasmuch, as you have men in your ranks of the highest scientific training residing on that great continent where the head quarters of the Institute is established, while my engagements here will not permit me leaving this colony but for a very limited period.About six years ago, during the time the mining boom was at its height, there came to this colony from England, Germany, and South Africa, several mining engineers, who in conjunction with the mining engineers here, formed an Institute which we soon found we were not able to maintain. The mining boom gradually died away, and many engineers have left the colony to find employment in other parts of the world. We made overtures to your Iqstitute to take us under your wing, which you were kind enough to do, and the outcome is that you have come over 1200 miles to hold a meeting in New Zealand. The paucity of members residing in this colony does not admit of a large attendance; but we heartily welcome you to our shores and hope you will enjoy a holiday visiting some of the principal mining centres and exchanging ideas, which not only improves our minds, and widens our field research, but also tends to lead to further economic improvements in the extraction of metals the earth contains...

Jan 1, 1903

By Stephanie Price

Engineering Associations ?Regulatory authority ?License individuals and firms ?Discipline licensed members ?Enforce against improper acts ?Programs for EIT?s, competence, etc

Oct 1, 2010

By Milner A, Brockway D, Hodges S

The combustion of brown coals in Latrobe Valley power stations produces approximately 500 000 tonnes of solid wastes each year. This material, which includes precipitator ash, char and furnace ash, is hydraulically sluiced to large ashing ponds and the supernatant solution is ultimately discharged to the sea. There are significant operational and capital costs associated with the current ashing system. The ash produced from the Latrobe Valley coals is unique and has a wide variety of potential applications including soil conditioning, concrete and cement extenders, fillers in non-metallic materials, components of building products. In addition, with the application of appropriate technology, it is possible to extract char, sodium sulphate, calcium carbonate and magnesium metal (as the chloride) in substantial quantities from the ash. Research has been carried out to explore the prospects of these various options for ash utilisation. The research has focused on detailed characterisation of the ash material and the potential extraction efficiency for various species under various conditions. From this work a conceptual process has been developed and subsequent studies have been directed towards understanding variables and optimising operating regimes for product extraction. Currently, the work is concentrating on the separation of char, the development of high-grade carbon products and the extraction of sodium sulphate.

Jan 1, 1992

By Glen Church, Don W. Deere, Christoph M. Goss

The Standley Lake Dam Rehabilitation Project in Colorado included the complete replacement of the outlet works. This required two 1.8m (6 ft) diameter microtunneled wet lake taps, 380m and 186m (1246 ft and 636 ft) long, a permanent valve shaft 12.2m(40 ft) wide and 32m (105 ft) deep, and a 3.5m (11.5 ft) diameter (962 foot long) outlet tunnel driven with a roadheader. The tunnels were driven in low-strength, expansive, and slickensided claystone. The paper addresses the site investigation, shaft construction, roadheader performance, shotcrete placement, tunnel convergence, long distance microtunneling, and wet lake taps.

Jan 1, 2005

By Z. Sun

Imposing a strong magnetic field is considered to be an attractive method to prepare materials with aligned or textured structures due to its intrinsic properties, e.g. non-contact and easily controllable. However, the nature of the strong magnetic field effect still remains unclear and further research is needed. In the present paper, the effect of a strong magnetic field on the solidification of a hypereutectic Al-Cu alloy was investigated. After magnetic field treatment, the primary phase was aligned parallel to the magnetic field direction. Meanwhile, the eutectic micro-structural constituent became elongated and thinner. A theoretical analysis was conducted to have a better understanding of the phenomena. During solidification, the magnetic Faraday and dipole-dipole interaction forces are considered to decrease the solute pile-up in front of the solid-liquid interface and modify the eutectic cell formation. The alignment of the phase is due to the shape magnetic anisotropy and crystal magnetic anisotropy.

Jan 1, 2010

By K. Rainer Massarsch

In some parts of the world, vibrators are used extensively for different types of foundation engineering projects. If used correctly and in suitable soils then vibratory pile driving for example is very efficient. However, soil conditions and the installation procedure have great significance for the driving resistance and affect the bearing capacity of vibrated piles. Also the intensity of ground vibrations which are transmitted to the surrounding soil is affected by the vibration process. In spite of the increasing use of vibrators and the rapid development of vibrator technology, many aspects of pile-soil interaction are not yet understood. In order to asses the importance of factors, which govern pile installation (and extraction), it is necessary to consider the entire chain of vibration energy transmission from the vibration source to the pile, the interaction between the vibrating pile and the soil and the wave propagation in the subsoil, Fig. 1. [ ] Fig. 1. Transfer of vibration energy from the vibrator through the pile into the ground In the present paper, some important aspects of vibratory driving and their significance for pile installation and soil compaction will be discussed.

Jan 1, 1995