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By R. D. Leitch, W. P. Yant, A. C. Fieldner, R. R. Sayers, S. J. Pearce

"The detection of leakage is a recognized problem in the safe and economic distribution and use of natural gas. Natural gas is practically odorless and therefore lacks he property of indicating significant leakage by the sense of smell, the means most widely used by gas employees and consumers for detecting leaks of the more odorous types of fuel eases. In view of the recognized value of the odor of gas for indicating leakage at the time of occurrence the Bureau of Mines has studied' the possibility of adding small amounts highly odorous substances to types of fuel gas (such as blue water gas and natural gas) that lack warning properties. These studies revealed that the mercaptans were promising substances to accomplish this purpose, not only for odorizing fuel gases but for other purposes° where it was desired to give warning through the sense of smell.Since completing the studies mentioned, the Bureau of Mines jointly with the American Gas Association has conducted further investigations dealing with the use of warning agents for fuel gases. The results of this work will be published later.The Bureau of Mines had been desirous of observing the practical use of ethyl mercaptan for detecting leakage of natural gas, particularly to determine whether the odor would permeate the ground and give indication of lea's in underground pipes. Opportunity for making these observations was recently given by E. A. Munyan, manager, gas department, Union Gas t Electric Co., who requested the bureau's cooperation in making leakage surveys of the company's distributing systems at Franklin and Middletown, Ohio."

Jun 1, 1930

The success of the In-Plant dust collection at the Albion Reid Quarry Plant situated at Para Hills, South Australia, is discussed in the light of co-operation at the design stage with particular emphasis on the duct- work and filter design. Other dust control facilities at the Plant are mentioned.

Jan 1, 1976

By A. B. Holland-Batt

The application of Reichert spirals and cone concentrators within the South African mineral industry is discussed, and the procedures used in the acquisition of design data are outlined. Computing techniques developed by Mineral Deposits Limited for the processing of test data for use in the design of production circuits are described.

Jan 1, 1982

By D. H. Ryan, J. T. Graham, A. Navarra, J. A. Finch, S. Somot

Pyrrhotite (Po) is widely considered to be the most significant mineral in the self-heating of sulphides. It is therefore desirable to determine the amount of Po in mineral samples. This is commonly accomplished through x-ray diffraction (XRD) or quantitative evaluation of materials by scanning electron microscopy (QEM-SEM). This paper introduces another quantitative method based on Mossbauer analysis that requires limited sample preparation and has the additional potential to detect the sulphur/iron ratio within Po. The technique is explored using pentlandite/pyrrhotite mixtures.

Jan 1, 2009

By F. Chiesa

Experimental results on thin and thick castings poured in aluminum A356 and magnesium AZ91E by the low pressure permanent mold process have been compared to the result of filling simulations for thin and thick castings. If the results of modeling is reliable when the liquid remains above the liquidus temperature, this is no longer the case when partial solidification occurs. The visco-elastic behavior of a partially solidified liquid is difficult to put into equation as it depends on the amount of shear it has been been subjected to. Attempts to predict misruns with a commercial software has been proven to be very difficult if not impossible; divergence of the numerical solution has been observed unless prohibitively long computing times are used. In order to overcome these difficulties from a practical standpoint, a simple method is proposed which consists in tracking the temperature of the advancing liquid metal front so as to make sure it will always be above so-called `Misrun Critical Temperature' (MCT) determined experimentally for thin and thick aluminum A356 and magnesium AZ91E castings. If the liquid metal front falls below this temperature, a cold-shut or misrun is likely to happen at this location. The values of MCT for thin and thick in aluminum A356 and magnesium AZ91E were determined experimentally on misrun castings of extreme geometries (a thin 2.5 mm wall cover and a 6mm to 25 mm thick bell housing). MCT was found to be lower for magnesium AZ91E and for the thicker castings.

Jan 1, 2011

By M. A. Mahtab

This report presents the geometric parameters (attitude, spacing, extent, and aperture) of fracture patterns in a selected portion (study area) of San Manuel copper mine, Arizona. The geometric parameters are quantified for input to structural analyses for studies of the influence of fractures on cavability of ores. Using an orientation analysis procedure developed earlier by the Bureau, three prominent and nearly orthogonal sets of fracture orientations were delineated in the study area. Sets 1 and 2 dip nearly vertically, and generally strike east-west and north-south, respectively, whereas set 3 is nearly horizontal. Both a horizontal rotation (of 14° to 26° for sets 1 and 2, respectively) and a tilt (of 20° for set 3) is shown to occur between the 1415 and 2015 levels of the mine. Gomparison of the three major rock types present in the study area (quartz monzonite, monzonite porphyry, and rhyolite) show that the rhyolite is characterized by short extent, small spacing, and tightness of fractures as well as the general absence of fracture set 3, which may account for its generally observed strong resistance to caving.

Jan 1, 1973

By James A. Finch, Jason S. Doucet, Cesar O. Gomez

"Exercising control over the physical environment of flotation as a step towards process optimization is the driving force for characterizing gas dispersion in flotation cells, a subject of considerable research and still not fully understood. From an operational standpoint, however, there are just a few variables that can be manipulated to manage gas dispersion on a cell-to-cell basis, the most important being gas rate (superficial gas velocity Jg). Measurements in eight plants demonstrate there is often no strategy for distribution of gas to cells in a bank, i.e., there is no particular Jg profile. Two exercises where Jg profiles were set allowed metallurgical performance to be manipulated and an optimum Jg profile to be selected. To facilitate setting Jg profiles, a multi-unit device based on McGill Jg sensor technology is introduced. Possible directions for gas dispersion management are discussed.INTRODUCTIONThe earliest patents regarding the flotation process ignored the importance of air and in certain cases, steps were taken to eliminate bubbles from the system (Nelson and Smit, 2005). Rickard (1916) described a keen metallurgist who observed better than expected performance and hypothesized that entrained air was enhancing the process. Within a few years of this observation, the basic concept of modern froth flotation was developed whereby air is dispersed into slurry to induce bubble particle contact.As research into flotation advanced, the link between performance and the flow-rate of air entering the cell was established. In the first volume of the International Journal of Mineral Processing, Harris (1974) described the importance of airflow-rate and derived parameters such as the superficial gas velocity (then called the superficial airflow velocity) as being important parameters for cell design and scale-up. Mehrotra and Kapur (1974) presented research suggesting that the rate of flotation was strongly correlated to the aeration rate. McKee et al. (1976) continued to demonstrate the importance of airflow-rate linking it to the entrainment rate of hydrophilic gangue material."

Jan 1, 2006

By M. E. Lombardi

Discussion of the paper of AI. E. LOMBARDI, presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 105, September, 1915, pp. 2109 to 2114. C. D. KEEN, Shreveport, La.-Did Mr. Lombardi include in his figures the purchase price of the property? M. E. LOMBARDI, Berkeley, Cal.-No. C. D. KEEN.-Suppose I pay $1,000 per acre for it, and in four or five years it is worked out. M. E. LOMBARDI.-That is a question of depreciation and must be added to my figures. MARK L. REQUA, San Francisco, Cal.-You say it cost $35,000 to $40,000 a year to maintain 1,000-bbl. per day production? M. E. LOMBARDI.-Yes, 1,000 bbl: a day would cost $40,000 a year to maintain.

Jan 12, 1915

By F. Tanaka

In April 1999, a two-year campaign of the Mitsubishi furnaces was achieved at Naoshima Smelter; the present one is expected to be extended much longer. An overview of basic technology for decreasing refractory wear in the Mitsubishi Process is presented. One of the main features of the process is the use of top blowing lance technology which has a different effect on the furnace refractory than other conventional processes. The refractory wear of concern is hearth wear caused by top blown powder injection, wear of the side wall caused by splashing droplets, and wear of the bath level refractories caused by surface waves of melts in the furnace. These have been systematically investigated for many years. This paper describes the results of various model tests and their application to practical furnace design and operation.

Jan 1, 1999

By A. Aly Selirn

An economic simulation model was developed to predict the amount of copper recovered from copper oxide deposits and the cost of producing it as a function of the deposit parameters. The economic simulation model includes models of fragmentation design and cost, copper extraction, solution distribution and recovery, effluent solution cutoff grade, and financial analysis. Cost and price indices were also developed to evaluate the economic feasibility of in situ leaching operations as a function of their starting date. Application of the models to various properties having the same area and different ore thickness shows that the effluent solution cutoff grade does not vary with the ore thickness nor with its grade. The percent of copper recovery is, however, shown to increase with the increase in the ore thickness and is independent of the ore grade. it is also shown that while the profit per unit of extracted copper increases with the increase in ore grade or ore thickness, the rate of return on total investment does not show any correlation

Jan 1, 1977

By I. Jones

Geologists, engineers, technicians and surveyors have successfully utilized technical software in the mining industry for over 30 years. Software for processing survey, geology, mine engineering and planning information make these functions more efficient by automating repetitive tasks and reducing data processing errors. While these systems have been improved incrementally overtime, new systems that represent giant leaps in technology have been introduced to help mining operations increase productivity and reduce costs. However, their widespread use within the industry has left individual companies without a competitive advantage. Additionally, the ability of these applications to provide the productivity improvements required in today’s uncertain market conditions has since peaked. The next wave of technology—integration of independent software applications—is just starting to emerge and will have a significant effect on the productivity of mining operations. To reap the productivity gains required to remain competitive, mining companies must exploit the collective knowledge and experience of every employee in the organization. Integration of independent software application allows companies to leverage information from all activities, enabling staff to make better decisions to improve productivity. This paper outlines the importance of integration as productivity enabler. Key performance indicators, strategic mine planning, resources management and mine-to-mill integration are discussed as processes that enable productivity. The Gemcom Enterprise Mining System (GEMS)is introduced as the industry’s first integrated solution that enables these productive processes. The paper concludes with a comment on the level of change required to realize the benefits of integration.

Jan 1, 2003

By Hiromichi Ohta

Precise thermal properties of molten materials are essentially required for analyzing the metal production process. These properties are also important as a clue to consider the dynamic structure of liquid materials. However, it is difficult to obtain the precise thermal diffusivity values of molten oxides at high temperature because of the experimental uncertainties arising from the bubble formation or the severe separation of radiative and conductive heat components. Recently a novel laser flash method has also developed for measuring thermal diffusivity of molten oxides at high temperature. In this new technique, the sample is melted in a metal crucible and heated to the desired temperature. A single laser pulse is flashed on the bottom of the metal crucible and the infrared ray irradiated from the same bottom surface is measured for obtaining the temperature decay, from which the thermal diffusivity of the liquid sample can be estimated. The usefulness and validity of this new laser flash technique have been confirmed by obtaining the thermal diffusivity values of silicate melts in the wide temperature range between 773 and 1673 K.

Jan 1, 2003

The iron ore mining operations carried out by Goldsworthy Mining Limited at Golds- worthy, Shay Gap and Sunrise Hill, in the Pilbara region of the North-West of Western Australia, are unusual insofar as the ore reserves occur in a number of widely separated and relatively small deposits, requiring deep mining below the water table, and even below sea level at the Goldsworthy pit. This paper has been prepared to describe some of the problems associated with these deep open cut mines, and the technology employed to overcome them, in order to provide an efficient and economical operation. The problems discussed are: 1. Development of the Dewatering System for the Goldsworthy Mine. 2. The Stability of Pit Slopes at the Goldsworthy and Shay Gap Mines. 3. Development of Diesel Electric Trucks for Lonq Uphill Hauls.

Jan 1, 1979

By Hiromichi Ohla

Precise thermal properties of molten materials are essentially required for analyzing the metal production process. These properties are also important as a clue to consider the dynamic structure of liquid materials. However, it is difficult to obtain the precise thermal diffusivity values of molten oxides at high temperature because of the experimental uncertainties arising from the bubble formation or the severe separation of radiative and conductive heat components. Recently a novel laser flash method has also developed for measuring thernnal diffusivity of molten oxides at high temperature. In this new technique, the sample is melted in a metal crucible and heated to the desired temperature. A single laser pulse is flashed on the bottom of the metal crucible and the infrared ray irradiated from the same bottom surface is measured for obtaining the temperature decay, from which the thennal diffusivity of the liquid sample can be estimated. The usefulness and validity of this new laser flash technique have been confirmed by obtaining the thermal diffusivity values of silicate melts in the wide temperature range between 773 and 1673 K.

Jan 1, 2003

By Kishore Kumar B., Eswaran Prasad C R, Srini Naik B., Ramakrishna Raju N

The authors through this paper intend to introduce the non-vibro technique of ground improvement by stone column, being used for the first time in India under the Western Dedicated freight Corridor in Mumbai area. New 2x25 KV double line dedicated freight corridor tracks, capable of carrying 32.5-ton axle load are proposed to be built on this stretch. Non-Vibro Displacement Stone Columns of 900 mm diameter were installed to improve the safe bearing capacity of the soft ground to take the loading of Dedicated Freight Corridor Railway embankment. Vertical footing load tests on single and three column groups were conducted to assess the improvement in the sub-surface condition after installation of stone columns. This paper describes load tests conducted on stone columns and analysis of the obtained results. The observed load settlement behaviour of the improved ground has also been presented. Behaviour of single and group of stone columns have been compared and criteria adopted for arriving at desired factor of safety based on the settlement observed, has also been discussed.

Nov 1, 2022

By V. Schenk

Dust exposure resulting from the exploitation and winning of natural resources below ground has presented a serious health problem since the beginning of mining. The boom phase of the German hard coal mining industry after World War II with at times up to 500,000 employees saw an increase of dust exposure of miners below ground as the mechanization of road heading and mining increased significantly. More and more miners were diagnosed with coal-workers-pneumoconiosis (CWP), a chronic and irreversible lung disease resulting in a significant impairment of pulmonary function. This realization led to a reduction of CWP in the German hard coal mining industry in the 1960s. The successful fight against CWP began with the introduction of technical dust prevention measures. By infusing the coal seam with water before mining, sprinkling and spraying of heading and mining machines as well as canopies with water, aspiration in places with high amounts of dust and the suppression of dust with chemical substances it is possible to significantly reduce the miners? dust exposure. All operating points below ground are checked and measured regularly with regard to dust exposure. Through the combination of these values together with the individual shift data a relatively precise profile of individual dust exposure can be obtained. This profile allows the targeted work assignment when certain predetermined limits have been reached, moving the miner to a work place with less dust exposure and thus reducing the chronic dust exposure. The state of health of the individual is known because since about 60 years ago extensive occupational health checks have been carried out regularly at least every two years which means that work restrictions can be imposed depending on the findings. Since the beginning of the 1980s more value has been attached to not only situational but also behavioral prevention. Given the comprehensive provision of protective masks, having a protective effect as well as the required comfort when being worn, each miner has the opportunity to protect his respiratory organs depending on the specific dust exposure. Through a combination of all these measures the German hard coal mining industry has succeeded in beating the classic coal miner?s disease CWP. For mines in the Ruhr valley this means that a miner who started work after 1978 will no longer develop CWP.

Aug 1, 2013

By Rhulani F. Maluleke, Francis W. Petersen, John H. Marsh, Johann de T. Steyl, Allan Nesbitt

"Pressure leaching of chalcopyrite and nickeliferrous pyrrotite at temperatures between 105 and 200 ºC has been proposed as a potentially viable route for the extraction of mineral elements from sulphide concentrates. In general, these concentrates contain iron, and the economic success of the processes is partially dependent on the choice of the environmentally acceptable iron-removal technique. One of the most widely used methods for the removal of iron from sulphate liquors is precipitation as hematite, goethite, or jarosite. The nature of the iron precipitate formed, dictates downstream dewatering and residue treatment and disposal options. However, a better understanding of iron precipitation under the defined process conditions would consequently be of benefit in process design and optimization.This study investigated the precipitation of iron in the autoclave at temperatures between 105 and 200 ºC. The effects of temperature, acid concentration, iron concentration, and the presence of other metal cations on the nature and composition of the precipitates were determined."

Jan 1, 2003

By H. -U. Lim, C. -H. Kim

The sixth underground pumped powerhouse cavern is under construction now in Korea. For the stability analysis of the five underground powerhouses, finite element method was used. For this analysis, in-situ rock stresses were measured by overcoring method and horizontal to vertical stress ratio was calculated 1.07-1.32 at four sites. Rock mass strength and elasticity were assumed from intact rock properties. The ratio of elasticity of rock mass was 0.16-0.55 of intact rock core elasticity. In general, elasto-plasticity with Mohr-Coulomb failure criterion was applied and the input cohesion and internal friction angle were approximately 0.12-0.22, 0.6-0.87 of intact rock strength parameters, respectively. Der sechste Untergrund-gepumpt-Powerhouse-Cavern ist jetzt im Bau in Korea. Für die vergan-gene Stabilitätsanalyse des fünf unterirdischen Powerhouses in Gebrauch wurde ein begrenztess Elementsmethode benutzt. Für die Analyse wurden In-Situ Felsenspannungen von overcoring Methode gemessen und Horizontale zu senkrechtem Spannungsverhältnis waren als 1.07-1.32 an vier Stellen kalkuliert. Felsenmassenkraft und Elastizität wurden von unversehrtem Felsenei-gentümern angenommen. Das Verhältnis der Elastizität von Felsenmasse war 0.16-0.55 von un-versehrter Felsenkernelastizität. Im allgemeinen wurde Elasto-Plasticity mit Ausfallskriterium des Mohr-Coulombs verwendet. Die Eingabebindekraft und die innere Reibungswinkel waren unge-fähr 0.12-0.22, 0.6-0.87 von unversehrtem Felsenkraftsparametern, jeweilig. En Coree, la sixieme centrale souterraine de la pompe d'accumulation dans la caverne est en construction. La methode d'element fini a ete utilisee pour analyser la stabilite de cinq dernieres centrales en service. Dans cette analyse, la reaction de la roche sur place etait mesuree par la methode d'overcoring et celle du rapport horizontal-vertical etait calculee de 1.07-1.32 en quatre places. L'intensite et l'elasticite de la masse de roche ont ete estimees de la roche intacte. Quant a l'elastic-ite, sa masse de roche etait 0.16-0.55 fois que celle de la roche intacte. En general, elasto-plasticite avec le critere de defaut Mohr-Coulomb etait utilisee et sa cohesion d'energie et son angle de friction interieure etaient supposees respectivement 0.12-0.22, 0.6-0.87 fois que la parametre de l'intensite de roche intacte.

Jan 1, 2003

By C. Ernest Birchenall, Gerd M. Rosenblatt

The pressure and molecular weight of the antimony vapor over solid solutions of tin in antimony, containing 97.4, 94.9, 93.0, and 90.7 at. pct Sb, have been measured from 445° to 545°C by the torsion-effision method. The vapor is all Sb, within experimental error. A solidus curve which differs somewhat from the accepted curve has been calculated using the measured antimony activities. Metallographic examination of additional annealed alloys substantiates the accepted solidus. The solid solutions, which show negative deviations from ideality, probably do not deviate greatly from regular solution behavior. HANSEN' considers the Sb-Sn phase diagram to be well established with the exception of the boundary of the (Sb) phase.* Although there have been no pre- Their data can be combined with data for the solid alloys to calculate the solidus curve of the (Sb) phase. This paper presents measurements of the pressure ant1 molecular weight of antimony over Sb-Sn solid solutions containing 97.4, 94.9, 93.0, and 90.7 at. pct sb. Measurements were made by simultaneous use of the volmer3 torsion and Knudsen, effusion methods. The results of these measurements have been combined with the vapor pressure of pure antimony5 to obtain the activity of antimony in the primary solid solutions. The solidus curve calculated from these data differs somewhat from the accepted curve and is rather uncertain. Metallographic examination of Sb-Sn alloys was carried out to clarify the position of the solidus of the (Sb) phase. EXPERIMENTAL The apparatus and technique have been described previously.5 The measurements were made with the same effusion cells and torsion wire used in the measurements on pure antimony. The torsion measurements were calibrated with mercury at 30" using a mercury vapor pressure of 2.96 x 10-3 mm Hg determined by concurrent, absolute, weight-loss experiments. As in the measurements on pure antimony, an extraneous vapor was observed to distill off during the first run after the cell had been loaded with A fresh sample of alloy and during the first minute or two of every run. The change in composition after a series of runs with one sample was of the order of 0.1 at. pct and thus completely negligible in the calculation of the thermodynamic properties. The alloys were prepared from pieces of Merck antimony and Matheson, Coleman, and Bell reagent-

Jan 1, 1962

By H. B. Bailey

SiNcE the gypsum deposits of Nova Scotia have been operated on a large-tonnage basis, it has become increasingly necessary that more study be given to the geological relation of gypsum to anhydrite. It was while attempting to work out some definite system of quarry operation for several operators that the factors relating to hydration as given in this paper became apparent. For convenience the words "the formation" are used to mean anhydrite and gypsum taken together as one bed geologically and forming a distinct unit from the rocks below or above. Also, the word "block" is used geologically to define a portion of the formation that is cut apart and separated by erosion from other portions. The formation is part of the Lower Carboniferous, the remainder of which is made up of red shales and shaly sandstones, coarse red conglomerates and limestones. Overlying the Lower Carboniferous are the even-bedded gray sandstones of the coal measures. To a large extent these sandstones have been eroded from above the formation and the usual cover is clay and unconsolidated sediments. The position of the limestone member which immediately underlies the formation usually furnishes the key to the general structure. Being harder, and subject to less erosion, it has a wider spread than the'formation, and measures for dip read on it have a value which can not be applied to dips taken on gypsum or anhydrite. This limestone usually is not more than 25 ft. deep, but it has a remarkable tenacity—one would almost say elasticity—under strain of earth movements. In many cases it stands as a barrier to the erosion which otherwise would have destroyed completely the remaining block of the formation. No bedded limestone is found within the formation except in narrow seams close to the bottom and in short irregular masses in highly disturbed strata where it has been caught up by fault action. This paper is not concerned with the general theories of original deposition and no opinion is expressed as to whether gypsum or anhydrite was first deposited from evaporating sea water. For purposes of study, and as an observed fact, except in the few cases where there has been extreme disturbance, a block of the formation is regarded as a block of anhydrite which has become partly hydrated into gypsum. 177

Jan 1, 1931