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By Robert Lee Stahl

Comprehensive field tests were made by the Federal Bureau of Hines at the Conda open pit mine near Soda Springs, Idaho, to determine whether surface geophysical techniques could be used to detect and delineate faults in phosphate deposits. The tests included seismic refraction, magnetometry, electrical resistivity, and airborne photography. Of the several geophysical techniques tested in the field, horizontal resistivity profiling was the most effective method for diagnosing faults. The method is quick, inexpensive, accurate, and can be easily used by mining company personnel to detect and delineate faults.

Jan 1, 1975

By R. P. King

"A model of the flotation process can be used effectively for design and control. For design purposes it can be used to predict the performance of a large plant from laboratory and pilot plant data. It can be used for control purposes to assess the utility of any proposed operating modification to an existing plant, and it can also be used to determine optimal control settings for best operating performance.A model has been developed that will allow for variations in feed properties and for variations in fineness of grind. The model can be used to assess the effects of reagent addition rate, aeration rate and pulp level on plant performance and these are the control variables that are used individually or together in all operating flotation plants. The model provides for a distribution in the values for flotation rate constants, particle size and mineral fraction, and, because of its complexity, requires a large computer when it is to be applied to a typical plant configuration. The computational method that is used to apply this model to such configurations is described in this paper, and particular attention is paid to the problem of allowing for feedback of tailings from cleaners and recleaners."

Jan 1, 2014

The United States has not begun commercial operations to tap its largest poten-tial sources of oil supply - oil shale and coal. The reason is that domestic petrol-eum has been plentiful in the past and liquid products probably could be produced from it at the lowest cost. In view of the ever-increasing need for petroleum in the United States, the critical international situation threatening foreign supplies, the growing demands for steel, and the heavy costs to industry of constantly discovering and developing new oil fields, it is believed that the prompt development of a synthetic fuel industry based on oil shale and coal is not only requisite to safeguard our oil supply but is an economically sound course for the foreseeable future, To neglect its development is to close our eyes and minds to our own resources at a time when they are needed critically. It also is apparent now that neither the Government nor industry would be taking any considerable economic risk in starting the initial plants, especially as measured against their potential value in meeting critical oil and chemical demands and in building a new industry in the West.

Jan 1, 1951

By J. E. Miller, W. E. DeVaney, L. Stroud

During a recent phase study of a natural gas, two stable equilibrium liquid phases were observed at temperatures below —200°F and pressures above 200 psi. This paper reviews the published literature on the occurrence of multiple equilibrium liquid phases and presents analytical data for the vapor and two equilibrium liquid phases of the liquefied natural gas at five experimental conditions. In addition, data for 30 conditions of two-phase equilibria are included. INTRODUCTION The low-temperature phase behavior of gases, most of which contained helium, has been investigated in the laboratories of the Helium Activity for many years. Since 1952, experimental studies of these systems have been continuous as part of the research program at Amarillo, Tex. Because of their value to private industries interested in participating in the Helium Conservation Program, several "Open File" reports containing phase equilibria data for heliurn-bearing natural gases have already been released by the Helium Activity. A paper containing information on the general phase behavior, operating criteria and extensive vapor-liquid data for two helium-containing systems was recently published.2 Additional publications presenting experimental data on the phase relationships of various gas systems are now in process and will be available in the near future. PREVIOUS EXPERIMENTAL WORK Although the formation of multiple liquids has been reported for various systems, to our knowledge this paper is the only substantiated evidence of a vapor-liquid-liquid equilibria in a naturally occurring gas. In 1940, Vink, Ames, and others13 reported the presence of two liquid phases in a hydrocarbon system consisting of mixtures of crude oils, solvents and natural gas. Eilerts and co-workers; published data on the recombined fluids from a gas-condensate well. This condensed gas, containing approximately 76 per cent methane and 24 per cent ethane-plus, exhibited two distinct liquid phases. Weinaug and Bradley 14 observed "unusual" phase behavior in a reservoir mixture. These workers postulated that the anomalous phase behavior was due to the "imminent formation of a second liquid phase". Botkin, Reamer, Sage and Lacey 1 studied two California crude oils that exhibited multiple phases. Kohn and Kuratal0 recently reported two equilibrium liquid phases in the methane-hydrogen sulfide system. Roof and Crawfordl1 and Eakin, et a16 also have reported experiments with binary systems that formed two stable equilibrium liquid phases. APPARATUS AND PROCEDURE A U. S. Bureau of Mines Phase Equilibrium Apparatus was used in conducting this study. The apparatus and procedures employed in its operation have been previously described3 and will not be repeated in detail ill this report. Briefly, the apparatus consists of a windowed cell which can be maintained within ±0.5°F for temperatures between room temperature arid -320°F. Pressure within the cell can be maintained within 0.1 per cent of gauge reading up to 800 psig. Equilibrium vapor and liquid samples are obtained in special containers4 for analysis by a mass spectrometer. Although the accuracy of the analyzer is about ±0.1 mol per cent, the reproducibility of the phase-equilibrium apparatus is considered relatively poor. Values reported from methane and nitrogen are considered accurate to ±l.0 and ±0.6 mol per cent. Data for ethane-plus in the vapor are accurate within 0.2 mol per cent; liquid-phase data for this aggregate compolnent are accurate within 1.5 mol per cent. For helium in the vapor phase, the analytical data are accurate within 0.2 mol per cent; liquid-phase analyses for this component were obtained by the charcoal adsorption method described by Frost8 and are accurate within 0.006 mol per cent. All of these references to the accuracy of reported values are conservative estimates based upon a statistical treatment of reproducibility data obtained with the apparatus.

By W. L. Price

I. INTRODUCTION Today, there are two conflicting trends facing the designer of the bulk material handling system. The first trend is the necessity to stockpile increasingly larger amounts of bulk material (coal, ore, stone etc.) as economically as possible. Fig. 1 illustrates such a typical large storage pile. The second trend is the increasing awareness of the ecological problems of today manifesting itself in a new concern over possible air pollution from storage pile surface particles. The conflict between these two trends can become dramatic when this bulk storage pile is located near a heavily populated area. Strong winds can easily create a severe local problem by blowing the particles from the pile surface toward residential and commercial areas, igniting a crisis in public relations. (2), (3), (4). To help define our combined subject and ecological culprit more accurately, Fig. 2 shows the commonly accepted size range of dust particles. A descrip¬tion of the present state-of-the-art of dust control for large storage piles is the intent of this paper. II. OPEN STORAGE PILE SYSTEMS - ALTERNATE CHOICES AND RELATIVE COSTS In discussing the open storage dust problem and possible solutions, one obvious question arises - what are the economics of placing large bulk storage under cover? Part or this answer will be found in Fig. 3 - an approximate unit capital cost comparison between several methods of storage. It will be noted that the cost curve(s) for the closed concrete silo storage illustrated in Fig. 4 is cheaper per ton at relatively small tonnage capacities, but as tonnage increases, the open pile storage unit cost (B) becomes more economical. Curve (T) covers the cost of open storage using the plow feeder arrangement shown in Fig. 5. A gravity draw-down pile with feeders at the base as shown in Fig. 6 represents yet another open storage choice.

Jan 1, 1972

By N. A. Sithole, S. A. C. Hockaday, P. J. A. Bezuidenhout

The Northern Cape Province in South Africa has high levels of annual direct normal solar irradiance and reserves of zinc (Zn) ores. The question arises as to the benefits of integrating renewable solar energy into the beneficiation routes of these reserves. The paper evaluates a novel flowsheet for the production and beneficiation of Zn in this region, maximising localised solar energy as a source for both electricity and process heat. Solar variability is discussed and the cost and benefits of thermal storage in the flowsheets are evaluated by its influence on the levelised costs of electricity and process energy over the project life-time at a possible implementation site. The results of the developed scoping model showed that solar photovoltaic integration to provide electricity for electrowinning without battery storage can lead to more than 10% cost saving on electricity over the lifetime of the project. Additional savings potential was identified when battery storage was included to enable the solar PV system to supply electricity during peak tariff periods. The solar thermal case showed the most promise with savings of 70% on heating costs for casting, while solar PV electricity without storage resulted in a 16% cost saving on heating for casting over the lifetime of the project. Solar PV electricity generation resulted in the avoidance of more than 20% of CO2 emissions from grid electricity use. Solar thermal heating can avoid up to 80% of the CO2 emissions associated with grid electricity use for remelting of Zn cathodes for casting. The CO2 emissions are indirect and not subject to South African carbon tax. Keywords: Solar process energy, zinc beneficiation, flowsheet evaluation

Jan 1, 2020

Established as a Division December 15, 1948 Evan Just, Chairman Richard J Lund, Past Chairman Granville S. Borden, Vice-Chairman J K Richardson, Vice-Chairman S H Williston, Vice-Chairman Allan Matthews, Secretary-Treasurer National Security Resources Board 17th and Pennsylvania Ave, N W Washington 25, D C

Jan 1, 1952

By Arun Verma

Thermal energy storage offers a means of effecting significant costs savings and conservation of premium fuels. Na2SO4 has been found to be a good material for storing thermal energy in the medium-temperature range, mainly because of its dimorphic nature and high heat of transition. Basic data and development of the salt to a practically usable block are discussed.

Jan 1, 1978

By J. H. Howard

The purposes of this report are to summarize the findings of the Committee on the Challenges of Modern Society Non-electrical Project (a working committee of the North Atlantic Treaty Organization) and also, thereby, to provide an introduction and review of the current situation regarding non-electrical applications to those who are interested in the subject.

Jan 1, 1975

By L. Trincado

Mantoverde is a heap leach-SX-EW plant that was commissioned in December 1995 at a production rate of 42,130 ton of copper per year and 5.4 million ton of ore per year. Copper production has steadily been increased to 57,290 ton in 2002. Forecast copper production for 2003 is 60,000 ton for an ore treatment rate of 8.5 million ton. Several improvements in the heap leach process have been implemented. The main process improvements are related to the optimization of heap height, particle size, irrigation rate and leach cycle, in addition to a better heap drainage design and a solution management system. A first dump leach operation was started in 1999 at a production rate of 1,922 ton of copper. A second dump leach operation was started in early 2002 at a production rate of 2,805 ton of copper. Dump leach production will be increased over time to as much as 24,000 ton of copper. The main heap leach process improvements, as compared to the original plant design, as well as the main dump leach operating parameters are discussed in this paper.

Jan 1, 2003

By W. J. Reagan

A survey of the literature on bottom-cast practice gives but Scant information as to some of the real facts concerning this most int'eresting method of steel manufacture, and some of the information available is very misleading. An exceptionally good description of this met,hod of pouring or teeming is to be found in an English publication2 on the heterogeneity of steel ingots. Quoting from this paper: (a) With bottom teeming, the metal rises steadily and progressively in the mold with the minimum possible agitation, the main force of the stream coming from the ladle being broken down or retarded by the down gate or runner. Further, the stream of metal from the ladle, under these conditions of casting, is invariably maintained at a much more continuous rate and is steadier than with top teeming. (b) In view of the facts referred to in (a) it follows that with bottom teeming the metal is not exposed to atmospheric oxidation to anything like the same degree as with top teeming. In this paper it is intended to detail briefly some of the advantages of bottom-cast practice and to discuss the possibilities of iron-oxide control in the basic open-hearth furnace. A description of the type of charge, ingot rnold set-up, etc., is found in detail in an earlier paper.3 Design of Ingot Molds In any kind of steel manufacture, ingot-mold design is important. L. H. Nelson4 lists in the order of their probable importance the following factors as influencing most the solidification of the ingot:

Jan 1, 1934

By T J. Sheer

Water vapour refrigeration (systems using water as the refrigerant) could potentially be used to provide chilled water at underground locations in mines, as an alternative to conventional refrigerators using refrigerants such as R-134a. The use of water as both the primary and secondary refrigerants is attractive in concept since direct-contact heat exchangers could be used, yielding higher coefficients of performance. The disadvantage of water is the very high specific volume of the vapour at low pressures, which leads to great challenges in compressor design, as has been reported previously in the context of slurry-ice plants for mine applications (Ophir and Koren, 1999). Steam ejectors have long been known as alternative compression devices for refrigerators, but no work has been done previously on the possibility of using ejectors powered by high-pressure water, which is readily available in mines from long pipe columns in vertical shafts. This paper presents the results of a laboratory investigation into the use of high-pressure water as the motive fluid in an ejector refrigerator. No previously reported liquid ejector system has achieved subcooling of the process fluid, ie a reduction in fluid temperature within the evaporator to a level below that of the motive fluid. In contrast, the present work demonstrated that subcooling could occur at motive water pressures above 5 MPa. Mine cooling applications were considered and it was concluded that while this concept would not be feasible as a mine-wide cooling source, there could be specialised applications where it would be beneficial. One application would be to cool backfill and thereby reduce the heat load at the working face. In this case the best performance would be achieved by using the ejector in combination with an energy recovery system such as a Pelton turbine or a three-chamber pipe feeder.

Jan 1, 2005

The long-term outlook Tor Australla's traditional mining products is for flat demand and continuing low prices. This has come about because of three far-reaching changes since earlier boom days: 1. Continuing declines in intensity of usage of basic mine products; 2. The failure of newer western and third world developing countries to realise growth expectations; and 3. Continued production pressure from third world countries (and first-world primary producers) in an effort to earn foreign exchange and rectify trade balances. These trends have led to a general situation of excess supply and weak demand. In this environment, the prerequisites for survival in the mining sector are first-class mines, modern and efficient production methods, low unit costs, aggressive marketing, and products with reasonable operating margins. Many of Australia's mines meet these prerequisites. Following the A$ depreciation and widespread unit cost reductions, most of these mines will be moderately profitable at current depressed commodity prices. They are well placed to benefit from price rises if these eventuate. A new generation of mines is concentrating on a more profitable product range (gold, diamonds, uranium, mineral sands). Australia's balance of trade remains firmly dependent on the primary mining and agricultural industries (Fig. 1). Despite optimistic talk of high-tech developments, tourism and a resurgence of manufacturing, these will remain a small component of Australia's export structure.

Jan 1, 1987

By D. L. Neylan

The Bureau of Mines evaluated various methods for identifying sources of mercury vapor in excess of the threshold limit value (TLV) of 0.05 mg of mercury per cubic meter of air set by the American Council of Government and Industrial Hygienists (ACGIH) for mines and mineral processing plants. Chemical spot tests and portable devices for mercury determination were evaluated, based on information from published sources and performance in laboratory tests. Among the parameters examined were sensitivity, interferences, cost, ease of use, and other factors pertinent to field application, More than 50 methods were evaluated. The investigators found that many readily available methods are suitable for identifying sources of mercury vapor in mines and mineral processing plants. The best method appears to be one that uses a commercially available mercury test paper sensitive only to mercuric ions. For some of the more promising chemical spot tests, this report includes step-by-step instructions for field application.

Jan 1, 1983

By Rodrigo Jerez

This paper describes a Mixed Integer Linear Programming model that was developed for planning the coal operations at Mountain Coals, Inc., in Kentucky. The model incorporates the use of stockpiles as practiced and allows the operator to find the least cost combination of raw coal feeds, washing densities and blending to produce the different quality coals as required by the coal contracts.

Jan 1, 1984

By S Zheng, Y Zhang, Z Wen, S Ma

Red mud (RM) is a solid waste product generated during alumina refinery process, and is usually stored in SFs (SFs) because it canÆt be disposed of easily. In this paper, environment degradation caused by RM-SFs was systematically assessed by the method of single factor pollution index based on the analysis data of water, soil and atmosphere sampled around one newly-built and one decommissioned RM-SFs, which are managed by an alumina production company in China. The results revealed that the ambient environment around RM-SFs is seriously polluted by alkali and mercury (Hg). The pH value of RM leachate, surrounding surface water and groundwater are all higher than the limit of water quality standards in China. And as a possible result of overflowing of high alkaline leachate, soil pH value for the decommissioned SF decreases with increasing distance between the sample collection points and the closest side of RM storage facility (RM-SF). Total Hg concentrations in RM leachate, surrounding surface water and groundwater all exceed Grade III limits of ChinaÆs Environment Quality Standards for Surface Water and Groundwater. However, the air quality was little affected as the daily average of TSP in the air is below grade II values of Chinese Ambient Air Quality Standard.CITATION :Wen, Z, Ma, S, Zheng, S and Zhang, Y, 2012. Assessment of environmental quality impacts caused by red mud storage facilities in China, in Proceedings Life-of-Mine 2012, pp 51-58 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By L. M. Demers, D. C. Kuhn, N. El-Ayouby, C. F. Stanley

"Oxygenated metabolites of arachidonic acid (MJ are produced by the alveolar macrophage (AM) and have been shown to mediate inflammatory reactions. We therefore assessed the production of eicosanoids by AM harvested from the lungs of rats ex· posed to a bituminous coal dust for 2 wk in an inhalation chamber in order to determine if AA metabolism was altered in a manner that may promote an inflammatory response in the lung. Exposure to coal dust resulted in a 66% increase in the number of AM harvested, an increase in thromboxane A2 (TxA;i) and leukotriene 84 (LTB,j) production to 222% and 181% of control values, respectively, and a decrease in prostaglandin E2 (PGE:i) production to '62% of control values. In AM harvested from rats allowed to breath clean air for 2 wk following coal dust exposure, PGE2 production returned to control levels but TxA2 and LTB4 production remained elevated. The TxA2 synthesis inhibitor UK 38,485 reduced TxA2 production in dust-exposed AM both immediately and 2 wk following exposure. Thus, exposure of rats to coal dust significantly alters the metabolism of AA in AM, with potentially important aspects of AA metabolism remaining altered even after a 2-wk recovery period. Based on the established role of eicosanoids in inflammatory and fibrotic processes, these results suggest that the alteration of AM eicosanoid production as a result of the inhalation of coal mine dust may be an important factor in the pathophysiology of coal workers' pneumoconiosis.The authors are grateful to Joan Greenwood and Barbara Scheetz for their excellent technical assistance and to Brenda Pavone for the preparation of the manuscript. This research was supported by the U.S. Department of The Interior's Mineral Institute Program administered through the Generic Mineral Technology Center for Respirable Dust under grant 1135142.Request for reprints should be sent to Douglas C. Kuhn, Ph.D., Department of Pathology, The M.S. Hershey Medical Center, Hershey, PA 17033.INTRODUCTIONPulmonary alveolar macrophages (AM) are activated by foreign particles and microorganisms that enter the small airways (Kass et al., 1966; Herscowitz, 1985). This defensive reaction involves phagocytosis, lysosomal enzyme release, and the generation of reactive oxygen species by the AM (Snella, 1986; Rich et al., 1987). A number of agents, including phorbol esters, zymosan, adenosine diphosphate, organic hydroperoxides, and calcium ionophore, have been shown to activate the AM in vitro (Badger, 1986; Marshall and Lands, 1986; Snella, 1986). The AM response to these activators appears to be mediated in part by the oxygenated metabolites of arachidonic acid (AA) (Bertram et al., 1988; Demers et al., 1987; Mcleish et al., 1987).The AM may metabolize AA through cyclooxygenase- and lipoxygenase- catalyzed pathways to produce a variety of eicosanoids including prostaglandin (PG) E2, thromboxane (Tx) A2, leukotriene (LT) B4, LTC4, LTD4, and several hydroxyeicosatetraenoic acid derivatives (HETEs) (Willis, 1970; Camp et al., 1983; Poubelle et al., 1986). The production of these eicosanoids may enhance the. defensive ability of the challenged lung since they stimulate chemotactic cell recruitment to the site of invasion, enhance extravasation of circulating immune cells, and promote local vasodilatation. However, continued stimulation of the AM population, with the consequent production of proinflammatory eicosanoids, may ultimately enhance the disease process by contributing to chronic bronchoconstriction, fibrosis, and the persistent release of toxic oxygen species."

Jan 1, 1990

By J. J. Shields

With the increased use of mechanized equipment in mining bituminous coal, production panels are mined out rapidly. To keep current with the rapid completion of production panels, development work must be speeded up also. Although the same type of equipment usually is employed in development as in production places in the same mine, past output per man for development usually was less than from production panels. A study of development practices in 14 mines reveals a tendency toward equalization of the output per man between development and production.

Jan 1, 1957

By Inoka E. Perera, Robert Hildebrandt, Gerrit V. R. Goodman, Krzysztof Cybulski, Zdzisław Dyduch, Michael J. Sapko, Marcia L. Harris

To prevent coal dust explosion propagations, rock dust needs to be lifted and suspended in the air with the coal dust during an explosion. The addition of anti-caking agents prevents caking of rock dust in the presence of water. Mining and rock dusting processes can frequently create alternating layers of rock dust and float coal dust on mine surfaces. For this test series, a thin layer of coal dust was distributed on top of a layer of either treated or non-treated rock dust in the Experimental Mine Barbara, Poland. The experimental results compare the effectiveness of treated and non-treated rock dusts to attenuate a propagating coal dust explosion initiated with either strong or weak methane explosions. Experimental results indicate that the treated rock dust performs better than non-treated rock dust in arresting a propagating explosion, especially in the presence of moisture.

Jan 20, 2020

By Dayu Long, Changhong Li, Yu Wang, Juzhou Li, Yongyue Hu

To address the problem of seepage failure that affects the stability of the fine-grained tailings dam, two kinds of prevention and treatment measures were proposed involving composite flocculants and composite curing agents. The orthogonal test was conducted to determine the optimal ratio flocculant (ORF) and the optimal ratio curing agent (ORCG). Then, numerical models were established to evaluate the effects of the prevention and treatment measures on the seepage and stability of the tailings dam. The results show that the mechanical properties and microstructure of the tailings are significantly improved by adding the ORF and ORCG. Furthermore, numerical studies suggest that the addition of the ORF and the ORCG to the tailings improves the factor of safety of the tailings dam, but the addition of the ORCG also increases the height of the phreatic line. It is also speculated that the addition of the ORF can prevent the formation of through failure zone in the tailings dam. Therefore, the optimal measure to prevent seepage failure in the tailings dam is adding an appropriate amount of the ORF, as it reduces the height of the dam’s phreatic line and lowers the risk of seepage failure. The typical area susceptible to seepage failure can be treated by adding the ORCG. However, it is important to ensure adequate drainage of the area and to maintain the phreatic line at a reasonable buried depth.

Mar 4, 2024