Search Documents

By K. R. Bixby

OPENING of numerous stripping operations in Ohio, Pennsylvania, and other districts, particularly outside the Middle West and Southwest where the large-scale stripping mines predominate, holds the limelight for the year 1940. Several factors are responsible for this expansion. One is the scarcity of untested and undeveloped properties in this central field. Another has been the development of earth-moving and preparation equipment suitable for these smaller tonnage tracts. Draglines of the Walker type, small long-range .hovels, and large-capacity tractor- drawn scrapers have to be considered. Wash boxes, designed for light tonnages, costing a few thousand dollars, have made their contribution.

Jan 1, 1941

By Christodoulos Xiouris, Ali Reza, James Karnesky

A rocket parachute signal flare is often used to signal a maritime emergency. In the general operation of these devices, a solid rocket motor propels a metal body to an altitude of approximately 1000 ft(305m).At the end of the rocket motor, a propelling charge drives a signal flare and parachute out of the metal body and ignites the flare, which then burns for approximately 40 seconds as it falls to earth. In this paper, we describe an engineering investigation of an accidental ignition of a rocket parachute signal flare, which caused injury to the user. The components of the flare involved in the accident were inspected via x-ray and microscopic imaging techniques, and compared with those of unfired flares recovered from the same vessel. Chemical analysis of residue on recovered components from the accident flare was also performed. These comparisons were used to determine the likelihood that the actuation mechanism had been deliberately manipulated. In the subject model of the flare, ignition of the rocket motor is accomplished through a percussion cap which is struck by a firing pin. Prior to activation, the firing pin holds down a pre-compressed spring. We present a comparison of the ignition system of the incident flare with those of other rocket parachute flares, which do not incorporate any stored mechanical energy.

By Atsushi Shibayama

The aim of this research was to develop a copper recovery process from mine tailings (0.34%Cu) using flotation followed by high-pressure oxidative leaching (HPOL) and solvent extraction. The results of HPOL using the concentrate of mine tailings obtained by flotation under the optimal conditions of the previous study shown that an efficient copper dissolution of 94.4% was achieved in an H2O media, while the copper concentration of PLS reached to be 2.9 g/L. The solvent extraction of PLS obtained from the optimal HPOL showed that 91.3% copper was recovered in stripped solution under the determined optimum conditions, in which the copper concentration achieved to be 44.8 g/L. Finally, a proposed copper recovery process from the concentrate of mine tailings was developed by combination of HPOL and solvent extraction, while a total copper recovery of 86% was achieved.

By Richard E. Otoo, Evan J. Owen, Virginia T. McLemore

According to the U.S. Geological Survey (USGS), a critical mineral is one that is essential to the economic well -being of a nation and whose supply may be disrupted due to geological, geopolitical or environmental factors (Nassar et al., 2020). For example, REEs are critical to the production of electricvehicle motors as well as wind turbines, yet China’s share of their global production rose to more than 95 percent in 2010 (IEA, 2021). China’s share has since declined, with production quotas dropping to nearly 70 percent by 2023 (Statista, 2023). This and similar situations with many of the critical minerals raise deep global concerns about supply-chain vulnerabilities (Bauer et al., 2011). Critical minerals are used in the production of renewable energy, electronics, agricultural products and common household items (McLemore, 2020). As the global demand for these minerals continues to grow, it is not sufficient to rely solely on scaling up production from existing operations. While increasing production from known deposits can provide short-term relief, long-term resource security requires discovering new, economically viable mineral resources. One of the most effective ways to secure future supply is through mineral exploration, which increases the global inventory of critical minerals and also minimizes risks posed by market monopolies and political instability. The major challenge of mineral exploration lies not only in identifying mineralized deposits but also in determining whether discovered concentrations are sufficient to warrant further investigation and development. A fundamental concept in this decision-making process is using cut-off grade. In this article, cut-off grade refers to the minimum concentration of minerals required to justify further exploration efforts based on factors such as type and size of mineral deposit, mining and processing technologies, associated byproducts/coproducts and the market price of these minerals. Typically, economic cut-off grades are used to determine whether a mineral deposit can be mined profitably. However, this article focuses on preliminary cut-off grades needed to establish whether the amounts of critical minerals within a deposit are high enough to justify further exploration and detailed evaluations. By comparing mineral deposit grades, size, production and extraction technology, and other economic factors with established and active mines, exploration teams can estimate cut-off grades that justify further exploration.

Aug 1, 2025

By Y. M. Jubeli

"Abstract - Gamma-ray spectrometry, an effective tool in geological mapping, was used to define boundaries between various lithological formations in three adjacent areas of Central Syria, namely, the Syrian Desert, Ar Rassafeh Badiayat and the Northern Palmyrides mountains. This paper describes the role of an airborne gamma spectrometric survey which was orginally undertaken to assist uranium exploration. Interpretation of the total count data obtained through the survey has led to significant modifications and corrections to the previously published distribution map of the palaeogene phosphate rocks.Another important result of the survey is the discovery of four previously unknown phosphorite horizons in the Rasm Al-Aawabed area of the Northern Palmyrides. In addition, previously unknown phosphatic horizons are outlined in the other study areas. The importance of this technique as an effective prospecting method, not only for U but also for exploring for the economically important phosphorite formations in Syria, is emphasized. Furthermore, its role in geological mapping is stressed, especially in areas that lack sufficient geological data."

Jan 1, 1997

By D. M. Soboroff

Etchants containing hexavalent chromium and sulfuric acid are used in a variety of surface-finishing operations. When the resultant spent solutions are discarded, substantial quantities of chromium are lost and pollution prob¬lems are created. To minimize the undesirable environmental effects while improving metal and minerals recycling technology, the Bureau of Mines is conducting research on a method for the economic inplant recycling of these waste etchants. Trivalent chromium, produced when the etchant reacts with a sub¬strate, is oxidized in the anode chamber of a diaphragm cell; other metals, dissolved during the etching operation, are transferred to the catholyte. When waste brass etchants are treated in this manner, all of the trivalent chromium is oxidized and more than 40 percent of the copper and zinc is removed. Similar copper removal and chromium oxidation are achieved with waste printed circuit board etchants and rinse waters from plastic etching operations. The electrical energy needed to regenerate 1 kg sodium dichromate is less than 9 kwhr. Regenerated brass etchants evaluated by two companies equaled or exceeded the performance of fresh etchants.

Jan 1, 1979

By A. H. Miller

TEMPERATURE considerations are of prime importance in the manufacture of steel products-front the time the metal is produced in the melting furnace, where the chemical reactions have a direct dependence on the temperatures of the bath, to the final machining of work on which the expansion due to the rise in temperature of the forgings during machining must be allowed for. Methods employed and difficulties encountered in some of the more important steps are here outlined. These methods are the result of years of experience, with many methods of temperature determination, and have been successful in routine works practice in the manufacture of high-quality steels. In the operations of melting, forging, and heat treatment, if the product is to be of the best quality each operation must be carefully followed through. A high-quality product cannot be obtained even with the best heat treatment if the steel is poorly melted, and, conversely, the best steel ever made may he spoiled by inefficient heat treatment. To perform the best work in any of these operations, temperatures must be accurately regulated.

Jan 8, 1919

By M. Melih Demirkan, Juan J. Gutierrez, Raghav Ramanathan

"As the capital of the United Arab Emirates (UAE), Abu Dhabi is one of the world’s fastest-developing cities. To sustain its significant growth rate, Abu Dhabi must surmount challenging engineering problems in the most efficient manner. One of the challenges facing Abu Dhabi is ground settlement caused by poor groundwater control practices in inherently difficult subsurface conditions. For construction projects in Abu Dhabi located near the Arabian Gulf, groundwater is frequently encountered and must be accounted for and addressed during design and construction. Abu Dhabi City CenterRecently, the Abu Dhabi government developed a geodatabase by digitizing, processing and qualifying an extensive amount of existing information (i.e., more than 26,000 borehole logs). Because of the evaluation and processing of the geodatabase, detailed maps of geotechnical and hydrogeological surface features were generated using 3D modeling. Ultimately, the geodatabase was used to develop risk maps indicating geohazards, such as sabhka (or salt flats), uncontrolled fill and cavities. This information identifies the location and extent of the areas vulnerable to surface subsidence. Dewatering can change pore water pressure, which, in turn, alters the effective vertical stress in a soil mass and can affect groundwater chemistry. Changes in pore water pressure and groundwater chemistry can significantly affect soil and rock. The potential effects of dewatering include:• Change in effective stresses and shear strengths in soils• Increase in seepage velocities and pressures• Erosion or transport of soil particles and piping• Settlement• Collapse of subsurface cavities or voids• Transport of groundwater containing contaminants• Dissolution of soluble materials, such as rock salt or gypsum"

Jan 1, 2017

By Y. M. Jubeli

"Gamma-ray spectrometry, an effective tool in geological mapping, was used to de?ne boundaries between various lithological formations in three adjacent areas of Central Syria, namely, the Syrian Desert, Ar Rassafeh Badiayat and the Northern Palmyrides mountains.This paper describes the role of an airborne gamma spectrometric survey which was originally undertaken to assist uranium exploration. Interpretation of the total count data obtained through the survey has led to signi?cant modi?cations and corrections to the previously published distribution map of the palaeogene phosphate rocks.Another important result of the survey is the discovery of four previously unknown phosphorite horizons in the Rasm Al-Aawabed area of the Northern Palmyrides. In addition, previously unknown phosphatic horizons are outlined in the other study areas. The importance of this technique as an effective prospecting method, not only for U but also for exploring for the economically important phosphorite formations in Syria, is emphasized. Furthermore, its role in geological mapping is stressed, especially in areas that lack suf?cient geological data."

Jan 1, 1997

By S Maryati

Surface mining activities disturb large areas, produce great sediment loads and tend to be a source of water pollution if they are not managed properly. Coal mining in Indonesia has a very high risk of soil erosion because the coal mining areas are generally located in tropical areas with a high average of rainfall (4000 - 6000 mm/year) and use surface mining methods. The main factors affecting erosion risk are climate, soil type, topography, vegetation cover and management factors. Thus, the monitoring of erosion risk in mining areas is very important due to the characteristics of coal mining in Indonesia. The objective of this research is to determine the ability of satellite images (remote sensing data) and geographic information systems (GIS) to provide an accurate and up to date spatial database for the monitoring of erosion risk in surface coal mining areas using the Universal Soil Loss Equation (USLE) method.The erosion risk analysis and spatial data processing are generated by the ArcGIS 9.3 software and need several data, namely: an erosivity map, erodibility map, a slope map, vegetation index map and land management or land cover map. The erosivity map is derived from the rainfall data, whereas the erodibility map is derived from the soil map. The slope map is derived from the SRTM-DEM (Shuttle Radar Topography Mission-Digital Elevation Model) and processed using 3D analyst tools. Furthermore, the vegetation index map and land cover map are derived from a satellite image using digital image processing techniques.This preliminary study produced results that show soil erosion monitoring, which is integrated with remote sensing and GIS technologies, has great potential for producing accurate, advance, and low cost erosion risk maps in coal mining areas. This map is very important for getting spatial distributions of the erosion and useful for developing erosion management plans.

Nov 22, 2011

By J. Budac, E. Krause, C. L. Stewart, D. Wrana, S. W. Laundry

"As part of an over-all arsenic management strategy, Inco has developed a novel process that converts a by-product high moisture copper/arsenic sulphide precipitate into a crystalline copper arsenate suitable for the manufacture of wood preservation chemicals.The copper/arsenic sulphide precipitate is atmospherically leached with oxygen and sulphuric acid, producing a crude (blue) copper arsenate precipitate, elemental sulphur, and a copper and nickel containing solution. The blue copper arsenate is dissolved with sulphuric acid, the molar Cu/As ratio is raised to 2, and a crystalline copper arsenate (olivenite) is precipitated by the addition of sodium carbonate. Dissolved copper is recovered using metallic nickel (or matte) and elemental sulphur, to produce a low-moisture (low-arsenic) precipitate suitable for standard nickel-copper processing.The process was successfully piloted at Inco's Manitoba Division between September 1990 and June 1991. The copper arsenate product typically analyzed 43% Cu and 25% As, and the moisture content was about 10%."

Jan 1, 1995

By D. Pappas

Over the past decade, the number of contractors working in underground coal mines has nearly doubled; however, the effect this has had on the industry's injury rates has been the subject of much speculation. The confusion exists because the U.S. Mine Safety and Health Administration (MSHA) database does not assign contractor hours to the individual mining operations where they worked. To better understand the safety record of the contractor segment of the industry, the National Institute for Occupational Safety and Health (NIOSH) undertook a comprehensive analysis of the data contained in the MSHA database. The first part of the study compared overall contractor and operator trends from 1983 to 2009 related to employment, hours worked and injury rate. One unexpected finding was that the larger contractors tended to have higher injury rates than the smaller ones. The second part of the study directly addressed the role of contractors on the safety record of 10 large underground coal mines. A detailed analysis provided both injuries and estimated contractor hours worked at these mines for the period 1992-2007. Comparison between the estimated contractor injury rates and the reported operator injury rates at these mines indicated that the contractor injury rates were significantly higher at most of the operations studied. However, the industry-wide data indicates that contractor and operator injury rates have converged since 2005 and are now equivalent. Mining Engineering, 2011, Vol. 63, No. 11, pp. 73-79. Official publication of the Society for Mining, Metallurgy and Exploration, Inc.

Jan 1, 2011

By M. Carrales, C. J. Jirik, W. D. Dietzman

In view of the developments and recent interest in recovering heavy oil , this report was prepared to present general information on more than 2,000 heavy oil reservoirs in more than 1,500 fields in 26 states . Information given on each heavy - oil deposit includes the following items : Field and formation , location , average or range of depth , average API gravity of oil , average thickness of formation , areal extent of field , total productive wells drilled in field , discovery date of field , field status in 1963 , cumulative production to Jan. 1 , 1964 , and all known types of secondary - recovery operations initiated ( active and terminated ) in the reservoirs . The geographical location of heavy oil accumulations in the United States is shown by a map , and a brief discussion of 14 different areas is given in the text . As of Jan. 1 , 1964 , 75 percent of the heavy oil reservoirs in the United States had produced more than 10 billion barrels of oil and are estimated to contain over 90 billion barrels of oil in place . It is also estimated that if the deposits which have had little or no production history , such as the one in Missouri , were included , the total remaining heavy oil in place would be in excess of 150 billion barrels . To find economical ways of recovering this vast reserve of heavy oil , industry is developing technology in several types of thermal - recovery methods . Some of the general considerations and more suitable limitations in selecting a prospect to study for thermal - recovery techniques are : Lithology , depth , viscosity of reservoir fluids , gravity of oil , reservoir thickness , oil in place , and permeability and porosity .

Jan 1, 1965

By Rameshwar Sah, L. R. Singh, SIVALINGARAJU BARISETTY, SHYAM YADAV, P. K. Ghorui

Fly ash is a by-product generated from combustion of coal in thermal power plant. Disposal of fly ash is a major environmental concern for the power plants. Though a considerable part of fly ash is used in cement making and brick manufacturing, substantial quantity remains unutilized. Silica and alumina are the major constituents in fly ash along with lime. Aluminosilicates and unhydrated lime present in fly ash, in presence of water, undergo a pozzolanic reaction and form cementitious bond which holds the particles together. Bentonite is commonly used as binder in micropelletization of process waste to attain the mechanical strength required for handling and transportation. The bonding of particles by bentonite is a physical mechanism, while fly ash bonding is a chemical mechanism. The present paper deals with the partial replacement of bentonite with fly ash in micropelletization without affecting the quality of micropellets.

Jul 30, 2021

Cement in 1975 indeed did operate in an unfriendly environment. World recession, escalating costs, fuel crises, reduced product demand . . . . all led to market conditions detrimental to industry profit margins and investment re turns. During the year plant utilizations fell, break-even points were raised, and competitive moves introduced to move built up inventory levels. A number of cement plants were temporarily taken out of production to help alleviate specific situations. Meanwhile, under resultant financial pressure, several companies omitted dividend payments, changed their top executives, and reorganized and reduced staff overheads. It was a difficult year for cement, yet a much more ominous note was sounded in permanent plant closings. Four more cement operations were shut down in 1975; to date in 1976 we know for sure of three additional plant closings, while rumour has it that at least one more may not be in production by year-end. The somber feature is found within the descriptions of the closed facilities, and in the stated reasons for their being taken out of cement manufacture.

Jan 1, 1976

By Jin-Hwa Song

Rolling temperatures and cross rolling ratios were varied to investigate the effect of crystallographic texture of alpha-phase on the anisotropy of mechanical properties in modified Ti-6A1-4V alloy. Hot rolling method was unidirectional and cross rolling, during which the rolling temperature was in the range of 830°C and 920°C. Cross rolling ratios were varied from 0.3 to 1.0 at 875°C. For unidirectional rolling, as the rolling temperature increased texture changed from the mixed basal and transverse texture to the simple transverse texture. Contrary to other work, it was observed that the maximum intensity of transverse components increased with the increase in rolling temperature. For cross rolling, on the other hand, the transverse texture component was almost suppressed at 830°C, giving rise to a symmetrical basal texture. With increasing cross rolling temperature, the transverse texture components developed again. A simple transverse texture, which showed two maxima appearing circularly 90° apart, was observed at 920°C. It was found that unidirectional rolling could not eliminate the transverse texture, which resulted in the anisotropy of mechanical properties. The anisotropy of mechanical properties obtained from tensile and V-notch Charpy test was closely related to the crystallographic texture and its intensity at each rolling condition. To obtain the isotropy of mechanical properties by cross rolling, it is suggested that cross-rolling ratios should be controlled above 0.5. The variation of rolling temperatures and directions has great influence on the anisotropy of impact value rather than tensile strength.

Jan 1, 2004

E. K. Landis, Philadelphia, Pa. (communication to the Secretary) : Mr. Firmstone's paper is of great interest; but he has unfortunately otnitted to state the most important point, viz., the percentage of sulphur in the two materials he compares; and this omission vitiates the conclusions which he draws. Comparing by grade, instead of silicon-contents (as in his Table III.), the iron made using limestone with that made using dolomite, we find for gray-forge the average of four analyses under limestone to be, Si, 0.644; S, 0.089 ; while one analysis under dolomite gives Si, 0.508 ; S, 0.070. For No. 2 iron, the limestone flux gives, as an average of 19 analyses, Si, 1.107; S, 0.051; while the average of 4 analyses made with dolomite flux gives Si, 0.630; S, 0.056. It will be observed, that no No. 1 pig is given under limestone, while 14 analyses appear under dolomite, averaging Si, 0.950 ; S, 0.028. As nothing is said about changed conditions, it is Fair to presume that the ore and fuel, as well as the blast-temperature (which is stated to have been uniform at about 750' F.) remained practically the same; and since the sulphur in the two fluxes is not given, it is impossible to know whether the lower sulphur for equal silicon-contents is due to the use of dolomite or to other conditions. The use of dolomite would produce a more fusible cinder, and the furnace would be hotter than when using limestone; therefore, we might expect to see a grayer iron. The amount of So. 1 iron made with dolomite seems to confirm this supposition; and, under these conditions, we might expect more of the sulphur to be volatilized, and to pass off in the gases. The easier fusibility of the cinder would also permit more rapid driving; and this should reduce the amount of silicon and sulphur in the iron, as the amount of reduced metalloids in the pig is directly proportional to the length of time it remains in the reducing-zone.

Jan 1, 1895

By A. S. Prokopovitsh

A spectrophotometric method for the determination of small amounts of copper in tungsten metal powder using the principle of solvent extraction has been developed by the Federal Bureau of Mines. The metallic sample is dissolved in hydrogen peroxide, tartaric acid added, the pH adjusted, and the excess peroxide destroyed by boiling. Copper is reduced to the cuprous state, and the reagent neocuproine (2,9-dimethy1-1,10-phenanthroline) is added to form a colored complex with the copper. This colored complex is then extracted into chloroform and the absorbance of the separated chloroform layer measured on a spectrophotometer. Copper contents as low as 1 p.p.m. (parts per million) can be determined. The method is limited to finely divided tungsten powder. The interest of the Bureau of Mines in developing more sensitive methods for the determination of trace impurities in high-purity tungsten prompted an investigation of the possibility of using solvent extraction-colorimetric methods. The organic reagents now commercially available make possible many extremely sensitive colorimetric methods for the determination of metallic ions. Extraction of the colored complex into a small volume of organic phase can be used to further increase sensitivity (4) .4/ This general approach has the added advantage that no special equipment beyond that normally found in an analytical laboratory is required.

Jan 1, 1961

By G. A. Crowder

Far infrared spectra, most of them in the region 15-200 microns and for both the liquid or solution state and for the vapor state, were obtained for twenty-seven compounds.

Jan 1, 1965

By I. L. Sills

Introduction So many minerals and mineral products are used in the glass industry that it would require an unduly long paper to deal adequately with all of them. Only those that go to make up the batch for the more common types of glass will be discussed here, and even with these only, the list is a lengthy one. It is true that for the body of the glass comparatively few materials are required-as silica sand, soda-ash, lime, and feldspar. The others are used mainly to colour or decolorize the glass, or to give it some other desired characteristic, such as high lustre, greater physical strength, or opalescence; but, although they may be present in very small quantities, they are just as in-dispensable to the glass industry as are the main constituents of the batch. Sand Sand is essentially quartz, the dioxide of silicon, Si02. Most glass contains from 71J to 75 per cent silica. Sand for use in the glass industry, or 'glass sand', is obtained both from deposits of unconsolidated material, commonly referred to as 'sand', and from solid rock-sandstone, quartz, or quartzite. For the manufacture of glass, the material must possess a high degree of purity, as noted below, so that, although sand is widespread in most parts of the world, and sandstone, quartz, and quartzite are not at all uncommon, it is only in certain places that suitable deposits are found. At the present time, most of the glass sand used in Canada is imported from France, Belgium, and the United States. The French material, from Fontainebleau, near Paris, is known the world over as a very high quality glass sand. That from Belgium is nearly as good and is lower is price.

Jan 1, 1934