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By W. W. Adams

Two important facts stand out as features of the metal- and nonmetal-mining4 industry of the United States in 1941 as compared with 1940: First, the number of employees and man-days of employment increased; second, accident-frequency rates, both fatal and nonfatal, decreased. Reports from mining companies to the Bureau of Mines covering underground, open-pit, and surface operations for 1941 re¬vealed the largest number of men employed since 1926 and the largest number of man-days worked since 1929. The combined fatal and non¬fatal accident-frequency rate for 1941, calculated on a basis of one mil¬lion man-hours of exposure to hazard, was (except for 1931 and 1932) the lowest since 1911, the earliest year for which figures are available. During this 31-year period, only 1938 and 1939 showed lower fatality rates, and only 1931 and 1932 had lower nonfatal-injury rates. Operating companies reported that 9,620 mines were active during all or some part of the year. These employed 125,290 men, an increase of more than 4 percent over 1940. The total volume of work performed at all mines, measured in terms of man-shifts, increased to nearly 32 million, a gain of 10 percent; man-hours of employment rose to almost 254 million, an increase of 10 percent over the 231 million man-hours worked in the previous year. The year's operations resulted in an average work-year of 255 days per man, an increase of 13 days per employee over the average working time in 1940. Although the 8-hour day prevails generally at most mines, the industry as a whole averaged 7.94 hours per shift, as in 1940.

Jan 1, 1944

By W. W. Adams

The first full year of the second World War for the United States presented a picture of the metal-and nonmetal-mining 4 industry which, without proper analysis and explanation, would convey a distorted view of achievements during 1942, especially because employment at gold and silver (lode and placer) mines-the largest group-declined to such an extent that the over-all totals for the country were reduced even though increases were made at mines producing copper, lead-zinc, iron, miscellaneous metals, and non-metals. A complete panorama of the metal-and nonmetal-mining industry, exclusive of coal mining, reveals a decrease in the number of men employed, the man-hours of employment, and the accident-frequency rates. Were the gold and silver (lode and placer) mines to be considered as a separate category; it would be seen that the number of men employed at all the other groups of mines increased appreciably over 1941. These other increases must be considered important, since these mines produced the vital war minerals that made valuable contributions to the military successes of the United States and its Allies during the year. A separate analysis of each of the various groups of mines may be found elsewhere in this bulletin. For the purpose of maintaining continuity in this series of bulletins, however, the discussion in this introduction will be confined to the entire metal-and nonmetal-mining industry (excluding coal mining, for which a separate bulletin, No. 462, has been published).

Jan 1, 1945

By W. W. Adams

Increased employment and a lower accident-frequency rate were the outstanding features of the metal- and nonmetal-mining4 industries of the United States in 1939 compared with 1933, according to reports furnished by individual mining companies to the Bureau of Vines, United States Department of the Interior. Except for 1937, the reports for 1939 showed gains both in number of employees and number of mar -hours worked over all years since 1929. The accident-frequency rate per million man-hours of exposure to mining hazards was lower than in any year since 1925. Reports for 1939 revealed a total of 111,909 men employed in and about mines, an increase of inure than 8 percent over 1931 The total volume of labor performed at all mires was slightly more than 299 million plan-hours, an increase of mare than 10 percent over 1938. As these gains suggest, the average employee had a longer period of work in 1939, the increase amounting to r workdays per employee.

Jan 1, 1941

By W. W. Adams

The metal and nonmetallic mineral mines (excluding coal mines) of the United States had a more favorable safety record in 1935 than in any year except 1931 and 1932 since annual statistics of accidents first became available in 1911. The accident rate was even lower than that for 1911, when the recorded rate probably did not reflect all of the accidents that actually occurred because many companies had not yet begun to keep complete records of accidents, especially those causing only minor injuries, and when, therefore, the number of accidents revealed by the companies' reports to the Bureau of Mines was probably not as complete as that reported for later years. Compared. with 1911, the accident rate covering fatal and nonfatal injuries in. 1935 decreased 13 percent. Compared with 1925, when the rate was the highest ever reported, the rate for 1935 decreased 47 percent and compared with 1934, 7 percent. The progress in safety which the mines of the country made in 1935 was not confined to any section or mining region; it was shared by a majority of the mining States and applied to underground mining operations, to open-pit mining, and to work at surface shops and yards. The rate for underground mining declined 8 percent from 1934; the rate for open-pit mining declined 14 percent, and that for surface shops and yards 12 percent.

Jan 1, 1938

By W. W. Adams

This bulletin covers all mines in the United States that were operated in 1936 to produce metallic ores and all mines that were operated to produce nonmetallic minerals other than coal, stone, sand, gravel, or their products. Reports from mine operators revealed a better safety record for fatal accidents in 1936 than in any other year except 1934 during the 26 years for which annual surveys of accidents in the mineral industries of the United States have been conducted by the Bureau of Mines. On the other hand, the record for nonfatal injuries, although better in 1936 than in any year prior to 1930, was not as good as it was from 1930 to 1935, inclusive.

Jan 1, 1939

By W. W. Adams

The year 1937 was signalized by increased employment in the metal-and nonmetal-mining 4 industry of the United States. Measured by the number of men working, there was a 17-percent gain in employment compared with 1936. In total number of man-hours worked at all mines, the gain was slightly over 18 percent. Hazards connected with mining resulted in more accidents to the workers than in 1936, but the increase in number of accidents caused only a slight rise in the accident rate because of the much larger increase in the number of man-hours worked. In fact, the fatality rate per million man-hours of exposure was lower in 1937 than in 1936, but the rate for nonfatal injuries increased slightly.

Jan 1, 1940

By William W. Adams

A new record in accident prevention was made by the metal-mining a industry of the United States in 1938, as signalized by a lower fatality rate than in any previous year. The rate was less than half as high as in 1911, the earliest year for which figures are available. A good safety record was also established in the prevention of nonfatal injuries, as the injury rate was lower than in any other years except 1931 to 1935, a 5-year period notable for its unusually low injury rates. Employment was more limited in 1938 than in 1937, both in number of men employed and total number of man-hours worked. The number of workdays per man also was smaller than in 1937. Operating companies reported that 7,233 mines were active in 1938 or some part of the year and that the total number of men employed was 103,027. This figure represents the summation of the average number of men employed as reported by the companies, the average for each mine being that for the period during which the mine was active. The number of employees at all mines in 1938 was 15,402 less than in 1937. Reports covering all mines indicated a total of 188 million man-hours worked during the year, or 21 percent less than the nearly 240 million man-hours worked in 1937. In the performance of this work accidents occurred that resulted in the death of 156 employees and the injury of 1.2,722, each injured employee being disabled for more than the remainder of the clay on which he was hurt.. The fatality rate for 1938 was 0.83 per million man-hours worked, which was 9 percent more favorable than the rate of 0.91 for 1937. Nonfatal injuries occurred at the rate of 67.61 per million man-hours worked, an improvement of 10 percent compared with the injury rate of 75.37 for 1937.

Jan 1, 1941

By W. W. Adams

Because of insufficient funds for printing, the Bureau of Mines was unable to publish its annual bulletin covering accidents at metal mines in the United States for the year 1933. A brief mimeographed summary of the principal statistical data for that year was released to the public late in 1934. Since then reports for 1934 have been received from the mining companies, and in order to avoid further delay in releasing this information to the mining industry and others interested in the prevention of accidents in mining, statistics for both years are presented in this publication with a minimum of interpretation and comment. The fatal-accident rate for the metal and nonmetallic mines (excluding coal mines) of the United States was more favorable in 1933 than in any previous year since 1911, the first year for which the Bureau of Mines obtained reports from the operators. Further progress was made in 1934, when the fatality rate was even lower than that of 1933. On the other hand, the nonfatal-accident rate, which had reached its lowest level in 1932, increased in 1933 and increased further in 1934, although not to such an extent as to prevent the rate for either of those 2 years from being better than that for any year previous to r1931.

Jan 1, 1936

By K. Narayan Prabhu, W. D. Griffiths

"Heat transfer during the unidirectional solidification of a cast iron alloy against cast iron chills was investigated using an inverse modelling approach. Chills of thickness 100 mm and 10 mm were used, to simulate gravity die cruiting conditions and the use of chills in sand moulds. In both cases transient heat transfer, measured by the interfacial heat flux and heat transfer coeffieient; declined from initially high values in the first few seconds of solidification, to values about an order of magnitude lower which persisted for the remainder of the experiments. In the case of the thin chill it became saturated with heat until it was no longer in a position to extract further heat from ·the casting. These results were interpreted by studying the resistance to heat transfer from the casting offered by the ·casting-chill interface and the chill itself for example, the thermal resistance of the casting-chill interface can be influenced by the deformation of their respective surfaces and their subsequent relationship.IntroductionDie casting cast iron offers several advantages such as energy savings, higher mould yield, and better surface quality over the sand casting process1 • The process is· environmentally' friendly because of the elimination of the sand. However the design and construction of metallic moulds is expensive and a faulty die design may result in a defective casting: A simulation based process design of die castings would enable die designers and solidification modellings to try better designs of dies on the computer and arrive at a cost effective solution more quickly. This has numerous benefits for the die caster, as he would be able to produce sound castings with very short lead times.The success of a solidification model to predict accurately the thermal history and the location of hot, spots inside a solidifying casting depends to a large extent on the heat transfer data prescribed at the metal/mould interface. Many measurements of the heat transfer coeffident (or the heat flux) between a solidifying aluminum alloy and a chill have shown that the heat transfer coefficient is a function of most of the variables of the casting process2 - 8. However heat transfer studies during the solidification of ferrous alloys are rather limited. The high temperatures involved suggest that the contribution due to radiation heat transfer cannot be neglected."

Jan 1, 2000

Abrasivity and wear resistance are not intrinsic properties of materials, but rather parameters describing the interaction between the wear part and the material exerting the wearing action. Moreover, wear or, at least, that part of the wear which is due to the cumulative effect of minute scratches, is linked to the hardness disparity concept. Abrasivity, in this context, is a relative concept, pertaining to a metal-rock pair, rather than to a rock. Based on this assumption, a methodology has been developed and checked against actual cases, enabling description of the abrasiveness of a rock or the abrasion resistance of a metal through the ratio of comparable quantitative indicators. The paper describes the methods and provides examples of applications to practical cases (namely: rock cutting, excavation by means of tunnel boring machines (TBMs), rock crushing, and hydro-mill cutting).

Jan 1, 2012

Abrasivity and wear resistance are not intrinsic properties of materials, but rather parameters describing the interaction between the wear part and the material exerting the wearing action. Moreover, wear or, at least, that part of the wear which is due to the cumulative effect of minute scratches, is linked to the hardness disparity concept. Abrasivity, in this context, is a relative concept, pertaining to a metal-rock pair, rather than to a rock. Based on this assumption, a methodology has been developed and checked against actual cases, enabling description of the abrasiveness of arock or the abrasion resistance of a metal through the ratio of comparable quantitative indicators. The paper describes the methods and provides examples of applications to practical cases(namely: rock cutting, excavation by means of tunnel boring machines (TBMs), rock crushing, and hydro-mill cutting).

Jan 1, 2012

By J. Pesl, R. Hurman Eric

Metal-slag phase compositions of molten iron and ilmenite smelting slags or solid titanate phases were determined between 1500° and 1700°C. The influence of oxygen partial pressure and impurity oxide additions including Al2O3, Cr2O3, MgO and SiO2 were investigated along with amount of reductant-carbon. The XRD revealed that the quenched slag crystallized as pseudobrookite (M3O5) solid solution in equilibrium with iron. Silica additions formed separate silicate phases because of its immiscibility in the titanate phase. Under strong reducing conditions iron oxide was almost completely reduced and the slag phase solidified as a consequence thereof. Cr2O3. SiO2 and MnO were also reduced to a high degree. Under weak reducing conditions the slag was fully molten and non of the impurity oxides were reduced. A significant portion of manganese, some magnesia and silicon, in the form of SiO gas, were removed via the gas phase due to their considerable vapour pressures. Alumina was not reduced under the applied conditions. A comparison of the experimental results with industrial data clearly suggested that industrial ilmenite smelting process operated under non-equilibrium conditions.

Jan 1, 2005

By Maria I. De Rosa

Table 46 and figure 16 show the number of fires and fire injuries for metal/nonmetal mills by state during 1990-2001. Table 46 also shows the injury risk rates, employees' working hours, and lost workdays. In all, 77 fires occurred in 26 states. Thirty-seven of the fires caused 41 injuries and 1 fatality (including 5 fires and 3 injuries involving contractors). The yearly average was 6.4 fires and 3.4 injuries. Fifty-four fires with 26 injuries and 1 fatality occurred at metal mills; 23 fires with 15 injuries occurred at nonmetal mills. The Ewhr value was 845 x 106 hr (Irr = 0.01), and the LWD value was 6,681. Minnesota had the most fires (16 fires and 5 injuries), followed by Arizona (9 fires and 3 injuries), Wyoming (8 fires and 3 injuries), Nevada (7 fires, 4 injuries, and 1 fatality), and Texas (4 fires and 7 injuries). Of these states, Texas had the highest injury risk rate value (Irr = 0.033). Table 47, partly illustrated in figure 17, shows the number of fires, fire injuries, fire fatalities, risk rates, employees' working hours, and lost workdays by time period. The number of fires increased slightly during the second period, then decreased during the remaining periods. The number of fire injuries show a decrease during most of the periods (an increase is seen during the third period), accompanied by a decline in employees' working hours during most of the periods. The Irr values follow patterns similar to those shown by the injury values. Tables 48-53 show the number of fires by ignition source, method of detection and suppression, equipment involved, location, and burning material by time period. Figure 18 shows the major variables related to fires for 1990-2001. Table 54 shows the number of fire injuries per number of fires causing injuries and total fires by year, ignition source, equipment involved, and location.

Jan 1, 2004

By Fathi Habashi

Tras pasar revista a diversos ejemplos de procesos químicos propios de la metalurgia extractiva —referencialmente clasificados como piro, hidro y electrometalurgia—, el autor muestra cómo, por ser más eficientes, económicas y/o cumplir con las modernas regulaciones ambientales, las últimas tecnologías vienen desplazando gradualmente a las más antiguas. Tal es el caso de las recientes investigaciones sobre una nueva tecnología para la producción electrolítica de aluminio que excluye la reducción de carbono, con el fin de eliminar la producción de CO2.

Sep 30, 2020

By Edelink Efrain Tinoco Falero

Na atualidade a produção e a utilização de DRI estão aumentando nos países desenvolvidos, principalmente devido à redução do preço do gás natural e do sucesso da nova tecnologia de extração de gás de xisto. Os custos operacionais e os problemas ambientais são, efetivamente, os fatores tecnológicos importantes a serem considerados na otimização da produção de DRI. Portanto, o teor de carbono do DRI tornou-se essencial em virtude da capacidade de gerar energia química no banho de aço, complementando assim a eletricidade em FEA, e as contribuições exotérmicas da oxidação de Si e C nos conversores LD. Este trabalho faz parte de um programa completo de cooperação entre a companhia de mineração Samarco e o Grupo de Siderurgia da PUC-Rio, lidando com as equações cinéticas da metalização e carburização simultânea em fornos de redução direta. Para este efeito, o reator foi dividido em três zonas internas: Redução, Transição e zona de resfriamento. Além disso, também foram consideradas três regiões concêntricas: periférica, média e centro. Á partir desses resultados, para um tipo de pelotas RD específico, mistura de gases utilizados nas instalações industriais e similar flui-dinâmica do processo, as equações cinéticas de metalização e carburização foram estabelecidas para cada zona. Um programa computacional METCARB, totalmente baseado nessas equações cinéticas, foi então concebido. Finalmente, uma validação adicional procedeu-se tendo em conta duas corridas operacionais industriais.

Aug 17, 2017

By Sasa Djokic

In developed countries, the difference between demanded and produced quantities of non-ferrous and rare metals are compensated by secondary raw materials recycling and reprocessing of by-products from both ferrous and non-ferrous extractive metallurgy. Utilization of non-ferrous and rare metals from the metallic secondary raw materials is very significant, both for recovery of the metal value and contribution to the environment protection. Similar to all non-developed countries, the extractive metallurgy in Serbia was based on available natural resources and not so strict environment protection regulations, which was either insufficient or completely absent. Today, Serbia is at the beginning of development of efficient and economical technical and technological solutions in order to ?ecologize? technogenic systems by waste materials, secondary raw materials and degraded soils regeneration (by recycling and revitalization). Several metallurgical technogenic systems in Serbia, together with secondary raw materials classification according to their potentiality for metal extraction by using the existing technologies and expected economical and ecological effects of recycling, are discussed in this paper.

Jan 1, 2005

By Shun-ichi Satoh

THE electric arc welding of cast iron has been studied by Braune, Lamberton, Schimpke, Kenyon, Gale Manufacturing Co., Wedemeyer, Candy, Neese, Miller, Carter, American Welding Society, Namack, Lebrun, Achenbach, Jansson, Kochendörffer and others.1 The writer of this paper has been able to obtain a series of cast irons, from gray to white, without using cast-iron electrodes but by coating on wrought-iron bars mixtures of carborundum (SiC) and graphite (C). In this work, he has found the curious phenomenon of barium- carbonate.

Jan 1, 1929

By Aline Lima da Silva

The reduction in SOFC operating temperature due to recent development in materials and fabrication techniques enables the use of ferritic stainless steels as interconnects for SOFCs. Ferritic stainless steels offer many advantages over traditional ceramic interconnects, such as higher thermal and electronic conductivity, as well as relative ease of fabrication. However, the formation of chromium oxide on ferritic stainless steel results in an increase in ohmic resistance and can lead to the loss of cathode catalytic activity (due to Cr volatilization, with cathode poisoning). The oxide growth depends on several factors, such as steel composition, temperature, oxygen partial pressure. In this way, knowing the phase stability, the oxidation behavior of the material and the oxidation kinetics is of great interest. In this context, a thermodynamic study of the oxidation of ferritic stainless steel 430 under oxidizing atmosphere (cathode), at the temperature of 750ºC, is carried out. As one can see, the thermodynamic system can be very complex, involving several phases (chromium oxide, (Fe,Cr,Mn)3O4 Spinel, iron-chromium oxides, etc.). The effect of oxygen partial pressure and alloying elements on phase distribution is evaluated. Thermodynamic modeling is compared with experimental results from literature.

Aug 8, 2018

By Batric Pesic

Reactions of metallic iron were studied in several different aqueous solution systems: water, medium salt solution used for the growth of T ferrooxidans, ferric iron solution and solution containing T ferrooxidans. Each system was studied under abiotic and biotic conditions in the presence of T ferrooxidans and as a function of pH, particle size of iron powder, temperature, ferrous and ferric iron concentrations. It was found that metallic iron reacts with water differently than does with ferric iron in water. Surprisingly, T ferrooxidans were non-functional in the dissolution of metallic iron. Also, the reactions of metallic iron with pure water were indistinguishable from the reactions with water containing medium salts for bacterial growth. The reactions with ferric iron were also independent of medium culture compounds. The mechanisms of metallic iron reactions with ferric ions are different from the mechanisms of metallic iron reactions with water.

Jan 1, 2001

By T. R. Carter, A. C. Colvine

"Rocks of the Grenville Province in southeastern Ontario are currently largely dismissed by many geologists as having little or no potential for discovery of significant deposits of metallic minerals. The present study demonstrates that the area contains numerous deposit types which elsewhere are major metal producers. Therefore, there is significant unrealized potential, especially for gold, zinc, uranium, and possibly copper.The variety of deposits of metallic mineralization include stratiform zinc in marbles; stratabound base metal sulphides in volcanic and sedimentary hosts; gold-quartz veins; quartzmagnetite iron formation; copper-nickel and iron-titanium in intrusive rocks; magnetite skarns; molybdenum in skarns and pegmatites; uranium and thorium in pegmatites, veins, and calc-silicate gneisses; hematite veins; dolomite marbles (magnesium); and barite-jluorite-celestite-galena-calcite veins. There has been significant production of iron, lead, zinc, magnesium, gold, silver, and uranium.The vast majority of the metallic mineral deposits are confined to late Precambrian supracrustal and related intrusive rocks of the Grenville Supergroup. Many of the deposits are stratiform and/or stratabound and occur within units toward the top of major volcanic successions and in the lower portions of younger carbonate-clastic sedimentary successions.Processes responsible for mineral concentration in the area include: (I) syngenetic hydrothermal activity related to both volcanism and sedimentation; (2) epigenetic processes related to diagenesis, regional metamorphism, and igneous intrusive activity; (3) magmatic processes related to igneous intrusions; and (4) supergene concentration and enrichment. The genetic classification of the mineral deposits presented is based on observed geological relationships and these interpreted geneses. The deposit types have counterparts in volcanogenic and sedimentary exhalative, Mississippi Valley type, magmatic, contact metasomatic, and lode gold deposits. Many of the exploration criteria for deposits of these types may be applicable in the Grenville Province, despite the generally high metamorphic grades and complex deformation."

Jan 1, 1985