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By S. P. Narayan

The hot deformation behavior of Pure Mg and Mg-0.29Ce alloy were studied by isothermal hot compression tests in the temperature range of 250 - 500°C and strain rate range of 10-3 - 102 s-1 in a computer-controlled 50kN servo hydraulic universal testing machine (UTM). The results show that the flow stress of Mg pure and Mg-0.29Ce alloy increases with strain rate and decreases after a peak value, indicating dynamic recovery and recrystallization. Process efficiency was increased by nearly 10 to 12% by addition of Ce in Mg. Mg pure exhibits instability zones between 250-275°C at 10 ? 102 s-1 and 400¬500°C at 101 ? 102 s-1 temperatures and strain rates respectively, rest is the safe deformation zone. Wherein, Mg-0.29 Ce exhibits two low efficiency zones from 250 ? 300°C at 10-2? 10° s-1, 400 ? 500°C at 101 ? 102s-1 and high efficiency zone at 450 ? 500°C at 10-3? 10-1s-1. 4D process maps were generated for the above said alloys which illustrate contours of power dissipation and instability in the 3D space of strain rate, temperature and strain.

Jan 1, 2011

By Lindaura de Souza Cândido d’Ávila, Robert Nogueira de Azevedo, Itavahn Alves da Silva, Mariana Carvalho Araújo

The present study aims at the reduction of the dolomitic limestone by the addition of lime added with high MgO (magnesium oxide) content in the sintering process. To verify the feasibility of the use of additive lime as an alternative source of magnesium oxide, sintering tests were carried out at pot grate with different percentages of additive lime addition and with proportional reduction of the calcite lime dosage, evaluating the effects on the sintering process. The results showed that the additive lime is a good source of MgO for consumption in the sintering process of iron ore.

Oct 1, 2019

By Josué Mesquita de Souza Junior

A concentração gravítica corresponde a uma das mais antigas e importantes formas de processamento mineral, sendo utilizada para beneficiar uma grande variedade de minérios. Neste contexto, a melhor maneira de investigar e prever resultados de processos gravíticos é a chamada “curva de lavabilidade”. Estas curvas apresentam a distribuição das partículas de um dado um material segundo as suas densidades e são construídas a partir de dados experimentais obtidos nos denominados testes de flutua-afunda. Para a realização destes testes são utilizados líquidos com diferentes densidades, os quais correspondem a substâncias muito tóxicas, voláteis, de difícil manuseio e, na maioria dos casos, muito caras. Além disto, por não existirem líquidos com densidades muito elevadas, os mesmos não podem ser usados no fracionamento de sulfetos ou óxidos metálicos, o que restringe o uso das curvas de lavabilidade a materiais leves. Pensando nisto, procedeu-se ao desenvolvimento do presente trabalho, cujo objetivo é apresentar uma nova metodologia para a construção das curvas de lavabilidade a partir da análise de imagens digitais. Com esta metodologia será possível construir curvas de lavabilidade de uma maneira mais rápida e segura, além de tornar possível a aplicação desta ferramenta para minérios que possuam partículas com densidades mais elevadas.

Aug 17, 2017

By Prakash AJ, Singh PK, Dhar BB

Safety and stability of underground mine openings, coal pillars and water dams in the near vicinity of operating surface mines are endangered from excessive blast induced vibrations. This paper deals with the investigations carried out in four coal mines. Simultaneous measurements at equal distances from the source indicated higher level of vibration on the surface than those produced in the underground workings. The values of peak particle velocity (PPV) measured on coal pillars, body of water dam were lower than those measured on roof and junctions of the roadways. The parting of coal (3-4.5 m) between two sections vibrated with higher PPV compared to the roof of top section and floor of bottom section. In one case the influence of total charge fired in a round was significant in generation of vibration compared to the maximum charge/delay where monitoring was done vertically below the source.

Jan 1, 1995

By Dwight D. Trueblood

The Benthic Impact Experiment (BIE) is designed to address the effects of sediment redeposition prior to the commencement of commercial mining. The experiment is being conducted in collaboration with Russian scientists from the Yuzhmorgeologiya Association aboard the R/V YUZHMORGEOLOGIYA. Sediment resuspension and subsequent redeposition during manganese-nodule mining is predicted to be one of the primary impacts on benthic communities living on the abyssal seafloor. The redeposition thicknesses that will cause significant faunal mortality in the deep sea are unknown. Sediment redeposition could adversely affect abyssal benthic communities through entombment, or through starvation caused by food dilution and obstructed feeding. This spring NOAA conducted the main portion of the BIE experiment, blanketing the experimental area with varying thicknesses of sediment using the Deep Sea Sediment Resuspension System (DSSRS). The DSSRS was conceived by NOAA scientists, designed and built by Williamson and Associates, and is the critical piece of equipment used to generate the controlled sediment redeposition environment on the 4800-m deep abyssal plane. The DSSRS consists of an 1800-kg sled, 4.8 m long, 2.4 m wide, and 2.2 m high. The sled was towed and powered using an 8,000-m, 26-mm single conductor cable having a 3,000 VAC capacity. As the sled was towed across the bottom, mud was ingested through two rear-facing, 45-cm wide intakes using two 7.6-horsepower pumps, and discharged 10 to 20 m above the bottom through two 20-cm diameter riser hoses. Each pump was instrumented with optical backscatter sensors providing real-time information about the discharge concentration.

Jan 1, 1992

By B. S. Butler

The principal ore deposits of Arizona are in the southern, cen-tral, and western portions of the state, which physiographically are part of the Basin and Range province, southwest of the Colo-rado Plateau (Pl. I). The Basin and Range province is characterized by numerous subparallel mountain ranges separated by plains or valleys. Most of these ranges trend northwest to north, parallel to the margin of the Colorado Plateau; but in southeastern Arizona, southern New Mexico, and northeastern Sonora, they trend northward, transverse too the edge of the Plateau. The mountains rise abruptly from plains or valleys, the margins of which in many places are pediments cut on hard rock. Some of the plains form closed basins (bolsons, playas), but most of them are drained. The Basin and Range province in Arizona is divisible into the Mountain Region and the Desert Region4 (Pls. I and II). The Mountain Region forms a belt 60 to 100 miles wide that contains most of the large ore deposits. Its longest range measures about 55 miles, the widest 20 miles, and the highest peak more than 10,000 feet above sea level or 7,000 feet above adjacent valleys or plains. Broad plain-forming valleys are exceptional, but several with maximum widths of 20 to more than 30 miles appear in the southeastern portion. In the Desert Region the mountains are relatively low, narrow, serrated, and steep, with sharply angular profiles. There are a few exceptionally large ranges of which the longest measures nearly 100 miles and the widest 18 miles. The highest peak is some 7,000 feet above sea level, and the maximum local relief amounts to about 5,400 feet. Broad and comparatively low desert plains form 50 to 75 per cent of the area.

Jan 1, 1939

By George L. Heath

This paper is devoted chiefly to the coal-fields of the western part of the province of Chili and the eastern part of the province of Shansi; but the outline of this belt will give some idea of the extension of the coal-fields over northeastern China. This part of China is topographically divided into: (1) the mountainous peninsula of eastern Shantung; (2) the coastal plains, extending W. and SW. from the gulf of Pechili; and (3) the mountains and table-lands N. and W. of the coastal plains. The plains extend N. and W. from the gulf to within from 10 to 25 miles of the Great Wall, while their SW. extension covers western Shantung and reaches W. along the Yellow river almost to the southern boundary of Shansi. A line joining the mapped coal-fields, shown in Fig. 1, almost gives the western boundary of the plains; since these areas lie on the border of the plains—except the Tsê Chou field, which is on the table-land, 20 to 25 miles from that border. The coal-fields which have been mapped and investigated by the author are shown in Fig. 1. The one at and around Tongshan is known as the K'ai-p'ing coal-field; the one W. of Peking has been called the Wang-p'ing coal-basin; the one SW. of Pao-ting and N. of Chêng-ting may be called the Lingshan coal-field; and the one at and around Tsê Chou is known as the Tsê Chou coal-field. I. The K'ai-p'ing Coal-Field. As is shown in Fig. 2, most of this field lies in the coastal plains, and is therefore covered by alluvium and loess, which have buried the older rock-beds, and the more gentle and older topographic outlines, to such an extent that most of the re-

Jan 1, 1902

By T. A. Rickard

FROM AN OLD MANUSCRIPT THE text for this contribution to the history of the Patio process is a page taken from a Spanish manuscript of Bartholomé Arzaj Sanches y Uela, now in the possession of the library of Brown University (see Figure 1). I owe the photographic print to the courtesy of the librarian. The date, as will be seen, is 1577. The subject is the treatment of silver ores at Potosi, in old Peru, but in modern Bolivia. The group of drawings (see Figure 1) is entitled "Arrangement of the machines in which the ores of silver are ground on the bank of Potosi, the one of two batteries and the other of one". First, top-left, we have the sketch of a "machine of one battery" operated by a water-wheel. From this mill the water runs in part along an aqueduct supported by pillars to the two-battery mill and in part down the hillside, where men are at work with "tubs, which are called cochas, in which are washed the charges of ore and amalgam". Along the top of the page are shown the "various offices in which are stored the copper, the salt, the ucha [llama dung, used for fuel], the lime, and other materials for the re-duction of the ores". To the right of these are "apartments and warehouses in which is stored the ore brought down from the mountain"?the cerro de Potosi. Through the arched portal come the "sheep [llamas] on which is brought down the ore". To this is added a reference to "the second gate, which closes the whole works". On the level above the aqueduct are seen six men carrying skin-bags that contain water. This is being sprinkled on the ore. On the extreme right are six more of these water-carriers. Next comes the two-battery mill. The mortero, or mortar, is marked on the right. Another description says, "Stone, on which the stamps crush the ore, which is called a mortar". To the left of these are indicated "screens of wire in which the ore is sifted after it has been crushed". Farther to the left, near the ore-washers, is a "shed, in which is placed the metallurgist to test the ore of the boxes". Along the left side of the page are sundry buildings, one of which is labelled a "shed in which are placed the cones of silver". Near it, lower, to the right, is the "furnace, in which are roasted the sulphides to facilitate treatment". Farther to the right is the "place where the Indians mix the charges of sulphide ore, which is called a buitron". Alongside is a "buitron in which the charges are prepared for reduction". Inside is a container, to which are attached the words "measure, called topo" On the extreme right is "another buitron in which the Indians mix the ores with their feet, as well as the heaps for the preparation of the reduction". Near the bottom, on the extreme left, is the "chapel where the holy sacri¬fice of the mass is celebrated". Under the first buitron is the "place where they dry the moist ores, called pãpear".

Jan 1, 1935

By Thokozani Lehae Hanes Malinga

O complexo Minas-Rio da Anglo American iniciou suas operações em agosto de 2014. A usina de tratamento produziu, em 2016, cerca de 15,5 milhões de toneladas secas de concentrado. O minério, explorado no município de Conceição do Mato Dentro (MG), passa pelas etapas de cominuição, classificação, concentração e separação sólido-líquido antes de ser bombeado por 529 km até o município de São João da Barra (RJ), onde é filtrado, estocado e embarcado para exportação. A lama e o rejeito da flotação são enviados para um espessador de 90 metros de diâmetro. Testes de sedimentação em bancada mostraram o efeito positivo da sedimentação dessa mistura de lamas e rejeito. A lama, composta predominantemente por partículas finas de hematita e argilo minerais, se adere a ao quartzo do rejeito, que possui maior diâmetro. Apesar dessa mistura aumentar a velocidade de sedimentação, ela propicia a formação de uma espuma com elevada estabilidade, devido a presença de finos da deslamagem e espumante da flotação. Foram feitos testes de bancada objetivando-se avaliar o efeito da retirada do rejeito da alimentação do espessador. A partir dos resultados foram traçados cenários com diferentes participações desse material e suas implicações no processo de sedimentação foram estimados.

Oct 30, 2017

By William H. King

The property of the Cupric Mines Co. is situated in the San Francisco mining district, Beaver County, Utah, 21 miles westerly from Milford (fig. 1), the rail and supply center for the area. Scheelite mineralization was not discovered until 1941, although the occurrence of lead and copper minerals had been known previously. S. VI. Hobbs, of the Federal Geological Survey, examined the Cupric property in November 1941 and prepared topographic and geologic maps of the area. This work was supplemented by additional investigations in January 1943 and March 1944 (fig. 2).

Jan 1, 1949

By B. R. Waples

Sometimes a project is born easy, sometimes a project has a hard time being born. Probably every project can say we had tremendous problems to overcome and they would all be right. This project had all things happen to it. Born easy, a hard time after being born, there were tremendous problems to overcome but here it is, a major copper project, a major operation, and a new source of copper for Mexico and the world market. La caridad is an ore body located in the state of Sonora in northwestern Mexico. It is at an elevation of 1,200 meters above sea level and the nearest major city is Hermosillo, the capital city of Sonora. Hermosillo is located approximately 270 kms (about 168 miles) to the southwest of la caridad. North of la caridad, 130 kms (about 81 miles), is the U.S. border town of Douglas, Arizona, which has a sister city on the Mexican side of the border -Agua Prieta.

Jan 1, 1979

By Daniel Asunción García Ramos

El presente texto señala la influencia del quebracho como agente tensoactivo que evita el problema causado por el azufre a través de concentrados, cuyas especies mineralógicas predominantes son: esfarelita, pirita, incrementándose la extracción de metales. En este sentido, este método hidrometalúrgico permite que los concentrados que tienen plomo y arsénico en su composición, sean neutralizados para neutralizarlos como sulfatos sólidos, mientras que los sulfuros de zinc y de cobre pasan a la solución acuosa en estado iónico para ser recuperados posteriormente por electrodeposición.

Dec 1, 2015

By Fernando Zúñiga y Rivero

El presente texto describe los principales métodos usados en las etapas de prospección por petróleo para así establecer la inversión en la búsqueda de petróleo. La exploración de petróleo es una de las más riesgosas dado que los estudios geológicos previos a la zona, no siempre se corresponden las espectativas de la inversión. Pese a estos inconvenientes, el petróleo se sigue consolidando como la principal fuente de energía del país, tanto por su Es bajo costo, poder calorífico y las ventajas para el transporte y manipuleo. De forma que la provisión de productos de petróleo, como su abastecimiento nunca ha representado un problema en el país, sobrepasando los 15 000, 000 barriles de petróleo hacia 1958. De otro lado, el circuito de prospección de petróleo comprende la roca reservorio, la roca madre y la roca sello, cuya acumulación de capas genera irregularidades y forma las trampas petrolíferas. Reunida estas condiciones para la acumulación de petróleo, hay posibilidades de que la zona a explorar contenga algún yacimiento petrolífero. Sin embargo, existen casos donde se hay una superposición de estratos a manera de reservorio que ocultan la posibilidad de un yacimiento, como es el caso del desierto de Sechura o la montaña del Perú. En estos casos, se emplea los métodos geofísicos de prospección que verifican el indicio de las condiciones estructurales del subsuelo. Entre los distintos métodos utilizados, tenemos a los gravimétricos, basados en la medición de variaciones de la atracción de la gravedad sobre la superficie de la tierra; los métodos magnéticos, que miden las variaciones del campo magnético terrestre, generados por las propiedades magnéticas anómalas del subsuelo; los métodos sísmicos que son los más usados dado que informan de forma precisa sobre la condición geológica del subsuelo, y los métodos eléctricos, que son los menos usados puesto que otorgan datos superficiales sobre las condiciones geológicas del subsuelo. Finalmente, para el costo de exploración del petróleo se tiene que equilibrar los siguientes factores: los métodos de prospección, costo de materiales y equipo, sueldos del personal, número de puntos de observación, facilidades de transporte y las clases de terreno y clima.

Jul 20, 1959

By J. G. Zafiratos

The leaching of a Greek low-grade manganese dioxide ore, not amenable to conventional mineral processing operations, was studied using a mixed culture of Thiobacillus sp. bacteria. The experiments were carried out in specially designed continuously aerated and stirred tank reactors arranged in two-tank series. The first tank of each series was loaded with an elemental sulfur culture suspension while the second was loaded with a manganese ore high density slurry. The bacterial culture had been previously adapted to grow on elemental sulfur and also in the presence of manganese ore and dissolved manganous ion. A two level full factorial design was constructed in order to study the effects of the ferric ion concentration in the leach solution, the "elemental sulfu weight to ore weight" ratio, the ore pulp density and the composition of the dispersed gas. The responses which were investigated included percentage manganese recovery, co-dissolution of iron and manganese dissolution rate. Parameters with constant values throughout the experiments were the leach solution pH, the nutrient medium composition, the dilution rate and the ore and sulfur grain sizes. It was found that the ferric ion concentration was the most significant factor and had a positive effect on the final percentage extraction of manganese from the ore and also on the rate of manganese solubilization from the ore. The effects of the other factors studied are discussed in detail.

Jan 1, 1997

By Edmundo Alfaro, Álvaro Ordoñez

La presencia de Las Tierras Raras o Rare Earth Elements (REE) y de metales alcalinos (Rb, Cs y Li), como elementos estratégicos, son de gran interés en el mundo por su empleo en nuevas tecnologías. Por trabajos y reportes de prospección geológica realizados por el INGEMMET durante los últimos años se ha evidenciado la presencia de aquellos elementos estratégicos en la zona sur del país. Por ello, el presente trabajo se orienta a presentar una investigación preliminar con minerales de la zona sur occidental de la región Arequipa.

Sep 29, 2023

By R. J. Leary

The natural gas-air burner described in this report was designed and constructed to meet the thermal requirements of a convective process for heating steel scrap. This process involved downward combustion of natural gas with air, blending the combustion products with diluent air, and then passing this tempered stream of gases downward through a porous bed of steel scrap contained in the furnace chamber. The scrap would be heated to a temperature limited by the adiabatic flame temperature of the gas stream in a period that depended on the rate at which heat was supplied per unit of bed cross section. The temperature of the gas stream would be limited to that beyond which an objectionable degree of oxidation would occur; for carbon steel this limit had been found to vary from 1,900° to 2,100° F. with the superficial velocity of the gas stream. The productivity of the process was dependent on the rate of heat input per unit of furnace cross section; for the 3-foot-diameter experimental furnace an input of 680,000 B.t.u. per hour was desired. The burner described was designed to meet these conditions of temperature and heat input. It provided for three streams of entering gases: (1) A primary air-fuel mixture too rich to be combustible, that is, above the upper flammable limit; (2) secondary air for combustion of the primary mixture; and (3) tertiary air, principally for cooling the combustion products to the temperatures desired for process operation. Downward combustion of the primary and secondary streams occurred in a flame stabilized on an annular port, while tertiary air flowed in an annular path surrounding the port and also through an axial channel whose wall formed the inner ring of the annular port. This burner performed beyond the designed heat-input rates while producing stable flames, which were adjusted readily to the temperatures desired. Gas-stream temperatures were easily controlled to within 15° F. of the desired value by simple manual adjustment of the flow valves.

Jan 1, 1959

By Peter Zhang, Daniel Su, Bo Kim, Zoheir Khademian

Building on the research results and knowledge obtained from the ongoing National Institute for Occupational Safety and Health (NIOSH) Gas Well Stability Research, researchers from the NIOSH provided detailed analyses on potential longwall mining and gas well casing interactions at an unconventional shale gas well pad in a West Virginia longwall mine. Following the recommendations from recent research findings, the 5-1/2-inch production casings in all five wells were left uncemented from 4,200 feet below the surface to the surface. Prior to the first longwall panel excavation, NIOSH researchers conducted sophisticated three-dimensional numerical modeling to predict longwall-induced deformations and gas well casing stresses, which were compared with post-first panel and post-second panel mining 40-arm caliper surveys. The pre-mining predictions and comparisons with post-mining 40-arm caliper surveys were presented to all parties involved, including the coal and gas operators, Mine Safety and Health Administration (MSHA), Pennsylvania Department of Environmental Protection (PADEP), and West Virginia Department of Mines (WVDOM), prior to the re-entry operation on December 13, 2022. To date, the re-entry operation is a resounding success.

Jul 1, 2023

By C. Sun

The Leeville underground mine has been in operation since 2006 and currently produces 3,300 tons of ore per day with an average gold grade of 0.4 opt. The mine has a large horizontal extent of 2,500 feet by 500 feet and a vertical extent of 20 to 200 feet. Based on the characteristics of the ore bodies, the deposits are divided into several mining zones. The geotechnical properties of mining zones are also different from one zone to another. A successful geotechnical collection system is very important for the mining designs and operations in the Leeville underground mine.

Jan 1, 2010

By Paul A. Pierce

In 1984, the Bureau of Mines evaluated an area previously identified as having "probable mineral resource potential" for copper, lead, zinc, gold, or silver within the Elkhorn Wilderness, about 5 miles west of Winston, MT. The purpose of this study was to determine whether the mineralized structures at nearby mines and prospects outside of the Wilderness extend into and contribute to the anomalous zone and, if so, to expand the domestic supply of strategic and critical mineral resources for future needs by identifying and quantifying resources on public lands. Fifty-eight soil samples, 23 rock samples, and 1 stream sediment sample were collected in the Staubach Creek area. Overall sample analyses suggest the anomalous zone in the Staubach Creek drainage is possibly associated with -.mall pyritiferous quartz veins. These veins or veinlets may be part of a system of northeasterly-trending structures prevalent in this art of the Wilderness. However, there is not sufficient evidence to prove that identified resources outside of the Wilderness extend into it in the Staubach Creek drainage, or that economic base- or precious-metal deposits are likely.

Jan 1, 1987

By George Wilkinson

"AbstractThe consistent relationship between the availability of electrical energy and our economic wellbeing is well known. As we develop the energy we need to nurture industrial civilization in decades ahead, we will at the same time reduce our reliance on dwindling supplies of oil and gas. Coal and uranium will be developed as our major fuel sources to meet medium-term. energy needs, followed by fusion and solar energy for the long term.IntroductionTHIS PAPER treats the matter of energy in a way that is quite different from that of the crisis-type atmosphere which surrounds so much of it currently in the news media. On the one hand, we lift the whole subject of energy out from its present-day involvement with short-term issues and take an important longer-term look at the solutions which lie before us. On the other hand, we recognize that short-term issues are important and, as we are reading and hearing, many of the right short-term solutions continue to elude our politicians, our policy makers, and even some of those with knowledge and authority in the energy field.A year ago, if you asked people how they would go about conserving energy, they would probably have said turn out the lights. They would probably say the same thing today, but they might also include other things such as driving the automobile more slowly or putting more insulation in the attic. However, their first impulse is still to use less electricity."

Jan 1, 1977