Search Documents

Many of the difficulties faced by the U.S. mineral industry in 1982 and 1983 emanated from the worldwide recession, from the high value of the U.S. exchange rate, and, in part, from actions taken by foreign governments to protect selected industries. While some problems will be minimized with continued worldwide economic recovery, others remain and may require special attention by U.S. policymakers. These problems include declining U.S. production capacity in selected mining and mineral processing industries, the impact of the high value of the U.S. exchange rate, and protectionist trade practices by competitor nations. Illustrative of the last is the International Trade Commission (ITC) determination in June 1984 that both the domestic steel and copper industries have been substantially injured by foreign imports. In its July 1984 recommendations to the President, the ITC suggested higher tariffs and quotas for 5 years on 70 percent of steel imports but conditioned the aid on cost-cutting and modernization steps by the domestic industry. In the copper decision, two commissioners recommended increased duties, two recommended that quotas be imposed, and one recommended that no relief be provided. The President decided in September to seek voluntary restraint agreements with nations that export steel to the United States and rejected both quotas and higher tariffs on copper imports. General Economic Setting This decade opened with the U.S. mineral industries struggling to deal with double-digit inflation, record high peacetime interest rates, and almost 7 years of oil-cartel-induced energy price increases that seriously affected the profitability of energy-intensive industries such as mineral production and processing.

Jan 1, 1985

By Wagner Fidelis Brum

Os desafios atuais no mercado de mineração de ferro requerem uma gestão de engenharia cada vez mais dinâmica a fim de tornar viáveis novos projetos, os quais contemplam reservas com minérios mais profundos, mais compactos e com teores menores do metal alvo. Além disso, estudos de viabilidade de alta complexidade têm como objetivo tornar rentáveis operações inseridas em ambientes repletos de restrições. Neste trabalho serão discorridas diferentes formas de se estruturar a engenharia a fim de atender tanto a projetos pequenos, quanto médios ou grandes. Nesse momento serão abordadas vantagens e desvantagens de cada modelo, bem como serão sugeridas estruturas para que se atinja uma boa qualidade de engenharia dentro do custo esperado.

Aug 1, 2018

When xanthates or dithiophosphates are used as collectors in sulphide ore flotation, adsorbed species may be identified by gas chromatography of the volatile products formed during low temperature pyrolysis. For collector additions ,as low as 20 g/tonne of ore, pyrolysis of the flotation products usually gives' an olefin directly related to the particular xanthate or Aerofloat reagent used. The method is able to provide valuable qualitative and quantitative data relating to the extent of collector adsorption and the resulting changes in the hydrophilic or hydrophobic nature of the mineral surface.

Jan 1, 1974

La presente investigación revela aspectos sobre los métodos geoquímicos aplicados a la exploración de depósitos minerales, como las aplicaciones prácticas e indicaciones sobre de las diversas técnicas empleadas en el campo y y laboratorio. La exploración química de los depósitos minerales como método de prospección, comprende la investigación e interpretación de anomalías químicas relacionadas a la mineralización dentro de varias sustancias naturales como rocas, aguas y vegetación para así localizar depósitos minerales ocultos. La naturaleza de estas anomalías se divide en dos grupos: las anomalías primarias formadas durante el periodo de mineralización y las secundarias, formadas por la destrucción y dispersión del depósito metalífero durante el ciclo de intemperismo y erosión. Sin embargo, existen algunas anomalías de naturaleza "residual" o "vestigial", las cuales son descubiertas mediante el muestreo sistemático de rocas o de los suelos que de ellas derivan. A esto se suma, la dispersión de elementos en solución puede dar origen a muchas variedades de anomalías secundarias que tienen importancia en la exploración geoquímica como las dispersiones secundarias en las aguas de fuentes, pozos y aguas corrientes, en las cajas de cuerpos mineralizados; en coberturas de carácter no residual sobre y cerca de depósitos mineralizados y aquellas dispersiones secundarias en vegetales. Paralelamente a esta exploración geoquímica, tenemos otras métodos comom los técnicas colorimétricas, basadas en reactivos que indican cambios de color y los de análisis espectográfico, que complementan paulatinamente dicho proceso minerológico.

Jul 20, 1956

Chromium, a critical mineral for which the United States is largely dependent on foreign sources, is the subject of a new report just issued by the Interior Department's Bureau of Mines. The report is the first in a new series called "Mineral Commodity Profiles" (MCP's). Designed to give an updated review of important events affecting critical minerals, it also presents a comprehensive description of industry structure, supply-demand relationships, technology, and outlook for the future.

Jan 1, 1977

Of the world's total production of gold the largest proportion comes from the more regularly consistent ore bodies, but in the aggregate an important part comes from those which are often irregular, uncertain and small. These smaller ore bodies are often high in grade and, as the capital required to work them is not large, they appeal to people seeking a quick and profitable return for a small outlay.These small mining concerns cannot afford detailed geological and petrological investigations and mapping, so they are very often dependent on local knowledge and experience which admittedly may be of really great value.Nevertheless the absence of skilled guidance may not only cause good opportunities for intelligent exploration to be lost, but discourage the seach for other ore bodies.lVIining engineers in the course of their travels in the examination of mines often come across such cases and also others where problems of finding lost ore bodies have been solved by the man on the spot. As records of cases are valuable and useful additions to the knowledge of ore occurrences, the writer now proposes to describe one such case coming under his observation in recent years.It is that of a small mine, known as the Idaho, at the southern end of the famous "Golden Mile" at Kalgoorlie (see Fig. 1). This mine has been a small and very erratic producer ever since it was abandoned by an English company which owned it forty years ago. Except for one period of four years it has always been owned and worked by parties of co-operative miners and during its time has gone through a tortuous career. Although it has often...

Jan 1, 1938

By Manuel D. Viera Flores

Existe un grave problema ambiental que ha pasado desapercibido a lo largo del tiempo y que Metaproject ha venido estudiando los últimos 10 años. Un problema mundial para el sector minero consistente en la acumulación de los neumáticos OTR (Off the Road) fuera de uso, como pasivo ambiental. Metaproject ha estado investigando y desarrollando un proyecto de re- valorización de estos neumáticos, a través de un desarrollo de I&D+i al que hemos llamado “Gestión Sustentable de Neumáticos Mineros”, que permitirá tratarlos como fuente de energía eléctrica potencial.

Sep 1, 2017

By Máximo Yaringaño

El presente texto describe la historia y las exploraciones realizadas en los distritos de San Gregorio y Colquijirca. Esta última se encuentra dividida en dos partes: Colquijirca propiamente dicha y Marcapunta, que es un yacimiento diferente -en tanto se halla emplazado en rocas volcánicas, mientras que San Gregorio y Colquijirca se hallan en rocas carbonatadas. Los tres yacimientos se encuentran en los Andes centrales del Perú, en el departamento de Pasco, Junín. La mineralización de San Gregorio está alojada en las unidades carbonatadas jurásicas del grupo Pucará, en su facies occidental; la mineralización de Colquijirca está emplazada en forma de mantos plegados en rocas carbonatadas de la formación Calera, correspondientes al grupo Pocobamba, de edad terciaria superior.

Apr 26, 1999

By I. M. Ahmed, R. S. Hassan, M. I. Aly

Extraction and separation of La, Sm and Dy ions from acidic sulfate-phosphate solutions was investigated using a cation exchange extractant, bis(2,4,4-trimethylpentyl) phosphinic acid, CYANEX 272, in kerosene. The influence of shaking time, equilibrium pH, extractant, sulfate and phosphate ion concentrations, diluent type and temperature was studied. The extraction was found to be pH-dependent, and increasing the phosphate ion concentration inhibited the extraction which was found to be endothermic. The stoichiometry of the extracted metal species was found to be MOH.H2OHSO4H2A.A2. Aliphatic diluents were found to enhance the extraction compared to aromatic diluents. The results showed that there was a separation mode between the metal ions when varying the hydrogen ion and sulfate ion concentrations, under the used experimental conditions. The investigated process was used for the recovery of La, Sm and Dy from the acid solution resulting from the leaching of low-grade monazite.

By Dave Kay, Young-Suk Song

To meet the needs of South Korea's rapidly expanding economy, a large number of infrastructure projects are under way to improve transportation efficiency within the nation. These projects include high-speed rail links between major population centres and improvements to the road network. Being densely populated and geographically mountainous, infrastructure development in Korea requires a significant amount of tunnelling. Owing to the predominantly hard granitic nature of rock, drill and blast is the preferred method of tunnel advance. The Korean tunneller, however, faces the same pressures as those of his international counterpart in that both cost and production targets need to be achieved while meeting expectations of both community and regulator.

Jan 1, 2005

By D Gelling

Mineral sands dry plants consist of a large number of repetitive unit operations with significant transport delays, in the form of stream pipes, conveyors and elevators. As part of the P255 mineral sands sponsorship and using the JKMRC developed conductor/non-conductor (CNC) gauges, control loops have been implemented at the multi-duty dry plant of Cable Sands Limited at Bunbury. This paper describes the loops for kV control on a rougher high tension roll machines (HTR). The options available are product grade control and ratio control using the JKMRC CNC gauges, which measure the percent conductors in a stream. The purpose of control is to stabilise the circuit operation against disturbances such as atmospheric and feed disturbances.

Jan 1, 2001

By Kenneth Pidgeon

The Boston Marine Industrial Park (BMIP) Boat Section, which is part of contract C04A2 of the Central Artery/Tunnel (CA/T) project, is currently under construction in South Boston, Massachusetts (Fig. 1). The Boat Section is approximately 900 feet long and varies in width from about 135 to 185 feet (Fig. 2). The depth to the top of the Boat Section base slab varies from about 28 to 31 feet below final ground surface and about 23 to 26 feet below normal ground water levels. The Boat Section is supported on 578 anchors drilled into the underlying bedrock each designed for a working load of 630 kips. Design and Construction Team The owner of the project is the Massachusetts Highway Department (MHD). The owner's representative is the Management Consultant, Bechtel/Parsons Brinckerhoff. The section design consultant (SDC) consisted of HDR Engineering, Inc. with GEI Consultants, Inc. as the geotechnical subconsultant. The general contractor was the joint venture of Kiewit, Perini, Atkinson, and Cashman. The boat anchors were installed by the subcontractor Delta Geotechnical Services, Inc.

Jan 1, 1994

By William W. Adams

Reports for the calendar year 1923 that have been transmitted to the Bureau of Mines of the Department of the Interior by mine officials of the various coal-producing States show that accidents in and around the coal mines resulted in the death of 2,452 men. The output of coal during the year, as reported to the United States Geo- logical Survey, was 641,476,000 tons; hence the fatality rate per million tons was 3.82 as compared with 4.15 for 1922, a decline of about 8 per cent. The average rate for the decade ending with 1922 was 4.11. This reduction of 8 per cent in the fatal-accident rate per million tons is equivalent to the saving of 210 lives--that is, had the fatality rate of 1922 continued through 1923 the number of lives lost would have been 210 more than they actually were. Not only was there a net reduction in the fatality rate from all causes combined, but each of the main causes of coal-mine fatalities also showed a decline. Falls of roof and coal, which generally account for nearly half of all deaths in coal mines, were responsible for 1,158 fatalities in 1923, which represents a rate of 1.81 per million tons as compared with 1.90 in 1922. (See Table 2.) Haulage accidents underground usually cause about 17 per cent of all fatalities, and the reports for 1923 show that 413 deaths were due to this cause, indi- cating a rate of 0.64 per million tons, as against 0.71 for the previous year. Gas and dust explosions killed 372 men, the fatality rate being 0.58; the rate for 1922 was 0.65. Seventy-five deaths were due to electricity, for which class of accidents the fatality rate per million tons was 0.12 as compared with 0.16 the year before. Powder and other explosives caused 114 deaths, representing a rate of 0.18 as compared with 0.19 for 1922. Of the 2,452 fatal accidents during the year, 2,249 occurred under- ground, 46 in shafts, and 157 on the surface. At bituminous coal mines the number of deaths was 1,943, of which 1,816 were under- ground, 31 in shafts, and 96 on the surface. At the anthracite mines

Jan 1, 1923

By E. F. Koppe

The Upper Freeport coal in the Freeport and New Kensington quadrangles, Pennsylvania, varies from a bony streak to a thick coal deposit often exceeding ninety inches, the "Double" or "Thick Freeport". Distinctive basal partings, a central bone layer, and a canneloid top bench may be present. The appearance of a sandstone roof, sandstone rolls, and bony coal at the top of the main coal bench can be anticipated in thin Freeport areas when basal partings are absent. When the two basal partings are present, a shale roof is normal. These effects are correlated with the original topography upon which the coal was deposited. The original depositional high areas tend to coincide with present structural highs. Preliminary data indicate that coal quality, in part, is affected by the deposi-tional setting. In "high" areas, a tendency exists for the main coal bench to contain higher percentages of fusain and mineral matter. Within limits, some-what higher ash fusion temperatures appear to correlate with paleotopographic highs. As a result of these findings, critical examination of the paleotopography and related sediments is indicated in other areas and other coals. The Upper Freeport coal is quite variable both in thickness and composition in the Freeport and New Kensington quadrangles of Pennsylvania (Figure 1). The coal horizon in these quadrangles is marked either by a thin carbonaceous shale bed or by a single bed containing a variable number of partings (binders). The complex coal zone known locally as the "Double" or "Thick Freeport" contains the Upper Freeport Coal Bed at the base; but in addition, it has an overlying bone layer and an upper coal bed occasionally capped with a canneloid layer. The "Thick Freeport" often exceeds 90 inches in thickness, whereas the normal Upper Freeport coal usually varies between 34 and 50 inches.

Jan 1, 1961

By Joseph Werner

El presente texto define la función y metas del supervisor de plantas concentradoras a través de tres términos: análisis(A), balance (B) y Control (C ). Asimismo, lo novedoso de la supervisión consiste en la sistemática integral del método aplicado, basándose en la formulación de modelos matemáticos de "simulación manual" orientado al tipo de plantas de mediano tamaño que se instalaron en el pasado por etapas sucesivas.

May 1, 1986

By I M. Turnbull

QMAP (the Quarter Million Mapping Programme, 1:250 000 scale) is a geological mapping programme which will build a digital geological database of the whole country and publish maps and books to document it. The programme was established in 1993, following a recommendation by a review panel appointed by the Ministry of Research, Science & Technology, and is funded by the government, from the Public Good Science Fund. The relevance and fundamental value of QMAP lies in the greatly improved geological knowledge it will provide for researchers and other end-users of geological information.   QMAP research involves assessment of previous work, field and laboratory investigations in key areas, and data storage, manipulation and publication using Geographic Information Systems (GIS) computer technology. The QMAP digital database of New Zealand geology will be completed by 2006, as will the series of 21 full colour printed geological maps and accompanying explanatory texts. Two are already completed and published (Kaitaia and Dunedin), and six other projects are well advanced.   QMAP information will also be available in digital form. Next year we hope to expand the scope of the programme to cover the reconciling and linking of many other earth science databases to QMAP, because we believe this will create a powerful research tool. The intention is to develop internet access to the databases, to make the information publicly available.

Jan 1, 1997

Alkaline leaching with sodium carbonate solution adjusted to pH 9·5 to 10·0 preferentially dissolves thorium from a mixture of rare earth and thorium hydroxides. Rare earth sodium carbonates form in the alkaline leaching stage.These are converted to rare earth oxides for use as optical and ophthalmic polishing agents. Quadrivalent cerium is extracted under similar alkaline leaching conditions.INTRODUCTIONAustralia has made significant contributions to mineral chemistry and mineral dressing. As often happens with an industrially immature country, research investigations often outstrip the ability or desire of commerce to exploit them. It is wrong to think exclusively in terms of export of raw materials. Imagination assists in developing world trends. The chemical utilization of mineral sands has interested a group of investigators, chiefly at the Commonwealth Scientific and Industrial Research Organization (C.S.I.R.O.) and, more recently, in the mining industry itself. From an international point of view the highlight of this work was Newnham's (1960) process for the separation of hafnium from zirconium. Earlier work at C.S.I.R.O. investigated the chlorination of rutile, zircon, and monazite. Assuming that titanium tetrachloride would be available in large quantities in the post war years, extensive work was done by Kraitzer, McTaggart, and Winter (1948) on organic compounds of titanium. This work led to the development of heat resistant paints, plastic compositions, and improved organic protective coatings that predated overseas work by up to seven years. (Post, Shiihara and Schwartz, 1961; Anon, 1955). Contributions were made to the production of refractory hard metals (Kraitzer, 1949; Kraitzer and Newnham, 1956). Pilkington and Wylie (1947) and Urie (1947) investigated the production of rare earths from monazite by an acid process.

Jan 1, 1963

By Haiping Sun, Samir Ganguly, Oleg Ostrovski, M. Yaser Lone

Wettability of graphite by synthetic SiO2-Al2O3-CaO-MnO slags with varied MnO content and by industrial slags was studied at 1350-1600 °C using sessile drop method under argon atmosphere. Initial contact angle was the lowest (110-115o) for the MnO-free slag. For slags with 10-40 wt% MnO, the initial contact angle was in the range 125-135o. The contact angle decreased with the contact time. The change in the contact angle with slag mass was found insignificant. The surface tension of slags obtained from the drop shape analyses was 500-800 mN/m and varied in a narrow range with temperature and MnO concentration. The reduction rate increased with increasing MnO content in the synthetic slag from 20 wt% to 40wt% and temperature. Increasing temperature also increased the rate of reduction. No correlation was observed between the reduction rate and MnO content in the synthetic slags in the range 0-20 wt% and in the industrial slags. The rate of SiO2 reduction from the molten slag was close to the rate of MnO reduction. The MnO-free slag had the largest contact area with graphite substrate. Keywords: reduction, wettability, graphite, slag, manganese, surface tension.

Jan 1, 2007

The consideration of environmental constraints and issues is a fundamental component of all stages of planning, development, operation and decommissioning mining and quarrying projects. Provision needs to be made at all stages for the cost of environmental components since it is of fundamental importance that they be recognised as an integral component of any project. This paper presents an approach to environmental costing, suggested levels for budgeting, and the cost benefits.

Jan 1, 1990

Innovative Technology for Optimised Thickening Sedimentation

Sep 13, 2010