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By Ronald Benito

El presente texto señala el algoritmo basado en grafos como la técnica que determina el límite óptimo de minado a cielo abierto. Por ello, se adaptó la técnica de Lerchs y Grossmann y intermedias (algoritmos) y fue usada para crear nodos, arcos y estructuras de árboles en tablas para determinar la máxima cerradura de un grafo.

Sep 1, 2013

By V. McLemore

New Mexico ranks 2nd in uranium reserves in the U. S., which amounts to 15 million tons ore at 0.277% U3O8 (84 million lbs U3O8) at $30/lb (EIA, 2006). The most important deposit in the state is sandstone within the Morrison Formation (Jurassic) in the Grants district. More than 340 million pounds of U3O8 have been produced from these deposits from 1948-2002, accounting for 97% of the total production in New Mexico and more than 30% of the total production in the United States. Sandstone uranium deposits are defined as epigenetic concentrations of uranium in fluvial, lacustrine, and deltaic sandstones. Three types of sandstone uranium deposits are recognized: tabular (primary, trend, blanket, black-band), roll-front (redistributed, post-fault, secondary), and fault-related (redistributed, stack, post-fault). Several companies are planning to mine these deposits by in-situ leaching.

Jan 1, 2007

By Alfonso Rizo-Patrón Remy

El objetivo del siguiente trabajo es señalar un método que permita la recuperación económica de metales preciosos como el oro, plata y otros metales básicos (tales como plomo y cobre) de sus respectivas menas naturales y de los concentrados o relaves que los contengan. Para ello, se utlizará dos formas de aplicación: La primera se da en el tratamiento por cianuración de las menas, donde el carbón mineral es el medio precipitante de los metales disueltos. Mientras que la segunda ocurre cuando el carbón ha sido separado de las pulpas cianuradas, conviertiéndose en un agente reductor de los metales de fundición. De forma tal que se logra una recuperación integral de los metales preciosos y básicos en las barras de fundición.

Jun 20, 1954

By W. R. Lindsay

Considerable attention has of late been given to the blasting of large amounts of ore in one operation, on account of the saving in labour and explosives and consequent low cost per ton, and also on account of the additional safety to employees. The blast here described, at the Hidden Creek mine. at Anyox, B.C., is not necessarily unique either in size or methods employed, but some interesting p10blems were encountered and the solutions of these may be of interest to others engaged in similar work. The ore consisted mainly of old scope-bottoms and sill pillars, although there also were some braces and parts of vertical pillars included. Some of the stope-bottoms were overlain by caved waste, and one of the problems was to break them in such a manner that the maximum amount of ore could be recovered without serious dilution with waste. The ore blocks, designated as the 385 silt and the 7 A-103 blocks, were under preparation for blasting for over a year, as conditions permitted. This work consisted in drilling long machine drill holes, varying in length from 14 to 20 feet. These holes were drilled with the Numa detachable bit, made locally, starting at 2~-inch diameter and bottoming at 2 inches for the longest length. The long hole drilling was used in the thinner sections of the area. For the stronger, thicker portions, powder drifts (3 ft. by 4 ft. in section) were driven for the powder charges. Reference to the plan and sections (Figures 2 co 8 inclusive) show the relative location of these, as well as the long drilling. The amount of explosives used in the powder drift charges averaged 0.25 pounds per ton of estimated burden, varying from 0.2 to 0.3 pounds per ton.

Jan 1, 1934

By Anna Arkhireeva, John N. Hay

Considerable interest has been shown recently in organically modified silicates (ormosils) because of the wide range of possible applications for these interesting organic-inorganic hybrids. These applications include the use of the hybrids as modifiers of a range of host polymer proper- ties. The ormosils can be synthesised by the conventional hydrolytic sol-gel process, as well as by the non-hydrolytic sol-gel route. To date, however, there are relatively few reports of the synthesis of sub-micron size ormosil particles of well-defined spherical morphology. Here, we report work to date on synthesis of such nanoparticles and also introduce our own work in the area.

Jan 1, 2003

By Jürgen Antrekowitsch

Typical zinc oxides recovered from wastes like steel mill dusts and neutral leaching residues are of a low quality because of impurities like fluorine, chlorine, lead and others. Therefore, they are not comparable to technical grade zinc oxides produced in “French” or “American Process”. Some new developments, most of them still in pilot scale, try to establish processes where higher qualities of the product should be achieved. Zinc oxides are not only supposed to be an input material for electrolytic zinc production. Far more, they should find their way into the zinc oxide market as a substitute for technical grade zinc oxides. Furthermore, a new field of application for these oxides has been investigated at the department of Nonferrous Metallurgy, University of Leoben. Because of a higher acceptance concerning different impurities in relation to zinc winning electrolyses, a use in electrolytic galvanizing shows an interesting option. Therefore, synthetic zinc oxides with different impurities were generated to study the effect of these impurities especially on the quality of the zinc layer. Typical steel sheets, as used for car bodies, were electrolytically galvanized and the resulting layer was analysed, as main impurities compounds of fluorine, chlorine, iron, lead and calcium were used for the investigations. Beside the layer quality, the current efficiency and the possible galvanizing speed were examined. The results give an indication, weather such an alternative application can be feasible from a technical and economical point of view or not. 597

Jan 1, 2008

By Fumihiko Sumiya, Kunihisa Katsuyama, Yuji Ogata, Yuji Wada, Yukio Katoh, Yoshikazu Hirosaki

In our previous work, the results of photographic observation using a high speed framing camera showed that the difference between precursor air shock wave velocity and detonation velocity was primary factor for the channel effect. It is assumed that the decreasing precursor air shock wave velocity can prevent the channel effect in charge hole.

Jan 1, 1996

By Wan Entong, Xie Junlin, Jiann YangHwang, Yang Chengwei, Chen Junfu, Zhang Jianjun, Cao Tongyou, He Feng, Peng Zhugang, Fang De

During the solidification process of peritectic steel (PS), the peritectic reaction often causes volume contraction which associated with surface longitudinal cracks, and using mould flux with low heat flux density help for alleviating surface longitudinal cracks. New peritectic steel mold flux with Co2O3 doping reduced the heat flux density, and the optimal content was found to be 2.0 wt %. Furthermore, basicity and Na2O addition were designed, and the minimum heat flux density required basicity of 1.4 and 10.0 wt %. Na2O content. As a result, the optimal peritectic composition was CaO(35.67wt% ), SiO2(25.48 wt %)，Al2O3(3.7 wt %)， MgO(2.53 wt %)，Na2O(10 wt %)，CaF2(14 wt %)，Co2O3(2 wt %).

Jan 1, 2015

By Dennis Molvik, Roberto J. Guardia, Brad Cowles, Rick Andrews, Robert A. Robinson

A 220-meter (m) segment of the Henderson/ ML King Combined Sewer Overflow(CSO) consists of two 1.8-meter-inside diameter (I.D.) pipe-jacked tunnels that pass beneath Interstate-5 and the BNSF and UPRR railroads. A seismic tomography survey was conducted to develop a 3-dimensional profile of the tunnel zone and better define potential obstructions. The tomography was conducted through three 11 cm high-density polyethylene (HDPE) pipes installed in a triangular pattern around the future tunnel alignments using horizontal directional drilling methods. The pipe-jacked tunnels have been successfully completed, thus permitting a comparison between the predicted obstructions and those actually encountered. The top HDPE tomography pipe was also used to monitor settlements with an experimental horizontal profiler above the advancing tunnels during construction and located two areas of ground loss beneath I-5 that were subsequently grouted.

Jan 1, 2005

By Judson C. Higgins

The paper addresses changes in surface transportation methods in the Industrial Minerals business starting with history, the changes to present time including such areas as energy costs, improved highways, changes in regulations and deregulation, and attempts to project future transportation trends. Transportation methods such as rail, piggyback, truck and barge are compared, and their impact on Industrial Minerals producer's costs and profits examined. The customer impact on our businesses due to deregulation is also discussed.

Jan 1, 1983

By Renee Y. Allee

The Chino open pit mine, concentrator, and smelter are located in Grant county in Southwestern New Mexico. Chino Mines Company is a partnership, two- thirds owned and operated by Kennecott Santa Fe Corp., and one third owned by MC Minerals Corp. (Mitsubishi) of Japan. The concentrator, with a design capacity of 37,000 tons of copper-molybdenite ore per day, was commissioned in July, 1982. Further design modifications have resulted in an increase in throughput capacity to 42,000 tpd

Jan 1, 1986

By Glenn Ferguson

BACKGROUND Metals Risk Assessment at Contaminated Sites ? The field of metals risk assessment has advanced rapidly over the last five years ? Significant uncertainties and data gaps remain that require additional research if accurate assessments are to be conducted ? Research is being conducted by regulators, external institutions and academia ? Risk assessment practitioners are in need of answers or solutions TODAY

Apr 1, 2005

By Howard H. Fields

Any mining engineer with a desire to operate independently, with some financial backing, and with no fear of heavy responsibility and long hours, should be able to make a comfortable living in Mexico. Barring a few inconveniences such as a lack of satisfactory liability or accident insurance, the difficulty of obtaining repair parts for vehicles, and the length of time required receive returns from shipments, the operation of a small mine is not at all difficult. It is, in fact, a little easier to find a good prospect in Mexico than in the U.S.

Jan 11, 1950

By R. A. Kinzie

THE major operating costs in a cement plant are labor, power, and fuel. The opportunities and methods of savings in labor and power parallel other industries. Because our industry's use of fuel is large and its method of use is unique, the devices adapted for saving fuel are of interest. In normal practice the raw material in the form of a dry powder or a mud is fed to a rotating inclined cylinder where it is dried, calcined, and clinkered. In a Lepol kiln the raw material is rolled up into little balls with water in the nodulizer, fed to a traveling grate on which it is dried and partially calcined and tben to a short kiln where the process is finished. The more usual methods of saving heat have been the use of long kilns with chains in wet process plants and the use of waste heat boilers in dry plants (fig. 1). At the Santa Cruz plant we have used a Lepol system kiln and achieved a fuel 'economy of 4.7 gal per bbl of clinker or about 704,-000 Btu per bbl. This can be compared with our old kilns using the same fuel and raw material which consume 7.8 gal per bbl or 1,130,000 Btu per bbl. These are gross Btu and not the net figures usually used in reports of foreign companies. Our average consumption for 1948 was 708,000 Btu per bbl of Lepol clinker, based on cement sold, and oil purchased. The overall fuel consumption for 1948 was 6.61 gal per bbl. The Lepol system consists of a nodulizer, a grate, and a kiln. There is the usual accessory equipment which is similar to that used in other cement plants. The following description covers the equipment in operation at our plant. The nodulizer is a cylinder 8 ft 10 in. in diam by 18 ft long set on a slope of 1/2 in. per ft, and rotated at about 10 rpm. It is driven by a 50 hp wound rotor motor drawing about 9 kw. The inside of the shell is cleaned by a continuously operating scraper which draws 0.1 kw. The dry raw material is fed to the nodulizer where, being sprayed with water, it rolls into small spheres about 90 pct being between 1/2 and 1 in. in diam and containing about 15 pct water. The nodules fall on the traveling grate where the hot gas from the kiln is pulled down through the

Jan 1, 1951

By R. A. Kinzie

THE major operating costs in a cement plant are labor, power, and fuel. The opportunities and methods of savings in labor and power parallel other industries. Because our industry's use of fuel is large and its method of use is unique, the devices adapted for saving fuel are of interest. In normal practice the raw material in the form of a dry powder or a mud is fed to a rotating inclined cylinder where it is dried, calcined, and clinkered. In a Lepol kiln the raw material is rolled up into little balls with water in the nodulizer, fed to a traveling grate on which it is dried and partially calcined and tben to a short kiln where the process is finished. The more usual methods of saving heat have been the use of long kilns with chains in wet process plants and the use of waste heat boilers in dry plants (fig. 1). At the Santa Cruz plant we have used a Lepol system kiln and achieved a fuel 'economy of 4.7 gal per bbl of clinker or about 704,-000 Btu per bbl. This can be compared with our old kilns using the same fuel and raw material which consume 7.8 gal per bbl or 1,130,000 Btu per bbl. These are gross Btu and not the net figures usually used in reports of foreign companies. Our average consumption for 1948 was 708,000 Btu per bbl of Lepol clinker, based on cement sold, and oil purchased. The overall fuel consumption for 1948 was 6.61 gal per bbl. The Lepol system consists of a nodulizer, a grate, and a kiln. There is the usual accessory equipment which is similar to that used in other cement plants. The following description covers the equipment in operation at our plant. The nodulizer is a cylinder 8 ft 10 in. in diam by 18 ft long set on a slope of 1/2 in. per ft, and rotated at about 10 rpm. It is driven by a 50 hp wound rotor motor drawing about 9 kw. The inside of the shell is cleaned by a continuously operating scraper which draws 0.1 kw. The dry raw material is fed to the nodulizer where, being sprayed with water, it rolls into small spheres about 90 pct being between 1/2 and 1 in. in diam and containing about 15 pct water. The nodules fall on the traveling grate where the hot gas from the kiln is pulled down through the

Jan 1, 1951

By R. Worrall

The global mining industry has been proactive over the last decade in finding ways to embrace the concept of sustainability. However, legacy mine sites (which include abandoned derelict and orphan mine sites) across the world continue to present issues for the global mining community, governments, local communities and NGOs. Unfortunately there has been much less academic focus on this area of mining and sustainability. This paper seeks to address how principles of sustainable development can be used to guide the development of processes for addressing post mining landuse issues for legacy mining areas. This is being done using a case study area located near Ipswich, in southeast Queensland, Australia. This area has a 160 year history of coal mining, and was one of Queensland?s crucial early industries. Mining in the area ceased in 2003 leaving a degraded landscape covering an area in excess of two thousand hectares adjacent to one of the fastest growing urban areas in Australia. A sustainability criteria and indicators framework for post-mining landuse on legacy mined land, developed from current best practice used for measuring sustainability across a range of industries is being developed. A review of current best practice suggests the framework should: (1) consider in equal measure environmental, social and economic factors; (2) have a minimum number of indicators which should be easy to identify and measure; (3) must have indicators with a meaningful output; and overall, the framework must consider particular requirements of the site being investigated. Application of the framework to the case study area is an ongoing aspect of this research, and the results will be evaluated through the use of expert stakeholders.

Jan 1, 2007

By J. A. Organiscak

This paper examines methods for limiting occupational silica exposures for roof bolting personnel in underground coal mining. A canopy air curtain and an air tube were evaluated as means to provide filtered air over the breathing zone of these personnel. Laboratory testing showed that dust reductions beneath the air curtain and air tube approached 60 percent and 40 percent, respectively, with low interference air velocities. The data also showed that dust reductions were highest for positions closest to the device and that these levels decreased with distance. This paper also evaluates a metal rake, a flexible insert, and a rigid insert for cleaning the roof bolter dust collector box. Less dust was produced when using the rigid insert. Surprisingly, the flexible insert was sometimes no better than scraping or raking the dust onto the mine floor. However, little dust got on the coveralls when using either of the inserts.

Jan 1, 2002

By Michael J. Pyrcz, Clayton V. Deutsch

Strategic project decisions are based on the distributions global variables, for example, total mineable resource, or recoverable oil volume. These global variables distributions are very sensitive to the input one point statistic, that is, histogram and rock type proportions. Representivity in the one point statistic retains significance in all spatial models. Spatial sampling bias and nonrepresentative sampling complicate this process of building representative one point statistics. This work outlines the cause of bias, the inability of standard declustering to correct for this bias and two methods for correcting bias in the one point statistics: "trend modeling for debiasing" and "debiasing by qualitative data". An example is presented of each technique based on a poly metallic data set.

Jan 1, 2002

The comminution circuit at Tarkwa Gold Mine was commissioned as a Single Stage SAG mill operated in closed circuit with hydrocyclones designed to process 4Mtpa. The circuit was later expanded by adding a secondary ball mill in closed circuit with hydrocyclones with a view to treat 12Mtpa. The change in the circuit configuration and assigning the low aspect ratio SAG mill for primary grinding application makes the Tarkwa experience unique in terms the optimisation strategy and operating philosophy. This paper reports the findings from a series of surveys performed on this plant. The surveys reported include data obtained when the SAG mill was operated as a single stage mill in closed circuit with hydrocyclones and also SABC mode under two different feed conditions. The differences in operating philosophy between the initial single stage SAG circuit and the current SAG/Ball mill circuit are discussed.

Jan 1, 2012

The BHP Billiton Cannington mine uses sequential flotation to treat a silver, lead and zinc ore supplied from an underground mine. The final products from the process plant are a silver rich lead concentrate and a zinc concentrate. Operational history of plant performance highlighted that the majority of valuable metal losses to final tailing occurred in the -5 ¦m fraction. Research completed on the flotation characteristics of this size fraction in plant feed resulted in the development of a split flotation process to improve the silver and lead mineral recoveries. Construction of a $A 9.5 million brownfield project to install the new split flotation circuit at Cannington was completed in July 2002. The circuit consists of three stages of cyclone classification to recover the ultra fine material to a final cyclone overflow stream, conditioning of this pulp to achieve optimal process conditions, and conventional rougher and three stage cleaner flotation to produce a silver rich lead concentrate. The rougher tail from the new circuit is recombined with the cyclone underflow streams and processed through the original lead-zinc flotation circuit. This paper discusses the circuit design, material properties, material selection for components of the circuit, operational practices and requirements to ensure the circuit succeeded in meeting production targets. The technology is subject of a number of patent applications including international application No PCT/AU02/00400.

Jan 1, 2003