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By Pedro Hugo Tumialán

El presente texto señala el proceso de mineralización del yacimiento metálico de Algamarca en Cajamarca a través de la descripción de la singularidad de sus características geológicas. De acuerdo a ello, se corta una inclinal de cuarcita de la formación Chimú del Cretáceo inferior, cuyo eje tiene un rumbo NW concordante al eje del anticlinal. Asimismo, el intrusivo Caupur es el causante de la mineralización de las vetas de Algamarca, las cuales resultaron por fuerza de compresión perpendicular al eje del anticlinal, formando algunas vetas dextrales y sinestrales, así como vetas de tensión perpendiculares al eje anticlinal. En este sentido, las vetas son angostas (O.la 0.3 m)peroricas en plata y su distribución se da en forma de arco de cada veta.

Nov 8, 1982

[A Aalseth, Earl P. (M 51) Geol, Amerada Petr. Corp., Box 1498, Billings, Mont. Abadie, Henry G. (M 43) Asst to Supvr of Oper, Long Beach Oil Dev. Co., 255 S. Santa Clara, Long Beach 7, Calif. Abbe, T. Waldo (A 56) Ass't Dist Oper Supt, Sun Oil Co., Beaumont, Tex. Abbott, J. L. (M 56) Partner, Pritchard & Abbott, 501, Century Bldg, Fort Worth, Tex. Abbott, Richard H. (J 51) Owner, Abbott & Howard, 422 W. Hermosa, San Antonio, Tex. Abbott, Seth J., Jr. (M 51) Tekoil Corp., .2;A6 Mercantile Nat'l. Bank. Dallas, Tex. Abbott,. William G. (M 50) Div Mgr, Rice Eng. & Op. Inc., Box 1142, Hobbs, N. M. Abderhalden, R. R. (J,59) Box 100, Carmi, Ill. Abel, Malcolm D., Gen Mgr, Bakke Oil Co., Midland, Tex. Abel, Raymond L. (M 28) Prof of Chem Engr, Univ. of Pittsburgh, Pittsburgh 13, Pa. Abel, Wayne K. (M 57) 1513 Patton Drive, Odessa, Tex.]

Jan 1, 1961

By B. J. Fryer, R. P. Taylor

"As a monitor of the processes involved in the formation of granitoid mineral deposits the coherent group behaviour of the rare earth elements (REE) actively reflects changing fluid characteristics. For example, in the porphyry environment, magmatic-hydrothermal fluids produce potassic alteration with strong enrichment in the light rare earth element s (LREE), reflecting their high pH, low fluid/rock ratios, and the dominant role of CI- complexing in metal (i.e. Cu, Au) transport. With increasing fluid/rock ratios and decreasing pH accompanying the progressive involvement of meteoric fluids (and the production of propylitic, argillic, and phyllic alteration) anionic species such as F - and CO, 2- become important in metal (e.g. Mo, W,) transport through complexing, and their activity in the hydro thermal fluids is illustrated by mobilization of the heavy rare earth elements (HREE).The relative involvement of CI- versus F - versus CO32- in metal transport in other granite-related systems can also be monitored through REE behaviour. Hence granitoid tin-tungsten mineralization and associated greisenization typically exhibit heavy rare earth enrichment and evidence the importance of F' and CO32- in metal transport. Similarly, heavy rare earth element enrichment in hydrothermal uranium deposits can be related to the transport of uranium as carbonate complexes. REE are widely accepted as powerful tools in the study of rock petrogenesis, but their use has been neglected in the investigation of mineral deposits. The recognition of the systematic variation of REE distributions in granitoid mineral deposits suggests that the application of REE geo chemistry, particularly when integrated with fluid inclusion and isotope studies, can provide (1) an effective method for identifying the physicochemical controls of metal transport and (2) a useful criterion for elucidating metal distribution."

Jan 1, 1983

By Andrey de Moraes Barcelos Casanova, Rebeca Vieira de Oliveira, Juliana Diniz e Castro, Danilo Abílio Corrêa Gonçalves, Patricia Freitas Rodrigues, Thiago Henrique Fernandes Dias Ferrão, Naiara Vieira Le Sénéchal, Rodolfo da Silva Teixeira, Andersan dos Santos Paula

Este trabalho avaliou a efetividade do tratamento térmico de solubilização de uma liga de NiTi com 58,5%at. Ni comparado a uma liga de composição equiatômica, elaboradas por vacuum arc remelting (VAR). A solubilização foi realizada à 950 °C, em forno de atmosfera não controlada, com tempo de encharque de 2 h, seguido de resfriamento rápido em água à temperatura ambiente. Foram analisadas imagens de microscopia óptica e de microscopia eletrônica de varredura, após preparação metalográfica, das amostras fundidas e solubilizadas, bem como, quantificação da segunda fase pela análise de micrografias ópticas. As propriedades mecânicas foram avaliadas pelo ensaio de dureza por microindentação Vickers. O tratamento térmico imposto resultou em alterações morfológicas na liga equiatômica e não foi possível verificar a dissolução completa dos precipitados da liga com elevado teor de Ni. Foi observado a diminuição da dureza com a solubilização do NiTi equiatômico, e aumento na liga Ni58,5%at.-Ti41,5%at.. Logo, para se obter uma solubilização ótima das ligas, se faz necessário um tempo de encharque maior.

Oct 22, 2019

By Francisca San Martin, Tomas Vargas, Willy Kracht

"In Cu-Mo deposits it is usual to find considerable amounts of pyrite (FeS2). When processing this kind of ore by flotation, pyrite is rejected using lime to increase the pH to alkaline conditions (pH ~10.5). In the case of using seawater without pre-processing, i.e., raw seawater, the lime consumption increases dramatically and the recovery of molybdenite drops due to the precipitation of magnesium hydroxide on its surface. In order to avoid these negative effects, alternative ways of depressing pyrite should be considered.The current work introduces the use of Acidithiobacillus ferrooxidans, bacteria commonly used in bioleaching, as an alternative to depress pyrite in seawater flotation. The paper presents the results of biodepression in three systems: fresh water, water with added sodium chloride at 35 g/L (which corresponds to the salt concentration in seawater ) and seawater. The results show that it is possible to bio-depress pyrite with A. ferrooxidans in natural seawater pH (7.8-8.2). A similar behaviour is observed when running the experiments in fresh water, and in water with sodium chloride added.INTRODUCTIONWater is a scarce but essential resource for human development. The main reason for this scarcity is that, although 70% of the earth's surface is covered with water, only 3% of the total is fresh water and an important part of this water is frozen, so that only 1% of fresh surface water can be used for human activities. In Chile, most of the mining activity is concentrated in the north of the country, located in the Atacama Desert, considered the world's driest desert. That is why some mining companies have chosen to use seawater in their processes. For example, Esperanza (Antofagasta Minerals), and Sierra Gorda (KGHM International) use raw seawater in their flotation processes."

Jan 1, 2016

By G. R. McMeekin

"THE TOPIC suggested for my contribution to this Symposium was ""Lead-Zinc Smelting - 40 Years of Pollution Control"". The history of the development of smelting industry at Trail and the control of sulphur dioxide could make quite an interesting historical study. However, in the field of environmental control, the public is not particularly interested in what you did yesterday, but rather what you are doing today and what you are planning to do tomorrow. I can't fault this approach, but because there are some subject lessons that history can demonstrate, I would like to tell enough of the story (under three headings) to bring a focus on matters of contemporary concern in regard to public relations and ecology. The three general headings suggested are: (1) time before the capture of by-product sulphur; (2) the capture of sulphur; and (3) the ecological and public relations conclusions from these."

Jan 1, 1972

By Seong-Taek Lim

Recently, 7xxx aluminum alloys have been evolved into new variants for thick semiproducts which have low amount of 2nd phases and low quench sensitivity. Commercial 7xxx alloys, especially in the thick forgings made of big ingots, often entail microstructural inhomogeneities and concurrent poor mechanical properties due to limited heating ranges and slower quench cooling. In this study, high strength aluminum alloy 7175 and 7050 are adjusted as an attempt to control the equilibrium phases (M-, T- and S-phase) to have optimum microstructure for the thick forging applications. The effects of the relative content of (Zn, Mg, Cu) on the evolutions of the coarse equilibrium phases, hardening response and resultant mechanical properties are investigated. Equilibrium phases (M,T,S) are evolved depending on the constitutional effect, primarily the change of Zn:Mg ratio, and cooling rate following solutionizing. The formation of the T- and S-phases is effectively controlled, and M-phases are homogeneously precipitated in the adjusted (dilute and high Zn:Mg ratio) alloys. It provides extended heating range and lower quench sensitivity than conventional alloys. The attempts ensure the microstructural homogeneity and improved properties, and is expected to be uniquely applicable in 7xxx thick forgings.

Jan 1, 2004

By John Newby, Ulf Gwildis, Ken Massé, Guillaume Roux

How to connect an effluent conveyance tunnel to riser shaft and diffuser arms of an outfall system is dictated by the ground conditions, which ideally include rock or soil strata of low permeability. Where such favorable conditions are beyond reach, both the complexity of designing and the risk of constructing this crucial system connection increase disproportionally. This paper describes the considerations that went into the approach of connecting a 5-m-diameter TBM drive with the in-river riser shaft of the Annacis Island WWTP New Outfall System in the highly permeable Fraser River sands at hydrostatic pressures exceeding 3 bar.

Jun 23, 2024

By C. Bazin

"Discrete transfer functions which use the grinding circuit feed tonnage to predict mass flowrates at reagent addition points in the flotation circuit were calibrated using a dynamic grinding/flotation simulator. Predicted values are multiplied by g/t ratios to calibrate reagent flow. The transfer functions are currently integrated into the distributed control system at Les Mines Selbaie.INTRODUCTIONThe development of adequate tools for the control of flotation processes is a continuous challenge. Since the early 1970's there have been numerous publications dealing with practical applications of flotation process control. A review of that literature shows that basic feedback and feedforward controls are the two preferred strategies for flotation processes. Some advanced control schemes started to emerge (e.g. Zaragoza and Herbst, 1988). Feedforward and feedback aim at reducing the effect of the following flotation process disturbances (e.g. McKee, 1991):0 Changes in throughput;0 Changes in feed grade;0 Changes in particle floatability (size, liberation, surface oxidation ... );0 Deliberate changes of set-point;Feedforward strategy acts on manipulated variables, mainly reagent addition, to attenuate the effect of disturbances such as changes of feed rate and grade. The feedforward strategy is driven by measurements of disturbances. Feedback control acts to compensate unmeasured disturbances, such as ore floatability, and to bring process variables to targeted set-points of concentrate or tails grades. The feedback control action is driven by set-point error, caused by either a deliberate change of set-point or unaccounted disturbances.This paper proposes a way to improve feedforward control schemes by addition of a simple model of solids transportation. The feedforward strategy considered in this paper is of ratio type, i.e. the manipulated variable is changed according to a predefined ratio between this variable and the measured disturbances. A typical example is the ratioed reagent addition to mass flow of ore."

Jan 1, 1993

By Larry A. Haas

The Bureau of Mines constructed a torsion effusion apparatus to measure the equilibrium vapor pressure of pure metals, alloys, and compounds at temperatures up to 1,500° K. The reliability of the apparatus was established by determining the vapor pressure of silver. The data obtained on solid and liquid silver in the temperature range 1,200° to 1,500° K can be expressed by the following equations:

Jan 1, 1965

By Wittenberg J. C, Reid A. F

A method is described for the rapid and effective production of polished section mounts of ore and mineral particulates to the standards required for automated image analysis. This requires mounting without segregation of particles by mass or density, and it is also preferable to avoid having particles in contact so that they can be recognised as individuals. To achieve this, the particle samples are first split to an appropriate degree in a rotary riffle, and the sub-sample mechanically diluted and thoroughly mixed with an inert filler of the same size range as the particles. Just sufficient epoxy resin is added to make the mixture fluid. During setting, the ore particles are mechanically supported by the inert filler particles, thus maintaining the particles in a random three-dimensional distribution. A rapid two-stage grinding process, based on the successive use of 600 mesh silicon carbide and 1200 mesh (10 um) corundum on cast iron plates, is followed by three stages of mechanical diamond polishing on cloth laps. Hand polishing is entirely avoided, as is the use of papers.

Jan 1, 1984

By Paul D. Tomlingson

During the next several months, SME’s E-Newsletter will feature 15 articles on maintenance management. The articles may be read online or downloaded and distributed within your organization. They will address maintenance management topics, offer guidelines to mining managers and provide techniques that the maintenance manager can use. The articles will stress equipment management, a strategy that the mining industry has accepted as a modern replacement for outdated maintenance practices. Equipment management is the mutually supportive interaction of all mine departments as they establish equipment needs, procure equipment, test, commission, operate, maintain, modify and eventually replace equipment. The successful application of equipment management principles can quickly and reliably produce cost reduction and performance improvement results while providing a dependable way of sustaining them. Equipment management embraces modern management techniques. These include reliability-centered maintenance, life-cycle costing, capital performance, the effective use of information and productive organizational models.

Jan 1, 2003

By Samuel Frimpong

The interaction of oil sands with a ground articulating pipeline (GAP) system has been simulated with the dynamic model established in this work by combining the multi-body and soil dynamics with the Automatic Dynamic Analysis Mechanical Systems (ADAMS) software. Mathematical models governing the interaction of the GAP system with the oil sand terrain have been modeled based on the theory of multi-body and soil dynamics. These models consist of GAP track-oil sand contact model for generating the contact force between oil sands and track and load-deformation oil sand model for capturing the dynamic behavior of oil sands. A virtual prototype has been created and simulated in the ADAMS environment. The simulation result of the effect of load on oil sand deformation indicates that maximum deformation value increases non-linearly with load varying from 0 to 60t. This study provides a solid foundation for further research and the GAP technology development.

May 1, 2004

By Herbert Clark Hoover, Lou Henry Hoover

As stated in the preface, the nomenclature to be adopted for weights and measures has presented great difficulty. Agricola uses, throughout, the Roman and the Romanized Greek scales, but in many cases he uses these terms merely as lingual equivalents for the .German quantities of his day. Moreover the classic language sometimes failed him, whereupon he coined new Latin terms adapted from the Roman scale, and thus added further confusion. We can, perhaps, make the matter dearer by an illustration of a case in weights. The Roman centumpondium, composed of zoo librae, the old German ceniner of 100 pfundt, and the English hundredweight of 1112 pounds can be called lingual equivalents. The first weighs about 494,600 Troy grains, the second 721,900, and the third 784,000. While the divisions of the centumpondium and the centner are the same, the Libra is divided into 12 unciae and the pfundt into 16 unizen, and in most places a summation of the units given proves that the author had in mind the Roman ratios. However, on p. 509 he makes the direct statement that the centumpondium weighs 146 librae, which would be about the correct weight if the centumpondium referred to was a ceniner. If we take an example such as " each centumpondium of lead contains one uncia of silver", and reduce it according to purely lingual equivalents, we should find that it runs 24.3 Troy ounces per short ton, on the basis of Roman values, and 18.25 ounces per short ton, on the basis of old German. If we were to translate these into English lingual equivalents of one ounce per hundredweight, then the value would be 17.9 ounces per short ton. [ ]

Jan 1, 1950

By H. C. Howarth

The preliminary tests referred to in this report wore made at the Bureau's Experimental Mine under the general supervision of G. S. Rice chief mining engineer, to determine whether rock dust way be used to extinguish or control mine fires. DESCRIPTION OF THE DUST USED The dust used for application by hand was made from draw slate taken from the Experimental Mine. This draw slate was crushed in a hammer-type crusher fitted with 1/16 inch by 2-inch slotted screens. A sizing test of the dust showed 96.5 per cent through 20 mesh, 69.4 per cent through 48 mesh, 46.2 per cent through 100 mesh, end 33.5 per cent through 200 mesh.

Jan 1, 1927

By Ali Nazem, Rennie Kaunda, Zoheir Khademian, Fei Wang, Raymond Henn, Alex Peretiatkol

"The field demonstration portion of the Underground Grouting and Ground Improvement (UG&GI) short course offered by the Colorado School of Mines was held on May 18, 2016 at Baski Inc.’s Yard in Denver, CO.Numerous full field scale demonstrations of grouting methods and equipment were conducted under various field conditions. As part of these field tests, permeation grouting testing and demonstrations were also conducted. Various cement grout mixes were injected into 1.5-m (60-in.) tall transparent sand columns under controlled conditions (Fig. 1). The objective of the sand column permeation grouting demonstrations in the study was to show students the effects of ordinary Portland cement versus ultrafine cement on the engineering properties of the grout, and the permeation height through various types of soil stratigraphic layers in the sand columns. Similar previous demonstrations have had a specific focus on various brands of Type I-II Portland cements and ultrafine cements with a range of water cement ratios and injection pressures. More detailed information about these previous studies can be found in published proceedings (e.g. Henn et al., 2009 -2011).Equipment and material usedThe five clear plastic sand columns were 191 mm (7.5 in.) inside diameter and 1,524 mm (60 in.) tall. Each sand column had a 19 mm (0.75 in.) diameter hole drilled at the base (bottom) of the blind flange for injection of the grout. A perforated plate and/or screen at the base of the sand columns helped to prevent sand from plugging injection port. A ChemGrout grout plant was used for the demonstration consisting of 0.36 m3 (97 gal) high shear (colloidal) tank mixer, a 0.36 m3 (97 gal) agitator tank and a progressive helical cavity pump with maximum output capacity of 77 L/min (20 gpm) at a maximum discharge pressure of 265 psi (18 bar) (Fig. 2). A simple grout header arrangement consisting of control valves, pressure gauges, flow meter, grout delivery and return line, and a short injection line was also custom built. Also used were infra-red thermometers to measure the temperatures of the grout mix batches, CRD and marsh funnels to measure viscosity, baroid mud balance to measure specific gravity, and a digital scale to measure weights. The grout materials used were Holkim Portand cement (Type I-II), Nippon Steel Sumikin superfine cement and U.S. grout ultrafine cement."

Mar 1, 2017

By Andrea Koschinsky, Sophie Paul

"INTRODUCTIONOnce again deep-sea mining has been receiving a lot of attention in recent years. Industrial and political advancements also call for environmental baseline studies and analyses to aid the development of standards and monitoring protocols. As part of the EU research project “JPI Oceans: Ecological Aspects of Deep-Sea Mining”, the RV Sonne cruise SO242 to the Peru Basin revisited the DISCOL area that had been artificially disturbed in 1989. This offered the unique opportunity to study a deep-sea site 26 years after a disturbance similar to manganese nodule mining had been carried out (Figure 1). A comparison of a variety of undisturbed and disturbed sites shed light on the re-establishment of a geochemical equilibrium and a range of baseline values. This information can help to inform standard development for monitoring and mining purposes.Heavy metal data and its applicationResearch findingsDuring the cruise, disturbed and undisturbed surface sediment was sampled. The pore water analyses show that the 26 years old disturbance is not visible in the metal profiles and that the pore water reaches equilibrium through diffusive fluxes relatively quickly. The sediment, however, shows some differences between disturbed and undisturbed sites in the upper 20 cm, even after 26 years. Lower concentrations in the usually manganese-oxide rich top layer, variations and “unnatural” peaks in the manganese profiles, for example, suggest removal or mixing of the top layer (Figure 2)."

Jan 1, 2017

By T. A. Lang

Concepts and equations have been developed to quantitatively determine the stability of a rock bolted coal mine roof as a structural (beam-arch) member consisting of reinforced rock units. The equations take into account: rock bolt tension, length, spacing, and orientation; size of opening, strength and physical properties of the rock; and loads from distressed rock, and were critically reviewed using sensitivity analyses and the results available from relevant previous analytical and physical model investigations. It is concluded that they can essentially be validated by using small scale physical models and the full size mine entry model at the USBM Spokane Research Center. However, a comprehensive research program, including analytical and laboratory investigations and field trials in typical mines, will be required to define and validate criteria and standards for using the equations as a basis for a rational design code for rock reinforcement installations to replace the semi-empirical rules now being used. For example, these studies have shown that the practice of installing vertical roof bolts with a uniform spacing equal to the bolt length is inherently unsafe and that the spacing should be reduced near the walls to prevent shear failure of the roof strata. The development of such a rational design code would provide enhanced safety in coal mining operations and warrants a high priority in the Bureau's ground control research program.

Jan 1, 1981

By William C. Cooley

A literature search and survey were prepared on the technology of surface hydraulic mining, with particular reference to its possible use in the United States forstripping overburden from surface coal mines. Extensive use was made of Russian references which were translated into English. The advantages and disadvantages of hydraulic mining and hydrotransport are identified as well as criteria for selecting potential applications. At present, the major U.S. application is in the phosphate industry of Florida and North Carolina. Potential locations for hydraulic stripping of overburden from coal seams are identified in the states of Alaska, Illinois, Montana, Washington and Wyoming. Other potential applications include the hydraulic mining of peat in Minnesota, and the stripping of overburden from lignite in Texas, Montana, North Dakota and South Dakota. Further research is recommended, particularly on the subject of dewatering of fine clay slimes to avoid water pollution and to permit rapid reclamation of mined areas.

Jan 1, 1976

By C. Clark, J. Seymour, D. Benton

"National Institute for Occupational Safety and Health NIOSH is conducting research on jackleg use and related accidents in underground metal mines. This paper provides an analysis and overview of jackleg drill usage, accidents, operational characteristics, and alternatives, based on information from injury reports, legacy research, stakeholder input, and published literature. Jackleg drills are involved in more ground fall accidents in underground metal mines than any other drill. Jackleg-related injuries are most prevalent at the face in the course of installing initial ground support. Alternatives to jacklegs for drilling and bolting under incomplete support in narrow underground openings are not yet available. Small mechanized bolting equipment needs to be developed to address jackleg-related accidents and improve safety at mines where jacklegs are being used. JACKLEG DRILL Description The term “jackleg drill” is a generic name for a class of handheld, rotary, percussion rock drills that are equipped with an attached reaction leg to provide stability and thrust for the drill (Figure 1). All of the drill and leg controls are located near the operator’s handle at the rear of the head portion of the drill. Jacklegs are classified according to the bore size of their pneumatic pistons which normally range from 6.03 to 8.26 cm (2.375 to 3.25 in) [Kurt, 1982; Clark, 2012]. Jacklegs typically weigh 460 N (103 lbs), but their weight can approach 535 N (120 lbs) after they are fitted for operation with drill steel and air and water hoses [McKibbin and Clark, 2001]. In underground mines, jackleg drills are commonly used to drill 3.8-cm (1.5-in) diameter holes 1.83 m (6 ft) deep in rock. Application The jackleg drill is primarily used in underground mines when the size of the ore body, the ground conditions, or the mining method do not permit large openings to be mined using mechanized equipment (e.g., narrow vein mining). Jacklegs are used to drill blast-holes for explosives and also holes for installing ground support. These versatile drills are used in nearly all phases of mining including exploration, development, production, and maintenance [Kurt, 1982; Williams et al., 2007; Chen and McKinnon, 2012]. The jackleg is used to drill holes in rock using drill bits attached to hollow steel bars called drill steels (rotary percussion drilling). After the hole is drilled, the jackleg can be used to install different types of ground support components, depending on the ground conditions and the specific ground support measures that are needed. For example, the jackleg can be used to install expansion-anchor rockbolts or resin-grouted rockbolts using the drill’s rotary-motion feature. On the other hand, the jackleg can also be used to install friction-type Split-Set™ rockbolts using the drill’s percussion (hammer-motion) feature. As shown in Figure 1, various washer-like bearing plates can be installed along with these bolts to provide additional ground support and to help secure surface control products, such as wire mesh and shotcrete that are in turn used to retain small, loose material between the bolts [Clark, 2012]."

Jan 1, 2016