Search Documents

By C. H. Lee, T. T. Wang

"Exampling of the tunneling task in the Tsengwen Reservoir Transbasin Diversion (TRTD) in southern Taiwan, this study investigates the application of the Drilling Survey System (DRISS) in both Drilling and Blasting (D&B)- and Tunnel Boring Machine (TBM)-excavated sections. In the D&B section, a nonlinear relationship exists between drilling energy and uniaxial compressive strength of rock mass, in which a reasonable coefficient of determination can be analyzed statistically. Additionally, the DRISS accurately predicted an unfavorable section with a valuable position. The magnitude of uniaxial compressive strength back calculated using DRISS data also matches those acquired from geological investigations with different approaches. Study results indicate that the DRISS is an effective tool for fore-probing of both D&B- and TBM-excavated tunnels. INTRODUCTIONModern advancements in geological and geophysical investigations, and drilling techniques, have provided valuable information for detecting and interpreting geological conditions of rock tunnels with a resolution of several to ten of meters (Brückl et al., 2001, 2008, Lorang et al., 2005). Nevertheless, construction risks remain considerable during tunnel excavation, especially when a tunnel was excavated by a Tunnel Boring Machine (TBM). Predictions of the local fault, shear zone, and other minor geological features, which may cause moderate collapse or excessive deformation of rocks surrounding the tunnel, before tunnel excavation is highly desirable for high-quality tunnel construction and economically efficient project management.Rather than conventional geophysical prospection methodologies, which always favor large-scale investigation with moderate precision, this study focuses on the drilling method probing ahead of a tunnel. The goal of such an investigation is not only to prevent catastrophic collapse, but also to provide quantitative or semi-quantitative information for estimation of the mechanical parameters of rock mass.For the tunneling task in the Tsengwen Reservoir Transbasin Diversion (TRTD) in southern Taiwan, a drilling survey system is adopted for fore probing. Data collected from both drilling and blasting (D&B) and TBM-excavated sections are analyzed statistically and discussed. The applications of the Drilling Survey System (DRISS) are addressed accordingly."

Jan 1, 2015

By R. M. de Carvalho

Empirical and phenomenological models of SAG and AG mills have dominated the scene for the last few decades, being used nearly every time a mill is scale-up or an attempt is made to improve its performance. However, in spite of their success, these models fail to describe the details of both the grinding environment and the breakage mechanisms. The result is a generally good track record, with a few ? but very important ? instances when these models fall short in their predictions, which can be very costly. Further, nearly all of these models require detailed calibration to industrial and pilot plant data, being costly in their application, although still with limited predictive capabilities. Recognizing these challenges, a new model framework has been proposed which overcomes the limitations of currently used models by coupling the microscale population balance model, the discrete element model and functions that describe internal classification at the mill grate. This model framework has already been applied to describe breakage in ball mills, with showing very promising results. However, in the case of SAG and AG mills a much greater level of complexity is involved in the model, given the interaction between the mechanical environment that is formed totally or, in part, by the ore itself, and the breakage response in the mill. The paper describes the model framework, demonstrating how it can address appropriately effects such as mill speed, mill filling and size distribution, on the response from the mill. Some of the advantages of the model are related to its intrinsic multi-component and dynamic nature, which allows simulating appropriately mixtures of ores of different competences in a transient manner.

Jan 1, 2012

By M. L. Jeremic

The design of the long-hole sublevel mining method was originally based on the traditional assumption that the principal load was due to the weight of the overlying rock, and that the horizontal stresses are equal to one-third of the vertical stress. However, as mining progressed, the virgin lateral stress was found to be equal to or greater than the vertical stress. The virgin stress in the rock mass is not uniform throughout the folded orebody and adjacent strata. From detailed investigations, three basic patterns of virgin stress in ore panels have been inferred: uniform, bent and twisted. Stresses induced by stoping are up to three times greater than original stresses in the rock mass; they cause heavy ground conditions and make extraction of ore difficult. In the last ten years, the original mining system has been modified several times in order to destress the ground and improve the extraction of ore.

Jan 1, 1978

By Lorna Ortiz-Soto

A series of titiania- and silica-supported Au, Pt and Pt-Au catalysts prepared through different synthetic routes have been investigated in terms of their structural properties, adsorption of CO, and catalytic activity for the selective catalytic reduction of NO by propylene and the oxidation of and CO. Catalysts prepared by incipient wetness impregnation from individual Pt and Au precursors, exhibited characteristics very similar to those of monometallic Pt catalysts. This behavior is consistent with a model in which the two metals remain segregated due to their miscibility gap, and only Pt participates in the adsorption of CO and the reactions under consideration. In contrast, catalysts prepared from a Pt2Au4(C=CtBu)8 organo-bimetallic cluster precursor exhibited different behavior both in terms of CO adsorption and their catalytic activity for the three reactions examined. The combination of the kinetic, spectroscopic and structural characterization data suggests that in this case Pt and Au remain intimately mixed in the form of Pt-Au bimetallic particles, and that the presence of Au modifies the behavior of Pt.

Oct 1, 2003

By A. Lopez-Valdivieso

Particle size enlargement processes play an important role in solid/liquid separation, and in beneficiation unit operations. In the latter, not only the size of the formed aggregates but also their surface properties are very important. Oil agglomeration has a special place among such processes: it is a selective process in which hydrophobic particles are agglomerated into hydrophobic agglomerates which can be recovered by flotation. This explains the broad applications of oil-assisted beneficiation processes not only in the beneficiation of fine coal, but also in agglomerate flotation of many different types of ores, and in coal/gold agglomeration.

Jan 1, 2004

By A. A. Brant

ONE of the reasons advanced for the decline in prospecting and discovery is that, as regards surficial examination, the law of diminishing returns is becoming applicable. Fewer surficially unprospected fields remain; therefore, fewer discoveries by such means result. Much in the nature of mineral resources remains to be unearthed, but even now, and more so in the future, will discovery depend on painstaking petrographic and structural mapping, aided, where necessary, by judicious applications of all the complementary scientific knowledge and devices (e.g., thin section microscopy, geophysics, and drilling) that experience proves effective in localizing a mineral deposit even beneath drift, lake, or muskeg. It is to be expected, then, that the rate of discovery will decrease, that the cost per discovery will greatly increase, and that the work of discovery will become more and more the careful, methodical assembling of field data, conscientiously interpreted on the basis of scientific knowledge by trained, experienced operatives. In view of these trends, the status of applied geophysics to Canadian mining exploration and development work might well be reviewed. The niche which geophysics may occupy relative to geological surveying and drilling has been clarified by the last twenty years' experience. The cloud of somewhat justifiable scepticism that followed the 'geophysical promotion' period of the late 1920's has lifted. Mining, exploration, and finance companies, in open-minded fashion, are seeking sound advice as to what are the scope and limitations of the geophysical methods at present practised. The purpose of this paper and the following one is, therefore, as far as lies within the author's power, to review briefly the geophysical methods at present in practice in Canada, and, at greater length, to joint out impartially and critically their scope, merits, shortcomings, an possible future development. The treatment will be non-technical, the hope being that an accurate statement of the present status of geophysics in Canada may do much to result in a sounder, saner growth of what, in the future, shall undoubted} y prove an increasingly useful tool in exploration and development work. ?

Jan 1, 1942

By Graham A. Davis, Michael Samis

The dramatic fluctuation in metal and energy prices in the last few years is causing mining companies to consider alternative analytical methods for mine design and valuation. The goal is to improve insight into unforeseen changes in the economic and project environment and to design projects that take advantage of management's ability to respond to these changes. Such flexibly managed projects will contain value that cannot be measured using traditional engineering economic approaches, further motivating the used of alternative, modern valuation methods. This paper considers the valuation of an uneconomic low-grade resource at an open pit gold mine using two of the most popular modern valuation methods, Dynamic Discounted Cash Flow and Real Options. Our analysis demonstrates that the conventional valuation method may incorrectly represent the value and risk attached to mining this type of resource because it is unable to recognize management's ability to respond to future events in a manner that minimizes losses and exploits advantageous business conditions. The results of this paper highlight the importance of recognizing flexibility and business uncertainty in both mine design and valuation.

Jan 1, 2003

By P. Duran

The metallurgical gas handling system at Chagres Smelter, like that of many smelters, can be the limiting constraint to processing more concentrate through the smelter. Mass and energy balances for the metallurgical gas handling system processing off-gases from the flash furnace and Peirce-Smith converters have been used by both operations and process engineering groups to help evaluate different operational scenarios in which the use of the installed capacity could be maximized and/or an operational strategy can be change with the purpose of removing a bottleneck or justifying an investment to relieve a constraint in the gas handling system. The present work describes the development of these process balances that were carried out in Exce®. The results were validated with operational data and, subsequently, some cases of industrial interest were simulated, detecting some conditions that were limiting the operation due to the present installed capacity in the Chagres Smelter.

Jan 1, 2007

By M. I. Kalashnikova, Y. M. Shneerson, E. E. Zhmarin, Y. V. Degtiarev, E. M. Vigdorchik

Separation of a magnetic fraction from nickel concentrate following matte flotation, and its treatment in a separate circuit enable reduces precious metals losses. The magnetic fraction is treated in two stages of oxidative leaching: atmospheric and pressure leaching. A study of the atmospheric stage, using mathematical modelling, is described in this paper. The mathematical model and experimental data were used to carry out industrial process calculations. The model enabled extrapolation of the results of batch laboratory test to industrial-scale continuous processing and the selection of optimal process conditions and large-scale equipment. In December 2004, commercial oxidative leaching tests were performed on the magnetic fraction at the Severonickel Plant (Monchegorsk, Russia). A comparative analysis of the mathematical modelling results and the actual process parameters is presented.

Jan 1, 2005

By M. S. Badollet

"IntroductionAsbestos as received by the manufacturer of asbestos products is •in the •form of either crudes or milled fibres processed to different degrees of texture. Frequently, the manufacturer finds that l:ihe fibres as he buys them are not adaptable to his plant processes, and, therefore, it is necessary for him either to contact the mine supplying the material and request a specific texture for the :fibre or to reprocess the fibre in his own plant.When the mine or mill manager is requested to change his milling equipment to produce a special grade of fibre with a specific texture, he would like to comply. However, if he began to make special fibre grades for each customer, he would be in the position of constantly rearranging his milling technique, adding more equipment, or building a new mill. In the end, his mill would he producing hundreds of different fibre grades of varying degrees of texture, which is a difficult accomplishment if he desires to maintain any quantity of production."

Jan 1, 1950

Between 1993 and 2003, a series of AG and SAG mill pilot plant trials were conducted using Hardinge Ical pilot plant scale SAG mills on numerous ore samples and ranging across a wide variety of operating conditions. The data from these tests were used to evaluate the design of SAG and AG mill circuits for over a dozen projects, of which about half were eventually constructed and commissioned. The data were also used in the development of SAG mill modelling, scale-up and simulation procedures by several consultants who had access to part of the data set. Recently, we have had the opportunity to bring this data together and further analyse the consolidated dataset. This paper reports on the outcomes of this analysis that has identified the impacts of different AG/SAG circuit flowsheets and operating conditions on energy efficiency and operating cost.

Jan 1, 2012

By R. M. Berry

A brief outline of refining methods used to (1) upgrade yellowcake to nuclear purity and (2) convert the uranium to the chemical and physical forms required by the fuel fabricators is presented. The uranium hexafluoride (UF6) production facility now under construction at Eldorado, Port Hope, is discussed. Technological improvements in uranium refining are considered.

Jan 1, 1969

By A. Pawelczyk, D. Hreniak, E. Zych, W. Strek, K. Grabas, A. Ostrowski

"Mongolia is a country rich in rare earth resources. In the experiments carried out samples of the Mongolian ore were processed to obtain a lanthanide concentrate. The concentrate underwent hydrometallurgical processing. At the same time radioactive elements were removed. The lanthanides were obtained in the form of hydroxides that were further processed in order to get concentrated products. As a result cerium, lanthanum and neodymium-praseodymium concentrates were separated in the process. Also a concentrate of remaining elements: samarium, europium, gadolinium, terbium, dysprosium, holmium and erbium was obtained. INTRODUCTIONAccording to the assessment of the US Geological Survey, Mongolia possesses 16.77 % of the world total rare earth (RE) resources (Daly, 2011); that is the second largest RE reserve in the world, estimated to be 31 million tonnes in terms of rare earth oxides (REO). In the face of Chinese RE trade restrictions, Mongolia emerged as an important economical partner in mining and exploitation of these critical raw materials. This country is recognized as having more than five large RE deposits in the southern provinces. The most important are Lugeengol (Lugin Gol), Mushgia Khudag, Khotgor and Khalzan Buregtei (Eurasia, 2010). The Mongolian government has taken measures to facilitate western investments, nevertheless the country is economically dependent on China, the basic trading partner, particularly where exports are concerned.In the late 1970s Hydromet Kowary Enterprise, Poland, took up, along with the Wroclaw University of Technology, research and technological study on lanthanides recovery from raw materials of Vietnamese and Mongolian origin and from Indian monazite sands (Kowalczyk, 1990; Kowalczyk & Mazanek, 1987; 1990). For that purpose, a rare earth processing plant had been constructed with the capacity of about 10 t/year of hydroxide concentrate. The facility included several technological operations like grinding, flotation, hydroxide concentrate production in the hydrometallurgical processing, particular RE separation, and production of commercial products in form of CeO2, La2O3, Nd2O3, Pr2O3, and misch metal. Additionally work had been carried out in Kowary on the manufacture of yttrium and europium oxides of high purity, which were intended for color TV picture tube production in Poland."

Jan 1, 2012

By A. J. Baer

"DEFINITION OF THE REGION AND ITS BOUNDARIESTHE EXPOSED PART OF THE GRENVILLE PROVINCE is the southeastern part of the Canadian Shield, characterized by crystalline rocks with K-Ar ages of about 1,000 million years. Its Canadian portion is bounded on the southwest by Georgian Bay •and by Paleozoic sediments south of a line passing through Orillia and Kingston, on the southeast by the St. Lawrence River valley and the north shore of the Gulf of the St. Lawrence, on the east by the coast of Labrador and on the northwest by the Grenville front, a linear tec-tonic feature that is a metamorphic transition zone and/or a fault. Rocks located to the southeast of the front have younger K-Ar radiom€tric ages than rocks located to the northwest of it.The region is formed of complexly deformed and highly metamorphosed crystalline rocks and in part differs from other areas of the Canadian Shield by the presence of large amounts of crystalline limestone and bodies of anorthosite."

Jan 1, 1970

By W. Lin, Z. Z. Dong, C. L. Zhou, Y. C. Kuang

The inversion of rock mechanical properties based on well-logging data is a common method to drillbit selection in petroleum engineering, the basic principle of which is to use deep-well logging data and experimental regression model to calculate rock mechanical properties. The profile of rock mechanical properties can be established. According to the profile, the type of drillbit can be selected in different formations, which will improve the economic benefit of bit use indicators. Compressive strength of rock is one of the most important parameters. Conventional method to establish regression models of acoustic velocity and uniaxial compressive strength is on the basis of rock core sonic experiments and uniaxial compressive experiments. However, with the increase of deep drilling operation, triaxial compressive strength prediction model will play a more vital role in drillbit optimization selection in deep wells and improving ROP (Rate of Penetration). Triaxial compressive strength is an important parameter to evaluate the formation strength property. In this paper, to the sandstone commonly encountered in oil drilling, combined the rock mechanical experimental results with the changing porosity experimental results under confining pressure, a new interpretation model of triaxial compressive strength based on well logging data is proposed. Firstly, three types of sandstone samples are collected. Then measured components, uniaxial compressive strength, triaxial compressive strength and porosity. Experimental results show that: confining pressure has a significant influence on sandstone strength, with the increase of confining pressure, triaxial compressive strength increase; furthermore, the triaxial compressive strength of different porosity sandstones have different change rules when confining pressures changes; sandstone porosity decreases with the increase of confining pressure and it obeys logarithmic function. According to the results, regression models of sandstone, in-situ uniaxial compressive strength model and uniaxial compressive strength model under normal pressure are generated. Meanwhile, using well logging data in the acoustic velocity, density and gamma value can derive in-situ rock formations uniaxial compressive strength and in-situ porosity. Eventually, a new model established in this paper, containing in porosity, uniaxial compressive strength, lateral pressure and power exponent of regression, can predict triaxial compressive strength which will guide drillbit selection.

Jan 1, 2015

By E. J. Wasp, T. L. Thompson, T. C. Aude

The paper will deal with some of the more important technical aspects of slurry pipelines as they apply to the mineral field. In addition, the use of these technical concepts in arriving at realistic economic figures will be discussed.

Jan 1, 1970

By C. Dragusanu, J. Sims, J. Connolly

Based on a statistical analysis of the categorical and numerical data from the established geological model, a geochemical classification of mineralization has been shown to be objective in nature and correlated to the envisioned metal extraction process. Multivariate chemical classification has the potential to discriminate within a combined response from different types of alteration and metal abundances. Distinct domains of chemical response determined by clustering analysis were used as a validating criterion for a geologically driven metallurgical testing program. The groups established are spatially linked to the geological process responsible for their genesis, providing clarity in geometallurgical and resource modeling.

Jan 1, 2011

By A. Kowalski

Telvis Limited, manufacturer of an emergency communication dispatcher's broadcasting system, now introduces the possibility of a remote software upgrade to its devices. The paper presents methods, features and ways to accomplish this task. It describes the mechanisms used and the opportunities that arise from the use of this type of functionality. The mechanism software update presented applies to devices on the surface and in underground areas of mines. The electronics used currently allow the use of remote software updates, but the mining equipment makes little use of these methods. This paper aims to start the discussion on this topic and tries to lay the path of development by showing one of the first examples of the application.

Aug 1, 2013

By Jean-Guy L. Gauthier

"With the Ontario Ministry of the Environment stipulating that the cumulative concentration of copper, lead, zinc and nickel in mine mill effluent must be no greater than 1.0 milligram per litre, it has become necessary for the mining industry of find some form of treatment for the removal of heavy metals from effluent waters.To comply with these guidelines, it became necessary for Mattabi Mines Ltd., which is situated 50 miles Northeast of Ignace in Northwestern Ontario, to develop a compact, cost effective and technically sound treatment process to remove heavy metals from their tailings overflow. A design committee consisting of mine metallurgists, environmental engineers, a Dutch research and development team and the equipment supplier engineering staff was set up to accomplish this.Using some new and innovative wastewater treatment equipment, the guidelines established by the Ontario Ministry of the Environment can now be met. The sludge produced from the precipitated heavy metals is sent directly to the concentrator, thus eliminating the danger of re-dissolution of the metals in a landfill site, while recovering some of the valuable metals that would otherwise be wasted in a sludge landfill."

Jan 1, 1980

By C. G. Anderson

As the global demand for copper and gold steadily increases and the need for environmentally sound processing also grows, successful hydrometallurgical treatment of enargite (Cu3AsS4) concentrates has come to the forefront. This type of concentrate contains considerable arsenic so that successful arsenic fixation, for example as scorodite, is of the essence. This paper outlines the successful application of low temperature and low pressure nitrogen species catalyzed (NSC) hydrometallurgical pressure oxidation of enargite concentrates. The successful stabilization of the arsenic as an iron arsenate compound is discussed. Also, the use of experimental design software is highlighted as a process application and optimization tool.

Jan 1, 2006