Search Documents

By Ray Brainard, Adriana Ventimiglia, Amanda Kerr

Preliminary design is underway for a new Southern Nevada Water Authority (SNWA) project that will ensure one of America’s most reliable water systems by providing continued, reliable water service to existing and future customers. The Horizon Lateral is a $1.6 billion water transmission pipeline that includes 7–10 miles of 108-inch finished diameter rock and soft-ground tunnels. The tunnels will traverse volcanic rock in or around the McCullough Mountain Range and the surrounding alluvial basin. The tunneling community will find relevance in hearing about this critical infrastructure project from a leading wholesale water utility owner with a proven track record for on-time, collaborative projects.

Dec 1, 2022

By Robert Stefanko

The most perplexing problem that has confronted mining engineers since the dawn of mining has been strata control. For the purposes of this paper, strata control will be defined as control of ground in the immediate area surrounding the, mine opening. To prevent movement of the surrounding strata into underground mine openings, miners have traditionally relied upon some type of artificial supports placed within the openings and located in a manner determined by trial and error from previous experience. Without the means to measure changes of stress in the supports and within the mine structure itself, an evaluation of the efficiency of the supports and mining system was impossible. Strata control thus remained an art with very little application of science. During recent years a revolution has occurred in mining. The modern mining engineer is contented no longer-with trial and error methods but is utilizing all the technological information at his command to obtain a solution to this age old problem. However, serious problems have arisen due to the lack of certain basic knowledge in three important areas: 1, The original stress distribution within the earth strata prior to mining. 2, Redistribution and concentration of the original stresses with mining activity. 3. The properties of rock that are significant in failure and its prevention.

Jan 1, 1960

By Bruce H. Mason

Lightweight aggregates are classified as those minerals, natural rock materials, rock-like products, and byproducts of manufacturing processes that are used as bulk fillers in lightweight structural concrete, concrete building blocks, precast structural units, road surfacing materials, plaster aggregates, and insulating fill. Other uses include architectural wall covers, suspended ceilings, soil conditioners, and other agricultural uses (Mason, 1989). One unusual agricultural use recently reported was for bedding on a crocodile farm on the south coast of Natal. It seems that female crocodiles became upset because there was no vermiculite in which to lay their eggs due to the late arrival of a consignment of vermiculite. The vermiculite was being used as a substitute for river sand to nest crocodile eggs (Griffiths, 1989). The various lightweight aggregate materials may be classified into four groups as follows: 1. Natural Lightweight Aggregate Materials-prepared by crushing and sizing natural rock materials, such as pumice, scoria, tuff, breccia, and volcanic cinders. 2. Manufactured Structural Lightweight Aggregates-prepared by pyroprocessing shale, clay, or slate in rotary kilns or on traveling grate sintering machines. 3. Byproduct Lightweight Aggregates-prepared by crushing and sizing foamed and granulated slag, cinders, and coke breeze. This group of lightweight materials, with the exception of slag, has become less significant and will not be discussed in this chapter. Other lightweight aggregates are beginning to appear in the marketplace. Some are the result of manufacturing processes on industrial byproducts and/or waste products, such as fly ash and incinerator residue (Bigner, 1992). 4. Manufactured Insulating Ultralightweight Aggregates-pre- pared by pyroprocessing ground vermiculite, perlite, and diatomite. The application of diatomite in brick and in extruded and aggregate forms has declined in recent years (Kadey, 1983) and will not be considered in this chapter. Lightweight aggregates for structural concrete and concrete masonry units, according to the American Society for Testing and Materials (1986) consist of "aggregates of low density used to produce lightweight concrete, including: pumice, scoria, volcanic cinders, tuff and diatomite; expanded shale, clay, slate, perlite, vermiculite or slag; and end products of coal or coal combustion" (Mason, 1989). Lightweight aggregates are distinguished from other mineral aggregate materials by their lighter unit weights-1 281 to 1 602 kg/m3 or less for loosely packed lightweight aggregates-as com- pared to 2 002 kg/m3 or more for crushed stone, sand, gravel, air-cooled slag, and other common mineral aggregates. The specific gravities of these lightweight aggregates are also used to classify them for use in concrete; they range from the extremely light materials, used for insulative and non-structural concrete to expanded shale, clay, slate, and slags used for structural concrete. Vermiculite and perlite are sometimes referred to as super light- weights. Insulating concrete (non-load bearing) weighing as little as 240 kg/m3 can be made with these aggregates. Natural aggregates such as pumice, pumicite, and scoria are normally made into concrete weighing about 400 to 480 kg/m3. Expanded shale, clay, and slate produced in a rotary kiln make structural concrete ranging from 1 201 to 1 842 kg/m3. Expanded shale and clay produced by sintering make concrete that ranges from 1 442 to 1 922 kg/m3. Air-cooled slag produces concrete ranging from 2 162 to 2 403 kg/m3. The low density lightweight aggregates are used primarily for insulating purposes. They have relatively low compressive strength. The middle density aggregates are used for insulation and for fill. Those at the upper end develop excellent compressive strength and are used in many structural applications (Anon., 1971). In recent years, the production of lightweight aggregates in the United States for all uses (including insulation and construction materials) has averaged about 19 Mtpy (Table 1). The production and consumption of lightweight aggregate is closely tied to the fortunes of the construction industry and the need to construct energy efficient buildings. Recent years have seen the production of lightweight aggregate approach the levels of the early 1970s. The period of 1979 to 1981 was a low point in production levels. The low levels of production were caused by significantly higher plant energy costs due to the large amounts of fuel and energy used in the production of most types of lightweight aggregate. Lower levels of construction activity also affect production levels. This chapter focuses on the use of natural lightweight aggregates and manufactured insulating ultralightweight aggregates, and on both the production and use of manufactured structural light- weight aggregates. Some additional comments are made on byproduct materials. Separate commodity chapters on vermiculite, perlite, pumice, and volcanic cinders are elsewhere in the volume. Discussion of the commodities covered elsewhere in the book will be limited to observations on their utilization and relation to other lightweight aggregate materials.

Jan 1, 1994

By T. Cyrul

The Polish underground mining has its long lasting tradition. High production of coal, that has recently been approaching 200 milion tons per year, put this small country among the bigest world producers of coal. To achieve such a high production, which mainly originate from very unfavourable mining and geological conditions, Polish scientists and engineers have to introduce new and original solutions to the mining practice. Many of the solutions on mining methods, ventilation, stability, subsidence etc., have had the world wide reputation, however, insufficient translations from Polish cause , that many of the recent Polish mining achievements are not known to foreign specialists.

Jan 1, 1986

"The use of gas, temperature and airflow sensors to monitor mine ventilation atmospheres offers numerous safety and operational bene-fits to mines. Detection of dangerous gases, changes to airflows and temperature variations are some of the obvious benefits of using at-mospheric sensors in mines. The prediction of atmospheric conditions between sensors however is potentially difficult, and gaining full cover-age a mine will require either many sensors or a method of extrapolat-ing and predicting atmospheric conditions between and downstream from a sparser array of sensors. A dynamic simulation computer model technique is demonstrated to predict time based changes to atmosphere conditions downstream from sensors. The dynamic model predicts the time based changes to conditions throughout a mine model by simulating the mixing, addition and dilution of gases and airflow changes in incremental time steps. The advantages of this method is that a real time overview of full mine atmospheric conditions can be viewed at all locations, even areas without sensors. In addition, with careful planning and consideration of potential contaminant sources, the number of required sensors can be minimized. INTRODUCTIONMine Ventilation Sensors The importance of continuously monitoring mine atmospheres has been recognised since mining underground began and the effects of harmful gases on human health were discovered. Through the 19th and early 20th centuries, coal miners would take canaries underground with them as an early detection system against life threatening gases such as carbon dioxide, carbon monoxide and methane (Figure 1). The canary, normally a very songful bird, would become agitated, stop singing and eventually die if not removed from these gases, signalling the miners to quickly exit the mine (Davalle, 2011)."

Jan 1, 2016

By B. S. Graves

Deep well disposal of selected industrial wastes has been proved feasible and acceptable in the New Orleans area by several industries including Shell Oil Company's Norco Refinery and Chemical Plant where three of the six successful disposal wells in this area are operating. Well design and procedures for restoration of capacity are based, in most cases, on the principles of brine injection developed by oil producers in South Louisiana. Geological formations in the Gulf Coast area are suited to this type of injection because receiving strata are porous, isolated from sources of potable water and their water is compatible with the liquid wastes to be injected. This method of disposal is a simple, complete and economical solution to the problems presented by certain hard to treat wastes.

Jan 1, 1964

By K. Häge

"Die Nachhaltigkeit der Braunkohlengewinnung in der öffentlichen Wahrnehmung wird nur weiter erfolgreich kommuniziert werden können, wenn durch konkretes Handeln glaubhaft gezeigt wird, dass die offenen Fragen fair und solide beantwortet werden. Dazu gehören insbesondere die neue innovative technische Lösung sowie das sensible Interessenmanagement. Die Braunkohlenindustrie hat gelernt, dass Offenheit und nicht zuletzt das beständige Bemühen um den Meinungsaustausch mit ihrem Umfeld wichtige Elemente sind. Der in Jahrzehnten erworbene Schatz an Glaubwürdig-keit ist eine Basis, auf der die Braunkohlenindustrie ihre Zukunft gestalten kann. Darüber hinaus sind politische Rahmenvorgaben erforderlich. Das öffentliche Interesse an einer sicheren und preiswerten Energieversorgung unter Einschluss der Braunkohle ist unverzichtbar. In diesem Kon-text kann dann die Braunkohle die an sie gerichteten Fragen der Ökonomie, der Ökologie und der Sozialverträglichkeit auch mit Hilfe von Indikatoren beantworten.ABSTRACTThe discussion of the sustainability of lignite mining can only be continued successfully if the indus-try acts in a practical manner and demonstrates trustworthiness by responding fairly and reliably to open questions. This includes new and innovative technical solutions as well as the sensitive management of interests. The lignite industry has learned that openness and the constant effort to exchange viewpoints within their environment are all essential elements. The credibility that has been gained over the decades is the foundation on which the lignite industry can build its future. Beyond that a framework of political guidelines is necessary. Public interest in a secure and inex-pensive energy supply that also includes lignite is indispensable. In this context, the lignite industry will then be able to answer the questions which are directed at them and concern the economy, ecology, and social tolerability also by indicators."

Jan 1, 2005

By J. Loeb, R. Ramanathan, P. Cameron

All mining operations, including iron ore, maintain a focus of continuous improvement and asset optimisation in their operations. As all the operations in the Mine-to-Mill value chain are inter-dependent, available technologies that address efficiencies across the value chain are once again in the spotlight as companies are driven to improve productivity and maximise mine site profits to increase return on capital invested. Core to continuous improvement is the need to understand the baseline and the impact of changes to the process. In this paper, we discuss some of the key attributes in the mine to mill process, including their influence on productivity and cost, the need for direct measurement and areas where they should be applied. Many initiatives can be considered to improve mine to mill processes. Mining operations are planned and executed based on designs and models to achieve the operation’s objectives. However, there are many variables in the different parts of the value chain, such as blasting, material handling, crushing and screening. Measurement of the key attributes establishes the baseline for Mine to Mill (or Pit to Plant) performance which is necessary to understand the impact of any proposed improvements to the process design and execution and to monitor the outcomes on an ongoing basis to sustain the improvements that have been implemented. We have focused this paper on two types of measurement – blast movement and particle size of materials through the mine to mill process. Several innovative technologies are already available to measure these attributes and assist operations improve productivity and mine site profits.

Mar 2, 2022

By W. H. Davitt

One might ask why someone like myself, involved in the determination of taxes, should be speaking at a "cost engineering" session of a national engineering society. While it is true that taxes, especially income taxes, whether they be federal, state, or local, are not usually thought of as a "cost" of doing business, it is equally true that these tax costs do reduce the distributable profits just as much, as the cost of power, supplies, or labor. Therefore, the consideration given to taxes is often as important as that given to other costs. Hopefully yea will recognize that, within certain limits, taxes can be controlled to an economic advantage. That question may then lead to another question: What does the amount of taxes have to do with me? I'm an engineer or manager; not an accountant or a lawyer. If I may take a few minutes of your time, I might be able to present in a brief discussion some interesting facts that will provide the answers to those questions. My discussion will be directed mainly to Federal taxes. However, much of it will be applicable to state and local taxes, also.

Jan 1, 1973

By Leon D. Keller

Hydraulic concentration of minerals has been practiced for a good many years. Until recently, however, the practice has been limited to a multiplicity of small pockets and relatively low tonnages and flows. The adaptation of the SiphonSizer to the concentration and classification of magnetite has changed this concept. Some fifty commercial units are currently in operation on magnetite, varying in size from 16 ft diameter circular unit to a 25 ft by 100 ft rectangular unit. Additional units up to 38 ft diameter are under construction. Depending upon the application in the flowsheet, upgrading-varies from 0.75% to 14% Fe in a single stage. To those not familiar with taconite processing, the importance of the struggle to economically remove as much silica as possible may not be fully appreciated. These figures pertaining only to transportation may be thought-provoking. If a 10,000,000 ton per year plant could reduce the silica content of their concentrate by 17, a savings in boat freight alone would amount to 100,000 tons at $2.00 per ton annually.

Jan 1, 1963

By Edward M. Downs

This paper is a brief review of the lubrication requirements of enclosed gearing on earth moving equipment, particularly as they apply to intermediate and large draglines and shovels used in open pit mining operations. It discusses the requirements of spur, helical and herringbone gearing in both horizontal and vertically mounted applications. The effects of base stock, oil viscosity, additive treatment, quantity of oil and method of application are considered. In addition, a newly designed circulating oil system for enclosed swing gear cases and the reasons for its development are discussed.

Jan 1, 1968

Thermal pretreatment can significantly improve industrial comminution operations by reducing energy requirements and increasing mineral liberation. The effect of pretreatment using conventional and dielectric heating followed by quenching on the fracture properties of a number single and multiphase brittle materials has been investigated. The reduction in the impact fracture energies and particle strengths with and without pretreatment has been measured in precise single-particle experiments using the Ultrafast Load Cell. Variations in the fragmentation pattern caused by different pretreatments were assessed by measurements of the progeny size distributions. The differences in the effect of thermal treatment on single and multiphase materials are discussed based on the experimental results.

Jan 1, 1995

By R. J. Roman

Controlled and uniform distribution of the leach solution to a heap is of primary importance to achieving the desired rate of metal recovery and PLS grade from the heap. The step used to engineer the irrigation system are the same whether drips, wobblers or sprinklers are to be used. The mining rate, leach cycle time and heap height influence the heap cell size which along with the irrigation method selected controls the design of the irrigation system. The steps in the design procedure are explained as are the advantages and disadvantages of each irrigation method.

Jan 1, 1996

By George K. Martin

This paper deals primarily with roof bolting in Kentucky coal mines from January 1, 1949, through December 31, 1954, a six year period. The Consolidation Coal Co? (Ky.), a division of the Pittsburgh Consolidation Coal Co., began systemmatic roof bolting in November 1948 in Mine #204, Elkhorn #3 Seam, at Jenkins, Kentucky, After the efficiency of roof bolting had been proven by the Consolidation Coal Co., this procedure was adopted by other companies throughout the state. In December 1954, approximately 46.4 percent of Kentucky's total production of coal from underground mines was obtained from roof-bolted areas. Statistics in this report will show the progress made in roof bolting during the six years, in addition to the roof bolting being done as of December 31, 1955. Significant progress has been made in the coal mines of Kentucky in reducing the roof-fall fatality, rates, during the past several years by adopting systemmatic roof bolting. The ground work by the Consolidation Coal Co, (Ky.) in cooperation with the Federal Bureau of Mines was based upon the previous experience of the St. Joseph Lead. Cc, in its Southeastern Missouri Mines and The Tennessee Coal and Iron Division of the United States Steel Corporation. The author gratefully acknowledges the cooperation and assistance given by officials of the various mining firms using roof bolts, the Kentucky Department of Mines and Minerals, and the Federal Bureau of Mines in furnishing photographs and information.

Jan 1, 1958

By R. J. Reuss

The ore at this new underground operation is a massive sulfide breccia with high copper values. A major highway and electric transmission line pass directly over the near-surface orebodv. The mining method being used is undercut and fill. A continuous miner together with a single boom, hydraulic jumbo is used for the mining. Backfill is a weakly cemented sand-gravel mixture that is pneumatically placed. The ore is treated by conventional crushing, milling and flotation.

Jan 1, 1992

"In this review, the sintering process is first described and analyzed to identify the key factors affecting the structure and quality of iron ore sinter. Under fixed sintering conditions, the granulation efficiency, nucleus stability and primary sinter melt volume and properties of the iron ore are considered to have significant influence on the sinter structure and quality. Discussion is then focused on the effects of the chemical, physical and mineralogical characteristics of the iron ore on these key factors, and the consequences for sinter quality.IntroductionSintering is the most economic and widely used agglomeration process to prepare iron ore fines for blastfurnace use. In modern blast furnaces, particularly in East Asia, iron ore sinter typically constitutes more than 70% of blast-furnace ferrous feed. High sinter quality and efficient sinter production are thus required both to withstand extreme operating conditions and maintain the productivity of modern blast furnaces. At the same time, due to the increasing depletion of high-grade iron ore resources from large deposits, iron ore producers are moving toward developing an increasing number of deposits of much smaller sizes to maintain current production levels. It is therefore imperative for iron ore producers to develop long-term strategies to maintain the quality and consistency of the iron ore fines they are producing while exploiting these smaller, complex deposits. The iron grade, gangue minerals present, overall mineralogy as well as physical characteristics of iron ore fines being mined from these different deposits vary considerably. Overall, ores now have highly complex mineralogy, are becoming more porous and friable, and contain increasing amounts of gangue minerals, which will have important implications for the sintering process and sinter quality.Blending is one of the most effective options being explored by iron ore producers to deal with multiple small complex deposits. This allows the iron ore producers to reduce the number of products and take full advantage of the unique characteristics of each individual deposit to achieve long-term product consistency while increasing production. Blending is also a common practice in sinter plants as it is almost impossible to produce from one single ore a high-performance sinter mixture with the required processing characteristics. A typical sinter mixture used in Japanese steel mills (Nakano and Okazaki, 2007; Matsumura et al., 2013) often contains five or more ores to achieve balanced sinter quality and productivity with relatively low cost of raw materials."

Jan 1, 2015

By James E. Lonergan

To determine the best materials handling system for surface mined materials, one must develop a mine plan for each candidate system based on the most efficient use of that system. This is essential for a fair, unbiased economic compari¬son of the candidate systems. This paper will present two case studies where an integrated mine planning /systems engineering approach has been utilized at different levels of detail in the analysis of an in-pit crushing/conveying system vs. total truck haulage at 2 open-pit copper mines.

Jan 1, 1985

By Young C. Kim

Because of the tremendous technological advances achieved in recent years in microcomputers, it is not only technically feasible but also economically viable to develop an automatic truck dispatching system using a microcomputer. Such an effort was initiated by the Department of mining and Geological Engineering, University of Arizona in the summer of 1983. Up to date results and experiences prove that today's microcomputers can be economically employed for such a system to be used at small to medium scale open-pit mines. An IBM/XT microcomputer with 10 MB harddisk storage, together with automatic sensing capability of truck movements at several key locations in the pit, formed the core of this system. System software is written primarily in MICROSOFT FORTRAN with supporting subroutines in MACRO assembly language. The software is designed to automatically monitor truck movement throughout the pit, to make heuristic assignments based on expected shovel availability and truck travel times, and to record production statistics. It is currently dimensioned to handle 50 trucks, 10 shovels, 10 dump sites and 3 material types. Due to the lack of funds to purchase the necessary communications hardware, the work related to the automatic sensing of truck movements has not been performed to date. Otherwise, the automatic truck dispatching-system is fully operational on a realtime mode.

Jan 1, 1984

By Carl G. Schwenk

Rusk County is located in the northwestern portion of the state of Wisconsin, roughly 130 miles east of Minneapolis (Figure 1). The topography is generally flat with dairy farming the principal activity. Forest and swamp lands are common, as well as pasture and cultivated ground. Rusk County falls near the southern terminus of the Precambrian Shield and is covered by a thick layer of glacial drift. Outcrops are quite rare, but the few available exposures indicate that the subsurface is comprised of steeply dipping metamorphosed volcanics and sediments of Early Proterozoic age. A thin section of flatlying Cambrian sandstone is sometimes found directly under the glacial till. The depth to Precambrian basement has been recorded to be as great as 150 feet beneath the surface.

Jan 1, 1976

By J. Kou

The adsorption process, density and structural property of the oleate layer adsorbed onto a hydroxyapatite (HAP) surface at six different concentrations and three pHs (pH 8, 9 and 10) have been studied using the technique of quartz crystal microbalance with dissipation (QCM-D). The present study demonstrated the versatility and accuracy of the QCM-D for surface adsorption characterization. The real-time measurements of frequency and dissipation shifts with a hydroxyapatite-coated sensor revealed changes in the hydroxyapatite surface during the entire adsorption process. Chemisorption and surface precipitation of sodium oleate were also observed on the surface of hydroxyapatite through the use of Fourier Transform infrared spectroscopy(FTIR). Chemisorption dominated at low concentrations and high pH values and formed a rigid and thin adsorption layer. Surface precipitation of calcium oleate and micelles dominated at concentrations higher than critical micelle concentration (CMC) and lower pHs and formed a thick but dissipated adsorption layer with a high hydration level. Three distinct adsorption behaviors were identified from the different slopes of ?D-?f plots. The adsorption density was less than a monolayer at concentrations <0.164 mM, but increased significantly at concentrations higher than 0.821 mM at all three pHs. The critical concentration at pH 8 was 0.33 mM, which was lower than at pH 9 (0.821 mM) and pH 10 (3.3 mM).

Feb 1, 2012