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By H. A. Wright

This report assesses the economic, legal, institutional and technical factors that affect the current and future status of implementation of mine monitoring systems in the United States. It begins with a description of a poll of the Mining Production Research Committee and the Mine Monitoring and Communications Committee of Bituminous Coal Research that was conducted to establish industry monitoring needs and constraints. Existing systems in the United States and foreign countries are then reviewed and compared with the requirements set forth by the industry committees. At the same time, state and federal mining laws are reviewed, and equipment currently available from suppliers of mine monitoring systems and components is discussed. A framework for cost/benefit analysis is established and a series of case examples for various monitoring functions are presented. The total values of the market for mine monitoring systems in 1980 and 1990 are estimated on the basis of industry statistics and system cost estimates.

Jan 1, 1982

By Damian R. Siebert

Risk-reduction measures implemented during the design and construction of a 21-story pile-supported building adjacent to a below-grade 100-year-old sewer structure were keys to a successful foundation system. Avoiding damage to the existing sewer structure during construction activities and the future ability to access the structure post-construction were the main concerns for the utility owner. Clear communication and a deliberate design process between all parties ? utility owner, building owner, structural engineer, geotechnical engineer, architect, and contractor ? were integral to the project?s success. This collaborative process helped all parties to understand the risks, both real and perceived, and to develop mitigation measures to reduce the risks. Bringing together all parties to engage in dialogue and encouraging open communication throughout the project were paramount to its success. By implementing the joint design plan, using mutually-acceptable construction techniques, and careful monitoring, the building foundation was successfully installed and all parties? risks were averted.

Jan 1, 2011

By Darrell Wilder

When designing excavation support systems in urban environments, it is often necessary to consider the effect of vertical surcharge loads from adjacent structures. Several methods are used in practice to establish the horizontal surcharge-induce pressure on the excavation support. According to the experience of the authors, these methods often seem to overestimate the effect of the surcharge and may have significant impact on the construction costs. This paper explores several of these procedures and provides a discussion as to the reasons for the differences in surcharge effect predictions between different procedures. It also provides practical recommendations for designers dealing with excavation support design.

Jan 1, 2006

By Fumihiko Sumiya, Shinya Tanaka, Yukio Kato, Kenji Tanaka, Tetsuya Sawada

When explosives are heated under an acidic environment due to metal sulfide and sulfuric acidity, their decomposition temperature falls remarkably and decomposition reaction occurs quickly, and then explosives have the risk of the deflagration to the detonation transition. Heat resistant commercial explosives which can be used under conditions of high temperature of 200ºC and an acidic environment were studied. We developed the explosive composition consisted of ammonium perchlorate (AP) as oxidizer, saturated hydrocarbon oil as fuel and binder, and calcium carbonate as decomposition inhibitor. The characteristics of this explosive composition show a heat resistance over 24 hours at 200ºC, and a detonation velocity over 2,500 m s-1. This explosive composition has a cap-sensitivity at temperature higher than 100ºC. Cost effective heat resistant commercial explosives were created by the optimization of the grain size of AP as a main component, the addition of saturated hydrocarbon oil and calcium carbonate, and the control of bulk density by the addition of micro-balloons.

Jan 1, 2003

By E. C. Olsen

This paper describes the unusual hazardous conditions encountered in mining thick, inclined coal beds under heavy cover in Carbon County, Utah. This description includes heavy roof conditions, sloughing ribs, steep pitches, and severe bouncing experience. Emphasis is placed on the top bench system of mining and development in the top half of a 16-ft seam, under the roof rock, which is bolted, and the recovery of the bottom coal on retreat; success of bolted roof and ribs; and shuttle car haulage on pitches up to 25%. The use of protective cages for operators of face equipment, the guarding of belt conveyor systems to prevent injury associated with deliberate entry, and the positive lockout of electrical equipment is described and illustrated. Most coal mining areas of the Western United States are characterized either by thick beds, steep pitches or heavy cover. Individually, each of these may present inherent safety hazards that in- fluence mining. When all are met at one location, the combined effect is to make the safe operation of the mining property a challenge to management. These combined conditions are met in the coal mines of the Columbia-Geneva Steel Div. of the United States Steel Corp., in southeastern Utah. This coal bed measures up to 16 ft in thickness, the pitch is as much as 25% and mining is under a cover approaching 3000 ft. The Sunnyside coal bed is found in the Book Cliff Mountains, a great escarpment extending from west of Castle Gate, Utah, some 180 miles to Grand Junction, Colo. West of Green River, Utah, the Book Cliffs swing sharply to the north because of the domelike uplift of the San Rafael Swell to the southwest. It is in this northerly extension of the Book Cliffs that the Sunnyside coal in the Blackhawk Formation of the Mesa Verde Group, Upper Cretaceous Age is found. The strata are transected by numerous faults with from a few inches to as much as a hundred feet of displacement. All of these faults have had some effect on the mining operation, either in roof control or, in the case of major faulting, the pattern of mine development. MINING PRACTICES Mining has generally been confined to the Lower Sunnyside Seam which measures from 7 to 16 ft in

Jan 1, 1963

By Klaus Hasselwander

Fluctuating SO2 gas streams represent a difficult task for designers of SO2 removal systems (with respect to designing the plant), but in spite of the designers great efforts to solve the problems, the operation of such plants requires much care and attention. A fluctuating gas flow usually results from metallurgical smelting processes. Both gas composition and gas flow rate may vary. The first part of this paper outlines some existing technical solutions and presents the Pros and Cons of the different solutions. These solutions outline are: - Sulphuric acid plants operated with a preheater permanent in operation - Sulphuric acid plants with concentration increase of SO2 gas either using regenerative SO2 removal or cryogenic partial condensation of the SO2 - Sulphuric acid plants with additional burning of sulfur to increase SO2 content - Single-stage sulphuric acid plants followed by a tail gas system (which is) designed for periods of low SO2 input In the second part, this paper describes some existing technical solutions for removal of SO2 at low concentrations (i. e. less than 0.1 - 2 %-by volume), which could be used as tail gas treatment system for acid plants. While selecting an appropriate solution, special attention should be given to operating costs, which usually to a large extend depends on the type of absorption agent and the costs for disposal of the sulfur compound produced.

Jan 1, 2009

By J. Dahner

Total milling cost is composed of energy, liner and grinding media costs. In primary high ball load milling, the grinding media play the biggest role in total milling cost. This cost can be drastically reduced by improving the impact condition inside the mill. The impact condition inside the mill is influenced by shell liner design (as well as feed end and discharge design) and the type of discharge. The improvement of the impact condition will result in a significant decrease in grinding media consumption. The softened impact condition allows for better alloy optimization, resulting in a further reduction in grinding media consumption. Optimized liner design can also improve energy consumption as less energy is wasted in the projection of the grinding media. Magotteaux utilizes tools to simulate and show the grinding media trajectories for shell and end liners. This paper will present some practical examples where the media and energy consumption can be or has been reduced by optimizing liner design. Keywords Comminution, grinding, liner design, grinding media wear.

Jan 1, 2011

By J. Roth

The purpose of the present study is to increase the safety of explosive storage. This was accomplished by: a) review of the histories of recent and past magazine explosions to define causes and trends; b) observation of present-day explosive storage conditions and practices at active mines; c) examination of existing Federal regulations on explosive storage to determine whether they address all conceivable safety problems, whether they contain redundant or obsolete standards, and whether their intent is clearly stated; d) recommendation, for safety improvements and for revision and clarification (if necessity) of governmental regulations. Magazine explosions are rare. A recent increase in magazine explosion frequency must be attributed to a large increase in deliberate (criminal or malicious mischief) explosions. Fires of various origins account for the remaining explosions of the past decade. During 1884-1926 several lightning-generated explosions occurred in non-metal magazines, but none recently. It appears that the contents of a well-constructed, metal magazine are immune to direct lightning strikes, regardless of whether the magazine is grounded or not grounded. Grounding a metal magazine cannot be harmful, but it may well be superfluous. Magazines were observed at 34 widely separated mines and storage problems were discussed with personnel at these mines. In general, storage conditions and practices were found to be satisfactory. Usually, only small quantities of explosives are stored on mine property since most explosives are brought in by suppliers when needed. MSHA and BATF standards on explosive storage appear to cover safety aspects adequately. However, certain revisions are recommended to clarify some of these standards and to reduce inconsistencies in their enforcement.

Jan 1, 1983

By Basil Dimitriades

The roles of hydrocarbons and nitrogen oxides in smog formation were investigated by the Bureau of Mines. Samples of automobile exhaust with varying HC and NOx levels were irradiated in a smog chamber under conditions that resulted in smog levels similar to those observed in the atmosphere. Results were used to define the patterns that describe the dependence of a number of smog manifestations on HC and on NOx. Using these dependence data and some simplifying assumptions, estimates were made of the ranges within which HC and NOx must lie in order to obtain specified levels of air quality.

Jan 1, 1970

We had a cold, gray winter here in Kansas City and I spent a lot of time watching out my den window at the squirrels and birds trying to get by in the lousy weather. I remember too well working in the cold, loading shots. I was frostbitten several times since I couldn’t tie in MS connectors with gloves on. Those old connectors had a piece of detonating cord on either end of a metal tube that held the delay and you tied them to the trunk lines with square knots. Doing this on a “warm” day in Alaska or Montana shooting ditch for a pipeline could be a frosty experience. Also remember how hard it was to connect up electric caps (detonators to you new guys) in the cold. Now I don’t want you to feel sorry for me ‘cause I suspect most of you younger fellows have also paid your dues in the cold and for that matter in the heat too. Wowee, the heat at the bottom of a Chicago dolomite quarry in August was enough to fry the brains of all that were there. Maybe that’s why the third deck of my brains doesn’t exist.

Jan 1, 2004

By B. J. Moore

This publication contains analyses and related source data for 269 natural gas samples from wells and pipelines in 18 States. All of the samples were obtained and analyzed during, calendar year 1979 as a part of Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted in the United States by the Bureau of Mines since 1917. In late 1965, the survey was expanded to include foreign gasfields. The analyses published herein were made by mass spectrometer and a special helium analysis apparatus, which are described in Bureau of Mines Bulletins 4862 and 576.3 The results of the investigation of the occurrences of helium are published annually to make the information available as soon as possible to the gas industry and the general public. Twenty-one previous publications have presented tine results of 11,883 gas analyses made prior to 1979. The first three, Bulletins 486,4 576,5 and 617,6 contain analyses and related source

Jan 1, 1980

By José Cayetano

El presente trabajo plantea un proceso para minimizar el contenido de bismuto en las celdas de electrorefinación, a través de la adición de carbonato de bario a la solución electrolito, de forma que el bismuto soluble presente en fase líquida, se precipite sobre la superficie del precipitado insoluble de BaSO4, bajo una coprecipitación por adsorción e intercambio debido al equilibrio dinámico entre el precipitado y la solución de electrolito conteniendo al bismuto. En este sentido, se reduce la presencia del bismuto en el electrolito de cobre en un 75%, adicionalmente se tiene la disminución del contenido de plomo en un 96%, de estaño en 48% y de plata en un 18% aproximadamente.

Oct 21, 2015

By M. Beth McClenaghan

This paper summarizes diamond exploration techniques used in glaciated terrain, focusing on indicator mineral and geochemical methods applied to glacial sediments. Understanding the ice flow history, depositional history, and stratigraphy of glacial sediments are essential to successful sampling, interpretation and follow-up of indicator mineral and geochemical anomalies related to kimberlites. Kimberlite indicator minerals survive glacial transport over long distances and the relative abundance of each mineral in till is a function of the primary mineralogy of individual kimberlites. Indicator mineral distributions observed at a regional scale define the net effect of glacial dispersal, often along different ice flow directions. Local-scale distributions define individual dispersal trains. The medium sand (0.25 to 0.5 mm) fraction of heavy mineral concentrates prepared from glacial sediment samples is best suited for indicator mineral surveys. The application of till geochemistry to diamond exploration is increasing because it is significantly cheaper than indicator mineral analysis and it can be performed quickly. The <0.063 mm (silt+clay) and 0.5 to 2.0 mm (coarse sand) fractions provide the best geochemical contrast between background and kimberlite-rich till. Kimberlite pathfinder elements that provide good contrast include Ni, Cr, Ba, Co, Sr, Rb, Nb, Mg, Ta, Ca, Fe, K, Ti and REE, the relative importance of which will depend on kimberlite composition as well as that of the surrounding bedrock.

May 1, 2002

By Alessandra Savazzini dos Reis

A crescente preocupação em relação às áreas de proteção ambiental e ao alto consumo de argila, matéria-prima da cerâmica vermelha, ocasiona a indisponibilização progressiva de reservas de argilas no Brasil. Com isso, vê-se a necessidade de incorporar resíduos na massa argilosa para confecção de produtos de cerâmica vermelha. A indústria de cerâmica vermelha brasileira consome cerca de 10 milhões de toneladas de argila ao mês para produção de telhas e blocos. Na própria olaria são gerados resíduos, tal como, o resíduo de massa cerâmica crua originado na etapa de conformação das peças. Este trabalho visa incorporar o resíduo de massa cerâmica crua na massa argilosa usada em cerâmica vermelha. O resíduo foi caracterizado por meio de ensaios de FRX, DRX, limites de Atterberg e distribuição de tamanho de partículas. Corpos de prova feitos com massa argilosa e resíduo em teores variando de 10% a 90% (massa) foram conformados, secos à 110ºC, queimados à 900ºC em forno industrial e submetidos a ensaios de absorção de água, porosidade aparente, massa específica aparente e resistência à compressão. Os resultados evidenciaram que as propriedades cerâmicas avaliadas nos corpos de prova da massa argilosa incorporada com o resíduo atendem aos valores das argilas-padrão brasileiras para cerâmica vermelha.

Aug 17, 2017

By R. D. Peterson

As underground mine operations expand, the ventilation systems supporting them become complex. Complexity increases with periodic ventilation changes. New diagonal connections require a rebalance of resistance to maintain airflow in affected splits in the system. Incidents of mine fires and explosions have occurred in U.S. coal mines when diagonal connections resulting from ventilation changes have resulted in changing airflow directions. MSHA regulations prohibit the reversal of airflow and poor ventilation practice in general, but regulations cannot stipulate or recommend proactive preventative measures because every situation is different. This paper discusses the phenomenon of diagonal branches and recommends practical precautionary measures that can be taken to prevent airflow reversal in planned ventilation changes.

Jan 1, 2012

By William F. Hahn

This report describes an illumination system suitable for use in a slope under construction, Simulator work was performed using actual lighting hardware to verify adequate light levels to meet MSHA proposed regulation (as published in the Federal Register, January 13, 1977). The sequence of operating activities for two different slope driving sites are discussed and lighting requirements are defined for each,

Jan 1, 1981

By Matthew Wallin

A part of the East Bay Municipal Utility District?s Folsom South Canal Connection Project, 430 feet of raw water pipe was installed using micro tunneling beneath the Mokelumne River. The access shafts for this crossing were constructed 50 and 35 feet deep through very dense sands and soft sandstone and siltstone. High groundwater and the immediate source of recharge from the river required watertight shaft construction methods. The shaft contractor, Drill Tech of Antioch, CA, used a brand new Bauer cutter-soil mixing (CSM) rig to construct the large shafts. The structural concept is similar to secant piles, but instead of creating cylinders of soilcrete, the CSM rig creates interlocking rectangular panels. This technology has been used previously in Europe, Asia, and Canada, but this was the first project to use CSM technology in the United States. Cutter-soil mixing technology has other applications beyond shaft construction, including retaining wall construction and levee reinforcement.

By N. C. J. Dempers, J. A. L. Parker, R. A. Wildenboer

More than half of global cobalt reserves are located in the Southern African Copperbelt, stretching over the northern tip of Zambia and southern area of the Democratic Republic of Congo. In these areas, cobalt is not typically produced as a primary product but as a byproduct of copper production. Ores from this region often contain uranium, which is readily leached under typical copper leach conditions and enters the process. Uranium does not pose a challenge to copper production, but it becomes a significant problem when it follows cobalt to the cobalt precipitation process and results in unacceptably high levels of U in the final Co product. This paper evaluates the existing process technologies that can be used to remove uranium from cobalt-bearing process streams, including phosphate precipitation and ion exchange. Advantages and disadvantages of the uranium removal processes are discussed, and important design considerations are highlighted.

Jan 1, 2023

By G. L. Smith

Central to the success of any mining company is the ability to manage capital investment effectively so as to ensure acceptable stakeholder returns within an overall strategic context. Critical to this process is the effective selection and implementation of a strategically aligned project portfolio that enables optimal resource exploitation while operating within mandated bounds and identified constraints. Consideration is given to the strategic long-term planning process, an investment prioritization methodology and specific tools and techniques based on the discounted cash flow philosophy.

Jan 1, 2007

By G. A. Smyres

The Bureau of Mines conducted laboratory studies to determine the feasibility of chlorine-oxygen leaching for treating low-grade zinc sul-fide flotation concentrates. Recovery of zinc sulfides by flotation from complex fine-grained sulfide ores is substantially higher in low-grade bulk sulfide concentrates than in the high-grade cleaned concen-trates required for smelter feed. However, there is no commercial process in the United States for the treatment of low-grade bulk zinc sul-fide concentrates. Leaching experiments using reactors of 500-mL and I-gal capacity were conducted on a bulk concentrate containing 19.3 pct Zn, 35.6 pct Fe, and 39.4 pct S. The effects of pressure, temperature, and percent solids on extraction were investigated. The chlorine-oxygen leaching procedure showed promise for treating the concentrates. Zinc extractions of 95 pct or more were obtained by leaching at 50 pct solids in the temperature range of 1000 to 1200 C. Zinc extractions by leaching with chlorine followed by oxygen at reactor pressures of 50 to 100 psig were independent of pressure.

Jan 1, 1985