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By J. Patrick Ryan, Thor H. Kiilsgaard, Charles W. Merrill, E. T. McKnight

The U.S. Treasury stocks of silver have been reduced at such a rapid rate to meet industrial and coinage requirements that they face exhaustion in 3 or 4 years. Alleviation of the silver problem will require increasing supply or reduc ing demand. This paper examines poss ible long-range resource development and research programs and improved secondary recovery. The possible reduction or elimination of silver in coinage and development and introduction of substitutes in the arts and industry are also discussed.

Feb 1, 1965

By C L Humphrey

Biological monitoring programs for environmental protection require techniques that will provide both early detection of possible adverse effects, and assessment of the ecological significance of these effects. Monitoring techniques must include responses sensitive to the impact, that can be subjected to rigorous statistical analysis and for which statistical power is high. Such issues in baseline research of 'what and how to measure?' and 'for how long?' have been the focus of a program being developed to monitor and assess effects of mining operations on the effectively pristine, freshwater ecosystems of the Alligator Rivers Region (ARR) in tropical northern Australia. Application of the BACIP design, utilising a form of temporal replication, to univariate data (single species) and multivariate (community) data is described. For new ventures in Australia (such as mining), monitoring programs should be designed to establish with high probability that an impact on the ecosystem no greater than a prescribed amount has gone undetected - as opposed to simply allowing development to continue as long as 'proof' of impact is not available. Such a precautionary approach represents a shifting of the 'burden of proof' and would require with the BACIP design, a minimum number of baseline years in order to achieve some desired level of statistical power in a test for impact. Power analyses conducted on two to five years (depending upon the technique) of baseline data from streams of the ARR indicate that the BACIP design would not impose developmental constraints on mining and that a policy of reversal of the burden of proof would provide the cornerstone required for managing such development in an ecologically sustainable manner.

Jan 1, 1994

By Ajay K. Jha1

Drilling and Blasting are two important unit operations in the production cycle of a mine and a strong link exists between these two and other unit operations/subsystems like loading, transportation, and crushing. Under the present concept of ? Mine to Mill?, it is important to optimize the drilling and blasting operations by applying scientific approach to drilling and blasting using sophisticated instruments and new technologies, which depends heavily on Information technology (IT) to meet this imperative. Development of innovative models and software has lead to blast optimization process. Till date, the blast results are evaluated in terms of available empirical approaches like powder factor, which are too simple to exclude some key parameters or lack in providing reliability because of non-availability of user friendly IT enabled techniques. Although with the help of developed approaches, formulation of user-friendly software to assist the site engineers in effective post blast assessment has started but there is a dearth of holistic approach to design an optimum blast considering the techno-economic feasibility of the subsystems and the geo-mining conditions to achieve blast optimization. The science of IT enablement in drilling and blasting is capable to build innovative models for achieving blast performances which will be doped with productivity, economy and safety with due regard to environment. The present paper discusses the use of existing IT enablement in various mines of India citing the Indian scenario and the future requirements for achieving the techno-economics in overall mining operations.

Sep 1, 2012

By D. L. Pitt

This paper, describing the milling methods at the concentrator of the Premier Gold Mining Co., Ltd., Premier, B. C., Canada, is one of a series being prepared by the United States Bureau of Mines on milling methods and costs in the various mining districts throughout the United States and Canada. ACKNOWLEDGMENTS The authors wish to acknowledge the assistance and suggestions given during the preparation of this paper by the engineering staff and accounting department of the Premier Gold Mining Co., Ltd., all of whom have assisted materially in gathering the data used.

Jan 1, 1933

By Jon A. Hummer, Aleksandar D. Bugarski, Shawn Vanderslice, Teresa Barone

A study was conducted to examine the potential of diesel emissions control strategies based on retrofitting existing power packages with exhaust aftertreatment devices and repowering with advanced power packages. The retrofit systems, a diesel oxidation catalyst (DOC) and diesel particulate filter (DPF), were evaluated individually using a US EPA tier 2 (ter 2) engine operated under four steady-state conditions and one transient cycle. The DOC effectively curtailed emissions of CO, and to some extent organic carbon (OC), elemental carbon (EC), and aerosol number concentration. The DPF system offered substantially higher reductions in OC and EC mass and aerosol number concentrations. Both, the DOC and DPF achieved reductions in the aforementioned emissions without adversely affecting emissions of NO2 and nano-sized aerosols. The strategy of repowering with an advanced system was examined using a US EPA tier 4 final (tier 4f) engine equipped with a cooled exhaust gas recirculation system and diesel exhaust fluid-based selective catalytic reduction system, but not with a DPF system. The tier 4f engine contributed substantially less than the tier 2 engine to the EC and OC mass, aerosol number, and CO, NO, and NO2 concentrations. The tier 4f engine was very effective in reducing aerosol mass, NO, and NO2 concentrations, but it was not equally effective in reducing aerosol number concentrations. The implementation of viable exhaust after treatment systems and advanced diesel power packages could be instrumental to the underground mining industry to secure a clean, economical, and dependable source of power for mobile equipment.

By S Hapugoda, J R. Manuel, M P. Ma, L Lu

Iron ore sinter quality depends heavily on the mineralogy, textures and physical structure of the sinter, which is formed upon solidification of the primary sinter melt. The interactions of the initial sinter melt with its surrounding materials will impact on the properties of the primary sinter melt and consequently the solidified structure of the sinter. By using a high-temperature visualisation system, in situ studies have been conducted on the effects of melt compositions (Al2O3, SiO2 and MgO) on the interfacial phenomena of the sinter melt on a natural iron ore substrate. It was found that the melt composition significantly influenced the wettability between the sinter melt and the iron ore substrate. The interactions between the sinter melt and the natural iron ore substrate were also examined. Such interactions can lead to further changes of sinter melt composition and hence the sinter melt properties that, in turn, further affect the wetting behaviour of the sinter melt.CITATION:Ma, M P, Lu, L, Hapugoda, S and Manuel, J R, 2013. Effects of melt composition on the interactions of sinter melt on a natural iron ore substrate, in Proceedings Iron Ore 2013 , pp 431-440 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By A G. Sheard

Fire safety requirements inside tunnels have become more demanding as tunnel designers consider the impact of potentially larger fires. Tunnel ventilation equipment is required to clear hot gases in the event of a fire. This is vital to maintain smoke free escape routes for people trapped in the tunnel and to facilitate safe access for emergency services. As the fire becomes larger, the temperature of clearing hot gases increases. Traditionally, engineers have taken into consideration gas temperatures of 250°C when designing tunnels. Because of larger fires, engineers must now design equipment to clear hot gas up to 400°C.Increasing the temperature of hot gases to 400°C requires tunnel ventilation equipment that goes beyond historic limits. As temperature rises, material strength reduces, consequently mechanically constraining fan aerodynamic performance. Developing tunnel ventilation equipment suitable for clearing hot gases at 400°C requires a fan technology that is more typical of industrial turbomachinery. The standards EN 12101-3:2002 and ISO 21927-3:2006 defi ne the necessary design criteria and testing methodologies to verify that a range of tunnel ventilation equipment is capable of extracting hot gases.This paper describes the process by which the authors certified in accordance with EN 12101-3 and International Organization for Standardization (ISO) 21927-3 a range of powered ventilators suitable for clearing smoke and hot gases at 400°C for two hours. Proving the high temperature capability of the new range provided a challenge as a consequence of the large physical sizes and high motor powers involved. Additionally, the need to install vertically, as well as horizontally, imposed high thrust loads on motor bearings, further complicating both mechanical design and testing. The paper presents the methods by which the authors overcame these challenges.

Mar 8, 2011

By P B. Hills

Increasingly over the past couple of decades, the importance of understanding the in situ stress regime in underground hard rock mines has become accepted by all. Providers have responded to this requirement and various techniques for undertaking the measurements have been honed while others have slipped from use. It is a simple, though not inexpensive task to engage a provider to undertake the require measurements, and a comprehensive report will ensue. So, what has actually been obtained? What should the geotechnical engineer do next? What tools are necessary to do so? Regardless of the method of measurement, the report will describe the location of the measurement site and describe the basis of the methodology used in undertaking the measurements and a log of the measurement program. Finally, it will include the results, which should incorporate the normal and shear stress components of the full stress tensor. Ground control management plans (GCMP’s) and stress summary reports and spreadsheets prepared by site geotechnical engineers always include the magnitude, trend and plunge of the principal stresses. Remarkably few site-based summaries include the full stress tensor. This is a significant gap as the full stress tensor is vital for any further data manipulation. However, without the algebraic tools to undertake those manipulations, their value is diminished. This paper seeks to provide a checklist of ideas to be considered. It provides commentary on the options available to dissect the stress measurement report and ensure that the maximum possible value is derived from it. The manipulation and presentation of component stress data is also discussed. The various methods of stress measurement are not the focus of the paper but some of the strengths and weaknesses of them over which the site geotechnical engineer has some control, are highlighted.

Nov 29, 2022

By Eugene Holman

UINQUESTIONABLY the petroleum industry not only can supply the world's present oil requirements but even can meet a considerable increase in demand if it should come. The United States produced last year 1 1/3 billion barrels of crude oil, or more than 60 per cent of the world's total. It could have provided more, if needed, because we has a large shut-in crude producing capacity. Our refining capacity of 4,500,000 0 barrels per day is more than 2 per cent above our average refinery run for 1940. Adequate crude supplies and manufacturing facilities also exist outside of the United States. Large crude reserves exist in South America, in Iran and Iraq, in Russia and Romania, in Sumatra and adjacent islands. The refineries of the Dutch West Indies, of Iran, and of the Netherland East Indies are well located in relation to crude reserves and world trade lanes. Furthermore, flexibility in the manufacturing facilities permits adjustment of yields to meet a considerable range in variations between demands for products. Only with regard to 100-octane aviation gasoline is there any apparent refinery problem. Even here so far as this country is concerned, additional refining facilities can be installed well within the time that would be required to turn out the airplane engines which will use this super fuel.

Jan 1, 1941

Australia is a hub for mining technology development. The paper describes many of the key players involved in mining research in this country along with some of the interesting research outputs to emerge over the past decade.

Jan 1, 2010

By A L. Bennett

It is well understood that designers and constructors must protect the existing surroundings of tunnel construction, particularly in the selection of excavation methods, ground support and waterproofing systems. However, while this can readily address the existing conditions, the tunnel owner and the designers need to consider the changes that are likely to occur during the life of the tunnel. It is typical for transport infrastructure to have a design life of at least a century. While the effects of constructing the tunnel on its surroundings are a short-term effect, the converse case, the protection of the tunnel, and the need to maintain its integrity, will affect developments over and adjacent to the tunnels beyond the foreseeable future. Decisions made during the design phase have the potential either to facilitate development or to hinder it for the long term.Examples principally from Australia, New Zealand, Singapore and Hong Kong show that the provision for future development is addressed in different ways. These have ranged from making no specific provision, putting the onus onto developers to ensure that the tunnels are not affected adversely, to including a loading allowance for future development in the performance specification or contract documents for a tunnel project.These two contrasting approaches have strong points and risks. A highly prescriptive definition of permissible loadings around the tunnel can provide unambiguous guidance for the approving authority and the developer, but runs the risk of being overly conservative to allow for all the envisaged works, while still missing a detrimental combination of effects that theoretically complies with the specified requirements. In contrast, a general requirement to not cause detriment is open to interpretation and potentially difficult negotiations to reach agreement between the tunnel owner/operator and developer and finally the appointed contractor (probably with no contractual relationship with the tunnel owner).In practice, a combination of prescriptive and performance requirements is likely to provide the optimum combination of clarity and flexibility. The author provides examples and recommendations on how such provisions could be structured.CITATION:Bennett, A L, 2014. Protection of ?tunnels in their future environment, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 495–500 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By R. R. Sayers

Under compuision of the present urgency to implement the President's promise to make the United States the arsenal for the democracies there is a tendency to demand a relaxation of restrictions on hours of labor and to speed up all industrial processes. The pressure is the more insistent with growing realization of the importance of the time factor in the success- ful prosecution of the war effort and the lack of skilled workers due to (2) operation of the draft, lack of an apprentice system in industry, and loss of skill by workers unemployed for long periods during the depression. With "total" war such as it is today the probabilities are that everyone will be required to exert greater effort (in many instances in activities to which they are unaccustomed) for longer periods than ever before has been necessary. The question arises, "What will be the aftereffects as well as the immediate effects on health, safety, and efficiency?" A review of the literature leaves the impression that this question has not been an- swered completely, especially as regards the ultimate effects. Mechanization, speeding up of industrial processes, mass produc- tion, and the small industrial concerns present many problems to indus- trial medicine. Does the tendency to expect the worker to produce at full speed all the time he is on the job decrease the effectiveness of the shorter working hours and cause undue fatigue, loss of efficiency, and increased accident proneness? The answer is important as this condition is likely to be intensified by the exigencies of the present emergency. According to Viteles (1)3, The increased tension under such conditions of work appears to offset the savings in muscular force made pos- sible by the machine. The tension, the speed, the subject- tion to specialization of work and a rhythm uncontrolled by the individual promote fatigue, characterized by a "decrease in the power to work, a decrease in pleasure taken in work, and a decrease in the enjoyment of the hours spent away from work."' The crowding of workers in temporary structures without proper provision for comfort and health may add greatly to the general fatigue factors already present in many industrial establishments. In 1932 Lockhart (2) stated that the production and maintenance of a healthy, satisfied industrial population is the most urgent necessity, involving problems so serious as to constitute a national task too great economically to be relegated to industrial concerns. If this was true in 1932, it must be doubly so today.

Jun 1, 1942

By Raphael G. Kazmann

Water occupies a dual role in our industrial society. It is the indispensable raw material, essential to life itself. It is equally an industrial nuisance, interfering with the production of industrial minerals, making construction difficult, flooding valuable land, and generally producing problems because it is in the wrong place at the critical time. The legal position of water as a nuisance, and the counter measures to be taken, have been well established procedures for determining the responsibility for damage caused by water, and the organization of drainage districts and flood control and levee districts have been legally tested many times. Thus there is rather adequate legal doctrine concerning water, the common enemy. But recently efforts have been made to regularize the position of water as a useful, industrial, commodity. Such laws are not new to the West, where the doctrine of appropriation for beneficial use is slowly becoming the water law. Elsewhere the University of Michigan has produced a "model" water law and efforts are being made to induce all of the states to use this law, or a slight variation of it, as the basis for legislation. There are many serious criticisms of the proposed "model"-law, and the writer strongly opposes many of the provisions. But the fact remains that water is, in itself, so useful and essential that laws have been, and will be, passed to insure the orderly development of our water resources and to prevent waste. The, most important aspect of these "water-use" laws is that, wise or unwise, the existing laws and the proposed laws have been "water oriented". "Water oriented" means that it has been tacitly assumed that the beneficial use of water, either surface water or ground water, is the overriding consideration.

Jan 1, 1960

By E. W. Davis

DURING late years, the proportion of beileficiated iron ore shipped from the Lake Superior District has increased very rapidly. By benefication is meant washing, screening, drying, sintering or any process by which the grade or structure of the crude ore is improved before shipment. In 1915, only 3,000,- 000 tons, or 9 per cent, of t6e total Minnesota shipment was beneficiated ore, compared with 13,500,000 tons, or 35 per cent, of the total Minnesota shipment in 1925. This increase is, of course, due to the fact that iron and steel can be made more cheaply after beneficiating these ores than they could have been had these ores not been so treated. Fundamentally, however, several causes contribute to the necessity for beneficiating iron ores, such as depletion of the reserves of high-grade ores, the iron ore leasing systems and taxation methods and, at the smelting plants, a better understanding of blast-furnace operations, increased operating costs and increased sulfur content of blast-furnace coke. As economic conditions change, it is by no means certain that the proportion of beneficiated ore shipped each year is going to continue to increase. Undoubtedly some of the beneficiation operations are not economically sound at the present time and what the future has in store for the iron ore industry is problematical. Generally speaking, the cost of fuel for blast-furnace operations will increase as time goes on and in order to continue to produce cheap iron and steel, some of the other costs must be lowered. Freight and labor rates probably can- not be reduced. The cost of producing iron ore cannot be reduced much below the present price. It therefore appears that the best opportunity for maintaining iron and steel prices at their present level in spite of in- creased costs of labor and raw materials is to use. less or cheaper raw materials. This, of course, contemplates an improvement in metallurgical processes all along the line and, as a matter of fact, we can confidently expect these improvements because scientific investigations will undoubtedly be even more productive in the future than they have been in the past.

Jan 1, 1926

By W. B. Berwald

The United States Bureau of lanes, in cooperation with the Natural Gas Department of the American Gas Association, has been studying actively for the past several years the problem of the flow of natural gas through high-pressure transmission lines. Numerous data on gas flow through pipe lines under many conditions of operation have been obtained by carefully conducted tests, and these data, together with all other available information, have been analyzed Carefully to secure practical facts for the use of operators in designing pipe lines and determining the effects of different operating conditions on pipe-line capacities. The first procedure in initiating this problem was to review, compile, and analyze all of the existing data on the flow of natural gas through pipe lines. Actual data applicable to pipe and operating conditions normally used in the transmission of natural gas were meager, and the several pipe line flow formulas developed by different investigators gave widely varying results when applied to problems of pipe-line design. Therefore, further experimental work under conditions comparable to those found in transmitting natural gas was essential before any definite recommendations could be made. The problem, as originally planned, included flow tests on pipe lines in operation, and in each test the measured delivery vas to be compared with the delivery calculated from several common pipe line flow formulas.

Jan 1, 1931

By H. C. Fowler

Hydrogen sulphide associated with the gasps and vapors from certain crude oils now produced in the United States has forced a serious health and safety problem upon the petroleum industry. Although the presence of hydrogen sulphide in or occurring with Mexican crudes has been known for some time, it was not until recently that crude oils which give off poisonous amounts of hydrogen sulphide have been produced to any extent in the United State. The injurious effects of this poisonous gas were first recognized by the refiners along; the Atlantic and Gulf Coasts upon receiving shipments of crude petroleum from Mexico. The problem of combating the hazards of the gases and vapors given off by this petroleum become more important as the use of Mexican crude increased. In 1925, the Bureau of Mines and Public Health Service under cooperative agreement with the American Petroleum Institute, studied the causes rend effects of hydrogen sulphide poisoning. Bureau of Mines Bulletin 2312 is report of this investigation, and although written with special reference to refineries, it nevertheless contains much information that is of value to the producer of petroleum.

Jan 1, 1927

By Denise Müller, Axel Preusse

"Due to multilateral underground use, mining subsidence is discussed more and more with regard to issues other than mining, such as post-mining topics, storage, or geothermal use. These discussions and the influence of the energy policy is why the situation in Germany is described as a transition from active to abandoned mining. Many PhD theses have been written within the last 20 years—every single one with a different topic but all with the same issue—the effects and challenges of mining subsidence.These challenges start with the research regarding geological and hydrogeological conditions, which is the basis for calculations like the angle of draw or predictions of subsidence due to water table drawdown. Furthermore, the research investigates issues like risk-management and financial planning. One of these issues is post-mining calculations; others include potential hazards of storage or the use of geothermal energy.This paper outlines an overview of German mining and the consequences due to subsidence. It deals with an overview of the circumstances related to hard coal mining, lignite mining, the use of geothermal energy, gas, and opportunities regarding underground storage. Basically, it describes the essential steps of processing mining subsidence, starting with monitoring to forecast and up to safety measures.With a glance back to the applied research of the prior two decades, we compare given forecasts with experiences already gained.Even though mining decreases, ground control does not.INTRODUCTIONAfter the Second World War, an economic recovery started in Germany, during which the mining industry provided an advantage. Areas like the Ruhr District or Saarland were characterized by hard coal mining. In addition, there was lignite mining in the Rhenish mining area and the middle German coal district. In the Lausitz area, there were gravel and sand companies for the construction industry and many other medium-sized mining companies. Especially in the Ruhr District and in Saarland, where large coal fields were built, mining played a major role. The number of mines increased, and the negative effects on the terrain got bigger. While minor open pits or quarries have influences on the landscape only, large open pits and underground mining lead to significant ground movements. This results in a larger importance of mining subsidence engineering. Calculations of subsidence and forecasts have been developed and refined within the last several years. Due to the fact that the mining areas were and still are densely populated, the forecasts are getting more and more precise."

Jan 1, 2018

By W. B. Berwald

The United States Bureau of Mines, in cooperation with the Natural Gas Department of the American Gras association, has been studying actively for the past several years the problem of the flow of natural gas through high-pressure transmission lines. Numerous data on gas flow through pipe lines under many conditions of operation have been obtained by carefully conducted tests, and these data, together with all other available information, have been analyzed carefully to secure practical facts for the use of operators in designing pipe lines and determining the effects of different operating conditions on pipe-line capacities. The first procedure in initiating; this problem was to review, compile, and analyze all of the existing data on the flow of natural gas through pipe lines. Actual data applicable to pipe and operating conditions normally used in the transmission of natural gas were meager, and the several pipe line flow formulas developed by different investigators gave widely varying; results when applied to problems of pipe-line design. Therefore, further experimental work under conditions comparable to those found in transmitting natural gas was essential before any definite recommendations could be made.

Jan 1, 1931

By Mary Ellen Bruce Large

"In partnership with California Department of Transportation (Caltrans), Federal Highway Administration (FHWA), and with support from International Association of Foundation Drilling (ADSC), Deep Foundations Institute (DFI) organized a workshop on quality assurance (QA) practices for acceptance of post-grouted drilled shafts in conjunction with DFI’s 40th Annual Conference on Deep Foundations. The 1½-day workshop was held on October 15-16, 2015 at the Oakland Marriott City Center in Oakland, CA.Post-grouting, in the context of this workshop and report, refers to the alternative design and construction of base-grouted drilled shafts wherein a grout distribution system is installed during construction and used to grout the base under pressure after the drilled shaft concrete has gained adequate strength, resulting in a stiffer axial-compression load-displacement relationship and additional possible ground improvement effects.The primary goals of the workshop were to•?Identify and summarize the state of the practice for design, construction, inspection, verification, acceptance criteria, reliability and performance of post-grouting.•?Identify gaps and needs in quality assurance that should be addressed for successful use of post-grouting.This report is structured to follow the workshop program: workshop presentations outlined the state of practice and views from owners, engineers and contractors on acceptance of post grouting methods for drilled shafts; and subsequent workshop discussions attended by a small invited group of participants focused on identifying areas of agreement and disagreement on post-grouting best practices, acceptance criteria, design and verification procedures, and inspection requirements. A partial list of attendees of the open and closed sessions is provided as Appendix A, and copies of presentations are included as Appendix B.FHWA and Caltrans are the primary audiences for this report, and its content will be used to develop a roadmap for deploying the findings into policy and practice. The secondary audience is the broader industry group, and the report content will be disseminated in a variety of formats."

Jan 1, 2016

By Mary Ellen Bruce Large

"INTRODUCTIONIn partnership with California Department of Transportation (Caltrans), Federal Highway Administration (FHWA), and with support from International Association of Foundation Drilling (ADSC), Deep Foundations Institute (DFI) organized a workshop on quality assurance (QA) practices for acceptance of post-grouted drilled shafts in conjunction with DFI’s 40th Annual Conference on Deep Foundations. The 1½-day workshop was held on October 15-16, 2015 at the Oakland Marriott City Center in Oakland, CA.Post-grouting, in the context of this workshop and report, refers to the alternative design and construction of base-grouted drilled shafts wherein a grout distribution system is installed during construction and used to grout the base under pressure after the drilled shaft concrete has gained adequate strength, resulting in a stiffer axial-compression load-displacement relationship and additional possible ground improvement effects. The primary goals of the workshop were to•?Identify and summarize the state of the practice for design, construction, inspection, verification, acceptance criteria, reliability and performance of post-grouting.•?Identify gaps and needs in quality assurance that should be addressed for successful use of post-grouting.This report is structured to follow the workshop program: workshop presentations outlined the state of practice and views from owners, engineers and contractors on acceptance of post grouting methods for drilled shafts; and subsequent workshop discussions attended by a small invited group of participants focused on identifying areas of agreement and disagreement on post-grouting best practices, acceptance criteria, design and verification procedures, and inspection requirements. A partial list of attendees of the open and closed sessions is provided as Appendix A, and copies of presentations are included as Appendix B.FHWA and Caltrans are the primary audiences for this report, and its content will be used to develop a roadmap for deploying the findings into policy and practice. The secondary audience is the broader industry group, and the report content will be disseminated in a variety of formats."

Jan 1, 2016