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By Charles E. Semler

The possible utility of selected compositions in the systems SrO-ZrO2-MgO and SrO-ZrO2-Dolomite for commercial refractory products was confirmed in this study. Specifically the compositions of interest are located in the sub-systems SrZrO3-ZrO2-MgO and SrZrO3-ZrO2-Dolomite. Both sub-systems have regions that are not affected by hydration, but the sub-system SrZrO3-ZrO2-MgO has a larger candidate compositional region. Solid state phase relations were determined for the subject systems over the temperature range 1600°C to 1300°C, with compatibility diagrams presented for each. The systems appear to show good refractory character with no apparent low melting compositions. As the compositions of commercial interest lie mostly in the higher ZrO2 portion of each system, information is presented regarding the firing treatment required to develop stabilized cubic ZrO2. A list of suggestions for further study of these systems, to further delineate the characteristics required for possible commercial utilization, is presented.

Jan 1, 1982

By K. A. Lewandowski

Leach heaps are plagued with problems due to fine material migrating downwards, clogging the spaces between the coarser ore particles, resulting in decreased metal recovery rates. The use of a binder in agglomeration would allow the fine material to be immobilized, increasing the availability for the solution to come in contact with all the ore. As much as 1.64*1012 BTU per year would be able to be saved if a 25% increase in copper recovery was experienced, assuming that 70% of heap leaching units converted to using agglomeration technology. This is equivalent to approximately 18% of the energy currently being used in leaching heaps.

Jan 1, 2008

By Dan Ifrim, Andre Solecki

Tunneling could be a major challenge to tunneling contractors as tunneling operations can be seriously affected by the Tunnel Boring Machine (TBM) performance. Specifying the appropriate TBM methodology, selection of systems and features, is critical for managing tunnel risks and contribute to successful tunneling project. The paper analyzes tunneling records from the recently completed City of Toronto’s Ashbridges Bay Treatment Outfall tunnel project and underlines the righteous selection of the TBM type and associated TBM systems in achieving good advance rates during tunnelling and managing project risks. The paper intends to draw attention of a few aspects of TBM technical specification importance and highlight the lessons learned from this process.

Jun 13, 2023

By Frederick G. Tickell

GEOLOGISTS have been quick to adopt new methods in locating new oil fields and in finding the extensions, laterally or at depth, of the old fields. For most of these new methods he is indebted to the physicist, the engineer, and the chemist, although he has also drawn from such ordinarily unrelated sciences as bacteriology and protozoölogy. These last-named sciences have been of help in problems dealing with the origin of petroleum and, although not of direct application to oil finding, have furnished evidence of value in learning what oil is made from and what are the natural agencies involved in its formation.

Jan 1, 1932

By R. H. Mullennex

Application of depositional analysis concepts is becoming an ever-increasingly more important and more useable tool in exploration and development of coals in the Appalachian basin. Over the past decade, a rather large number of studies, papers, and publications have addressed various aspects of depositional environments of coals and, to some extent, applications to development. As would be expected as regards a subject so complex as Pennsylvanian sedimentation in the Appalachian basin, certain academic studies have produced conclusions at variance in some aspects to those of other studies. Overall, however, there has been a building- block progression and general refinement with time of understanding of the depositional settings and other factors controlling Appalachian coal distribution, quality, and other minability parameters. Most attempts to explain coal seam characteristics have revolved around a basic deltaic model. Some have attributed certain seam attributes to upper delta plain deposition, other attributes to transitional-lower delta plain settings, and yet others to lower delta plain environments, and so on. While these approaches have provided valuable insight into some general coal characteristics, they are somewhat incomplete and are, in a sense, too broad for specific mine-scale applications. Further, it is apparent that in order for widespread peat accumulation to occur, there must be a drastic decrease in the energy of the depositional system and amount of sediment being brought in, compared to the active deltaic and coastal processes responsible for deposition of the large volume of clastic sediments that dominate the Pennsylvanian system of the Appalachians. Consideration of this fact implies that peats (coals) may not necessarily reflect depositional settings that are directly coincident with those associated with adjacent rocks. Cecil and Englund (1985) address this point, and quite correctly state that "the primary controls on major stages of peat formation are allocyclic processes involving paleoclimate, eustatic changes in sea level, and tectonics." While this statement is inarguable, it does not negate the importance and usefulness of depositional analysis in predicting reserve characteristics that may impact mining and marketability.

Jan 1, 1986

By Shanxi Wu, Jialong Li, Haoyu Hu, Jiqing He, Zhaohui Wang, Bochao An, Shenyi Zhang

There are a large number of thick alluvium and thin bedrock deposits at depth in the Henan coal base. The degree of surface mining is high, and the surface environment is seriously damaged. Using indoor experiments, numerical simulation, and field measurement, it is studied the influence of the mechanical properties of thick alluvium on the surface subsidence characteristics of thick alluvium thin bedrock deposits at depth, taking Zhaogu No. 2 coal mine as the research background. The results show that the compressive strength and elastic modulus of the alluvial layer are linearly negatively correlated with the alluvial layer particle size, linearly positively correlated with the confining pressure, and nonlinearly positively correlated with the loading rate. The thickness of the alluvial layer has the greatest influence on the displacement of surface subsidence and the range of surface subsidence. The advancing mining rate of the working face has the greatest influence on the surface horizontal displacement. The mechanical properties of the alluvial layer affect the evolution characteristics of the caving arch and towering roof beam. The influence range of the 11012 working face is about 550 m, β is about 55.5°, and the maximum subsidence rate of the surface is 12 mm/day. The mining process and separation grouting can be adjusted to control the overburden displacement to reduce surface disturbance and protect the surface ecological environment. The research results of this paper can provide a research basis for the study of surface subsidence under similar geological conditions.

Apr 28, 2024

By Z. Xu, Z. Li

Colloidal interactions play a critical role in mineral processing, including grinding, physical separation (particularly flotation), dewatering, and tailings management. Despite great energy input in comminution to liberate valuables from gangues, heterocoagulation between valuables and gangues would prevent the separation of valuables from gangues. On the other hand, selective coagulation/flocculation to increase the size of desired fine particles could enhance physical separation and dewatering, while dispersion is needed for fine grinding. To control the state of colloidal dispersions by creating favorable conditions, it is of paramount importance to study colloidal interactions in a relevant system and understand underlying mechanisms. This review summarizes recent advances in developing the-state-of-the-art techniques and novel methods of measuring colloidal forces, including atomic force microscope, surface force apparatus, zeta potential distribution measurement, quartz crystal microbalance with dissipation, and our recently developed integrated dynamic force apparatus. The basic principle of each technique was introduced first, followed by a summary of critical information derived for the relevant mineral processing systems. Finally, the pros and cons of each technique were discussed to emphasize the use of complementary techniques that assist in solving fundamental problems in mineral processing.

By Irving Hartmann

The record of safety in the use of permissible explosives in United States coal mines has been excellent, due in great measure to the persistence with which research has been carried on in the Bureau of Mines, to the development of permissible explosives, and to the cooperation of mine operators and workers in using permissibles in a recommended manner and in the effective though gradual replacement of black powder and other nonpermissibles. The demand for increased rate of coal production, changes in mining conditions and minim methods, and introduction of new mining machinery have resulted in modified or new blasting practices. To keep abreast of these developments the Bureau of Mines conducts investigations under actual mining conditions at the Experimental coal mine near Pittsburgh, Pa. Several years ago an extensive study was complete to determine conditions under which the allowable charge limit for permissible explosives per shot hole might be raised from 1.5 to 3 pounds without undue risk of gas or coal-dust ignitions. As a result of the study, this increase in the charge limit was authorized under certain specified conditions in 1948,5/ greatly facilitating production schedules.

Jan 1, 1954

By Joseph Grumer

Reported fiscal year 1973 studies of fires and explosions seek to develop capabilities during mining operations to detect and quench ignitions of gas in the face area, to detect and quench by means of passive or triggered barriers explosions propagating in rock-dusted coal dust, and to detect incipient fires early enough for easy extinguishment. Research discussed includes minimum air velocities to lift coal or rock dusts, surveys to determine adequacy of rock dusting, chemical agents to quench gas or coal dust explosions and their relative efficacies, spectra radiated by explosions, and nozzle sprays of extinguishants.

Jan 1, 1973

By Richard E. Thill

Engineering properties of rock are essential in most phases of mining from site reconnaissance through mineral processing. Review of the literature indicates, however, that property data is scarce for most coal measure rocks in the United States. The Bureau of Mines, U.S. Department of the Interior, has undertaken a wide-ranging testing program to provide more complete property data for coal strata in the U.S. coal basins. The property data are expected to have application in geophysical exploration, the development of pre- mining and hazard detection probes and instrumentation, mine design, engineering and rock mass classification, subsidence engineering, and ground control. This paper describes the comprehensive program encompassing in situ geological, geophysical, and geotechnical properties and laboratory determinations of acoustic, electromagnetic, physical, mechanical, and index properties and discusses results for 500 ft of coal measures at a minesite in the Northern Appalachian, Eastern Coal Province.

Jan 1, 1982

By John (Jack) D. Young, Frank M. Wheeler

Metallurgical plants are typically large, complex facilities. Their design is a multidisciplinary activity with a wide range of inputs, based on: the business case; metallurgical and process requirements; and the main processing equipment selection. Many constraints limit what can be achieved. Appropriate phasing of the design and development, and clear go/no-go decision criteria, are critical to successful implementation of a plant design project. Risk management concepts are used as a framework for successful project development, working from the business case, through project development, to implementation and startup, paying constant attention to technology, safe design, and sustainability. 1.1 INTRODUCTION The subject of “Metallurgical Plant Design” is the design of metallurgical plant facilities in the broadest sense. Plant design represents the culmination of many multidisciplinary activities: knowledge of process metallurgy is applied to design facilities to manufacture useful, economical, metal-based products. In the field of metallurgy, plant design is often overlooked, and its unique requirements are commonly not well understood, let alone appreciated. This book is a contribution to remedying this situation. The focus is the specifics of the metals industries, because an extensive literature already exists on the general topic of plant design.

Jan 1, 2015

By H. C. Miller

For nearly a score of years the American petroleum industry has faced the problem of maintaining its economic structure while oil -producing potentialities greatly exceeded the increasing market demand for oil and its products . However , the combination of maximum civilian demand with rising defense requirements caused an all - time peak in crudeoil production in the latter half of 1941 , with a daily production (as estimated by the Bureau of Mines ) of 4,139,000 barrels in December - an increase of 16 percent over the daily production of 3,573,000 barrels in December 1940. In the event of a long war , a continuing , steady, and adequate supply of petroleum and its products for military and required civilian needs is essential, and the efficiency of recovery of oil from natural underground reservoirs will have to be maximum. Whereas it may not be possible to increase production in some fields , the output from others may have to be drawn at a much faster rate than formerly . More than 10 years ' experience in operating oil fields under proration control has demonstrated to petroleum engineers that some of the efficiency of recovery of oil from reservoir sands and rocks is sacrificed if the oil and gas are withdrawn at too . rapid a rate . As petroleum is an irreplaceable natural resource for which suitable substitutes probably will not be available in desired quantities for many years , any producing method that jeopardizes the quantity of oil that may be recovered from underground reservoirs must be considered at this time of declared war against aggressor nations as conflicting with the best interests of national defense . At best, the efficient recovery of oil is a complex problem . It involves not only a knowledge and application of the fundamentals of fluid flow through porous mediums, but the sources of energy responsible for the movement of oil and gas through reservoir sands and porous rocks to wells must be known to determine the best practices for extracting these hydrocarbons . Reservoir energy is of two kinds - (1 ) water under hydrostatic head underlying the oil in the extraneous parts of the reservoir system and ( 2 ) natural gas under pressure as "free " gas in the reservoir or in solution in the oil . Inasmuch as the efficiency of oil recovery depends largely on the manner in which reservoir energy is used to move oil through reservoir sands and porous rocks to wells , optimum practices for withdrawing the oil cannot be determined until it has been established that the oil in the reservoirs is being forced to wells by an internal gas expansion, by a natural water drive , or by a combination of gas expansion and water drive . There is a fundamental difference in the performance characteristics of gas - expansion and water - drive reservoirs . In a strictly gas - expansion reservoir the energy available to move oil and gas through the porous formations to wells results solely from gas pressure , which is maximum when the reservoir is tapped by the first well . Pressures decline as oil and gas are withdrawn ; consequently, the energy available for moving oil and gas through the oil - bearing formations to wells decreases with production . Curtailing the oil - production rate or shutting in gas - expansion reservoirs entirely will not act to replenish energy previously used in the production of oil and gas ; in their operation , therefore , it is especially important not to waste reservoir energy - the production of oil with high gas : oil ratios will be reflected in lower ultimate recoveries of oil .

Apr 1, 1942

By Cloyd M. Smith

A FEW years ago, the Ventilation Committee established the practice of presenting one topic each year for discussion at the annual meeting. The practice has met good response on the part of committee members and I suggest that it be continued. The topic chosen for this year, "Underground Anemometry," is a topic which has bothered me for more than 20 years. It seems to me that the coal industry is content to rely on slipshod methods for measuring the rate of flow of air underground, so I prefaced my discussional charge to committee members with the statement that I regard air measurements made in the usual way, with hand held anemometer, as no good. Agreements and disagreements came in from more than a dozen engineers, some of whom are with operating companies, coal and metal; some with manufacturers; others with government agencies.

Jan 1, 1949

By George W. Heunisch

The properties of Neutra-Fix® and Neutra-Ment® , two new lime substitutes for the treatment of acid mine drainage (Arm), have been compared with lime and Alkament®, two products presently in use for AMD treatment. The two new products are basically dolomitic byproducts and produce sludges that are more compact than those from lime. Sludge settling rates are faster than lime with iron concentrations after 24 hours that comply with EPA regulations. Material utilization and optimum pit are reported.

Jan 1, 1984

By R. Nilsson

In the present work, an assessment of the sulphide capacities of a number of binary and ternary slag systems have been carried out in the light of a sulphide capacity model. The model is based on the expression: {CS- exp (-A G °/R T) ? ao2 / fs2-} where AGO is the standard Gibbs energy change for the above reaction, ao2 is the activity of oxygen ions and f, is the activity coefficient of the sulphide ion in the slag. In the present model, the ratio (ao2/fs2) is optimized for the experimental data available in literature. The systems assessed are the binaries MnO-SiO2, CaO-SiO2, Al2O3-CaO, as well as the ternaries CaO-Al2O3-SiO2 and CaO-MnO-SiO2. In the case of all these systems, the experimental data available in literature were complemented by measurements carried out at the Division of Theoretical Metallurgy. The sulphide capacities of some FeO- containing binary, ternary and quaternary slags are also examined. The potentiality of the model to estimate the sulphide capacities of complex slag systems from binary and ternary data is demonstrated.

Jan 1, 1996

By JUAN DIAZ, Kray Luxbacher, Steven Schafrik, Dionissios T. Hristopulos, Zach Agioutantis

Methane gas is emitted during both underground and surface coal mining. Underground coal mines need to monitor methane gas emissions to ensure adequate ventilation is provided to guarantee that methane concentrations remain low under different production and environmental conditions. Prediction of methane concentrations in underground mines can also contribute towards the successful management of methane gas emissions. The main objective of this research is to develop a forecasting methodology for methane gas emissions based on time series analysis. Methane time series data were retrieved from atmospheric monitoring systems (AMS) of three underground coal mines in the USA. The AMS data were stored and pre-processed using an Atmospheric Monitoring Analysis and Database Management system. Furthermore, different statistical dependence measures such as cross-correlation, autocorrelation, cross-covariance, and variograms were implemented to investigate the potential autocorrelations of methane gas as well as its association with auxiliary variables (barometric pressure and coal production). The autoregressive integrated moving average (ARIMA) time series model which is based on auto-correlations of the methane gas is investigated. It is established that ARIMA used in the one-step-ahead forecasting mode provides accurate estimates that match the direction (increase/decrease) of the methane gas emission data.

Aug 2, 2022

By W. F. Watts

The U.S. Bureau of Mines has conducted research on methods to reduce and to measure diesel particulate matter (DPM) aerosols in underground coal mines. One objective of this report is to present findings from an investigation of the DPM reductions obtained by an engine-mounted integrated control system consisting of a dry system (DS) and a diesel particulate filter (DPF). Another objective is to present results from the usc of a size selective personal sampler to measure DPM concentrations in an underground coal mine. Bureau laboratory tests of the integrated dry system and diesel particulate filter (DS-DPF) have shown that DPM emissions can be reduced up to 97 pet with little change in gaseous emission concentrations. The DS-DPF is undergoing certification tests conducted by the Mine Safety and Health Administration (MSHA). Subsequent to passing all safety requirements, it will be tested in an underground coal mine. A baseline survey of DPM concentrations and aerosol size distributions in a cooperating mine was completed in August 1988. A prototype DPM personal sampler was tested during this survey. Based on results from this test, an improved unit has been developed. This unit is scheduled for extensive field testing by MSHA in 1989.

Jan 1, 1989

By A. Lubinski, C. R. Stewart, K. A. Blenkarn

Storage porosity has been considered one of the important pore geometry characteristics of heterogeneous-porosity limestones. Storage pores are only containers for fluids, in contrast to flow channel pores which both contain fluids and provide continuity for fluid flow. The concept of another geometry characteristic, "poro-striction", is presented as a second pertinent variable in describing limestone pore space. In simple terms, poro-striction is a measure of the flow resistance between storage and flow channel pores. Alternating-flow core-testing theory provides flow relationships which can be used to divide the pore space of heterogeneous-porosity media into flow channel and storage pores and to measure the "porostriction" of the latter. Experimental application of this theory to naturally occurring heterogeneous limestones shows that "porostriction" and the ratio of storage to flow channel pores can be estimated. Porostriction and porosity ratio are microscopic characteristics which should influence oil-recovery efficiencies during certain types of displacement processes. A knowledge of pore geometry should be valuable in designing or selecting the most effective oil-recovery process for heterogeneous limestones containing storage porosity. INTRODUCTION The primary and secondary recovery of oil from limestone (carbonate) reservoirs has been and will continue to be a major source of the world's supply of petroleum. Oil recovery from this type of formation is strongly influenced by the size, shape and arrangement of the pore spaces which hold the formation fluids. Therefore, it is expected that better knowledge of pore geometry would lead to design of more effective recovery processes. The concept of storage and flow channel pores has been presented as an important characteristic of limestone porosity.1 In this concept, storage pores are only containers for fluids, whereas flow channel pores are those pores which both contain and transmit the fluids. The work reported herein involves the concept of an additional pore characteristic called "porostriction". This characteristic can be visualized as the flow resistance between the storage and flow channel pores. This resistance is an important pore geometry characteristic because it determines how easily gas and oil can replenish fluids removed from the flow channel pores. Fatt and co-workers at the U. of California have studied the effect of storage porosity and a factor similar to porostriction on transient-flow response of models of porous media during a pressure build-up or drawdown test.55 These models consisted of porous sandstone cores with artificially simulated storage pores. It is the purpose of this paper to describe tests which permit the storage porosity and porostriction of actual reservoir core samples to be estimated. The tests used for this purpose involved not transient tests but, rather, an alternating-flow technique in which pressure and flow are varied according to a sine-wave relationship. This technique may offer advantages over transient methods. THE POROSTRICTION CONCEPT Before discussing alternating-flow (A.F.) tests in core samples, it is necessary to define the porostriction parameter. For this purpose attention is focused upon an elemental volume v representative of a porous medium having both flow channel pores and restricted-access storage pores. For such an elemental volume, it is considered that the storage porosity is combined to form a single pore and that the access into the storage porosity may be represented by a single capillary tube connecting the single pore to the flow channels of the elemental volume. Let the radius of the capillary tube be designated as Rc and its length as L,. When fluid flows into or out of the pore, the following equation (Poiseuille's law) relates flow rate q to pressure drop p, and the physical characteristics of the tube and the fluid of viscosity jx.

By Joseph Kuti

Longwall mining is the term used for the underground extraction of a wide and deep panel of coal. Such a panel may be blocked out by one or more entries on either side ("head" and "tail") of a longwall face. If all the entries are pre-driven, the panel extraction is termed longwall retreat mining. With one exception, all the longwall faces in the United States are of this type. (1) prior to the general decline in the rates of production with Continuous Miners, the development of the multiple entries generally kept ahead of the longwall extraction rate. This is no longer the case: longwall extraction rates far exceed the rate of development. In addition to this problem, in newly established mines, the development of a haulage and bleeder system based on multiple entries results in a lead-time of three years or more before longwall mining can be applied. This is one reason why earlier projections and much of the optimism attached to longwall mining as a principal "savior" in the energy crisis should be viewed with some caution.

Jan 1, 1978

By K. B. Bengtson

This task report provides the process technology, preliminary design, capital and operating costs for a 25 TPD pilot plant to produce cell-grade alumina using a clay/hydrochloric acid extraction - HCI gas induced crystallization process. The report consists of six volumes: I - Process Technology and Costs; II and III - Equipment Lists, Specifications and Quotations; IV and V - General Specifications; VI - Drawings. The process was selected by the Bureau of Mines as the more promising method to produce cell-grade alumina from clay based on the results of the two previous task reports under this contract: Task I - Comparison of Six Processes (alunite, anorthosite-lime sinter, clay/sulfurous acid, clay/nitric acid, clay/hydrochloric acid evaporative and gas-induced crystallization) and Task 2 - Comparison of Two Processes (clay/nitric acid and clay/hydrochloric acid - gas induced (crystallization). The pilot plant process utilizes a unique dual crystallization process to produce aluminum-chloride-hexahydrate crystals having sufficient purity when decomposed to meet stringent alumina product specifications. The size of the 25 TPD pilot plant has been selected to permit scale-up to commercial size plants of equipment, technical and economic parameters. The capital cost estimate for the pilot plant, exclusive of fee and escalation, for a southeastern U.S. location is $52,311,000 expressed in 1979 dollars. The total time required to construct the pilot plant including engineering and procurement is 32 months. The operating cost to produce the estimated 9,000 tons of alumina required for testing in Hall cells is $40,91[0],190 expressed in 1979 dollars.

Jan 1, 1979