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By Haitao Wang, Shen Wang, Dongyin Li, Yongjia Xu, Jinzhao Liu, Xiangjun Chen

The safe and efficient driving of the roadway along the gob is becoming an increasing challenge due to the influence of the integrity and bearing capacity of the side coal and rock mass in the gob under the roof cutting mining mode. The mechanism of protection of the gob-side roadway is shown by modeling the influence of roof cutting and the application of a destress technique on the lateral coal and rock mass zones. The distribution characteristics of stress, displacement, and fracture in the overburden are analyzed by numerical simulation method under the three working conditions. The results indicate (1) construction of row holes and blasting can form artificial structure’s fracture plane above the roadway, which can effectively cut the connection of overburden. The artificial structure’s fracture plane decreases the peak value of the lateral coal body’s support pressure. The peak point and the critical location of the stress reduction area are both transferred to the deep part at the same time, providing adequate space for the gob-side roadway. (2) The stress arch foot in the lateral rock mass rises to the rock layer at the bottom of the roof cutting plane after top cutting, as does the high-pressure area of deviator stress. The fracture plane prevents lateral coal and rock mass instability and limits the negative effects of roof deformation above the gob-side roadway. (3) The triangle slip fracture zone moves to over the roof cutting drilling zone due to the fracture plane, showing a high position compared to its original zone.

Jul 11, 2023

A new mine has begun production of antimony ore and concentrates in Serbia, Yugoslavia. The mine is operated by the mining and metallurgical enterprise "Aajaca." Initial production is running at approximately 45 thousand tons of ore per year, yielding about 1,500 tons of concentrate. The mine is located on the mountain Kopaonik-Raiceyoj Gori. It is planned to expand production eventually to approach the level of 300,000 tons of ore per year. This level will be a significant addition to the world supply of antimony and will place Yugoslavia among the world's major producers. Currently the United States produces only about 6 percent of its primary requirement for antimony. COBALT -Anglo American Corporation, Ltd. reportedly is considering restarting the Tenke-Fungurume copper-cobalt project in Zaire. Construction on the project was suspended in January because of inadequate financing and political uncertainties. Technical feasibility and financing on a smaller scale than previously envisioned are now being considered. However, an increased copper price may be necessary before any decision to proceed is made.

Jan 1, 1976

By D. B. deur Mostert

This paper was presented at the Coloquium on Management Techniques in the Mining and Metallurgical Industry, which was organized by The South African Institute of Mining and Metallurgy and held in Pretoria during June 1988. The author asks whether technical audits are of any use to management. Technical auditing he defines as an evaluation undertaken by an outsider of whether a technical activity is being carried out correctly. After examining the types of technical auditing, and its prerequisites and procedures, he describes its application in regard to quality, and to production processes and their adequacy. He then answers his question by saying that, not only are technical audits very useful, but they form an essential element in the provision of quality products. In addition, they give management the opportunity of testing whether the activities of the organization are being conducted correctly. This is their most important function in that they alert management to areas of potential growth, modernization, and innovation. However, the use to which technical auditing is put remains the key to its value; that is, its value depends on the positive action that each manager takes as the result of a technical audit.

Jan 1, 1989

Mine drainage and mine reclamation are topics of major interest to the mining industry, federal and local governments, and the general public. This publication and its companion three volumes are the proceedings of a conference held in Pittsburgh, Pennsylvania, April 24-29, 1994. There were twelve sessions (69 papers) that dealt with mine drainage, including modeling, geochemistry, prediction, treatment, control strategies, characterization, hydrology, and case studies. These sessions comprise volumes 1 and 2. The six sessions (34 papers) that dealt with reclamation and revegetation of disturbed lands are included in volume 3. Volume 4 includes the six sessions (34 papers) that dealt with such topical issues as fires at abandoned mine sites, subsidence, hydrology, mine wastes, and policy. Poster session presentations are represented by 49 papers and 92 abstracts that have been placed in the back of volumes 2, 3, and 4, consistent with the subject of that volume.

Jan 1, 1994

By R. H. Widmyer, G. M. Wood

This investigation was prompted by the absence of a simple, accurate method to predict optimum second stage separation pressure in three stage separation operations. Three stage separation as used here includes two separators plus the stock tank. The first stage pressure is usually fixed by gas sales conditions and the third stage is at atmospheric pressure. Thus, the second stage pressure is the only one that may be varied in-discriminantly during production operations. No variations in temperature were considered in this study, even though it will vary among systems, for a change in temperature has little effect on the optimum pressure. Optimum pressures may be determined from flash calculations, but these are tedious unless a computer is available. An early attempt to develop a simpler method&apos; yielded an equation which gave the optimum pressure only as a function of initial and final pressure. Experience, however, confirms theoretical relationships which show that composition as well as pressure and temperature must be a factor. This indicates that the basic relationship should be an equation of the form, where P, is second stage pressure, P, is first stage pressure, A is a function of P. (stock-tank pressure) and the system composition, and n is a function of the number of stages and the system composition. Fig. 1 shows the basic variation of P2 with P for a fixed system composition. A series of such figures clearly showed the effect of composition. The peak of each curve reflects that second stage pressure at which the stock-tank recovery (gal/MMcf) residue gas is a maximum value. DEVELOPMENT OF NEW CORRELATION Wellstreams having 17 different analyses, ranging from low gravity crude to condensate, were used to determine the effect of composition. Each wellstream was flashed through three stages to determine the optimum second stage pressure for each first stage pressure. Equilibrium vaporization ratios proposed by Latham and Campbell were used throughout. The heptane plus fraction, for simplicity, was assumed to have the properties of octane. The results were subjected to an empirical analysis in an attempt to develop a correlation- that would be (1) simple, (2) accurate, and (3) eliminate the need for any flash vaporization calculations. This analysis yielded two equations, one for wellstreams having a specific gravity greater than one (air = 1.0) and one for those less than one. For crude streams (specific gravFor condensate (specific gravity < 1.0),

By L. C. Reese

? Good construction and inspection presumed. ? Capacity-computation factors are independent of construction method. ? To account for variable or uncertain site conditions, anticipated construction problems, and/or minimal inspection, increase factor of safety. ? Conduct load tests and/or develop easily implemented design alternates (e.g., straight shaft in case bell can&apos;t be formed) to reduce factor of safety.

Jan 1, 1988

CONTENTSThe significance of values givenINTRODUCTIONTHE ORE1. DATA SECURED FROM THE MILLING PLANT AS OPERATING BETWEEN 1938 AND 1942(a) Mill Recoveries(b) Mill Flow Sheet(c) Scheelite-Garnet Association(d) Detailed Examination of Mill Performance during 1942Crushing UnitsCoarse Rolls DischargeFine Rolls DischargeFeed to Huntington MillsFinal Ground ProductProduction of -200-mesh Scheelite SlimeSummary of Information on Crushing and Grinding Circuit(e) Detailed Examination of Mill Performance During 1942Concentrating UnitsLocation and Nature of Scheelite LossesSize Distribution of Scheelite LossesDistributor Spigot ProductsSummary of Information on Concentration Circuit(f) Detailed Examination of Mill Performance During 1942 Gravity Plant Feed2. EXAMINATION OF MINE SAMPLES TAKEN DURING 1942(a) Introduction(b) Nature of the Ore(c) Sampling of Mill Feed(d) Testing Technique(e) Minus 1/8-inch Ores-Naturally Broken Fractions(f) Recoveries from Plus 1/8-inch Fractions-Crushed to Minus 1/8-lnch(g) Probable Recoveries Obtainable from Weathered Ores140 Contour120 Contour90 Contour(h) Examination of an Ore Sample from the 90-foot Adit(i) Run-of-Mine Ore(j) Evidence of Maximum Sizes of Scheelfte Present in Run-of- Mine Ore(k) Summary of Information on Liberation and Recovery from the Ores as Mined in 1942 and from the Mill Samples

Jan 1, 1944

By Robert C. Bates

Published information discussing uranium mine radon daughter controls and related costs was examined and used to develop an estimated (projected) cost per ton for any level of control. Results show a clear power function increase of cost for conventional dilution ventilation as the annual exposure limit is lowered. Projections can be made using any assumed changes in consumer price index (CPI) and radon daughter working level months exposure limit. Bounds on the estimated costs are provided, and applicability of the final equation is discussed.

Jan 1, 1983

By F. Rosenblum, P. Spira

"Techniques were developed to determine the oxygen demand of sulphide ore pulps in the laboratory and in concentrators. The effect of variables which influence oxygen demand was studied, and it is shown that the oxygen demand is a measure of the degree of oxidation of the sulphide surfaces. It is suggested that in investigating the significance of oxygen in flotation, the oxygen demand of the pulp is a more suitable parameter than the dissolved oxygen content.Oxygen demand measurements are being carried out with a view to determining the effect of aeration on mill metallurgy and devising improved methods of predicting aeration requirements of sulphide ores.The importance of pulp oxidation in the flotation of massive sulphide ores has long been recognized. At the Noranda concentrator, chalcopyrite could not be floated satisfactorily without a pre-flotation aeration step because the necessary dissolved oxygen was consumed by the large amount of pyrrhotite in the ore. With aeration, pyrrhotite and pyrite were depressed by surface •oxidization, and the resulting thiosulphate level in solution gave a good indication of the end of useful aeration. 1'he present study was prompted by the need to find an alternative criterion for cases where recycled mill water may contain a relatively high concentration of thiosulphate. Preliminary experiments suggested that the rate of oxygen uptake by the pulp -its oxygen demand -might be a practical measure of the end point of aeration as well as a significant parameter in the flotation of massive sulphide ores.Although it has long been realized that oxygen is an important variable in flotation, analytical difficulties precluded detailed plant investigations. Measurements of' dissolved oxygen in mill pulps were first reported by Ralston(i) in 1929. A titration method was used, and because of the delay occasioned by the preparation of clear solution samples, the values obtained were believed to be low. It was quite evident, however, that pulps in the grinding circuit had a lower oxygen content than in flotation. More recently, Woodcock(2,3) used a polarographic probe to carry out oxygen surveys in six Australian concentrators and he generally observed a similar pattern. A large number of other solution parameters were monitored, such as pH, redox potential, reducing power, and reagent and metal concentrations, with the aim of detecting correlations among the measured variables. A few potentin.lly useful relationships were found ""or specific operations in certain plants."

Jan 1, 1974

By K Gordon

A methodology for assessment and remediation of acid mine drainage (AMD) developed at the Sullivan Mine in the West Coast Region has been applied to the closed Blackball Mine, Blackball, West Coast Region. AMD from the Blackball Mine has low pH, high acidity, and elevated levels of iron, aluminium, manganese, nickel, zinc and arsenic. The AMD flows at a variable rate (36 - 101 L/s) into adjacent Ford Creek, causing an increase in acidity and trace element concentrations in the creek. To test the effectiveness of treatment with a simple limestone-based treatment system, a column leaching experiment was conducted over a nine day period. The results show effective removal of acidity, reduction in the concentrations of iron, aluminium, manganese and zinc, and production of alkalinity. To determine if this treatment method reduces the toxicity of the AMD to aquatic invertebrates, a 96 hour ecotoxicity experiment was conducted. The results show a significant decrease in mortality in the treated AMD compared to untreated. The column experiment, in conjunction with the ecotoxicity work, suggest that a passive treatment system consisting of a limestone leaching bed and an open limestone channel may be sufficient to treat the AMD from the Blackball Mine. Further work, such as large-scale treatment trials, is recommended.

Jan 1, 2004

By D. C. Seidel

This report describes generic procedures and equipment arrangements for conducting laboratory-scale hydrometallurgical and related waste-management experiments. It provides a starting point for personnel who have received or are receiving professional training, but do not have specific experience in laboratory procedures. With guidance, it also has application as a resource for technician training. The publication contains chapters on laboratory safety, feed-sample preparation, leaching, solids-liquid separation, and recovery from solution.

Jan 1, 1995

By M. Cross

INTRODUCTION The results of the Japanese dissective investigations have [l-4] transformed our understanding of how the blast furnace operates. These studies revealed an internal structure of the furnace burden with five main zones, as illustrated in Figure 1. In the granular zone the charged material retains its structure whereas in the cohesive zone the iron ore particles are at advanced stages of reduction and form a semi-molten mass with a relatively high flow resistance. In the active coke zone molten iron and slag flow through a matrix of loosely packed coke. The raceway is a relatively small void space generated by displacement of coke due to the hot blast momentum, whilst the hearth is packed with coke, slag and molten iron. [ ] It is now well appreciated that furnace control is largely achieved and maintained by using the burden charge distribution to determine the gas glow distribution within the furnace and, hence, the shape and extent of the cohesive zone. In fact, Wakayama et a1 [5] of Nippon Steel Corporation state that optimum furnace operation is synonomous with the formation of a desirable cohesive zone shape, which in turn is almost solely determined by the burden charge distribution and its mechanical properties [6]. Much of the development work on operating furnaces since the dissective investigations has been oriented towards the identification of external furnace measures which reliably predict the shape of the cohesive zone. Currently the most popular measures are top gas temperature, velocity and CO/CO, ratio profiles [5]. More recently pressure distributions as evaluated from a series of wall measurements down the height of the furnace are also being utilised [7] to identify the position and shape of the cohesive zone. A great deal of emphasis has been placed upon achieving a consistent quality in the burden charge materials, establishing a suitable set of operating conditions and only making changes when forced to, ie., the operation for some reason moves outside a desired operating range or the production requirements change. Operational control schemes based upon this philosophy (eg., Kawasaki&apos;s GO-STOP system [8]) have been remarkably successful at achieving both high production rates and relatively low fuel costs. Mathematical models have long been used as tools to assist in the analysis of the blast furnace process. Although, the models have been useful in post-operative analysis and for identifying trends, etc., they have not proved reliable for detailed design criteria or as the basis for effective control schemes. Such mathematical models have moved from simple statistical correlation, through overall and stagewise heat-and-mass balance calcu-

Jan 1, 1984

By Walter L. Fisher

The public interest in the Alaskan situation is such that, with the consent of the President, I have concluded, at the request of the American Mining Congress, to make at this time a candid, if somewhat informal, expression of the views I have formed as Secretary of the Interior, under whose official supervision much of the administration of the Territory is now placed. Pressure of other matters imperatively requiring attention has prevented their presentation in as precise and comprehensive a form as I had hoped. The absence of the President from Washington has also prevented the submission to him of what I have prepared. I wish to say, however, that no one is more earnest than he in the desire to see a policy of prompt and wise development inaugurated in Alaska, and that the general policy contained in this address has been discussed with him, meets his approval, and will have his support. I have recently returned from an altogether too brief but nevertheless a most interesting and profitable visit to those portions of Alaska that are more immediately involved in the questions now under public consideration. Favored by extraordinary weather and the cooperation of steamship and railroad lines and the assistance of all of the governmental agencies, including the Revenue-Cutter Service, I visited every port in Alaska that seems likely in the near future to become an important entrance to the country. I examined all of the harbor and town sites which for this purpose have attracted any considerable public attention. I traversed the entire length of each of the three railroads that have been constructed in the Terri.tory and made a short trip from White Horse down the upper Yukon. Both before and during the journey I examined a mass of books, records,' and papers relating to the country and its resources. I had conferences with official committees representing the principal communities I visited and with numerous individuals, residents both of the coast and of the interi.or, and conferred with engineers, miners, prospectors, railroad officials, business and professional men.

Jan 1, 1911

Minerals are vital to any industrialized civilization. Annually, the United States uses more than 4 billion tons of new mineral materials, or about 40,000 pounds per person-about half being mineral fuels and the other half being metals and nonmetallics. Stable and economic domestic mining, mineral, metal, and mineral reclamation industries are essential to the economy. The value of United States energy and processed materials of mineral origin exceeds $200 billion annually. Although a number of minerals are imported, especially some designated as "strategic and critical," most U.S. mineral supplies are derived from the domestic mines and processing facilities that you will be seeing, reading about, and visiting as you use this visitor guide. We hope you enjoy your experiences. This pamphlet, a guide to mining and mineral operations that may be observed or visited and some other points of interest relating to minerals, is in-tended to aid tourists and students who are interested in mining. Some may wish to study our Nation&apos;s romantic past; others may plan to enter the minerals industry as a career; still others may have a primary interest in conservation practices. The pamphlet is also intended to aid State and local officials, Chambers of Commerce, and mining firms in answering some of the many questions of tourists and students.

Jan 1, 1977

By Jack Touseull

On November 15, 1972, the Bautsch mine, a lead-zinc mine in Paleozoic dolomites, experienced a massive rock failure involving 3 to 5 million tons. Because this failure was large and extended to the surface, it was included in the Federal Bureau of Mines investigations on "Massive Rock Failures." Analysis of the rock mechanics and mode of failure revealed that failure at the Bautsch mine was the result of the interrelationship of many factors. Factors related to the failure were found to be external and internal to the mining environment. Unlike internal factors, external factors were not apparent and, therefore, many external factors were investigated; some of which are not normally considered in rock mechanics analyses. External and internal factors determined to be of significant importance were: (1) precipitation, (2) fractures, (3) plastic clay layer, (4) topography, (5) rock alteration, (6) bedding, and (7) mining zone dimensions. Because of the conditions at the mine, failure could have been predicted without extensive instrumentation. Application of basic geologic and engineering principles to the internal and external factors could have predicted failure. Alternately, failure would, in all probability, have been delayed by years if, after 1962, mining had been curtailed in the area of failure.

Jan 1, 1980

By Joan T. May

Federal Bureau of Mines studies showed that some organic amine hydrochlorides can be used as dehydrating agents for producing anhydrous magnesium chloride from hydrates and brines. Laboratory-scale tests showed that double salts are formed by reacting 35 percent magnesium chloride brine or spray-dried magnesium chloride with pyridine hydrochloride. Heating decomposed these double salts to anhydrous magnesium chloride and recycle pyridine hydrochloride. Pyridine hydrochloride also chlorinated any magnesium oxide in the spray-dried magnesium chloride. The anhydrous magnesium chloride obtained by the method described contained less than 0.8 percent oxygen. More than 98 percent of the organic amine hydrochloride was recovered.

Jan 1, 1978

By Jerry C. Tien

Changes and the pace of change in China’s coal industry have been extraordinary during the past several years. At least 35 of the 94 former coal bureaus have been restructured into different mining companies and groups. Some of the more productive and efficient ones were further strengthened through consolidation and expansions. And several have even formed, or are in the process of forming, strategic alliances with utility companies, railroads, ports and chemical companies to secure additional reserves and coal sales. In addition, the improvement in coal pricing during the past two years has enabled China’s coal industry to move ahead with some needed changes. Coal mining accidents, though, remain a major concern for the Chinese government. Accidents remain high even though the government has made efforts to shutdown more than 55,000 unlicensed, unsafe small coal operations throughout the country.

Jan 1, 2003

By W. L. Swager

Tramp (undesirable) elements introduced into iron and steel castings via purchased ferrous scrap are evaluated as to their likely degree of future threat to the quality of castings. Conclusions are based on analysis of literature and on nonmail surveys of foundries, scrap processors, trade and technical associations, and others. The existing tramp-element problem is expected to be persistent, but amenable to improved control by foundries and their suppliers. Four recommendations for action are given.

Jan 1, 1981

By Philip C. Tully

These modifications to the Redlich-Kwong equations for pure hydrogen and neon were developed after an unsuccessful attempt to generalize a modification technique previously developed for helium. New coefficients of the B terms were developed by minimizing the residuals. No changes were made in the coefficients of the A terms. For normal hydrogen, B was changed to [0.08063Tc PcT] for temperatures from 980 to 423° K and pressures up to 1,050 atm. The average deviation in Z was 0.36 percent with maximum deviations less than 1 percent for all but a few low-temperature points. For neon, B was changed to [PCT 0.1025T], for temperatures from 120° to 973° K and pressures up to 1,500 atm. The average deviation in Z was 0.34 percent with maximum deviations less than 1 percent for all but a few high-pressure and low-temperature points. Efforts to attain a lower temperature range to comparable accuracy with this type of modification were unsuccessful. In the range of applicability, these equations should be used with caution when calculating derived thermodynamic functions, such as the isobaric specific heat.

Jan 1, 1968

Study on Flotation Experiment of Complex Copper-Lead-Zinc Polymetallic Sulfide Ore in High Altitude Area and its Industrial Application

Sep 13, 2010