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By R. F. Chaiken

The Bureau of Mines has conducted a study of mine fires in the Anthracite Region of Pennsylvania to determine the most effective approaches to fire control in this area. The problems involved in controlling an anthracite fire include the geological and mining conditions in this area, the propagation characteristics of anthracite, the fire control methods available, the hazards associated with these fires, and the mar-ginal effectiveness of past fire control projects. From this genecal background, fire control options were discussed as they apply in ISBO to the Centralia mine fire. Probable effectiveness, feasibility, and costs were assessedv The options evaluated include four excavation plans, flooding, hydraulic flushing, water curtain isolation, mining to construct an underground carrier, burnout control, and relocation of the community. The most advantageous from a technical viewpoint is an excavation method combining complete excavation of the fire zone within the borough with trenching to confine the remaining fire. It appears that for many anthracite fires, as for the Centralia mine fire, there are no available control measures that have a moderate cost, are proven effective, and produce minimal disruption on the surface.

Jan 1, 1983

By Manfred Krutein

Ocean mining has a number of problems which are critical to its development: ? Political hurdles on national and international stages ? The worldwide economic situation, with the possibliity of a recession ? Financial difficulties in funding further work ? Technical problems for the development of ocean mining and transport subsystems ? Demands for technology transfer This paper touches the last two points and provides some thoughts for discussion and creative objectification. The many technical problems of ocean mining will be identified and some proposed solutions will be investigated relative to the state-of-the-art technology of ocean mining and nodule transport. An outlook into the future attempts identification of the steps necessary to eventually develop components for workable systems that are not only technically but also economically feasible.

Jan 1, 1978

By Robert A. Siokler

Approximately 75 percentage of the earth's land surface is comprised of shale or shale-like materials. Shale itself is composed of the residue from an almost infinite variety of weathered parent materials which have undergone deformations ranging from intense to negligible. Under standard test procedures, shales exhibit a very wide range of physical properties particularly if the test specimen is subjected to a change in moisture content, when the original test values may vary from 0 to 100 percentage. It is this wide variation in physical property values compounded by its ubiquitous presence that makes shale such a problem material to engineers. In reviewing the literature relating to shale, it is evident that the "problem" has been approached from many directions. In order to understand why shales behave as they do, investigators have sought mineralogical, geological, chemical, electrical, and physical answers. Each study yields valuable academic information, but few contribute much of value to the engineer in the field. Many valid relationships between shale strength or competency and clay type, clay content, organic content, water content, grain size, cementation, density, porosity, etc, have been established. Yet it is very difficult to extend these understandings to the in situ condition with results that can be used by the field engineer. One major reason earlier work has not produced better information lies in the ambiguity of the definition of shale. It is apparent that no one laboratory parameter can be successfully used to provide sufficient engineering information to properly describe in situ conditions. For example; shale with swelling clays will produce low strength values provided: the swelling clay is in sufficient quantity, the clay is dispersed throughout the medium involved, and there is a low value of cementation. Shales with high unconfined compressive strengths have been found with very low shear strengths. Sandy shales often provide as many ground control problems as clay shales. Shales of similar nature may provide good roof conditions in one part of a mine yet in another part of the same mine the apparently identical shale may cause substantial problems. A clear need exists to classify shale in a manner which will enable the engineer to better predict the strength and durability of shale-like materials. Studies at the University of Missouri-Rolla (UMR) have focused on finding parameters which influence durability and competency, while being discretely discernible through uncomplicated testing. Initial research concentrated on distinguishing shale8 on the basis of standard physical tests such as: unconfirmed compression, triaxial shear, and slake durability. As results accumulated, however, it became evident that moisture content played a much greater role in determining competency than had been recognized previously. As a result the focus of the research turned to developing tests which would evaluate the influence of moisture on shale behavior. The above work then became a foundation for a second phase of investigation in which a suite of standardized tests were developed to provide a classification procedure. From this study five tests were identified as being critical: Moisture Activity, Atterberg Limits, Submersion, Unconfined Compression, and Shore Hardness.

Jan 1, 1986

By J L. Mauk

The Martha epithermal Au-Ag deposit contains multiple generations of quartz veins with a range of textures. We examined: +        vein textures, +        crosscutting vein relationships, and +        the paragenetic sequence within the pit walls as well as a wide range of hand specimens. Samples include host rock, breccia, and veins, but these groups are not distinct; instead, they form a continuum.   Veins at Martha mine show a wide range of textures on a local scale; these textures also change significantly over both the lateral and vertical extent of the pit. Common textures include crustiform bands, comb quartz, colloform bands, platy quartz, massive quartz, drusy quartz, sedimentary textures and brecciation.   Vein grades relate to textures. Many textures, including crustiform, platy, cherty, and sedimentary textures display predominantly low grades, but some textures are linked with high grades, such as ginguro, massive and comb quartz where they are associated with visible base metal sulphides and/or electrum. Host rocks and most breccias are low grade, as most samples contain <2 ppm Au.

Jan 1, 2006

By R. F. Balazik

By March 2001, shrinking global markets, reduced consumer spending and declines in domestic manufacturing and industrial output ended the longest economic expansion in US history and pushed the nation’s economy into its first recession in a decade. Aggravated by the terrorist attacks of Sept. 11, the recession led to large reductions in the domestic production of processed mineral materials. Some of the most significant production declines in the US metals industry were registered by aluminum, copper and steel producers. They faced strong foreign competition, higher energy costs and lower prices for their products. However, homebuilding and other domestic construction sectors — major users of nonmetallic mineral products such as cement, brick, glass and stone — remained strong enough to help raise the output of industrial mineral materials slightly above previous year levels. A strong US dollar continued to weaken the competitive stance of US metal and nonmetallic mineral materials companies alike against foreign producers in markets at home and abroad.

Jan 1, 2002

By W. W. Staley

This paper discusses the design of small head frames that will fill the needs of prospectors and small operators whose operations are conducted through shafts. The head frames considered were designed to handle relatively small tonnages. It was assumed that the shafts in which buckets are used would not exceed 300 feet in depth and that not over 60 tons of rock would be hoisted, in, 14 hours. In the design of the larger head frames, a hoisting capacity of about 250 tons per 6 hours from a depth of 300 to 500 feet was assumed. Under these conditions, hoisting speed, rate of acceleration, and weight of rope have a negligible effect on the head frame design and, therefore, have been ignored in the following, discussion. Because timber is relatively cheap and easily obtained in most mining areas, the discussion has been confined to timber construction.

Jan 1, 1937

By Enrique Albarrán, Julian Hernández

"In 1942 The “Presa Mixcoac” dam was built, along with 15 other dams, to control the rain fall waterin the mountains west of Mexico City. Mexico City’s population at that time was around 1.5 millionpeople, and the dam was way out of the city."

Jan 1, 2016

By Vaughan R. Voller

"The wide range of length and time scales found in solidification processes are outlined and discussed. Methods for Direct Microstructure Simulation (DMS) are introduced. Key features in sharp interface and phase field models are presented. Concepts in micro-macro solidification modeling are covered. Basic details of microstructure and segregation models are provided. A description of a recent segregation micro-macro model is presented in detail.IntroductionA solidification process involves the containment of a liquid region, which, due to cooling, transforms over time to form a fully solid product. The development of the solid microstructure and the segregation of solute components during this transformation are controlled by phenomena that occur across a wide range of length and time scales. A ""successful"" model of a given solidification process needs to account for these phenomena. Standard models of solidification employ a discrete grid of node points and associated volume elements in the special domain, with a discrete time step to track the transient changes of nodal values, describing the composition and microstructure. Through the use of such models significant progress has been made towards a complete understanding of solidification process and phenomena (see the conference proceedings in Refs [1-9]). As solidification models become more sophisticated, however, they all run into the problem of resolving the full range of disparate space and time scales.Two approaches can deal with this problem1. Direct Microstructure Simulation (DMS) where the grid size and time step are chosen to scale with the smallest length and time scales of the given problem.2. Micro-macro modeling where the grid size and time step scale with the macroscopic process scale and phenomena at smaller scales are accounted for via sub-grid modeling and volume averaging.Currently full DMS of solidification is beyond the reach of available computer power and the application and development of micro-macro models is an important and critical research area."

Jan 1, 2001

By A. M. McKim, J. S. Ambler

"The iron ore of the Scully Mine is upgraded from 36 per cent Fe to 66 per cent Fe through single-stage crushing, wet autogenous milling, sizing by vibrating screens and two-stage spiral separation, followed by a process in which the concentrate is dried and then further improved by high-tension separators. The capacity of the concentrator is 17,000 long tons of concentrate per day. Discussion of the operation will recognize the special problems encountered in handling preponderantly fine ore, relate issues of interest regarding wear and review mechanical innovations found to be advantageous at Wabush. The modern trend toward big equipment, thoroughly instrumented, has been the theme of design. Effects on availability must be a consideration in this choice, and sectionalizing of circuits to minimize these consequences is as important as streamlined maintenance."

Jan 1, 1969

By M. Leslar

Slope monitoring has been an important issue in static terrestrial lidar for some time. Several solutions for monitoring the progress of a slide have been devised over the years. All of these solutions have required users to be in the field operating the lidar equipment. This paper presents a new system developed using the Optech ILRIS-HD or ILRIS-LR lidar and the scripting language of PolyWorks to produce an autonomous slope monitoring system. This system has proven invaluable in detecting and alerting mine workers to potential danger within their mine sites. It has already been deployed in two mine sites and is scheduled to be installed at a third.

Feb 27, 2013

By Norman G. Foster

The mass spectra of four tertiary butyl substituted thiophenes are reported. A comparison and contrast with earlier structure correlations made by API-RP48 mass spectroscopists is presented. The fragmentation routes of these types of molecules are discussed and explained in terms of existing theories in mass spectrometry. Low ionization voltage data are presented to support the mechanistic picture developed. Structures are inferred about some of the ions, and these are correlated with existing theories. Metastable peaks in the spectra are used to support the fragmentation paths. The presence of doubly charged ions in the spectra is noted and the possible implications toward mechanisms discussed. The general picture of simple, small fragments leaving the ion moiety upon further fragmentation is developed in detail. Some suggestions are presented for further work utilizing isotopically labeled molecules to establish firmly the general picture of fragmentations of the alkylthiophenes.

Jan 1, 1966

By Gene R. Reid

The contract objective is the development of an Automatic Fire Control System for Mobile Underground Metal Mining Equipment. The Phase I Report, which described the projected data handling plan, was published on July 24, 1975. The Phase II effort covered the period from July 24 through December 2 and accomplished the following objectives: ? Acquisition of data in accordance with the project data handling plan. Data were acquired through visits to twenty mine sites in ten states and Canada; visits to Bureau of Mines and MESA facilities; visits to mobile equipment manufacturers; and an extensive literature search. ? Analysis of accumulated data which provided the following specific types of design inputs: selection of the type of mobile underground equipment found to represent the greatest overall fire hazard; typical operating conditions for the vehicle; characteristics of the reported fire experiences; and performance, cost and maintenance factors affecting potential purchases of automatic fire control systems for underground mining equipment. ? Development of the AFCS design concept. Utilizing the data analysis results and considering the state-of-the-art of fire control system components, a recommended design concept was developed with particular emphasis placed on the need for a low cost and reliable system. Design trade-off studies are provided for the recommended system and for four alternate system concepts.

Jan 1, 1975

By P. Walford, C. Mealin, D. Good

"The geology of the Ore Fault Ni-Cu deposit has been reinterpreted in the light of recent studies of the geology of the Neoarchean Bird River Sill Complex and the occurrence of economic Ni-Cu and Zn-Cu-Ag mineralization. The Ni-Cu sulfides are hosted by the lower of two parallel NNW-trending and moderately W-dipping mafic-ultramafic intrusions related to the Bird River Sill Complex. The bod¬ies intruded a bimodal volcanic suite consisting of weakly deformed mafic flows and felsic pyroclastic rocks. The mafic volcanic rocks are geochemically related to the MORB-type rocks of the Lamprey Falls Formation, and the felsic volcanic rocks are related to arc-type rocks of the Peterson Creek Formation. The original pyroxene- and olivine-dominated mineralogy of the sills has been replaced by variable ser¬pentine-amphibole-talc-carbonate assemblages.The Ni-Cu sulfide assemblage exhibits textures and geochemical signatures typical of orthomagmatic sulfide mineralization. The sulfide minerals are associated with cumulate layers of magnetic ferrochromite that range in thickness from a few to tens of centimeters. A later event of Zn-Cu-Ag sulfide mineralization associated with quartz veining and garnet-chlorite alteration along a fault that strikes north, dips vertically, and cuts all rock types. The mineralized fault is cut by the NE-trending Peterson Creek shear zone. Where the Ni-Cu and Zn-Cu-Ag mineralized zones intersect, remnant magmatic features such as amphibolite or cumulate ferrochromite bands occur within quartz veins or local chlorite alteration. The mixed zones contain a very unusual polymetallic assemblage of Ni, Cu, Zn, Ag, and platinum group elements (PGE)."

Jan 1, 2009

By J. R. Thoenen

This paper outlines briefly results of seismic measurements recorded in the vicinity of quarry blasting under practical operating conditions. The data cover field work done from January to the middle of August 1930, during which time records were made of 61 blasts in 19 quarries. Of the tests made, one was in biotite-gneiss, two in dolomite, two in a flintlike volcanic complex, three in gabbrodiorite, five in trap rock, and six in limestone. One quarry was in Alabama, two were in South Carolina, two in New York, four in Kentucky, five in Connecticut, and five in Massachusetts. Explosive charges ranged from 0.30 pound to 41,900 pounds, and the method of shooting varied from mud caps through hammer and wagon drill holes to churn drill holes and coyote tunnel shots.

Jan 1, 1937

By G. M. Kintz, Charles B. Carpenter, G. W. Jones

"INTRODUCTION At 9:12 a. m. on April 16, 1947, the ammonium nitrate cargo in hold 4 of the S. S. Grandcamp, a 7,176 gross-ton Liberty ship owned by the French Government, detonated at pier 0 of the Texas City Terminal Railway Co., Texas City, Galveston County, Tex.This detonation was the first of a series of explosions and fires that took the lives of approximately 600 persons, injured 3,000 other persons, and caused a property damage and business loss that will exceed $58,800,000. It has been estimated that the life, accident, and workmen's compensation insurance loss will be $8,200,000.At 1:10 a. m. on April 17, 1947, the ammonium nitrate cargo in hold 5 of the S.S. High Flyer, a 6,214-gross-ton Liberty ship owned and operated by the Lykes Bros. Steamship Co., Inc., detonated at pier L. This explosion materially increased the property damage caused by the first explosion, in between 50 and 100 persons, and is believed to have taken the life of only one person.The exact number of casualties resulting from the Texas City disaster may never be known. On June 22, 1947, 65 days after the explosions, the red Cross and the Texas Department of Public safety repoted:,""Identified dead, 405; unidentified dead, 63; believed missing, 100; injured, 3,000; hospital¬ized, 600; still in hospitals, 37."""

Feb 1, 1948

By C. L. Emery, A. V. Corlett

"The stress equilibrium is disturbed in a body of rock by a mine opening and is restored by a redistribution of the stresses around the opening. The pattern of the redistribution of unilateral stress around an opening has been established by mathematical analysis and photoelastic measurements. The pattern for multilateral stress is found by superimposition of unilateral fields. The mathematical analysts do not use the elastic moduli as parameters and they are not significant in photoelastic work. The medium is isotropic. The concept of unilateral stress from vertical loading and the classical pattern of its stress distribution around openings does not explain commonly observed failures around the perimeters of mine openings. They show evidence of compression where tension is postulated.When it is recognized that few minerals and perhaps no rocks are Hooke Solids, most rocks must be St. Venant Solids. The components have varying degrees of elasticity and viscosity. The assembly will be-have elastically to rupture under shock loading, but when loaded short of rupture will adjust viscously to equilibrium. Similarly, the highly elastic components may initiate rupture before equilibrium can be established when stress is instantaneously relieved. Polycrystalline adjustments may produce permanent deformation. The mechanics of consolidation, especially in sedimentary deposits, ac-quire a stress component normal to the direction of compaction which can exceed that of the loading. It is one source of prestress. There are others. The principles of prestress design are based on the normal beam reactions, modified by a built-in compression in the lower chord. When the beam is loaded to design limits, the lower chord retains some compression and the whole beam depth is effective in compression. Some of the . common evidences of failure in compression over a mine opening can be duplicated in a prestressed experimental model.When the triaxial stress pattern is recognized and suitable measuring techniques are devised, mine design can be done on a rational basis."

Jan 1, 1959

By Stefan Mede

Robot Supported Moulding—this is the name of Herrenknecht Formwork’s entry to the world of automated segment production. What had been considered impossible for a long time, has been achieved by Herrenknecht experts together with the Swiss company Marti AG: unmanned segment production on the working line. The moulds open and close autonomously with the help of a hydraulic system. A robot cleans and greases the moulds at one work station and inserts the injection sockets at another. The next step will include further automation and digital networking of all processes from production to installation in the tunnel.

Jun 13, 2021

The Round Hill gold-scheelite deposit is located three kilometres from Macraes Flat and approximately 60 kilometres due north of Dunedin, New Zealand. A mining feasibility study is currently being undertaken on the deposit by BHP Minerals (New Zealand) Limited, who are the managers and operators of a Joint Venture with Home Reef Mining Limited. BHP has a 70 per cent equity in the project area.

Jan 1, 1987

By Roberto Busato Belger

- Fertilizer Business Overview - Supply -Demand Balance in the World - Supply -Demand Balance in Brazil - Brazilian Market Growth Opportunities - Fosfertil Operations - Fosfertil Expansion Plan - Salitre Project - Project Characteristics - Technical Challenges and Solutions - Technical Support Studies Conclusions

May 1, 2010

By Pfeifer H. C, Nicacio P. A D

Sinter has been used as part of the metallic charge in large-scale blast furnaces for many years with the well-known benefits in terms of productivity and fuel consumption. However, because of the high investment in a conventional sinter plant, small blast furnaces and the associated integrated mini steel plants have not taken the advantages of using sinter. Recently KTS Korf Tecnologia Siderurgica, a division of Mannesmann Demag Ltda in Brazil, has developed a mini sinter plant for which the investment is compatible with small blast furnaces. Consequently, it is of great interest to evaluate the economical impact of using sinter in such small-scale integrated steel plants. In order to compare two alternatives, ie 100 per cent ore and 70 per cent sinter in the blast furnace burden, mass and heat balances for the entire operation from sinter plant through the blast furnace and EOF-based melting shop, were performed to evaluate the final production cost of the liquid steel. It was found that, depending on the sinter feed price, substantial savings can be obtained with the use of sinter.

Jan 1, 1999