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By Thomas M. Barczak

Wood cribs are used extensively to stabilize openings in underground coal mines. This U.S. Bureau of Mines report describes the results of full-scale testing of several multitimbered wood crib configurations. Multitimbered configurations are wood cribs that are constructed with two or more timbers per layer. Nine different crib configurations were evaluated. Configuration parameters under study included the aspect ratio (height-to-width relationship) and the percentage of solid rr:aterial used in crib construction. Test results and generalized wood crib behavior are discussed and recommendations are made concerning crib constructions to maximize strength and stability. Crib performance is enhanced by reducing buckling effects by decreasing the aspect ratio and geometry considerations that increase the moment of inertia. A cost benefit analysis of multitimbered wood crib configurations is made. Generally, increasing the percentage of solid provides more resistance at less unit construction cost. A comparison of laboratory results and underground observations of several wood pack wall supports suggest in situ load capacity is less than that measured in laboratory testing. Reasons for the apparent decrease of in situ load-bearing capability include load rate effects, stiffness of reaction surfaces, and varying boundary conditions that alter the load transfer mechanics of the crib structure.

Jan 1, 1991

By S. W. Parr

THE extent to which geological carbonization has taken place in the process of coal formation is a fundamental factor in all considerations relating to classification, oxidation, deterioration, spontaneous combustion, and especially in all considerations relating to destructive distillation having as an objective the production of marketable coke and by-products. Moreover, it may be readily shown that a. striking relationship exists between the geological decomposition or geological carbonization processes and those artificially produced by heat. This may be well illustrated by bringing again to view some of the charts more commonly met with 25 years ago, as in Fig. 1. 1 FIG. 1. In this figure the line of geological decomposition by decay, pressure, etc., because of its relation to the line of carbonization by destructive distillation, becomes of special significance when we attempt to formulate any system of classification which shall be reasonably scientific and at

Jan 2, 1926

By S. Clark Komardi

Freeport Indonesia, Incorporated produces 180,000 tons per year (200,000 STPY) of 32% copper concentrate. A 111 kilometer (69 mile) pipeline transports the concentrate slurry to the sea coast. Rheology characteristics of the concentrate slurry must be monitored continuously to assure that the pipeline does not plug and that mini- mum degradation of the pipeline occurs. Factors affecting the rheobgy include particle size, percent solids, pH, and reagent additions. This paper includes a general pipeline description, slurry rheology factors affecting operations, and the problems encountered and their subsequent resolution. Six years successful operation of the worlds longest copper concentrate slurry pipeline has provided a unique insight into slurry behavior.

Jan 1, 1980

By P. Somasundaran, Yee-Ho Wang

Carrier flotation of anatase impurities from clay using oleate is compared in this study with conventional flotation. The role of relevant parameters such as carrier size, carrier amount, dissolved calcium and carbonate, conditioning speed, pH, time and temperature and collector concentration is investigated in order to elucidate the mechanisms involved in carrier flotation. Addition of coarse calcite particles is found to contribute towards the enhanced separation of anatase from clay mainly due to aggregation of anatase fines with calcite and the subsequent flotation of the aggregates.

Jan 1, 1980

By M. Adnan Goksel

The hydrothermal agglomerating process described (U.S. Pat. 3,235,371, (1966)) is different from the conventional high temperature processes. Green pellets or briquettes made with mixtures of moist iron ore concentrates and burned or hydrated lime fines are hardened in an autoclave at 198°C and under steam pressure for 1/2 to 5 hours, with or without previous drying. Under the neutral conditions, oxidation of magnetite does not occur as in the conventional processes. The resulting agglomerates are hard and resistant to abrasion and weathering, and they do not disintegrate in the Linder test. The equipment required for the process is not complicated, and favorable operating costs are projected because of the low temperature and efficient heat recuperation. A low capital investment makes the process attractive even when the annual pellet production is below a million tons.

Jan 1, 1968

By H. O. Hofman

PAGE Part I. Decomposition OF Zinc Sulphate by Heating in Air, . 811 I. Introduction............ 811 II. Zinc Sulphate Used,..814 III. Fumes and Pyrometers,........ 816 IV. Heating Zinc Sulphate—Dehydration,...... 817 V. Heating Zine Sulphate—Decomposition...818 (a.) Beginning of Decomposition..818 (b.) Rapidity of Decomposition,..819 (c.) End of Decomposition..823 (d.) Retardations in Heating.-Curve,..825 (e.) Formation of Basic Salts,..826 Part II. Decomposition OF Zinc Sulphate by Heating with Carbon (Reducing Roast), .830 I. Introduction,........... 830 II. Experiments and Results ,.........832 III. Summay,........... 834 Part 111. Formation of Zinc Sulphate by Roasting,... 834 I. Introduction,........... 834 IT. Description of Blende,......... 836 III. Outline of Operations,.........838 IV. Details of Experiments.......... 839 1. Decrepitation,.......... 839 2. IgnitionPoint,....839 3. Sulphatizing-Roast of Joplin Blende..840 4. Sdphatizing-Roast of Warren Blemde ,..843 5. Sulphatizing-Roast with Addition of Pyrite...848 6. Summary of Sulphutizng-Roasts,....... 854 Part IV. Appendix : Formation of Zinc Ferrate...856 Part I. Decomposition of Zinc Sulphate by Heating in Air. I. Introduction. With the exception of lead sulphate. all common metallic

Jan 1, 1905

By Xiaoning Yang, C David Pearson, Brian W. Stump

An experimental study of ground motion from explosions designed to remove overburden in an open pit coal mine is reported. The purpose of this study is a characterization of these ground motions in the distance range of several tens of meters to several kilometers. The investigation has focused upon both single cylindrical sources with different explosive configurations as well as arrays of charges in the production mode. Critical to this study of source configuration and coupling is experimental control of the individual explosions, the timing of the explosions and the geological properties. The height of the explosive charges, their depth and charge distribution were monitored in the field. High speed photography as well as velocity of detonation measurements were made on the multiple explosion source so that detonation of individual charges could be documented.

Jan 1, 1994

By C. C. Harris

The use of Alyavdin's equation Y(x,t) = 1-e(-bt) for describing the effect of grinding time on size distribution is discussed. The equation transforms into linear form by expressing it as log-log reciprocal (1 - Y) versus log t. For plotting, specially divided grids are available; Rosin-Rammler or Weibull charts may be used. The data of Herbst and Fuerstenau are especially useful for illustrating the Alyavdin-Weibull chart in two applications: (1) presenting data (which are relatively unaffected by experimental scatter) and comparing them with theoretical predictions, and (2) as a test for the zero-order kinetics production hypothesis. The chart based on the Alyavdin-Weibull equation is suggested as a useful aid in the analysis of kinetic data (/ versus f), though not as a procedure in its own right. Proposed applications are (1) displaying data with excellent clarity, since it avoids the kind of congestion inherent in some other plotting methods, and (2) as a test for assumed kinetic relationships. Sometimes, equation 1 describes the data quite closely, and in these cases the parameter values appear to be related to certain operating conditions.

Dec 1, 1971

Jan 1, 1932

By Elzbieta Mielczarski, Jerzy Mielczarski, Jan Drzymala, Yann Duvalm

Polyethylene glycol monoalkyl ethers (CnEm) render quartz hydrophobic while feldspar remains hydrophilic. As a result quartz can be separated from feldspar in small frothless flotation devices such as the Hallimond tube. The separation can be accomplished at room temperature at pH < 7 and C16E33 concentrations between 10-5 and 10-4 M for quartz particles smaller than 0.4 mm. No separation is observed when feldspar ore containing about 60 % of feldspar and 40% of quartz is subjected to flotation in a laboratory flotation machine. The reason for the lack of separation is a low hydrophobicity of quartz in the presence of polyethylene glycol monoalkyl ethers and high intensity of mixing in the flotation machine. The flotometric tests showed that the contact angle of quartz in monoalkyl ethers of polyethylene glycol solutions is less than about 18 degrees and depends on the structure and concentration of the ether and the pH of the system.

Jan 1, 2003

By T. G. Joseph

Mines must manage variability from within their operations as well as those imposed upon them by external forces. This paper provides a framework to manage both internal and external variability through the review and adjustment of the mine plan where applicable to minimize lost production and maintain operational safety.

Nov 1, 2011

By P Clark, P A. Kirsch, R Tapia Rivera

Community members’ sources of information about companies’ social investments are often influenced by the messages in a variety of communication channels, such as newspapers, television and social media. In this sea of communication channels, corporate communications may not always have the desired effect in influencing community perceptions. This paper explores the efficacy of communication between mining companies and communities in Chile through content analysis of corporate sustainability reports and newspaper reporting.Chilean media reporting between 2005 and 2013 is examined to identify community perceptions of corporate social investments made by mining companies. Content within the Chilean newspapers El Mercurio (national) and Soy Chile (regional) is contrasted with content from corporate sustainability reports published by The National Copper Corporation of Chile (Codelco) and Barrick Gold Corporation, Canada (Barrick) for the same period. The objective is to identify differences in the way that corporate social investments are reported by companies in sustainable development reporting and by media in newspapers.Overall, the study demonstrates that the media’s framing and reporting of corporate activities was more negative than positive. Moreover, media outlets tended to focus upon the ‘negative impacts’ or ‘damage’ to communities brought about by mining developments. Conversely, companies’ public communications were largely focused upon direct improvements in livelihoods (health, education, etc) of neighbouring communities. This preliminary study provides a baseline for the development of new formats of effective communication with neighbouring communities. The paper advocates for an increase in participatory mechanisms with affected parties, which could lead towards a greater mutual understanding of the impacts and draw parties closer together.CITATION:Tapia Rivera, R, Kirsch, P A and Clark, P, 2014. Challenging Perceptions? Sustainability Reporting, the Media and Mining, in Proceedings Life-of-Mine 2014 , pp 413–426 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By G. L. Mowrey

One critical element of the U.S. Bureau of Mines (Bureau) autonomous mining research program is the development of a reliable coal interface detection (CID) system. Several candidate CID concepts currently being investigated by the Bureau include vibration, passive infrared, radar, and natural gamma radiation (NGR). To establish which CID sensor technologies need to be developed for a given seam, coal and adjacent rock samples (i.e., immediate roof and floor) are being collected from selected major coal seams in the U.S. and are being analyzed in terms of NGR and other geophysical measurements. Results of the NGR measurements indicate that, in general, all shale and shale-like materials (e.g., drawslate, slate, and fireclay) have higher NGR readings than the coal seam. Consequently the NGR method appears to be a potentially useful CID tool, provided that the immediate roof and floor are both composed of a high percentage of shale-type material.

Jan 1, 1990

By Loic Galisson

"Urban tunneling projects are usually extensively monitored. Most of the instruments used rely on benchmarks providing a sustainable datum throughout the life of the project. The monitoring program also is based on a predicted model of deformation induced by specific construction methods. Events can interfere with those assumptions and eventually alter the stability of these datum. In addition, the anticipated ground conditions and hence the theoretical deformation model often differ from reality. Satellite Radar Interferometry provides useful information to overcome the weakness of the hypothesis made before construction. It is also a powerful tool to ensure the continuity of the monitoring program throughout the life of the project, accurately describing the true effect of the project on the surrounding environment. This paper emphasizes the benefits and limitations of this technique for urban tunneling applications, illustrated by examples of major tunneling projects around the world. MONITORING URBAN TUNNEL PROJECTS Why Monitoring? Retrofitting existing tunnels or constructing new tunnels – including access and retrieval shafts, portals and cross passages – implies an alteration of the neighboring soil structure. Excavating, dewatering, grouting, loading tie backs, etc. artificially modifies the natural equilibrium of the pore-water pressure, of the water table level and of soil stability. In many cases, the effects are immediate: ground loss, deformation of utilities, settlements of buildings, and distortion of infrastructure are a few examples resulting from construction activity.Instrumentation and Monitoring Scope To control and mitigate the risks of damage associated with the above effects, tunnel projects usually include an instrumentation and monitoring program. Depending on the level of geotechnical, structural and environmental risk, the magnitude of this program varies. Projects with a low exposure to risk may restrain the program to conventional methods such as limited topographical surveys and intermittent manual readings of geotechnical instruments. On the other hand, iconic projects with high risk or with controversial history may implement complex and extensive instrumentation plans, involving highly technical solutions such as Automated Motorized Total Stations (AMTS – see opposite Picture 1), Multi-Point Borehole Extensometers (MPBX), In-Place Inclinometers (IPI) and a wide series of fully automated geotechnical, structural and environmental sensors. In this case, all the devices are usually connected to field data loggers collecting raw data around the clock at frequencies ranging from days to seconds, depending on the sensors."

Jan 1, 2016

By D. Moradkhani

Copper metal has important role in the basic industrials, as if it did not exist, modern human life would not develop! Copper leaching, as the first step, is important step in copper production processes. In this research, efficient factors on the leaching have been investigated. For this reason, four efficient factors on leaching namely pH, liquid to solid ratio (L/S), temperature and time, as independent variables, were optimized using response surface (RSM) with D-optimal. A quadratic equation was used to create response and contours. According to the results from analysis of variance (ANOVA), the value of determination coefficient (R2=96.77%) indicates that the model was good fit. Optimum experiment condition also was found: pH of 1, L/S of 8.24, temperature of 26.06 ? and time of 43.64 min. At this condition, the maximum recovery of copper was equaled to 92/38 in which good desirability achieved.

Sep 1, 2012

By André Chagnon, Héroux. Yvon

"Résumé - Cette étude porte sur l&apos;altération de la matière organique et des argiles dans les boues carbonatés dévoniennes du facies ""F&apos; de la Formation de Pine Point et ses équivalents stratigraphiques la Formation d&apos;Evie et l&apos;unité bitumineuse de la base de la Fonnation de Hom River. La matière organique se compose principalement de bituré solide et de quelques fragments de fossiles (organaclastes). La majorité des échantillons ne renfement que de l&apos;illite et des inter-stratifiées illite/smectite.Si on compare les températures d&apos;homogénéisation (Th = 100°C) des inclusions fluides de la sphalérite et des dolomites associées a la minéralisation aux températures estimées à partir de la réflectance de la collinite (84°C à 117°C), l&apos;on ne peut pas conclure à la présence d&apos;une anomalie thermique dans le district minier de Pine Point. De plus, la réflectance des organoclastes n&apos;est pas plus élevée dans le district minier de Pine Point que dans les localités plus éloignées des gites. L&apos;analyse des minéraux argileux conduit à la même conclusion: aucune anomalie thermique n&apos;est décelable dans les unités échantillonnées à l&apos;intérieur du district minier de Pine Point quelque soit l&apos;indicateur utilisé.La kaolinite et la matière organique altérée, affichant des valeurs anomales de sa réflectance, se trouve essentiellement en présence de soufre et de sulfures. Cela suggère une origine authigène de la kaolinite et une altération de la matière organique reliées au phénomènes de minéralisation.Abstract - The alteration of organic matter and clays is studied in the Devonian Pine Point Formation carbonate muds, ""F"" facies, and its lateral equivalents the Evie Formation and the bituminous unit at the base of the Hom River Formation. The organic matter is mainly composed of solid bitumen with few fossil fragments (organoclasts). Most samples contain only illite and mixed layer illite/smectite.If we compare the Th (100°C) from fluid inclusions of sphalerite and dolomites associated with mineralization to the temperatures calculated from the reflectance (Ro) of the collinite (84°C to 117°C), we cannot detect a thermal anomaly in the Pine Point mining district. This result is based on the reflectance values of organoclasts from the mining district that are not higher than those reflectance values measured on organic matter (OM) away from the ore deposit. A similar conclusion is reached from the clay study: none of the parameters used allow us to identify a thermal anomaly in the samples from the mining district.The kaolinite and the altered OM showing anomalous Ro values mainly occur with sulfides and sulfur. This association suggests an authigenic origin for the kaolinite and an alteration of the OM due to the mineralization events."

Jan 1, 1994

By R. J. Wysor

J. S. UNGER, Pittsburgh, Pa.-On page 22 reference is made to 36 carloads .of dust shipped. Did the material in that last sample come from a; furnace running on pig iron, ferro alloys, or spiegel? R. J. Wysor.-Pig iron; we have not made any ferro alloys; or spiegel at Bethlehem in the last 3 years. J. S. UNGER.-DO you use domestic or foreign ores? R. J. WYSOR.-In regular practice, largely foreign ores. J. S. UNGER.-How much per unit does it cost to produce that? R. J. WYSOR.-You might say it does not cost anything; we do not change our blast-furnace practice at all to obtain the dust. Although it has been a profitable byproduct, I would rather not have it unless we could reclaim it on a large scale, as we would have better working stoves. J. S. UNGER.-Does the trade take it as readily as natural salts? W. J. WYSOR.-The fertilizer dealers have been anxious to get it. This did not happen, however, until the war started. J. S., UNGER.-They have been willing to take anything since the war started. R. J. WYSOR.-Yes. However, we could have sold the material before the war; in fact, about 4 years ago, we had a contract ready to sign, but we did not think it would pay us to bother with it then. W. H. Ross, Washington, D. C.-We of the Fertilizer Division of the Bureau of Soils have been particularly interested in Mr. Wysor&apos;s investigations on the possibilities of recovering potash from the blast furnace, and we look upon the results he obtained as among the-most important that have yet appeared on the subject of finding new sources of .American potash. About 5 years ago we undertook a corresponding investigation on the recovery of potash in the cement industry. Representative samples of raw mix and ground clinker were collected from the different cement plants in this country with a view to analyzing each sample for potash. With the data thus obtained and knowing the ratio between the raw mix and the cement produced and the output of the latter, we thought it possible to calculate approximately for each plant the quantity of potash that escapes daily from the kilns. After partly completing the work, however, it had to be abandoned for a time. It was again taken

Jan 4, 1917

By Russell A. Luke

"Modular Mining&apos;s computerized LHD position monitoring and dispatching system commenced operation at the De Beers Finsch Mine in mid- J99J. A sophisticated blend of proven and new technologies links the dispatcher at the workstation console on the surface with the LHD operators several hundred metres below. The dispatcher allocates each LHD to a priority tip and loading drive based on instructions provided by the miners and shift bosses underground. LHD operators receive tip and loading drive allocations on the vehicle computer console which communicates data via a Leaky Feeder radio network. The operators interact with the console to notify the dispatcher of delays, breakdowns, and changes in tip and tunnel status. The underground terminal displays allow shift bosses to monitor the progress of the LHDs as they pass infrared beacons (IRs) located in the tips loading drives and rim tunnel main haulage ways. The terminals also provide on-line statistics for the current and previous shifts. Future enhancements include optimized dispatching and interfacing to a PLC system controlling ventilation. Further, token ring-based loop UHF radios are being investigated as an alternative to the Leaky Feeder data radio network. IntroductionFinsch first contacted Modular about an LHD monitoring and dispatching system in late 1988. At that time, Modular declined a request for a formal quotation but agreed to perform an engineering feasibility study. The study was issued in mid-1989 and confirmed Finsch&apos;s belief that an underground system could be developed with technology available at that time. A contract for the system was signed the following year and, in May of 1991, the system began operation. By the end of 1991, LHDs on both production levels of the mine were under the control of the system."

Jan 1, 1993

By T J. McGavin

This paper examines the fire life systems implemented in two existing tunnels and discusses whether the standards used were appropriate. It focuses on the Terrace Tunnel as this upgrade and refurbishment is complete.The New Zealand Transport Agency (NZTA) manages six tunnels on the State Highway network with two of these built in the last seven years. The Terrace Tunnel, opened in 1978, was refurbished with modern fire life safety systems in 2010–2012. An interim upgrade of the Mt Victoria Tunnel, opened in 1931, was also carried out at this time.In present times, few existing tunnels have undergone significant upgrades and refurbishments. The Terrace Tunnel required: new power supplies, control buildings, lighting, wall panels and jet fans, a deluge system, emergency exit lights and way-finding lights, a public address (PA) system, a radio rebroadcast system, lane control sign (LCS) and variable message sign (VMS), an over-height detection system (OHD) and a new tunnel management system.In the absence of suitable guidelines, various standards were used to carry out the refurbishment. The Austroad Guide to Road Tunnels and AS4825 Tunnel Fire Safety, although designed for new tunnels and not specifically intended for existing tunnels, provided a framework. A multi-criteria assessment of risk (MCAT) was carried out to determine the systems to be provided.The Terrace Tunnel has perhaps set a benchmark for refurbishing existing tunnels as few projects of this type have been completed recently. This paper examines the process and the outcomes.CITATION:McGavin, T J, 2014. The refurbishment of the Terrace and Mt Victoria Tunnels, Wellington, New Zealand, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 87–94 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By G J. Harbort, Z Pokra

It has been observed in several Jameson cell installations where the source for flotation feed is deslime screens, that the recovery of coal particles greater than 0.5 m is not as great as that of finer material. Consequently, a research project was undertaken at a CHPP in the Bowen Basin, Queensland, to assess the possibility of increasing the recovery of coarser particles (+0.5 mm) within the downcomer of the Jameson Cell. The effect of decreasing turbulence and agitation in a commercial-scale downcomer was investigated to assess the effect on the recovery of both coarse and fine coal particles. This paper details the findings of the testwork, summarising the results relating to differences in the operating parameters within the downcomer.

Jan 1, 2005