Search Documents

By Patrick F. R. Murphy

The mechanization of platinum group metal (PGM) underground reef mining in South Africa has posed a challenge to mining engineers for several decades. This is primarily due to the shallow dip angles and narrow thickness (<1.1m) of the tabular orebodies mined, and the issues faced in developing reliable drilling, bolting and loading machines suitable for such hard-rock mining applications. Presently, mining is typically conducted using hand drills and scraper shovels. These methods, however, are intensive in terms of manual labor, and limited in terms of productivity, and improved methods are desired. This paper will review the technical features of a 4 tonne, low-profile, LHD for narrow-reef PGM mining, developed by EJC Loaders Division.

May 1, 2003

By Ralph H. Sweetser

N Greenup and Carter counties, in the northeastern part of Kentucky, are the remains of many old charcoal furnaces built and operated during the period from 1818 to 1892. They were all included in what was called the Hanging Rock district. In the summer of 1930 I visited ten of these old blast furnaces, as follows:

Jan 1, 1931

By Remo Grandori

The Umiray Angat 13,2 km long tunnel in Philippines have been bored through extremely variable and difficult ground conditions including a number of special events. In particular the following adverse conditions were found: faults in decomposed ground, high temperature rocks, extremely rapid and important convergence phenomena, water inflows up to 800 litres per second. The special El Nino climatic conditions caused a long dry season and lower the level of the lake that was granting the access by barge to the site under the minimum navigable level. Many equipment have had therefore to be transported to site by a 10 ton capacity helicopter, after having been partially dismounted. For the same reason most of the tunnel drive have been bored servicing the site by 1 ton capacity helicopters to transport materials, spares and personnel. In order to overcome the above geological and logistic problems several innovation were introduced and tested in this project. Despite all that difficulties the 13,2 km of tunnel were bored in about 24 months, with a global average of 500 m/month.

Jan 1, 2001

Ceremonies for the induction of five mining industry pioneers into the National Mining Hall of Fame will be on Sept. 12, 2009 at the Charles F. Barber Pavilion of the Museum Convention Center in Leadville, CO. The five inductees are: Paul A. Bailey, 82, Richard T. Moolick, 89, William Braden and Alonzo Pawling and Henry Harnischfeger. Paul A. Bailly was president of Bear Creek Mining Co., the U.S. exploration subsidiary of Kennecott Copper, from 1961 to 1967. In 1968, he joined Occidental Petroleum Corp. and was tasked with creating the company?s international mining division, Oxymin, which he led as president through 1983. During his distinguished career, Bailly participated in numerous significant mineral discoveries, developed a new exploration philosophy and made important additions to the mineral exploration literature. William Braden was the first to recognize the immense potential of the El Teniente orebody in Chile. He founded Braden Copper Co. and developed the El Teniente Mine which now, 100 years later, remains the world?s largest underground copper mine. Braden?s endeavor survives to-day as the El Teniente division of the Chilean state copper company, CODELCO. T. (Dick) Moolick established a lasting legacy in the mining industry, first during a 35 year career with Phelps Dodge Corp. and then as the driving force in establishing the National Mining Hall of Fame and Museum in Leadville. The Hall of Fame and Museum ? a monument to the memory of the men and women who pioneered the discovery and development of the United States? natural resources ? has become one of the fi nest museums in the western United States.

Jan 1, 2009

By R. E. Zane

[The Northwest Experiment Station of the Bureau of lines, in cooperation with the College of Mines, University of Washington, has completed a detailed investigation of the physical and chemical properties of western cokes made or used in the Pacific Northwest, as evaluated by standard methods. 4/ One of the chemical properties determined, to which more or less importance has been attached, was reactivity or combustibility. As no standardized procedure is available, it was necessary to develop a workable method for evaluating this property. The combustibility of coke is usually measured by the formation of carbon dioxide with time at a particular temperature or by the reduction of carbon dioxide to carbon monoxide. Analysis of the resulting gases commonly is required to evaluate the result. The method described in this paper is simple and direct in that the sample of coke or other carbonaceous material is weighed as it burns; the loss in weight and time is indicated by a balance and clock arrangement. Gas analyses are not rewired. Methods similar in principle have been used by Tu, Davis, and Hottel6/ and by Oshima and Fukuda7/ for determining the combustion rate of carbon and for studying the effect of ash on combustion characteristics. Both methods: are more elaborate in procedure and apparatus required than teat described here. Brief the method comprises burning a sample of coarsely grained. coke or]

Jan 1, 1940

By P. H. Morris

To achieve the full potential of sub-aerial co-disposal the properties of the co-disposed wastes must be known and understood. A description is given of the morphology and properties of waste deposits that were formed during 19 field trials of sub-aerial co-disposal at the dual Goonyella-Riverside mine in Queensland and at Hunter Valley No.1 and Warkworth mines in New South Wales

Jun 19, 1905

The relationship between the maceral composition of coal and the strength of the coke produced from that coal has received a great deal of attention in recent years.Studies using two Bulli Seam coals, and blends of Bulli and Wongawilli Seam coals, from the IIIawarra Measures of the Southern Coalfield of New South Wales were carried out.The optimum range of vitrinite was found to lie between 45 per cent and 60 per cent (mineral matter free).Above and below this vitrinite range coke strength deteriorated. Coke strength indices increased with rank, and the optimum vitrinite content increased with an increase in rank. These changes require confirmation as trends by testing a third level of rank. It was noted that vitrinite content decreased with an increase in the specific gravity of separation of the coal.Use of petrographic analyses will increase confidence in choosing coals for coking, provided the coals are well known. Such analyses offer the possibility of greater flexibility in coal purchases and the possibility of producing a marketable blend from coals, which have limited market potential. Critical base coals for blends can be conserved.Significantly more work is required before coal reserves can be utilized to optimum advantage. This work would require extension of the studies discussed in this paper and, in particular, the testing of a wider range of rank.

Jan 1, 1971

By F. G. Boehm, T. S. Golosinski, P. M. Tucker

"In an earlier paper(1) the visits to several European mines using the bucket-wheel excavator (BWE) technology were described. It was during this trip that information was gathered on some interesting developments related to this type of mining, taking place elsewhere. It was learned that an across-the-pit system (XPS) comprised of a BWE and stacker has been operating successfully in a Hungarian mine for some time. Also the use of stackers with 225 m long booms and draglines with 125 m booms and 125m3 buckets in Soviet mines was indicated. Such equipment could be of great value to some Canadian strip mines, in particular the equipment proven useful in severe climatic conditions of U.S.S.R., similar to those of the Canadian prairies.To follow up on this information a field trip to Hungary and the U.S.S.R. was organized by the Department of Mineral Engineering, University of Alberta, to study the applications and performance of the systems in question. Visited were the Thorez mine near Visonta, Hungary, U.S.S.R. Ministry of Coal Mining and Skotchinski Institute in Moscow, Karagandashakhstoi Institute (designers of Ekibastuz mines in the Kazakh Republic) and Kostenko mine in Karaganda, Vostsibgiproshakht Institute (designers of Irsha Borodinski, Kharanovski, Moguntski and Tugnuski mines in Siberia) and the eastern Siberian Unit of the U.S.S.R. Coal Mining Ministry in Irkutsk as well as Azeiski mine located some 250 km northwest of Irkutsk. The findings of this field trip are presented."

Jan 1, 1985

By Stephen M. Smading

The Jinping-II hydroelectric project in China features four parallel headrace tunnels approximately 18-km- (11-mile-) long. Two will be excavated by tunnel boring machines (TBM) and two by drill-and-blast. A nearby fifth tunnel is being excavated by a 7.2-m (23.6-ft) TBM to draw down ground water in advance of excavating the headrace tunnels. Unique onsite assembly of a 12.43-m (40.7-ft) main beam TBM and backup system was completed on Sept. 18, 2008 in the remote mountains of the Sichuan province. The equipment was assembled onsite, without previously having been assembled and tested in a factory, using a method called onsite first time assembly (OFTA). This paper addresses the following topics: ? Project description including geology and terrain. ? The decision process leading to onsite, first time assembly, the assembly process and logistics, and lessons learned. ? Design features of the TBM and backup system. ? Operational history from startup to the writing of this article.

Jan 1, 2009

By Alan A. Campoli

The mining industry has long been searching for an effective structural application that prevents weathering and falls of loose rock, debris, and sediment. J-Crete is a fiber-reinforced, engineered, cementitious composite rock application that is designed, tested, and successfully utilized as such a material. Laboratory evaluation of J-Crete material properties has shown the final compressive strength to be in excess of 7,300 psi (50.34 MPa), with 24 hour strength in excess of 1,500 psi (10.34 MPa). The flexural tensile strength is in excess of 600 psi (4.1 MPa) and is provided through a unique combination of polyvinyl alcohol (PVA) fibers activated by a proprietary liquid additive that prevents them from clumping and enables even distribution throughout the grout. Tensile bond strength in excess of 350 psi (2.4 MPa) at 28 day cure tightens the strata and holds loose material in place. Practically impervious to gas and liquids, J-Crete protects strata against long-term weathering, does not require screening to be effective, and has proven to be a successful waterproofing material. J-Crete has demonstrated the potential to alleviate coal mine roof cutters in soft, wet clay formations. J-Crete reinforces coal mine ribs by bonding directly to the rib, conforms to the strata, strengthens the rib, and eliminates sloughing due to long-term weathering; stabilizes coal mine entries by bonding directly to the brow and roof, and creates a monolithic shell with double reinforced corners.

Jan 1, 2012

To improve communication among Government, industry, and academic researchers in the field of thermodynamics, the Federal Bureau of Mines sponsored a Workshop on Techniques for Measurement of Thermodynamic Properties in August 1979. Participants at the workshop presented 33 papers on the subjects of temperature measurement and control, general calorimetric techniques, low-temperature calorimetry, high-temperature calorimetry, galvanic cells, ionic solutions, and heterogeneous phase equilibria. A special invited lecture was presented by E. F. Westrum, Jr., on the resolution of lattice heat capacity. This Information Circular comprises the proceedings of the workshop and includes the texts of papers presented and discussion by attendees.

Jan 1, 1981

By L. J. Health

Synthetic rock with predictable porosity and permeability has been Prepared from mixtures of sand, cement and water. Three series of mixes were investigated primarily for the relation between porosity and permeability for certain grain sizes and proportions. Synthetic rock prepared of 65 per cent large grains, 27 per cent small grains and 8 per cent Portland cement, gave measurable results ranging in porosity from 22.5 to 40 per cent and in permeability from 0.1 darcies to 6 darcies. This variation in porosity and permeability was caused by varying the amount of blending water. Drainage-cycle relative permeability characteristics of the synthetic rock were similar to those of natural reservoir rock. INTRODUCTION The fundamental behavior characteristics of fluids flowing through porous media have been described in the literature. Practical application of these flow characteristics to field conditions is too complicated except where assumptions are overly simplified. The use of dimensionally scaled models to simulate oil reservoirs has been described in the literature. 1-3 These and other papers have presented the theoretical and experimental justification for model design. Others have presented elements of model construction and their operation. In most investigations the porous media have consisted of either u ncon soli da ted sand, glass beads, broken glass or plastic-impregnated granular substances—materials in which the flow behavior is not identical to that in natural reservoir rock. The relative permeability curves for unconsoli-dated sands differ from those for consolidated sandstone. The effect of saturation history on relative permeability measurements is discussed by Geffen, et a1.4 Wyga15 has shown quite conclusively that a process of artificial cementation can be used to render un consolidated packs into synthetic sandstones having properties similar to those of natural rock. Many theoretical and experimental studies have been made in attempts to determine the structure and properties of unconsolidated sand, the most notable being by Naar and Wygal.6 Others have theorized and experimented with the fundamental characteristics of reservoir rocks. This study was conducted to determine if some general relationship could be established between the size of sand grains and the porosity and permeability in consolidated binary packs. This paper presents the results obtained by changing some of the factors which affect the porosity and permeability of synthetically prepared sandstone. In addition, drainage relative permeability curves are presented. EXPERIMENTAL PROCEDURE Mixtures of Portland cement with water and aggregate generally are designed to have certain characteristics, but essentially all are planned to be impervious to water or other liquids. Synthetic sandstone simulating oil reservoir rock, however, must be designed to have a given permeability (sometimes several darcies), a porosity which is primarily the effective porosity but quantitatively similar to natural rock, and other characteristics comparable to reservoir rock, such as wettability, pore geometry, tortuosity, etc. Unconsolidated ternary mixtures of spheres gave both a theoretically computed and an experimentally observed minimum porosity of about 25 per cent.7 By using a particle-distribution system, one-size particle packs had reproducible porosities in the reproducible range of 35 to 37 per cent.6 For model reservoir studies of the prototype system, a synthetic rock having a porosity of 25 per cent or less and a permeability of 2 darcies was required. The rock had to be uniform and competent enough to handle. Synthetic sandstone cores were prepared utilizing the technique developed by Wygal.5 Some slight variations in the procedure were incorporated. The sand was sieved through U. S. Standard sieves. A 18-20 sand denotes that the sand passed the Number

Jan 1, 1966

By R. Le Houillier, M. Nagamori, A. J. Plumpton

"Asbestos tailings are a typical serpentine, hydrated magnesium silicate, consisting primarily of antigorite and a few per cent of unrecovered fibrous chrysotile. Serpentine has unique thermal properties in that dehydroxylating calcination at 600 to 700°C can yield an amorphous structure in which most of the magnesia is liberated from the original bond with silica and thereby rendered chemically active. The amount of activated magnesia can be quantified by selective leaching with a weak acid such as acetic acid. Many wet processes have been proposed to extract magnesium values from calcined or natural serpentine by means of various acids and their ammonium salts. However, the only commercial utilization of serpentine today is found in dry processes such as the production of fused magnesium phosphate fertilizer .The present paper reviews the physical chemistry of the dehydroxylation of serpentine and also various wet and dry processes in order to provide a general view regarding the chemical transformation of asbestos tailings.IntroductionAsbestos fibers occur as chrysotile, a serpentine polymorph. More than nine tenths of mined asbestos ores consist of massive non-fibrous serpentine, primarily the polymorph antigorite, which is discarded as tailings after fiber extraction. For many decades, Quebec has been a world leader in the production of asbestos fibers. As a result, colossal tonnages of serpentine have accumulated in the Eastern Townships&apos;!&apos;. Serpentine minerals are found in large deposit s throughout the world, and significant research efforts have been made, particularly in Japan and the USSR, mostly in attempts to extract magnesia or silica values therefrom.The chemical composition of serpentine (chrysotile and antigorite) may be ideally expressed as Mg3Si2Os(OH). which corresponds to 43.7% MgO and 43.3% SiO2. Natural serpentines often contain a few per cent of Ni-bearing magnetite and other impurities, and therefore the contents of MgO and Si02are both about 40% or lower.Serpentine (hydrated magnesium silicate) is virtually insoluble in weak acids. However, when dehydroxylated under controlled conditions, &apos; it decomposes to an amorphous state in which magnesia and silica are isolated and chemically active. The magnesia so activated is readily soluble in weak acids. This unique characteristic of calcined serpentine, first discovered in 1942,, has since attracted the attention of innumerable researchers, whence many processes have been proposed."

Jan 1, 1980

By A. Thielen

In experiments for the production of steel the principal problem has always been the introduction into, or removal from, the iron of a definite quantity of carbon. Although the solution of this problem had engaged a more or less blindly and empirically directed effort for a long time, it was only with the development of analytical chemistry that the rôle which carbon plays in the constitution of steel was disclosed in its full significance, and that many of the problems confronting the steel-maker were thereby more clearly defined than before. For a long time, and to a certain extent even to this day, the percentage of carbon in steel has been the controlling means of deter mining its quality and hardness. In many cases the percentage of carbon alone has been relied on for judging large consignments, such as the large deliveries of wire-billets and blooms to America during the past twenty years; and though to-day the influences of the other constituents are recognized and many other considerations are taken into account, and though, moreover, some special steels, such as the Hadfield manganese steel, apparently dispense to a certain extent with the assistance of the carbon, yet fix our Bessemer, Thomas, Siemens and crucible steel the carbon still remains one of the most important constituents, and I venture to say it is indispensable. In order to produce in the Bessemer converter a steel of a certain required percentage of carbon, two methods, as is well known, present themselves. By the one the decarburization process is stopped when the desired carbon limit in the bath has been reached ; by the other the bath is completely decarburizecl, and then a calculated amount of carbon added in the form of spiegel, ferro manganese, etc. In Germany the latter method only was adopted, and it was retained when the Thomas-Gilchrist process for the production of low-Phosphorus steel from high-phosphorus iron eame into use, since from the nature of the new process complete decarburization is neces-

Jan 1, 1891

By M. S. Borges

The need for the waste management industry to reach environmental patterns, technological innovation, and a technological demand of the productive sector is covered by this study. The environmental care and responsibility in the industrial sector and the necessary cultural changes for companies and entities is also emphasized. A collaborative tool was developed to help all partners involved in the environmental administration. This tool focuses on the interaction among residue generators in the productive chain. It was developed for a vehicle assembler company supported by entities or institutions with emphasis in the research, development and innovation, with expertise and capacity for new products creation, as well as reuse, recycling and reduction of by-products generation. The work aims to establish a tool for socio-environmental management, focusing on promotion and interaction between industrial waste generators sectors.

Jan 1, 2010

By I Lumsdaine

QNI Pty Ltd operates the Yabulu Refinery located 25 kilometres north of Townsville, North Queensland. The plant treats nickel laterite ores sourced from the Philippines, Indonesia and New Caledonia. The cobalt head grade and overall recovery expectations for the 2001/2002 financial year are 0.161 per cent and 53.8 per cent respectively. Cobalt is a valuable byproduct derived from the nickel refining operation which utilises the Caron Process. Any increases in cobalt recovery that are achieved from the existing relatively low level provide significant improvements to the bottom line of the operation. Towards the end of 2000, a project was undertaken to characterise cobalt losses with the sole purpose of improving cobalt recoveries using a variety of analysis techniques. The Time-of- Flight Secondary Ion Mass Spectrometry (TOF-SIMS û University of South Australia) method was used to verify the presence of surface bearing cobalt species, originating from either co-precipitation or adsorption mechanisms. Cross-section examinations were also performed using Scanning Electron Micrscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDXS). These techniques indicated the presence of high cobalt concentrations (in the order of several per cent) within a select number of roasted and leached ore particles. The phenomenon of cobalt losses due to incomplete leaching within specific ore particles was not widely documented within the Refinery prior to these studies. In order to quantify losses via this mechanism, Mineral Liberation Analysis (MLA û JKTech Centre) was also performed on key samples. This paper serves to document a systematic approach in determining the source of significant valuable mineral losses in an established, operating plant. It discusses the use of a variety of analytical techniques, which have been adapted for the minerals processing industry, but are strongly relevant for plant investigations in the hydrometallurgical industry.

Jan 1, 2002

By A. J. Hynes, Lutes. G. G., Ravenelle. J. -F.

"The Anomaly A area of the Clarence Stream gold deposits in southwestern New Brunswick contains mineralized structures that bear geometrical relationships to regional folding events. The four mineralized zones of Anomaly A (AD, MW, 93, and Murphy) are hosted by turbiditic graywacke, quartzose wacke, siltstone, and argillite sequences of the Kendall Mountain Formation. A regional scale structural analysis reflects at least four deformational events, three of which appear to control the folded geometry of Anomaly A (D2, D3, and D4). F2 and F3 folds are coaxial and are refolded into a dome and basin geometry by F4 folds. The mineralized zones are subparallel to axial surfaces of F2 folds. Structural analysis of a mineralized zone exposed at surface indicates that gold mineralization is hosted by a quartz-vein system that comprises veins generated during both D2 and D3. Threedimensional representations of Anomaly A created using drill-core data and ®GoCAD suggest that the quartz-vein system was emplaced in fault structures during D2 as well as within brecciated dilation zones during D3. Three of the four zones that make up Anomaly A have F2 hinge surfaces that can be linked through a geometry compatible with the style of F3 and F4 folds. The apparent continuity of these three zones indicates the potential for kilometer-scale mineralized structures at Anomaly A. Le secteur de l’Anomalie A du gisement aurifère Clarence Stream contient des zones minéralisées qui montrent des relations géométriques avec les épisodes de déformation régionale. Les quatre zones minéralisées de l’Anomalie A (AD, MW, 93, Murphy) sont comprises dans une séquence turbiditique composée de grauwacke, de wacke quartzitique, de siltstone, et d’argilite appartenant à la Formation de Kendall Mountain. Des quatre épisodes de déformation étudiés par l’entremise de cartographie structurale, trois semblent contrôler la géométrie de l’Anomalie A (D2, D3, et D4). Les plis P2 et P3 sont coaxiaux et sont replissés en dômes et bassins par les plis P4. Les zones minéralisées sont subparallèles aux plans axiaux des plis P2. Une analyse structurale effectuée sur une zone minéralisée exposée à la surface indique que la minéralisation aurifère est localisée dans un système de veines de quartz qui contient des veines générées durant D2 et D3. Des représentations en trois-dimensions créées avec le programme informatique ®GoCAD à partir de données de forages suggèrent que le système de veines est localisé dans des zones de failles D2 ainsi que dans des zones de dilatation associées avec D3. Trois des quatre zones qui forment l’Anomalie A possèdent des plans axiaux P2 qui peuvent être liés par l’entremise d’une géométrie qui respecte le style des plis P3 et P4. La continuité apparente de ces trois zones indique qu’une structure minéralisée pourrait s’étendre sur plusieurs kilomètres dans le secteur de l’Anomalie A."

Jan 1, 2008

By D. Janicijevic

This paper describes the process of scraper winch pull force measurement and shows the results of the actual winch pull force in extreme stall situations as well as during the face and gulley cleaning. It was found that by slowing down the motor and causing it to slip, torque up to 3.5 times higher than the nominal can be developed, resulting in the same increase of winch pull force. On the other hand, measurements of the actual force needed for cleaning of the face and the gully have shown that the currently used winches are too powerful. The extra torque that can be developed by the already too powerful winch motor poses a significant danger and necessitates the implementation of measures that will eliminate this risk.

Jan 1, 2008

? Develop a six year capital budget for future emission controls at Western Springfield Power Plant that would provide long-term operating certainty

Jan 1, 2005

By Peter J. Nicholson

A new method of constructing retaining walls, in-situ, prior to excavation has been developed. This "Vertical Earth Reinforcement Technique" VERT, has been demonstrated at a full scale test wall at the National Geotechnical Experimentation Site at Texas A&M University. This 10 meter high wall, was constructed of elements of soil mixing in an array that forced composite behavior between the soil mixed elements and the in-situ soils. Inclinometers and extensometers were used to verify the performance of the wall. The construction and results of the testing are presented.

Jan 1, 1998