Search Documents

By Steve Kral

A few months ago, Congress passed, and President Bush signed, a national energy bill. Designed to decrease the nation’s dependence on foreign sources of energy, the bill earmarked several billion dollars to increase the use of U.S. coal reserves. The bill also modified permitting regulations to speed up development of the coal reserves located on federal land. Coal currently supplies more than half of the nation’s electricity needs. And as housing starts continue to in-crease and with the nation’s appetite for electronic gadgetry, the demand for energy in the United States will only go up. That means coal producers must expand production while at the same time containing costs so they can enjoy this period of improved coal prices.

Jan 1, 2005

By Emily Wortman-Wunder

As the 2010 president of the Society for Mining, Metallurgy, and Exploration, Inc., I am pleased to present the 2010 issue of Transactions of the Society for Mining, Metallurgy, and Exploration, Vol. 328. A significant portion of the contribution that we as a professional society make is the publication of professional and technical papers that accelerate the advancement of scientific knowledge and enable transfer of technology. Communication within the mining community is the key to a successful society. Through books, magazines, meetings and electronic media, we accomplish the technology exchange that is fundamental to the existence of the Society. This technology exchange continues a tradition that dates back to the 1871 meeting of 22 mining engineers in Wilkes-Barre, Pennsylvania, that resulted in the founding of AIME; those individuals envisioned that these transaction volumes “would form a most valuable and greatly needed addition to our professional literature.” This volume certainly fulfills that pledge. The 2010 Transactions is the first Transactions to take advantage of new publication technologies. It appears solely as an e-book. The decision to go to an all-digital format for this longstanding publication was a difficult one, but one which will certainly better serve the mining community. I am excited about this development and the opportunities it presents. The 2010 Transactions also contain some of the most exciting research from the past year, including new developments in mineral processing, safety and exploration. Be sure not to miss the two Minerals & Metallurgical Processing issues on the subject of gold hydrometallurgy. This 2010 Transactions comprise of a total of 78 technical papers (582 pages including index), including all 21 papers (136 pages) that were published in 2010 in the Technical Papers Section of Mining Engineering magazine (Vol. 62) and all 34 papers (231 pages) that were published in 2010 in Minerals & Metallurgical Processing (Vol. 27). Addition, this volume contains 23 papers (194 pages) that are being published for the first time in this issue. The papers presented in this volume were written by some of the most distinguished professionals in the industry worldwide. All 78 technical papers were peer-reviewed. The process of review and publication requires much hard work by authors, reviewers and our publications staff. As the 2010 president of SME and on behalf of all our members, I would like to extend our gratitude to all whose volunteer efforts contributed to the publication of this volume.

Jan 1, 2010

By W. H. Strickland, R. H. King

Ultrasonic ranging sensors are inexpensive, have no moving parts, have no lenses to clean, are normally small and unobtrusive, and can measure distances through moderate amounts of dust, smoke, and humidity, so they are well suited to underground mines. In the work reported here, conducted by the U.S. Bureau of Mines, researchers tested ultrasonic ranging sensors for their abiity to define rib line features for computer-aided navigation of underground mine mobile equipment. The investigation began with laboratory tests of field of view, angle of incidence, intersensor variation, and ranging accuracy of the individual rangers in a ring array produced by Denning Robotics of Wilmington, MA. The results showed that the sensors have good accuracy and low variability. Additional experiments at AMAX's Henderson Mine showed the sensors could accurately and reliably measure the distance to mine features, including convex and concave corners and rib intersections. The results showed that when used properly, the ranger data are accurate enough for reliable mine vehicle navigation When used incorrectly, ultrasonic rangers do not provide the anticipated data. Therefore, this report explains the principles of ultrasonic range measurement, describes the ranger's strengths and weaknesses, and explains proper ranger use and data analysis.

Jan 1, 1993

By André Rosiak

No processo de forjamento a quente, devido aos ciclos térmicos e mecânicos a que o material é submetido, diversos fatores influenciam e ampliam a gama de propriedades mecânicas que podem ser obtidas nas peças metálicas produtos deste processo. A proposta deste artigo é estudar a influência dos fatores tempo de austenitização, temperatura e deformação sobre a variação da dureza do aço ABNT 4140. Para isso, o material foi mantido em diferentes temperaturas, durante diferentes períodos de tempo e, posteriormente, forjado e tratado termicamente em patamares semelhantes aos de recozimento direto e revenimento. Esta pesquisa corresponde a uma das etapas do projeto BRAGECRIM (Iniciativa Brasil-Alemanha para Pesquisa Colaborativa em Tecnologia de Manufatura).

Aug 17, 2017

If one can embrace the medical analogue, much of the mining industry currently suffers from a massive bacterial infection. When pyrite-bearing or sulfide-bearing rock formations, tailings, or mine wastes are infected by Acidithiobacillus ferro-oxidans, the likelihood of forming acid rock drainage (ARD) is almost guaranteed. The ?pharmacy? of antibiotics available is extensive, ranging from solid alkaline amendments like limestone to liquid ?medicines? such as sodium lauryl sulfate, sodium thiocyanate, waste milk, and bipolar lipids. Unfortunately, the ?geo-medical? teams of geochemists, microbiologists, engineers, and mine managers lack the tools to surgically apply these active ingredients where they are needed most with a minimum of waste. Distribution of fine grained limestone on the surface of an acidic mine waste dump is analogous to applying a bandage soaked in antacid to treat an upset stomach. The implementation of up-to-date best management practices has not healed the patient; an equivalent combination of hypodermic needle, cyber knife, and arthroscopic probe is clearly needed. Using an engineered, flow-able or pumpable foam or pHoam? as the medicinally analogous ?dextrose delivery solution? for solid and/or liquid ?geo-antibiotics?, the authors have combined off-the-shelf technologies that have been previously applied in solving geotechnical problems in the mining industry. A patent for the innovative process is pending. This paper discusses method concepts and the advantages it could provide over conventional BMPs.

Jan 1, 2012

By Laura McNally

In 2006 McNally International Inc. in a Joint Venture partnership with Aecon Constructors was the successful bidder on two York Region Tunnel Projects: Bathurst Collector/Langstaff Trunk Sewers; and YDSS Interceptor Sewer 19th Avenue Project. These projects comprise a total of 13 kilometres of 2.74 meter finished diameter tunnels and are both part of the York Durham Sewer System (YDSS). Both contracts require the use of EPB tunnel boring machines with a precast concrete segmental liner. The following provides an overview the two projects.

Jan 1, 2008

By Pedro Hugo Tumialán de la Cruz

El presente texto describe el proceso metalogenético del oro en el Perú a través de la revisión historiográfica que incluye la distribución geográfica del oro y la ocurrencia del oro con relación a los rasgos morfoestructurales. En este sentido, el Perú se divide en varias provincias metalogenéticas, cuya relación con el tipo de intrusivo varían de acuerdo a la mineralización. Asimismo la intensidad en la mineralización de las etapas geológicas es diferente de las metalogenéticas. Las antiguas (Cretácico Superior y Paleozoico Superior) serán mejores, mientras que en las jóvenes (Terciarias), el oro se presentará solo como subproducto.

Nov 20, 1978

By Jean R. Garcia, Paulo J. R. Albuquerque, Renato P. Cunha, Osvaldo Freitas Neto

"Abstract Results obtained from in-situ load tests carried out on drilled displacement piles sunk in a porous, lateritic and unsaturated soil deposit, are analyzed in this paper. Three slow-maintained load tests were performed on deep instrumented piles with a diameter of 0.37 m and around 12 m long. The soil deposit consists of a superficial, silty clay “porous” layer 6 m thick, with an average standard penetration blow count (NSPT) of 4 and cone tip resistance and sleeve friction (qc and fs) of 1.5 MPa and 48 kPa, respectively. Under this layer there is a residual stratum 10 m thick, geotechnically consisting of a “porous” clayey silt with an average NSPT of 7 and qc and fs of 2.4 MPa and 202 kPa, respectively. The water table was reached at a depth of 17 m below ground level. The results of the field load tests yielded a maximum pile load (average for the tests) of 1428 kN, which is twice as high as corresponding experimental values from standard bored piles with similar geometric conditions. Exhumation of one of the tested piles was carried out after the test, in order to check integrity and shaft conditions. Numerical finite element analyses, using the commercially available French Code LCPC Cesar®, were performed in order to back-analyze the geotechnical soil parameters for a post execution pile condition. The results permitted a better understanding of the improvement of the subsoil given the intrinsic execution characteristics of this particular pile. It was also possible to note that drilled displacement piles have great potential to become an economically viable solution in tropical soils, given the enhanced behavior of such piles when compared to alternative (cheaper) techniques. In fact, it has several advantages which should make it a key foundation type in the Brazilian market in the future.IntroductionMost buildings in tropical soils use, as the main type of foundation, deep bored or auger type piles. These types of foundations can be performed in various ways, for example with or without soil extraction, with or without bentonite mud and so on. Two main processes maybe formulated: the first execution process is typified by bored pile types, continuous flight auger piles etc., which do not cause excessive soil displacement during excavation. With respect to the second process, one could mention, amongst others, driven piles (precast concrete or steel), Franki piles and drilled displacement piles, which do displace the soil during excavation by pushing the soil laterally around the hole in order to allow either the penetration of the pile or the excavator auger."

Jan 1, 2014

By AMIRA P588 Research Team

This contribution summarises new knowledge and data, obtained during a three year ARCAMIRA funded research project, on the mineralogical and geochemical characteristics of hydrothermal alteration associated with low sulfidation, gold-silver epithermal deposits. These data are used to develop exploration vectors for use at both deposit and district scales, plus techniques have been established to distinguish ore grade epithermal systems from barren or low grade systems. Deposits investigated were Ladolam, Papua New Guinea, Gosowong and Mt Muro, Indonesia, Cerro Vaguardia, Argentina and Bimurra and Twin Hills, Australia.

Jan 1, 2005

By Richard F. Flanagan, Robert H. Marshall

The Republic of Singapore’s Public Utilities Board is implementing the Deep Tunnel Sewerage System Project. The project’s deep tunnel component, 48 km of deep, large diameter sewer tunnels has been successfully completed (the works are in the defects liability period). Six International Design/Build tunnel contracts utilized eight Earth Pressure Balance TBMs ranging up to 7.23 m in diameter to deal with varied ground types ranging from deep soft clays to fresh granite. Numerous access/workshafts were constructed and using various support systems. This paper provides an assessment/overview of the tunnel contracts, tunnel excavation methods and equipment, and the shaft systems. Suggested enhancements to similar future projects are provided.

Jan 1, 2007

By L. Bergkvist

"History can provide many answers with regard to what today’s mining industry looks like and how we got to where we are today. It has always been self-evident that safety has to be given the highest priority and, throughout history, many mine workers have been injured, become ill and have even sacrificed their lives due to the way in which attempts have been made to extract the ore, often due to ignorance of the dangers being faced. In more recent stages of history we have seen certain dangers being compensated by means of higher wages and bonus systems in order to have the work carried out: one example of this is when the rock heating method was employed and the men who first went underground to put out the fires that were burning, were paid extra. The working conditions, to which these people were exposed, with smoke-filled closed spaces, shortened their life expectancy considerably and today we can ask ourselves whether it is really possible to value these efforts just by higher wages. In all mines worldwide the working environment has been improved and many mining companies have a zero vision where work-related injuries and accidents are concerned. Despite this, incidents of varying severity still occur and a continuous improvement process and ongoing training is necessary in order to constantly minimise risks and improve the working environment. Atlas Copco takes this into account in all its development and we not only review our own production units but also the needs of our customers, with regard to the machinery that is produced in order to cater for customers’ safety and production objectives. Underground mining probably started at the beginning of the 11th century when people with modest tools tried to extract ores that were present in the bedrock. Methodology has developed enormously over the years with a strong focus on increased efficiency and higher production. In different parts of the world the development is driven forwards at different rates depending on which controlling factors are regarded as necessary. Political decisions, profit goals and productivity have partly controlled the development, but the greatest factor where improvement is concerned still remains with increased understanding of the totality. During more than 1000 years since underground mining has been conducted, all individuals at all levels have constantly improved their expertise and the human element has been of great importance with regard to the development that has been made, even though technology often occupies a leading role when we describe the improvements made."

Jan 1, 2011

Close spatial relationships between the deposits of the Etheridge Goldfield (23 000 kg of bullion) and various regional geological and geophysical features suggest that genesis of the ore deposits was a multi-stage process that started with magmatic and metamorphic stages in the mid-Proterozoic, climaxed with structural and hydrothermal stages in the late Palaeozoic and terminated with an oxidation enrichment stage in the Cainozoic. Acceptance of this hypothesis permits classification of the Georgetown region into areas likely to contain deposits of the Etheridge type and those unlikely to do so. Consequently there is little scope for the discovery of extensions of this field. However, the stratigraphic interval between the source rocks of the Etheridge field and stratigraphically bigger host rocks of the Croydon field may contain disseminated replacement gold deposits of the Carlin type. The potential host (pyritic carbonaceous and locally dolomitic siltstone of the Candlow Formation) is locally faulted and cut by granitoids and the extension of a mineralised, long-standing zone of structural weakness.

Jan 1, 1980

By William E. Sopper

Heat-dried municipal sludge was applied to a barren burned anthracite refuse bank in 1974. Sludge was applied at rates of 0, 40, 75, and 150 dry metric tons per hectare" Ten species of trees were planted and five species of grasses and legumes were seeded for evaluation. One plot was also irrigated with sewage effluent. The 150 t/ha sludge application rate produced the best overall herbaceous vegetation growth response. The 40 and 75 t/ha sludge application rates produced the best tree seedling growth response. Foliar analyses for trace metals indicated no phytotoxity problems. Analyses of leachate water at the three-foot soil depth indicated that the sludge applications did not impair water quality. Results of the study indicate that treated municipal sludge can be used to revegetate land disturbed by mining activities without adverse effects on the vegetation or water quality.

Jan 1, 1978

By Doug Anderson

Blast vibration seismograms are generally collected strictly for compliance with regulations. The peak levels (including dominant frequency) are typically all that are looked at. However, these records contain a lot more information about how a blast has performed. The seismogram is actually a record of explosive energy that was not used in fragmenting rock. The trick is to determine how to extract information that would be useful in analyzing blast performance.

Jan 1, 2013

By T Howard, J E. Everett

BHP Billiton Iron Ore has replaced the conventional product quality control batch system at Yandi with the Continuous Stockpile Management System (CSMS) centred on a fully integrated æcontinuousÆ stockpile flow from mine planning through to port reclaiming. With increasing tonnage rates, tight operational coupling associated with the original batch system caused production interference which achieved final product quality but in an increasingly inefficient manner. This innovative approach places a continuous emphasis on product grade control and takes full advantage of the most appropriate blending opportunities of the mine to port planning and production system in order to reduce the natural variability of the ore to an acceptable level. To implement continuous control, product variability throughout the process is classified as long-term and short-term. Long-term variability is best controlled through the monthly mine planning process which determines monthly grade targets while taking into account optimum mine development. In the past, attempts to control long-term variability were made at the port through selective stockpiling and reclaiming which reduced operational efficiency. Short-term variability is best controlled around the monthly mine grade target by daily mine production scheduling, train sequencing, stacking into port stockpiles of appropriate size and systematical stockpile reclaiming. The implementation of the new system has maintained customer accepted shipping grades and has provided significant improvements in resource utilisation, operational efficiencies and costs.

Jan 1, 2002

By Charles "Chick" Rodgers

"The Key Lake uranium mine is the largest single uranium producer in the world. It is owned 2/3 by Cameco Corporation and 1/3 by Uranerz Exploration and Mining. Cameco is the operator. Current production is fourteen million pounds per year of uranium oxide (U308).The mine's location is 570 kilometres north of Saskatoon on the southern edge of the Athabasca Basin approximately at latitude 57° 11 'north and longitude 105° 34' west. Access to the mine is by an all-weather road and a private airstrip.The mill was commissioned in 1983. A molybdenum plant was constructed in 1989 in response to increasing molybdenum content in the yellowcake or final product. Early test work had showed that the first ore body to be mined, the Gaertner deposit, would present few problems with regards to molybdenum in the product. However, the test work also showed that the higher molybdenum content of the Deilmann ore, the second Key Lake orebody to be mined, would result in increased molybdenum concentrations. Without the molybdenum plant, penalties would become excessive and some product might not accepted by the refineries.This paper will describe the current Key Lake mill process with emphasis on the molybdenum solvent extraction process. It will cover the chemistry of the process, process development in the mid 1980's, and current operating practices.The Key Lake milling process consists of five individual plants, crushing and grinding, leaching -counter current decantation (CCD), solvent extraction, yellowcake/crystallization and bulk neutralization (Figure 1. Simplified Mill Flowsheet). A detailed mill flowsheet can be found in the appendix."

Jan 1, 1996

By P. G. Gresse

The Orange-Vaal River system is known to be the primary secondary source for alluvial diamond deposits in the northern Cape and along the west coast of Namaqualand. The higher order sources for diamonds contained within this system are still not defined entirely to satisfaction, but certainly include kimberlite pipes exposed in the catchment regions of these rivers. The focus of alluvial diamond mining along the Orange-Vaal system recently changed from the traditional areas in the upper catchment regions?the Barkly West, Christiana, Bloemhof, Wolmaranstad, Schweizer-Reineke region, and the lower regions near the mouth of the Orange River at Baken, Alexander Bay and Oranjemund, to the area between Douglas and Prieska?the so-called mid-Orange region (Figure 1).

Jan 1, 2003

This document is Volume II of a two-volume report on underground and surface coal mine fires occurring between 1950 and 1977. Volume I discusses the methods of data acquisition, data analysis procedures, results and conclusions. This volume contains (1) a master list of all fire incidents obtained from MSHA reports, (2) an annotated bibliography of all MSHA reports, journal articles on selected incidents, and non-reportable fires (appendix), and (3) indexes to be used in accessing incidents in the master list and annotated bibliography. These three types of information provide the reader with a complete summary of coal mine fires during the period from 1950 through 1977 and a convenient means to locate incidents of specific interest. The body of this volume is organized around two tables and a series of indexes. The two tables are master lists of underground and surface fire incidents. They are followed by 14 indexes keyed to the master list and annotated bibliography. The appendix contains three different parts: o The annotated bibliography of MSHA fire reports (one section each for underground and surface mine fires) o The annotated bibliography of journal articles about selected fires from the MSHA bibliography o A listing of non-reportable fires (one section each for underground and surface mine fires) Descriptions of the contents and use of each of the three major components of this volume (i.e., master list, indexes, and appendix) are presented in Section 2.0.

Jan 1, 1979

Overcasts are indispensible ventilation control devices to permit one airway to pass over another without mixing in room and pillar coal mining. The airflow distribution inside the overcast depends on its spe-cific configuration at which the flow enters into it. This study uses 3D numerical simulation to examine the pressure and velocity distributions inside an overcast. The effects of the overcast angle on the flow field are also examined. The flow is assumed to be turbulent and isothermal and the standard k-e model is utilized. Simulated results display flow separation and recirculation regions of different sizes occurring not only upstream and downstream from the overcast but also inside it. The results also show that the size of the recirculation regions in-creased with the increase in the angle before and after the overcast influencing significantly the flow field and pressure losses. The stream-lines are plotted to show the 3D structure of the flow field. The results from the simulation can guide overcast design commonly used in un-derground coal mines. Keywords: 3-D simulation, Overcast, Room and Pillar, Turbulence, Recirculation Region

Feb 27, 2013

By Michael J. Rinker, P. A. Tibble, M. Wiseman, R. V. Nicholson

Tailings, from an active copper-zinc operation, containing about 10% sulphur were investigated to assess the onset of acid production and potential lime requirements for treatment of drainage. Oxygen consumption rates were measured over two years to verify spatial and seasonal variations in sulphide oxidation rates. Shallow cores were collected to assess the quality of tailings porewater and to characterize solids that had been subjected to oxidation and depletion of neutralization potential (NP) for several years. Oxygen consumption data were used to quantify rates of NP depletion and onset of acid drainage from the near- surface tailings. Based on measured oxygen consumption rates and identification of NP remaining in the tailings, future lime use in the treatment plant was expected to rise significantly without mitigation. Geochemical modeling calculations were calibrated with observed oxygen consumption rates and the model results agreed well with actual lime use in the waste water treatment plant during operations. The modeling also demonstrated the benefits of lower lime demands and treatment costs after closure as a result of construction a soil cover on the acid generating tailings.

Jan 1, 2000