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The Effect of High Power Nanosecond Electromagnetic Pulses on Selectivity of Pyrite from Arsenopyrite

Sep 13, 2010

Using DEM to Model Industrial Banana Screens

Sep 13, 2010

By G. R. Corbett

The introduction of roof bolts to Phalen Colliery in the Sydney Coalfield, Nova Scotia (annual output of 2Mt) has been successfully implemented in maingate and tailgate entries over the last four years. Monitoring of the roof bolted areas continues to be an integral part of the quality control program as the results are utilized to maintain safety and to aid in long-term design strategies. Although all gateroads in the Phalen Colliery have converted to roof bolts as their primary means of support, the majority of intersections which intersect the main slopes remain supported by large steel structures. Several intersections within the Phalen Colliery were monitored as they were created by the mining process. A comparison is made between intersections supported with only traditional 6.4 to 6.7 m steel structure and intersections supported by 2.44 m fully resin encapsulated roof bolts in conjunction with 7.6 m fully cement grouted cable bolts. Detailed monitoring was conducted using CA NM ET's intrinsically safe sonic probe extensometer datalogger which has the ability to read up to sixteen probes simultaneously at programmed intervals. The density of the data from the datalogger has allowed a better understanding of the deformation of cable bolted intersections than was possible with manual monitoring. Test results have helped mine operators to design safer cable bolted intersections.

Jan 1, 1995

By W. G. Miller

An overall study was conducted to evaluate the properties and processes influencing the rate and magnitude of consolidation for oil sands fine tailings produced using different extraction processes. As part of this overall study, consolidation tests using slurry consolidometers were carried out for caustic and non-caustic fine tailings. The influence of a change in bitumen extraction process (caustic versus non-caustic) on consolidation properties, namely compressibility and hydraulic conductivity, was determined, as was the effect of adding a coagulant (calcium sulphate [CaSO4]) to caustic fine tailings. For fine tailings originating from two different oil sands ores (Ore A and Ore B), results were presented in terms of variation in average void ratio with time (settlement), void ratio with effective stress (compressibility), hydraulic conductivity with void ratio and coefficient of compressibility and hydraulic conductivity with sodium adsorption ratio. Findings indicated that chemical characteristics of fine tailings (water chemistry, degree of dispersion) do not have a significant impact on their compressibility behaviour and have only a small influence at high void ratio (low effective stress). The biggest advantage of non-caustic fine tailings and treating caustic fine tailings with coagulant is an increased initial settlement rate and slightly increased hydraulic conductivity at higher void ratios. Thereafter, compressibility and hydraulic conductivity is governed by effective stress.

Aug 1, 2010

By W. G. Miller, J. D. Scott, D. C. Sego

An overall study was conducted to evaluate the properties and processes influencing the rate and magnitude of consolidation for oil sands fine tailings produced using different extraction processes. As part of this overall study, consolidation tests using slurry consolidometers were carried out for caustic and non-caustic fine tailings. The influence of a change in bitumen extraction process (caustic versus non-caustic) on consolidation properties, namely compressibility and hydraulic conductivity, was determined, as was the effect of adding a coagulant (calcium sulphate [CaSO4]) to caustic fine tailings. For fine tailings originating from two different oil sands ores (Ore A and Ore B), results were presented in terms of variation in average void ratio with time (settlement), void ratio with effective stress (compressibility), hydraulic conductivity with void ratio and coefficient of compressibility and hydraulic conductivity with sodium adsorption ratio. Findings indicated that chemical characteristics of fine tailings (water chemistry, degree of dispersion) do not have a significant impact on their compressibility behaviour and have only a small influence at high void ratio (low effective stress). The biggest advantage of non-caustic fine tailings and treating caustic fine tailings with coagulant is an increased initial settlement rate and slightly increased hydraulic conductivity at higher void ratios. Thereafter, compressibility and hydraulic conductivity is governed by effective stress.

Jan 1, 2010

By J. A. Botín

In modern mining, the core of mine planning and design is the block model, a simplified representation wherein the ore deposit is divided in a number of virtual rock cubes, each characterized by technical and economics parameters. Mining engineers use this model to design the mine and develop production schedules. Traditionally, sustainability issues are not considered in the mine design, planning and engineering processes but rather are incorporated in the later stages of the feasibility evaluation as necessary expenditures and operating costs. This paper describes the results of a research project aiming to develop a methodology to incorporate sustainability parameters directly into the block model, so that they become an integral part of the design, planning and scheduling processes. It is considered that the incorporation of sustainable parameters into the block model would yield a more responsible mine design and improve mining projects sustainability performance

Feb 27, 2013

OWING to two large falls of ground which resulted in serious accidents occurring towards the end of 1908, it became evident that the "open chamber" system then in use was unsuitable for the conditions existing in the Mount lVIorgan mine. It will be admitted that in all mining operation, the first consideration is the economy of the system adopted, combined with its safety and ability to give the desired output. A sectional system with square sets has been introduced into the mine, in which due attention has been paid to these factors. In this paper a brief description of this system will be given. An outline of those previously used will be ineluded, as it is necessary to understand the eonditions which existed in the mine at the initiation of the sectional system. Outside the actual mining methods employed, various points that might prove of interest will be touched on.The square set system of mining has been in use throughout the stopes in the gold ore in the upper levels of the mine since underground operations were started in Mount Morgan.

Jan 1, 1910

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 Paul Harvey

Following initial discovery in 1991, BHP Billiton Diamonds Inc opened Canada?s first diamond mine, the Ekati Diamond Mine TM (Ekati) in the Northwest Territories on October 14th, 1998. Four short years later on November 29th, 2002, saw the opening of North America?s first underground diamond mine - the Koala North mine. Nestled between the original Panda open pit and the new Koala pit which is in the early stages of production, Koala North represents the only underground kimberlite mining venture in arctic conditions outside the new underground mines being developed by ALROSA in the Yakutsk region of eastern Russia. Extensive underground kimberlite mining has been practiced in the Republic of South Africa for much of the 20th century and continues today. Underground mining represents a key component of the long term business plan for the Ekati. As various open pits reach their economic limit, continued recovery of high value ore at depth is dependent upon the ability to productively mine the kimberlite pipes by underground methods. As a function of its location, size, and value, the Koala North pipe is ideally positioned to host the first underground mine at Ekati . In addition to being a production source for the operation, Koala North is designed as a learning mine, from which to gain valuable experience in preparation for the potential mining of other larger, higher value pipes by underground methods in the future. Fortuitously Koala North was available for development so the learnings could be integrated into the Panda mine design prior to completion of the Panda pit. Establishing our first underground diamond mine, and applying the open benching mining method in arctic conditions brings a unique combination of mining challenges together in a harsh climate and remote environment. This paper examines the design and establishment of the Koala North mine. Discussion includes experiences gained from the first year of development, production start-up, and provides a brief overview of our potential underground future at Ekati .

May 1, 2003

By W. L. Swager

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

Jan 1, 1981

By D. Caiden, C. S. Covil, P. J. Chamley

The paper describes the background to alternative delivery models, drawing on international experience, and introduces Project Alliancing/Contract Partnering, common risks and risk sharing on tunnel projects. A plea for early contractor involvement in design is made before describing some whole life design implications for tunnels. The paper concludes with four short case studies; Channel Tunnel Rail Link in the UK, Hull Waste Water Tunnel in the UK; Island West Sewage Transfer Station in Hong Kong, and the New Southern Railway in Australia.

Jan 1, 2005

Selective Removal of Arsenic from Acid Mine Drainage Containing Ferrous Ion Using Sulfide Precipitation Method

Sep 13, 2010

By D. D. Munro

Finsch Mine is a kimberlite diamond mine located at Lime Acres in the Northern Cape Province of South Africa. The mine was founded in 1961 and started surface mining in 1964. Underground production commenced in 1990 using a modified blast-hole open stoping method for the mining of Blocks 1, 2 and 3. Block 4 is currently being mined as a block cave. The process of identifying and optimizing a method to mine the Block 5 orebody started in 1991, and in 2006 incline caving was identified as being technically feasible. This paper aims to document the process employed in developing this method by the Block 5 prefeasibility team as well as discuss the technical challenges encountered during this process. The paper commences with a history of Finsch Mine and highlights the complex geology and threat of sidewall failure that prompted the decision to use block caving as the mining method for Block 4. A literature study of mines that implemented mining methods upon which the incline cave was conceptualized is then presented. These practices were then used to form the basis for the designs on which the initial geotechnical modelling was done and built upon through an iterative process of modelling and design changes. The ventilation of the mining area, initial productivity simulation results, and the applicability of automation and comminution processes in the incline cave are also presented. The paper concludes with an investigation into some of the challenges of the mining method, and shows that that incline caving is a technical option available for further investigation in determining the optimal mining method to be employed at Block 5, Finsch Diamond Mine. Keywords massive mining, incline caving, geotechnical modelling.

Jul 1, 2013

A three?stages countercurrent fluidized bed prototipe reactor to neutralize the SO2from smelter gases has been developed. For gases with 8 vol-%SO2, at 800°C and for 4 h mean reaction time of the limestone, the capture of SO2 is 99%, with off gases with 0.07 vol-%. For 2 vol-%SO2, the total capture of SO2 can be obtained at 750°C and 4 h reaction time. The calcine obtained contain a blend of unreacted limestone and calcium sulphatewith minor amounts of residual lime.

Jan 1, 2006

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

Study on Mineral Processing of Refractory Copper-Nickel Ore

Sep 13, 2010

By Hernán Parra

El presente trabajo señala la fase de tratamiento metalúrgico de pirrotitas que contienen oro, donde en la concentración por flotación se encontró un esquema adecuado para tratar pirrotitas auríferas considerando las restricciones ambientales que no permitieron incorporar técnicas de cianuración directa, que es como suelen tratarse es-tos minerales en el mundo. Asimismo, se propuso el uso de concentradores centrífugos para recuperar el oro libre fino en una primera etapa gravimé-trica, y concentradores de mesa Gemeni para obtener concentrados de alta cali-dad disponibles para fundición.

Sep 9, 2007

By F. Cihangir, A. Kesimal, K. Karaman, B. Ercikdi

Uniaxial compressive strength (UCS) and shear strength parameters(cohesion and angle of internal friction, Cand F) of rocks are important parameters needed for various engineering projects such as tunnelling and slope stability. However, direct determination of these parameters is difficult and requires high-quality core samples for tests. Therefore, this study aimed to explore the applicability of the Brazilian test (BT) - a simple, less sophisticated and inexpensive method for both specimen preparation and testing - to estimate the UCS and shear strength parameters of rocks. Thirty-seven rock types were sampled and tested, 24of which were volcanic, 8 were metamorphic, and 5 were sedimentary. Statistical equations were derived to estimate the UCS and shear strength parameters of rocks using the BT. The validity of the statistically derived equations was confirmed using predictive analytics software (PASW Statistics 18). A strong linear relation was found between BT and UCS values. BT and UCS values exhibited prominent linear correlations withthe cohesion values of rocks. The Mohr envelope was also used to determine the cohesion and friction angle of rocks using BT and UCS values. It is deduced from the current study that the BT values can be used to estimate the UCS and cohesion. However, no relation was observed between the angle of internal friction values and the UCS and BT for all rock types. Therefore, different approaches are suggested for the estimation of the internal angle of friction for application in the preliminary design of projects.

Jan 1, 2015

By Louis, Jordan

THIS paper presents in an abbreviated form the chief points of interest in an investigation of the tarnish-resistant qualities of silver alloys, an investigation which has been carried out as a joint research by the Bureau of Mines and the Bureau of Standards and will later be reported in detail in an official publication from these bureaus. In 1923 a Commission of Gold and Silver Inquiry was created by a Resolution of the U. S. Senate to study the causes of the depressed condition of the gold and silver industry. In cooperation with this commission the Bureau of Mines made a preliminary survey to determine in what ways, if any, it might be possible to increase the uses of silver. One of the possibilities indicated by this survey was the development of silver alloys which should be non-tarnishing, or at least less-tarnishing, than the usual sterling silver (copper-silver). The preparation of a rather wide variety of silver alloys and the determination of their behavior under accelerated tarnish tests in the laboratory was therefore undertaken by the Bureau of Mines and Bureau of Standards as a joint investigation.

Jan 1, 1927

The U.S. economy and, consequently, the demand for minerals grew at more moderate rates in 1995 compared with stronger performances the previous year. Demand for metals such as steel and copper was relatively stable. For example, the decline in steel consumed in motor vehicle manufacturing (reflecting lower vehicle sales) for the first half of 1995 was offset by an increase in steel consumed in construction during the same period. More detailed information on events, trends, and issues in the mineral and material sector Is presented below and in the commodity sections that follow. Overall Performance The value of processed materials of mineral origin produced in the United States during 1995 was estimated to be $395 billion, an increase of almost 10% compared with 1994. The estimated value of U.S. raw nonfuel minerals production in 1995 was $38 billion, about 7% more than in 1994. The value of U.S. minerals production has increased in 30 of the last 35 years.

Jan 1, 1996