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By A. P. Paiva

The solvent extraction properties exhibited by some /V,N'-tetrasubstituted malonamides to efficiently and selectively recover iron(III) from concentrated chloride leaching solutions can be found in the recent literature. The iron(III) extractive chemistry exhibited by some of these derivatives is revisited, in order to compare their chemistry with that shown by a few of the new malonamide compounds. The generally good extraction efficiency towards Fe(III), from >4 M hydrochloric acid solutions, and the relative ease of Fe(III) stripping by distilled water are remarkable findings that are confirmed for the malonamide derivatives described in this work. Furthermore, additional data regarding their selectivity towards Fe(III) extraction over several base metal ions and their behavior when subjected to successive Fe(III) extraction-stripping tests are also presented and discussed.

Jan 1, 2006

By Jueun Lee, Jong-Hwa Yoon, K. Rider, Bernard J. Martin

Whole body vibration is known to affect movement accuracy [1], however little is known about changes in the organization of movement and movement strategies used to limit the influences of perturbations. The specific aim of this work is to analyze the motion and coordination of upper body segments of seated operators performing reaching tasks under whole-body sinusoidal vibration exposure and simulated vehicle ride motion. The long-term objective is to model reach coordination and predict the dynamic behavior of the upper body motion under vehicle vibration exposure. Method The reach task consisted of pointing with the right hand index finger to targets located on touch screens placed in front of the subject, 45° overhead and 90° to the right in the mockup cabin of an HMMWV placed on a 6 DOF ride motion simulator. The task was performed under stable (no vibration) and vibration (sinusoidal vibration or simulated ride motion) conditions. A motion capture system was used to record kinematic data of reflective markers to recreate body link trajectories. Joint angles (torso, shoulder and elbow; Figure 1) were then computed using quaternions. Coordination between body links was defined as a) the joints angle-versus-angle relationships between the upper arm and lower arm, and b) the joint motion onset relationships between torso, upper arm and lower arm in the time domain. Results Angle–versus-angle relationships. The relationship between upper arm vs. lower arm angle and torso vs. upper arm angle for a far forward reaching movement in the stable (solid lines) and vibration conditions (dotted lines) are illustrated in Figure 2. Fig 2A compares the control condition with a 4 Hz lateral vibration while Fig 2B compares the control condition with a 6 Hz vertical vibration. It appears that under vibration exposure the reduced upper arm extension is compensated by an increase in torso flexion. This effect is seen in the last phase of the movements (encircled areas). In addition, the lower arm extension is delayed under 6 Hz vertical vibration (Fig 2B left panel). Time of joint motion onset. The timing relationship between torso, upper arm and lower arm is largely a function of the target to be reached. Examples of delays between body links are illustrated in Figure 3. The control condition is compared to a 6 Hz vertical vibration for three

Jan 6, 2006

By Oscar Morales

El presente texto describe el proyecto de expansión de producción de la mina Recuerdo a través del estudio de las estructuras, equipos, maquinarias y el personal que labora actualmente. En este sentido, el incremento de la producción se desarrolla por la mecanización del método de explotación, donde se utilizan los equipos LED Diesel y jumbo neumático Toyo ensamblado sobre ScoopHST-IA. El manejo del equipo optimiza la perforación en tajeos en un %50, a comparación de las perforadoras manuales. Asimismo, refiere el uso de la computadora para algunos trabajos en la mina como la preparación de informes mensuales, presupuestos y programas de producción anual para la División Mina.

Nov 8, 1984

By R G. Barker

This paper reviews the annual status of the New Zealand mining industry (metallic minerals and coal) including key aspects such as mineral production, mineral exploration expenditure, commodity price trends, key industry players, market activity and other significant commercial factors.   Strong commodity prices during 2006 have been underpinned by a number of key factors including US dollar weakness and emerging market demand, particularly from countries such as China and India. In real terms commodity prices have recovered significantly since 2002 and are currently at 20-year highs.   New Zealand exploration spending on metallic minerals (predominantly gold) is at a 15 year high driven by rising global commodity prices. New Zealand gold production in 2006 was about 340,000 oz and is expected to grow in 2007 as new mines at Frasers and Globe-Progress (Oceania Gold) and Favona (Newmont) come on stream. Gold production broadly lags 10 years behind exploration spending and exploration activity over the last five years remains well below that seen in the early 1980Æs. Expenditure on coal exploration shows a similar trend with strong growth from a low base over the last five years, reaching over $11 M in 2006. Total coal production in 2006 was 5.9 Mt, an increase of 10% on 2005 with imports from Indonesia adding a further $1.1 Mt.   Newmont and Oceana Gold are by far the largest public gold mining companies operating in New Zealand, although only Oceana Gold maintains a presence on the local stock exchange. Other metals explorers with New Zealand projects include a range of public-listed Juniors (market capitalisation less than NZ$50m) domiciled largely in New Zealand, Australia and/or Canada. Capital-raising on public markets directed towards New Zealand exploration is estimated at around NZ$12 M for 2006, the bulk of this coming via Glass EarthÆs NZ$10 M IPO on the NZAX in October.   The New Zealand Coal sector is dominated by the state-owned enterprise Solid Energy with around 80% market share by production. Other domestic coal competition remains limited, and includes the L&M Group, Pike River Coal, Eastern Corporation, and New Vale (acquired by Solid Energy in 2007). Pricing parity comes mainly from imported coal and global thermal coal prices have remained strong during 2006 at around US$45-55/t, driven by continued expansion in Chinese demand. Coking coal prices have eased 16% since 2005 to around US$98/t in 2007.   Although recent increases in exploration spending suggest a renaissance in the New Zealand minerals sector, long-run trends indicate that we have simply rebounded from a low base over the last five years and much work is still to be done to stimulate further growth in the mining industry to maintain minerals production at current levels. Key industry challenges include marketing exploration opportunities to local and overseas investors, building a critical mass of NZX-listed explorers and providing an internationally competitive environment to attract further capital and expertise.

Jan 1, 2007

Texture Transition in Ordered CuAu, by E. A. Starke, Jr., J. C. Ogle, and C. J. Sparks, Jr., Trans. TMS-AIME, 1969, vol. 245, pp. 169-70. pole figures should have had two parts not one. On the Estimation of Oxygen Absorption by Continuous Molten Metal Streams, by J. Szekely, Trans. TMS-AIME, 1969, vol. 245, pp. 341-44.

Jan 1, 1970

By W. W. Stephens

As part of the Bureau of Mines program directed toward more effective utilization of the mineral resources of the United States, a number of processes for production of sponge iron have been investigated. The use of sponge iron as a raw material for production of steels and other ferrous alloys offers several possible advantages over the conventional pig-iron and scrap process, especially for utilization of the smeller, widely distributed iron-ore deposits of the western United States. Although considerable information has been made available on various processes for production of sponge iron, little information 118.6 been published heretofore on the problems and costs involved in melting the sponge iron for production of steel. The present Paper reports the results of tests conducted at the Bureau of Nines pilot plant at Redding, Calif. in which several different types of sponge iron Were used as charge material for production of steel in a 4-ton-capacity basic arc furnace.

Jan 1, 1949

By Dennis Dolinar

In this National Institute for Occupational Safety and Health (NIOSH) investigation, numerical modeling is used to evaluate the degree the pillar strength is increased with a rectangular pillar over a square pillar. Three-dimensional models are developed with pillar sizes and geometries typical of underground limestone mines in the United States. Physical properties for the models are based on geotechnical surveys of nearly 30 underground limestone mines. To examine the effects of pillar length on pillar strength with the modeling, a parametric study was conducted where the pillar width was held constant while the length and height were varied resulting in width-to-height ratios ranging from 0.5 to 1.5 and width to length ratios ranging from 1 to 6. There are two aspects to pillar strength and failure. At relatively low stresses, pillars can fail as a result of geologic structure. At greater depths and sufficient extraction ratios, the pillars can also fail as a result of the vertical stresses exceeding the pillar strength. The effects of increasing pillar length regarding both strength aspects are presented in this study. Equations were developed for the increase in pillar strength with both height and length based on the model results. The results from these equations were compared to those from previously developed empirical equations for rectangular pillars. For the more slender limestone pillars with a width-to-height ratio below one, there is little increase in pillar strength for length-to-width ratios above 2 and almost no increase with length for a width-to-height ratio of 0.5. Only with the more squat pillars is there a significant improvement in strength with length. The gain in pillar strength with length for the pillars is explained by the change in the ratio of the area of the pillar affected by the ends to the area of the pillar. For the squattest pillar, the change in strength is also affected by an increase in pillar confinement along the central length of the pillar as the pillar transitions from a square to a long rectangular pillar. With geologic structure, added pillar length can significantly improve the pillar strength, depending on the strike of that structure with respect to the long pillar axis.

Jan 1, 2007

By D. Brunner, G. R. Baiden, H. J. Yazici

System simulation is an increasingly popular technique for analyzing and improving existing as well as newly designed underground mining operations. An engineering firm that specializes in simulation helped a major metals producer build a long-range planning model of an existing underground mine. Subsequently the team adapted this model to assess technology alternatives in the design of a new mine. The two models differ in the level of detail used for modeling the development process. This paper discusses the differences in approach between the models along with the experiences gained and challenges faced during the construction and use of the models.

Jan 1, 1999

By Paul J. Axtell

Two new railroad bridges in Kansas City, Missouri are founded on drilled shafts embedded into the soil and underlying shale. The uncertainty arising from the non-homogeneous, anisotropic nature of most shales, and the variability of shales across the U.S., makes it a difficult material to assign appropriate design properties. As was the case on this project, the uncertainty of foundation performance in shale can lead to overly conservative designs, particularly with drilled shaft foundations. An extensive Statnamic axial testing program was performed to verify that the load-settlement behavior of the drilled shafts would be acceptable for the intended railroad traffic. Axial Statnamic testing was applied in three increasing cycles of 927 kips, 1007 kips, and 3177 kips, respectively. The maximum movements recorded at the shaft head during each of the loadings were 0.052 inches, 0.062 inches, and 0.257 inches, respectively. The loads applied in each of the respective Statnamic tests were not sufficient to reach the capacity of the shaft; so direct comparison of measured and calculated capacities is not possible. However, evaluation of the estimated design capacity can be accomplished based on results from the Statnamic testing program by utilizing normalized load transfer relations presented by O?Neill and Reese (1999). Such comparisons necessarily require extrapolation of the data measured in the Statnamic tests following typical load-displacement response. Results indicate the Kulhawy and Phoon (1993) method for estimating side resistance in Pleasanton shale rock sockets, assuming a smooth socket, appears to agree well with observed behavior during Statnamic testing. Accordingly, the O?Neill and Reese (1999) method for estimating the toe resistance in intermediate geomaterials, assuming cohesive rock with Rock Quality Designation (RQD) between 70 and 100, appears to agree well with observed behavior during Statnamic testing. Finally, based on Statnamic testing at varying load magnitudes and normalized curves developed by O?Neill and Reese (1999), the contribution of side resistance to the capacity of a deep foundation can be determined assuming no load is transferred to the base of the foundation during lower magnitude testing. Furthermore, higher magnitude testing can provide a means to evaluate the accuracy of design end bearing calculations.

Jan 1, 2006

By Charles O'Connor, Ben Tisa

International Training Resources is a company consisting of personnel with extensive law enforcement and military special operations experience, The staff members are qualified to train and certify, assist and advise law enforcement officers and agencies, at any level, in critical incident policy, procedures and tactical resolutions. Successful critical incident resolution is comprised of many elements of professional skills and personnel. (Command staff, negotiators, snipers, tactical teams, uniform patrol, K-9, bomb squad, etc.) Recently, tactical teams have been developing the capability for the use of explosive methods for rapid entry into crisis locations. This document ‘will briefly describe the environment, operational issues and courses of action associated with developing a complete tactical breaching program for utilization by SWAT teams in response to operational conditions in critical incident situations. This topic is being presented to the I.S.E.E. evaluators under “Interesting Blasting Projects” and “Public Relations” categories. Tactical operations differ significantly from traditional industry practices and we appreciate the opportunity to show the industry other professional applications of explosive materials and techniques. Presently, of the few schools from which law enforcement officers can receive training with explosive breaching methods, International Training Resources is the only company currently teaching and certifying officers which has received total endorsement by the California Peace Officer’s Standards and Training Commission (P.O.S.T.) and the state blaster’s licensing commission. We have pioneered the combining of law enforcement needs and blasting industry technology to train tactical officers, nationwide, in the mission essential skills necessary for explosive breaching.

Jan 1, 2000

By Russel Santillana

El presente texto revisa el proceso de concesión y el concepto de distrito minero como una zona geográfica que reúne las condiciones de formación tectónica para considerarse una zona metalogenética. En este sentido, el Estado es quien debe reformar el sistema de concesiones mineras para poder así conocer y disponer de sus recursos minerales en el menor tiempo posible. De otro lado, las concesiones de exploración son siempre mayores que las de explotación -en tanto se conocen los límites determinados por la Ley General de Minería. Asimismo, el nuevo sistema de concesiones deberá involucrar al desarrolllo de programas de exploraciones para que estos conduzcan a una explotación racional de las concesiones mineras del país.

Mar 1, 1977

By Peter G. Kovalchik, Rudy J. Matetic, Susan B. Bealko, Adam K. Smith

Overexposure to noise remains a widespread and serious health hazard in the U.S. service providing and goods producing industries. Excessive noise can lead to poor verbal communication and reduce the ability to recognize warning signals. These dangerous work conditions can also cause stress and fatigue. Occupational hearing loss is a permanent illness, with no recovery currently possible. Method: National Institute for Occupational Safety and Health (NIOSH) has recognized Noise Induced Hearing Loss (NIHL) as one of the ten leading work related diseases and injuries in the United States, and has emphasized its importance as one of the critical areas expressed in the National Occupational Research Agenda. Results: One of the most serious noise problems in the goods producing industries is the operation of continuous mining machines during underground coal mining. In order to minimize occupational hearing loss, noise hazards are “designed out” early in the design process. NIOSH is leading a national initiative called Prevention through Design (PTD) to promote this concept. This paper describes the quiet by design approach of a noise control that reduced noise exposures of continuous mining machine operators by 3dB(A) using the four functional areas of PTD, namely Practice, Policy, Research, and Education.

By Emmanuel N. Zevgolis Ismene-Polyxeni Kostika

Keywords: reduction, kinetics, laterites, rotary kiln, dust In this work, the reduction kinetics of dust from nickeliferous Greek laterites is investigated. The dust is a by-product from laterite treatment in rotary kilns and it comes from washing towers, electrostatic filters and polycyclones. Laboratory made pellets from this dust were also examined. Reducibility was studied in the temperature range of 700°C to 850°C in a laboratory tube furnace. Kinetic analysis of the results showed that at lower temperature values the mixed kinetic model verifies the experimental results of dust and pellet samples. At higher temperatures (800° and 850°C) diffusion becomes the rate controlling mechanism. The calculated activation energy values verify also the above mentioned results.

Jan 1, 2005

By Ann G. Kim

Fires that occur in abandoned coal mines, waste banks, and in coal outcrops constitute a serious health, safety, and environmental hazard. Toxic fumes, the deterioration of air quality, and subsidence constitute the greatest hazards from these fires. Although tires on abandoned mined land (AML) occur in every coal-producing state, the severity of the problem varies. Methods to extinguish or control AML fires, including excavation, fire barriers, and sealing, are generally expensive and have a relatively low probability of success This U.S. Bureau of Mines report includes information from a variety of sources, i.e., agencies of the Federal Government, State agencies, research reports, conference proceedings, product information, and technical literature. This information has been collated into a comprehensive discussion of AML fire problems. Data on past fire control projects and on the estimated extent of the current problem have been compiled. Factors affecting the occurrence, propagation, and extinguishment of AML fires are discussed. Conventional fire control methods are described, and their probable effectiveness is evaluated. Information on the hazards of AML fires and safety considerations is included. The status of current technology, recent improvements in fire control methods, and areas of current research are discussed.

Jan 1, 1993

By Douglas A. Anderson

The simplest method used to predict ground vibration from blasting is scaled distance -the distance from a blast divided by the square root of the Pounds per delay. Pounds per delay is defined as the number of pounds of explosive detonated within an 8 millisecond (ms) interval. Based upon this definition, regression plots of peak particle velocity vs. scaled distance have been used to determine likely values of peak particle velocity.

Jan 1, 1989

By Gandhi

Piled raft foundation under uniformly distributed vertical loads has been analyzed using Finite Element Method. The soil is considered to be linear elastic, isotropic, homogeneous. The raft,pile and the soil have been idealized with eight noded brick elements. Parametric study have been carried out varying pile length, soil modulus, raft thickness, and pile spacing. Design charts have been produced to achieve 50% load sharing between pile and raft for optimum design. Data available in literature is compared with the design chart results and found satisfactory.

Jan 1, 1996

By Floyd G. Anderson

This report reviews and summarizes information on prevention and suppression of dust in mining, tunneling, and quarrying published in the United States from 1961 through 1967. Unpublished pertinent data developed or assembled by the Bureau of Mines during this period also are included.

Jan 1, 1969

By C. R. Hairfield

With ever rising energy costs, it is increasingly important for mines to operate with energy efficiency. As a large portion of a mine?s energy consumption is often attributed to the operation of mine ventilation fans, maintaining an efficient ventilation system is a critical pro-active way for mining companies to reduce power costs. A common way to measure a mine?s ventilation system efficiency is to calculate the volumetric efficiency, which is simply a calculation of the percentage of total mine air that is usefully employed for production. The purpose of this study is to document a nationwide comparison of the volumetric efficiency of U.S. underground coal mining operations. The results will aim to show just how efficient today?s coal mine ventilation systems are and what factors may be causing their various efficiencies and inefficiencies.

Jan 1, 2009

By Janet M. Epps

The international climate regulating environmental management in mining is rapidly evolving through the combined influences of the development of international guidelines, resolutions, protocols, treaties and conventions; the influences of the international lending and aid institutions who seek a consistent but constantly evolving standard of environmental performance from their clients; the legal precedents being developed in courts al over the world; and the activities of multinational countries who tend to rapidly upgrade technological performance through their international activities (particularly influencing developing countries). In this rapidly evolving regulatory environment, the more 'models' available to this international pool of resource materials that demonstrate practical. cost-effective and (most desirably) incentive based regulatory mechanisms, the better will be the eventual body of 'international standards' we will al have to work with. Australia can make a significant contribution to this process, however, it has only been on the margin of this dynamic, North American and European led process, up to this time. It is in the Australian minerals and energy industry's best interest to take an active part in the evolution and direction of this process.

Jan 1, 1996

By Kurt R. P Petersen

This paper discusses the current approaches to modelling the DMS cyclone within the De Beers group. Current efforts are split into short term value-adding process understanding and longer term semi-fundamental analysis of separation mechanisms. To date, the basic applied approach has yielded significant value to the group, enabling operators to focus on simple diagnostic measures to control their process. The more involved modelling approach has given rise to a new understanding of the separation field, in particular that the high density gradients within a cyclone are highly localised, indicating that separation of medium to heavy density material takes place low in the cone. The model has proven to be conceptually robust, but still requires further development and validation to become a complete modelling and simulation tool for De Beers.

Jan 1, 2006