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By David Newman

In Eastern Kentucky, the Darby seam has had an extensive history of coal bumps and pillar bursts. The combination of high overburden, strong rock and coal, subjacent and superjacent mines, and retreat mining has produced incidences of violent pillar failure. The influence of these factors on pillar stability and the potential to bump is illustrated in two case histories. In the first case history, a bump occurred unexpectedly during the retreat mining of a five heading continuous haulage panel. Alternative cut sequences and pillar dimensions were analyzed to identify a geometry that would reduce the potential for future coal bumps or bounces during retreat mining. The viability of the alternatives was constrained by the reach of the continuous haulage system, the overburden depth, and the presence of thick sandstones in the main roof. Each alternative was numerically modeled cut-by-cut to examine the mechanism of stress transfer, as a pillar row is retreat mined. This approach highlighted which cuts were being made in highly stressed portions of a pillar and therefore more prone to coal outbursts. Validation of the numerical modeling was accomplished by comparing the cuts where bumps and outbursts had occurred underground to the highly stressed cuts shown within the models. Recommendations of the barrier pillar width between adjacent panels, pillar dimensions, and changes in the retreat mining sequence were proposed based upon the overburden thickness, geology, and the result of the numerical modeling. The second case history documents a nine-entry panel 3,600-feet long that was retreat mined a distance of 2,064-feet without a significant roof fall or roof-floor convergence. Mine management became concerned about the potential for a coal bump or a large roof collapse within the gob and the resulting air blast. The stress on the pillar line and within the remnant pillars in the gob was quantified through numerical modeling. Changes in mining practices on the current panel were implemented to avoid a bump in the active panel. A barrier was established between the current and the future panels to protect the future panel against abutment pressures from the void area. A change in pillar centers was proposed in the adjacent panel to absorb the side abutment pressure from the gob of the active panel.

Jan 1, 2008

By A. N. Clay

In recent times, there has been criticism of the minerals industry over the lack of quantifiable boundaries between inferred, indicated, and Measured resources. A recent initiative through the United Nations aims to try to converge the mineral resource classification systems. Since the oil and gas industry uses a probabilistic approach to defining reserve boundaries, it is appropriate to introduce a similar statistical methodology for minerals. The Venmyn Variance Tower has been developed based upon traditional statistics to utilize historical and ongoing information in order to quantify variance of geological and chemical parameters and the boundaries and logic for quantitative mineral resource classification. It is proposed that a less than 50% variance from the mean of all sample parameters is required to achieve the classification threshold to define an inferred Resource whereas between 20-10% is needed for an indicated Resource and less than 10% variance from the mean is needed to declare a Measured Resource. These limits are similar to those used by the oil and gas industry, and it is suggested that these thresholds be adopted as an industry standard to ensure consistent quantitative reporting. While this process is intended to use statistics of an orebody to provide quantifiable and defendable boundaries, it cannot be carried out unless the geology of the mineral deposit is understood and the borehole samples can be categorized into appropriate populations for which the statistics are valid. This means that competent geologists are always required to work with and understand the implications of the Variance Tower results. This paper is intended to form the basis of a series of publications that establish a process to take mineral projects along a quantifiable and logical development path. Hence, no specific field example of the practical application of this process is given here.

Jan 1, 2012

By Janine Acasi, Robert D. Rogers, Jonathan K. Trautman, Richard C. Cronn, James H. Wolfram

The demand for phosphate will continue into the future, because phosphate is currently irreplaceable as a plant nutrient and in many chemical applications. Phosphate is not recycled, so the supply must be replenished through a process of mining and purification. The most energy intensive part of the process, separation of phosphate from the ore, requires 54 to 78% (depending on the method used) of the estimated 0.5 quads of energy consumed by the U.S. phosphate industry. This paper provides data from a project designed to determine if a biotechnology can be developed to separate phosphate from its ore. Several hundred microorganisms (both bacteria and fungi) capable of solubilization of phosphate ore have been isolated from the environment. Work is ongoing to determine the mechanism for solubilization. In addition, how these organisms could be used in a bioprocess is being investigated.

Jan 1, 1989

By M. Matema

Paper written on project work carried out in partial fulfilment of BSc (Eng.) Metallurgy and Materials Engineering Small and large welded aluminium specimens were tested in fatigue and the results compared with design curves for aluminium in specification BS8118. Metallurgical tests were also performed on the specimens in order to correlate microscopic and macroscopic phenomena. The small-scale fatigue test results were in reasonable agreement with results in BS8118, whereas the large-scale fatigue tests showed that BS8118 is conservative.

Jan 1, 2005

By D Craw

Formation of gold-bearing veins in Otago Schist was intimately linked to the structural evolution of the schist belt. The currently-exploited Macraes gold deposit formed in a regional scale shear zone during latemetamorphic uplift of the schist belt. Further exploration for this type of deposit will be facilitated by an increased understanding of the late-metamorphic structural evolution of the schist belt. To this end, a three-dimensional cross section through the Otago Schist has been drawn using structural data gathered at outcrops in a 20 - 40 km wide transect across central Otago. This is the first continuous detailed structural section to be drawn through the belt. The section spans an area from Textural Zone 1 metagreywacke of the Torlesse terrane in the northeast through TZ 4 schist in the central region and across the Caples-Torlesse boundary to Textural Zone 3 schist of the Caples terrane in the southwest. Two different late-metamorphic structural generations are identified in this section: the long-recognised Manorburn Generation, and a new æPoolburn GenerationÆ. The location of the Caples-Torlesse boundary has been refined on this transect by field mapping combined with whole rock geochemistry.

Jan 1, 2001

In all the industries that require blasting operations using explosives, there exists numerous unwanted side effects of the blast which may pose as environmental hazards. These hazards face prominence, especially in India, where there are very stringent rules and regulations governing the use of explosives. The environmental hazards associated with blasting operations as a whole can be tacked successfully to a certain extent depending upon the ultimate expectations of ,the post-blast effects and the limitations of the environmental obligations as specified by the authorities from time to time and from place to place. The main parameters which require attention to limit the post-blast results to the optimum level are ground vibrations, dust pollution, gas pollution, air blast effects, noise pollution & fly rocks etc.

Jan 1, 1995

By Daniel Briones

El presente trabajo señala las bases que fundamentan la aplicación de los Sistemas de Gestión Integrados y se ofrecen argumentos que sustentan los mecanismos usados para integrar los sistemas de Seguridad (NOSA), medio ambiente (ISO 14001) y calidad (ISO 9001); y la necesidad de su uso como herramienta de gestión por parte de la organización, llegando a todos los niveles hasta alcanzar la madurez del Sistema. Asímismo, se describen algunos ejemplos del impacto positivo, que ha significado la implementación de este Sistema en la unidad de producción Uchucchacua (cuarta productora mundial de Plata,), desde el inicio del Proyecto, hasta lograr la revalidación de la Certificación de las normas ISO 14001, y la cercana certificación en OHSAS 18001 e ISO 9001.

Sep 12, 2005

By G. Styles, K. Lye, R. Tenbergen, M. Mayhew

Requirements to produce a higher bulk concentrate grade have necessitated extensive use of on-stream analyser data and computer programming to obtain the targets set for Frood Stobie Mill as required by overall milling considerations.A brief history of milling process changes associated with the changes from a low grade (3% Ni) bulk concentrate in the sixties to a high (6 to 8.5%). Nil bulk concentrate currently will be presented.The heart of the presentation will be the computer control schemes for ""self optimisation"" of the distinct flotation sections in the plant within certain restraints to achieve targets set by the mill metallurgist.

Jan 1, 1985

By M. Rahmanpour

"Mine planning is a multidisciplinary procedure that aims to guarantee the profitability of a mining operation in changing and uncertain conditions. Mine plans are normally classified as long-term, intermediate-term, and short-term plans, and many factors affect the preciseness of these plans and cause deviations in reaching the objectives. Commodity price is the heart of mine planning, but it has a changing and uncertain nature. Therefore, the determination of mine plans in the presence of uncertain mineral price is a challenge. A robust mine plan reduces the risk of early mine closure. A procedure is presented to determine the value at risk (VaR) in any possible mine planning alternative. VaR is considered together with downside risk and upside potential in order to select the most profitable and least risky plan. The model is tested on a small iron ore deposit. IntroductionMining projects are normally evaluated with the objective of maximizing economic value, as measured by the net present value (NPV). The aim of mine planning is to develop a yearly extraction plan that guides the mining operation to the highest NPV (Dagdelen, 2007; Yarmuch and Ortiz, 2011). This plan considers the technical constraints such as blending requirements, block sequencing, and pit slope (Caccetta and Hill 2003). Thus, the mine plan affects the economics and the payback period of mining operations.Mine planning is a procedure based on which the profitability of the mining operation is guaranteed in changing and uncertain conditions (McCarter, 1992). However, conventional mine planning ignores the volatility and uncertainty of future commodity prices and does not allow for managerial flexibility. It is common practice to assume a deterministic and constant commodity price through the mine life. The problem with this approach is that the commodity price is the heart of the mine planning procedure and governs the profitability and feasibility of the operation; thus ignoring price volatility will result in a sub-optimal mine plan."

Jan 1, 2016

By E. C. Lane

[This is the tenth in a series of retorts on properties of commercial motor fuels, made in accordance with a cooperative agreement between the Cooperative Fuel Research (C.F.R.) Committee e end the Bureau of Mines of the United States Department of the Interior. The first report rave data on motor gasolines sold during .e winter of 1935-36.3/ The present report presents analytical data for 1,732 samples, representing the products of approximately 50 companies, which, as in previous surveys, include both lame and stall suppliers. In addition, the Pacific coast is represented by data that were averaged by the Pacific Coast Technical Group before being submitted and are published exactly as they were received. As in previous surveys, the data are divided into the three groups of samples of regular-price, premium-price, and third-grade gasolines, and each group has been averaged separately. he number of samples, items, and brands comprising each groan), exclusive of those of the Pacific coast, are as follows: Regular price, 934 samples, 230 items, and 50 brands; premium price, 465 saris samples, 184 items, 40 brands; third-grade gasolines, 360 samples, 177 items, and of these terms as used in the surveys are follows: Sample: The individual supply of gasoline obtained at the filling station and analyzed in the laboratory.]

Jan 1, 1941

By K. G. Gorling, S. J. Wallden, N. B. Lindvall

It is the policy of The Metollurgical Society to provide, in the TRANSACTIONS OF THE METALLURGICAL SOCIETY OF AIME, a prompt and accurate medium for publication of reports of significant new research in both the scientific and engineering aspects of metallurgy. Papers submitted to the Society are judged by competent reviewers according to established criteria for technical merit, accuracy, originality, and presentation. STAFF: Editorial Director, Rixford A. Beals; Associate Editor, James J. Burke; Assistants, L. Capria and R. K. Larkin. PUBLICATIONS COMMITTEE OF THE METALLURGICAL SOCIETY: A. W. Thornton, Choirmon; Dennis Carney, John Chipman, J. C. Fulton, J. H. Hollomon, H. tl. Kellogg, A. E. Lee, R. Maddin, J. D. Sullivan, and O. Swan. Review and selection of manuscripts is under the supervision of the following Publications Committees: Extractive Metallurgy Division T. B. King. Cha~rmon; S. J. Dickenson, R. P. Hermsdorf, R. Schuhmann, Jr.. and P. T. Stroup. Institute of Metals Division: Robert Maddin, Chairman. F. Lincoln Vogel, Jr., Vice-chairman, W. A. Backofen, R. W. Balluffi, J. H. Bechtold, M. B. Bever, R. S. Busk, C. G. Goetzel, Paul Gordon, C. D. Graham. Jr., Robert F. Hehe-mann, R. I. Jaffee, F. E. Jaumot, Jr., lrving R. Kramer, A. J. Leno, Horold Margolin, C. J. McHorgue, Russell A. Meussner, J. 6. Newkirk, H. W. Paxton, G. E. Pell~ssier, I. S. Servi, Alan U. Seybolt, A. J. Sholer, and Sack Wahsburn. Iron and Steel Division: J. C. Fulton, Chairman; T. B King, F. C. Langenberg, W. O. Philbrook, and T. B. Winkler. Published bimonthly by the American Institute of Mining Metallurgical and Petroleum Engineers Inc., 29 West 39th Street, New York 18, N. Y. Telephonne pennsylvania 6-9220.Petroleum Subscription Engineers$20 per year for non-AIME members in United States and North South and Central 6-9220.SubscriptionAmerica $25 toreign; $5 for AIME members. Single copies, $4.00, iinalo copies Southfpr;ign,andCentral $5 00. The AIME 'is $25not responsible for any statement made or opinion expressed in its publications Copyright 1958 1958 by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. . Registered coble address, AIME New York . . . Indexed in Engineering Index, Industrial Arts Index, ...and Chemical Abstracts . . . Application for second class mail privileges IS pending at New Yark, N. Y. Volume 212, Number 2.

Jan 1, 1959

By A. D. Davis

Limestone-based material is effective for reducing arsenic concentrations below the current limit of 10 parts per billion for drinking water, typically resulting in final concentrations of about 4 to 6 ppb. However, in laboratory and field testing, further reductions to the 1 ppb range are difficult to achieve with limestone unless other material such as iron is added. The removal mechanism with untreated limestone appears to be the formation of a low-solubility precipitate of hydrated calcium arsenate, in the form of arsenate-apatite. Likely reactions and thermodynamic data indicate a theoretical removal limit of about 2 to 4 ppb for arsenic using raw limestone. Limestone also can reduce concentrations of cadmium and lead below 1 ppb in water, resulting in >99% removal efficiency. Thermodynamic constraints appear to be favorable for reactions involving the formation of otavite during cadmium removal and the formation of hydrocerussite during lead removal.

Feb 27, 2013

The Mineral Density Separator (MDS) was developed by Mintek to predict mineral separation in a plant, evaluate efficiencies and develop scale-up parameters. This study investigated the influence of particle size on the results of the MDS, the misplacement of material in the MDS and the possibility of replacing heavy liquid float and sink analyses of coal with MDS analyses. Six tests were done with coal of different size ranges. Each MDS layer was subjected to a float-sink analysis whereafter each float fraction was screened to determine the particle size distribution. The results indicated that MDS results represent float-sink analyses when compared to an ash curve. There is some misplacement in the different MDS layers, but this does not seem to influence the results negatively. Keywords Mineral density separator, sink-float analyses, heavy liquid analyses, washability curve

Jan 1, 2006

By Yifan Ding, Shemek Oginski, Patrick Finn

The Manhattan section of the New York Water Tunnel No. 3 constructed by the Schiavone/Shea/Frontier-Kemper Joint Venture is a $668 million project. The contract includes a tunnel drive of 8.85 km (29,045 feet), tunnel lining of 14.77 km (48,468 feet)and construction of nine shafts ranging in depth from 143 m (469 feet) to 169 m(555 feet). Construction methods for excavation of the shafts are presented including raise bore, ground freezing, soil excavation, blasting, slashing, muck handling, rock support and shaft final concrete lining.

Jan 1, 2007

By G. Danko, R. Tiwari, J. Knowles

Many excavation and loading tasks require equipment operators to simultaneously coordinate the motion of multiple machine links, in order to achieve complex tool trajectories. Efficiency, ore selectivity, and machine wear, are all affected by the skill level and attentiveness of the operator. A software-based kinematics reconfiguration system designed to assist operators with various tasks has been implemented on a small experimental excavator using our new differential control architecture. Kinematics transformation and feedback control algorithms are being developed and tested using computer simulation, and the results implemented on the experimental excavator. Several task-specific kinematics transformations, including a virtual revolute-to-Cartesian machine reconfiguration and computer-assisted bucket steering and stabilization have been successfully tested. Progress, challenges, results, expected benefits, and planned work are described.

Jan 1, 2006

The Government signalled its intention in the Economic Statement on 17 December 1987 to improve the fairness of the taxation system and to facilitate the process of economic adjustment by: removing tax concessions that benefit some taxpayers at the expense of other taxpayers,ensuring that those who can afford it shoulder their fair share of the tax burden,securing a revenue base which will provide sufficient resources to maintain effective social services,reducing artificial protection and concessions that discriminate against some sectors, and encouraging confidence through an economic environment with a medium-term orientation. The Government has clearly stated to all sectors that tax preferences will be phased out and businesses need to look inwardly to their investment policies if they are to survive in an open economy. This paper will address the effect of these Government objectives on the taxation structure for all forms of mineral exploration in New Zealand. The present tax structure will firstly be analysed, in particular setting out the tax advantages available to the industry. The effect of changes to the tax system within the recent past which relate to mineral exploration will then be examined. Finally the paper will address the question of possible future changes, particularly in the light of Government's intention to move towards a tax system which does not provide an advantage for any one sector of the economy.

Jan 1, 1988

By Todd M. Ruff

Blind areas around construction equipment are a major contributing factor in incidents involving a piece of equipment striking a worker. In highway construction, these types of incidents result in an average of 22 deaths a year in the United States. The Spokane Research Laboratory of the National Institute for Occupational Safety and Health, in cooperation with the Washington State Department of Transportation, is evaluating methods to decrease these incidents. One such method uses devices that assist equipment operators in monitoring blind areas around the equipment to prevent collisions with workers or other objects. Several camera and sensor systems are available for this application. These systems were evaluated on various trucks used in road construction and maintenance. Tests were conducted on sanding trucks during the winter months, which allowed researchers to investigate the effectiveness and limitations of various technologies under the most extreme conditions. Tests were also conducted on dump trucks and utility vehicles during the warmer months to study the effectiveness of the systems in highway work zones. Results showed that many difficulties arise when using camera and sensor systems in cold, snowy climates. And, while the operation of these systems is more reliable during the warmer months, challenges still exist in using them on equipment in congested work areas.

Recent literature is reviewed with emphasis on the design and scale up of mixers. Most important aspects of mixing have resulted from the study of Newtonian fluids and only a minor attempt has been made to extend the work to non-Newtonian materials.The rheology of non-Newtonian materials is outlined and the typical behaviour of mineral slurries is indicated.The importance of flow velocity, flow pattern, and fluid turbulence is discussed with relation to suspension of solids and rate of reaction.Data on experimental leaching of ore from Mary Kathleen, Queensland, show the effect of different mixing impellers.In conclusion, factors involved in the selection of a mixer are presented with emphasis on economic appraisal after pilot experimentation.INTRODUCTIONThe subject of mixing has attracted considerable attention during recent years, but relatively little work has been undertaken for the study of non-Newtonian materials. Most work has been restricted to Newtonian fluids because there are less inconsistencies in such study.Mixing, by definition, implies blending or combining, and ranges from gentle mixing which blends the contents of a large tank in 24 hours to violent mixing which completely homogenises the contents of a tank within seconds. Metzner and Otto (1957) have pointed out the present lack of knowledge on the degree (or quality) of mixing. Apart from this fact the design of mixers for Newtonian materials would seem to be reasonably certain.Both capital and operating costs rise rapidly with increasing mixer size. Therefore the design, or selection, of a mixer is a matter for economic consideration in the overall aspect of plant design and operation.

Jan 1, 1961

By Steve Kral

Mining is a risky business. The cost of exploring for new mineral deposits is high and the success rate of finding one worthy of development is relatively low. And once a deposit is identified, there is no guarantee that it will become a mine. Mining companies have to spend a lot of time and money on due diligence, prefeasibility and feasibility studies, and sustainable development and environmental issues before deciding whether the deposit will become a profitable mine. And then there are the millions of dollars spent in developing the deposit and building a mine. No wonder the mining industry has trouble attracting investment capital. Companies take a large risk in developing reserves and investors take a similar risk in investing in them. So mining companies must be as accurate as possible in determining mineralization that makes it to reserve status. After all, reserves are a company’s most important asset and one of the critical factors analysts and funding sources look at when determining if a mine or mining company is worth the risk.

Jan 1, 2003

By G. W. Harris, J. J. K. Daemen

Slightly shorter, modified version also published in CIM Bull., vol.94, no.1047, Feb. 2001, p.52-55. To minimise ore dilution induced by blast movement in surface mines it is necessary to quantify such movement. This will allow more accurate location of the grade boundaries on the surface of a blasted rock pile before excavation. A method has been developed and tested for measuring accurately the direction and magnitude of subsurface blast movement, using a caesium vapour gradiometer and a real-time, differentially corrected global positioning system to locate the pre- and post-blast positions of magnetically enhanced target objects placed in blastholes inside a bench. The procedure does not necessitate disturbance of the blasted rock and the movement information is available sufficiently quickly to allow for modification of the selective mining boundaries for each surveyed blast. It was found that the maximum depth of target detection was 18 m and the overall accuracy was plus or minus 1 m horizontally and 1.2 m vertically

Jun 21, 1905