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By P. L. Woolf

Blast furnace coal injection tests conducted by the Bureau of Mines in cooperation with a consortium of 22 steel companies in 1963-1964 are described. These tests were part of a program of extensive investigation of auxiliary fuel injection in the Bureau's experimental blast furnace located at Bruceton, PA. Seventeen coal tests are described on various coals ranging from anthracite to subbituminous. Factors affecting maximum rates of injection were studied. These included coal size, coal type, and oxygen enrichment. The effect of high sulfur content coal and the means to control metal sulfur were investigated. An epilogue briefly describing the commercial experience with coal injection from 1960 to the present has been included.

Jan 1, 1985

By L. H. DeWald

During the examination of various commercial brands of copper wire bars, which had exhibited different degrees of adaptability for being drawn into fine gages of wire by the present-day high speed machine, it was found that each brand had a more or less characteristic crystal macrostructure. The extremes of these macrostructures are similar FIG. 1.-EFFECT OF METAL TEMPERATURE IN CASTING ON CRYSTAL MACROSTRUCTURE OF BAR. Reading from left to right, metal temperatures were 1166" C., 1149" C., 1132" C.. 1121" C., 1093" C. to the maximum variation shown in the photomacrographs reproduced in Fig. 1. As the various brands did not differ materially in chemical composition, it was concluded that the differences in structure were the result of variations in casting technique.

Jan 1, 1931

By Jean-Guy Levaque, Robert Ethier, Ron J. Elliot

This paper presents data gathered during a comprehensive study on the impact of improvements to fragmentation in a major Limestone quarrying operation. The full impacts of gains in fragmentation are tracked through the mucking, crushing, and grinding phases of the operation.

Jan 1, 1999

By David Cole, Paul Cooper, Dale Preece, Jerome Stofleth

The Explosive Destruction System (EDS) has been designed at Sandia National Laboratories for the disposal of chemical munitions (phosgene, mustard gas, sarin etc.), many dating back to World War I. EDS is a portable system that is trailer mounted and consists of a vessel into which a chemical munition can be loaded and opened for neutralization with linear and conical shaped charges. Gases are contained within the sealed chamber. The linear shaped charges split the munition in two and the conical shaped charge (CSC) is aimed at the explosive burster, in each munition, which is detonated by the resulting shaped charge jet, Toxic chemicals remaining in the vessel following detonation are neutralized and disposed of. This paper documents the development of a new CSC needed to reliably detonate explosive bursters in an expanding array of chemical munitions that are beyond what the EDS device was originally designed to eutralize. Design of this new CSC was controlled by the need to deliver energy above the detonation threshold into the explosive after penetrating the outer steel casing, fluid, the burster casing and finally the explosive. Design considerations were driven by jet conditions at the steel/explosive interface inside the burster. Parameters to consider in CSC design include: 1) diameter, 2) liner thickness, 3) liner position in body, 4) explosive weight, and 5) liner shape or interior (apex) angle. The effects of these parameters on final CSC performance are examined in detail. CSC’s that meet the design specifications have been manufactured and tested. The performance of these charges are compared with the original design requirements.

Jan 1, 2002

By Raj K. Rajamani, Sanjeeva Latchireddi, Dave Plummer, Stieger. Julius

"The Cortez SAG mill liner design was recently modified to improve the mill operating energy efficiency. In addition to the expected benefits, the design change unexpectedly played a significant role of verifying the proposed grinding circuit expansion for the Cortez Hills project as well as illustrating current SAG mill bottlenecks. This paper will discuss the evaluation that addressed operator and maintenance observations, historical PLC data, and “crash stop” observations to calculate charge motion, packing between lifters, and slurry transport through grate and pulp lifters. The performance of the new shell and discharge end liner design will also be discussed as well as their role in the possible grinding circuit expansion.INTRODUCTIONCortez Gold Mines commenced operation in 1969 with its Mill #1 rated at a nominal 2,000 tons per day. Mill #1 was a conventional rod mill/ball mill circuit followed by an 8-stage CIP circuit. In the early 1990s the Pipeline deposit was discovered and subsequently Mill #2 was built to process the increased ore volume. Mill #2, commissioned by mid-1997, was a nominal 10,000 tons per day SABC circuit followed by an 8-stage CIL circuit for oxide gold ore. Operating and commissioning details of this plant have been published elsewhere (Powell, 1998). By late 1998, there was not enough ore volume to support both mills so the smaller, higher operating cost Mill #1 was put under its current care-and-maintenance status. A simplified flowsheet of the current mill is shown in Figure 1."

Jan 1, 2007

By S Robotham, P C. Stewart, K Maher

A data science based dilution study was conducted to identify the causes of dilution at South32’s Cannington Mine (Cannington), a large open stoping operation. In terms of industry benchmarks for unplanned dilution, Cannington is already performing very well, and so opportunities for improvement are more difficult to identify. The study is based upon back analysis of nearly 150 case studies from the mines reconciliation database, and has quantified the relative effect and significance levels for the following dilution parameters; time until paste filling, faulting and cable bolt reinforcement. Specifically, significant contributions were associated with faults and stope open duration. Quantifying the effect of faults on stability graph accuracy enabled a site specific adjustment to improve the predictive ability of the Cannington stability graph (unstable stope specificity improved from 63 per cent to 74 per cent). Despite Cannington’s already high levels of stope performance compared to industry benchmarks, data science methods have identified a complex interaction between identified dilution factors (ie stope open duration, presence of faults and cablebolting). Specifically, a third order Factorial ANOVA (Analysis of Variance) provided evidence that stope open duration reduces the effectiveness of cable bolts in faulted ground (average dilution = 2.1 m, p-value = 0.13). These results are consistent with site observations of a relationship between the stope open duration and the extent of failure when unravelling on a fault, even when cables are present.CITATION:Maher, K, Stewart, P C and Robotham, S, 2016. A data science approach to identifying and quantifying causes of dilution at Cannington Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 491–500 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Francisco Vitor Vasques Barbosa

Após 10 anos da aprovação da portaria 598 do Ministério do Trabalho, e ter realizado Laudo de Inspeção em mais de 60 sites industriais de grande porte, a PDCA Engenharia tem sido envolvida no processo de adequação do sistema de gestão de manutenção e operação das instalações elétricas de seus clientes. O relatório de inspeção preconizado no item 10.2.4.g da NR-10 estabelece a obrigatoriedade de se levantar os aspectos não conformes, estabelecer um plano de adequação definindo responsáveis e prazo de execução. Com os efetivos de manutenção reduzidos, nossos clientes passaram a envolver a PDCA na implementação das ações de adequação. Este trabalho consiste entre outras coisas na identificação das intervenções críticas de operação e manutenção das instalações elétricas (15 a 20 no máximo por site), analisá-las do ponto de vista dos riscos elétricos e adicionais associados a cada etapa de execução, estabelecer as medidas de controle necessárias para a mitigação destes riscos, redigir procedimentos e treinar o pessoal envolvido. Outros procedimentos devem trabalhar a eliminação dos riscos para os trabalhadores não autorizados (leigos), que interajam indiretamente em instalações elétricas e serviços com eletricidade. Apresentamos um resumo desta experiência recente com clientes da área Química/Petroquímica e da área de Logística.

Jul 31, 2018

By John L. Thames

The benefits of water harvesting as an alternative to conventional reclamation were demonstrated on the Peabody Coal mines in Northeast Arizona. The project produced food crops for four years, and demonstrated that a catchment/crop area ratio of about 2.5:1 was sufficient to obtain sufficient water from the 11 inch annual precipitation to produce garden and fruit varieties in quantities equal to or exceeding national production averages. The economic returns exceeded those of the conventional practice of returning the mine area to rangeland by at least ten fold. Subsidence of the regraded spoil was the only major problem in maintaining the system. Although, water harvesting systems have the potential of providing high economic returns and greater social benefits, as demonstrated by this project they are presently at variance with the strip mining regulation.

Jan 1, 1984

By S McKinley

"The White Mountain sediment-hosted gold deposit is located in north-eastern China. Mineralisation is associated with silica–hematite–altered polymict breccias that occur within dolomite at or near the contact with overlying sandstone. Economic gold grades are controlled by the distribution of the polymict breccias and can transition rapidly to low or zero grade over short distances. This results in sharp and highly irregular ore contacts on whose accuracy proper stope design and ore control is reliant at this blasthole underground mine.Short-term planning and ore control utilise a grade control model created from infill drilling and grade control sampling (ie face and wall sampling). Typically, the grade control model was maintained by time-consuming manual editing of earlier made contacts to incorporate any new data. This approach also was quite error-prone due to: the complexity of the breccia and ore grade contacts irregularly oriented and/or insufficiently dense drill holes inconsistent incorporation of grade control sampling. These errors resulted in unplanned dilution and ore loss due to inaccurate interpretation of the ore contacts.The primary advantage to implicit geological models over conventional, manually-built wireframe models is that they can be updated very quickly and frequently. In a mine setting, the power and efficiency of using an implicit model is greatest where the use of manual inputs or editing can be minimised. Recently a workflow was set-up for the mine geology team to create an implicitly-modelled ore shape for short-term planning needs by using all data, especially all grade control samples. The resultant 3D shapes provided metre-scale accuracy and consistently reconciled complex ore geometries much faster and to a higher degree of quality relative to the wireframe model. The mine stakeholders can now obtain an accurate ore model that will always be in sync with available data.CITATION:McKinley, S, 2017. Application of implicit geological modelling to improve the grade control process at White Mountain gold mine, Jilin Province, China, in Proceedings Tenth International Mining Geology Conference 2017, pp 385–392 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 20, 2017

By K. J. Liles

Research was undertaken by the Bureau of Mines to determine the technical feasibility of producing lightweight aggregate from the waste glass fraction of municipal incinerator residues. Tests were conducted to determine the amount and optimum size of glass, the amount of sodium silicate, and the method used to form the material to be expanded. The most suitable mixture, 78 percent glass, 20 percent clay, and 2 percent sodium silicate, was pelletized and then expanded by exposure to a temperature of 1,550° F for 15 minutes The resulting lightweight material had a bulk density of 38 lb/cu ft and exhibited excellent pore structure. Concrete test cylinders made from the light weight aggregate had a unit weight of 104 lb/cu ft and a compressive strength of 2,550 lb/sq in after a 28-day steam cure.

Jan 1, 1976

By Bradley V. Johnson

This publication summarizes the in-house and contract research and development projects conducted since 1974 by the Bureau of Mines for the control of noise and vibrations from surface mine blasting.

Jan 1, 1982

By Teele Tuuna, Voglers Eesti OÜ

Blasting operations are a strong and important part in any kind of building and mining industry, a shot-firer profession is one of the oldest professions in the civilized world. It still serves an important and ongoing purpose in the modern economy all over the world. Europe, nowadays, values strongly the mobility of workers, the movement of know-how and labor force between different countries inside Europe. There are no borders for most of the everyday professions.

Jan 1, 2018

By Andrew Chapman

The scope of the SA (Situational Awareness) working group is to analyze the effectiveness of information delivery systems in mining equipment and develop a unified display design, to mitigate against the proliferation of screens within equipment cabs. This working group comprises a variety of stakeholders representing a cross-section of relevant mining and mining-related organizations. This stakeholder network will help guide the direction of the working group towards a common, mutually beneficial end. For now, the focus is on shovel displays; however it should be noted that this work is expected to form the foundation for similar work with other equipment in the future.

Aug 1, 2013

By Rainer Kahrger

This paper is a follow-up to the paper presented at the SME meeting in April of 1996. Since then, the El Abra facility has been started up, 9 months ahead of schedule, and has processed about 45 million tons of ore and produced over 700 million pounds of copper. For those unfamiliar with the El Abra materials handling and leaching facilities, a brief overview of the facility is provided. The paper will then deal in detail with such aspects of Conveyor 103, the long regenerative overland conveyor, including: actual running resistance starting and stopping procedures emergency brake test at 10,000 t/h Additionally, we shall take the opportunity to report on a catastrophic culvert collapse in October 1996, which stopped the conveyor abruptly at full speed and under high load condition, causing a belt breakage. We would like to use this opportunity to thank the management of El Abra and Cyprus Amax for providing assistance and allowing us to present this paper. The El Abra team deserves a great compliment for building this one billion dollar facility in record time in a remote area of a high-altitude desert with no existing infrastructure, and for bringing it so quickly up to full operating capacity. The El Abra management had to assemble a completely new operator team. Considering the above circumstances, it took a great effort by all involved to achieve success. The official performance test which was required by the lending banks was successfully concluded in November 1997.

Jan 1, 1998

By Louis J. Cabri, Donald Hoy

"Samples with contrasting gold mineralization were studied quantitatively prior to metallurgical tests. The AD samples are coarser-grained and characterized by abundant Sb minerals (jamesonite, berthierite, stibnite). The finer-grained MW sample has abundant pyrite and pyrrhotite, with arsenopyrite and galena next in abundance. A large number of gold mineral particles were determined by SEM investigation of hydroseparation concentrates, ranging from 150 to 597 per sample. The grain-size distribution of the gold minerals shows evidence of bimodal grain-size distributions (volume %), with the coarse fraction being most significant in sample MW-1 (maximum ECD=308µm). The coarsest gold minerals in the AD samples range from 139µm to 281µm ECD.The deportment of gold minerals is as electrum, aurostibite, native gold, and a possible new mineral (AuNiSb4). Gold also occurs in nisbite. The gold minerals are dominated by electrum in three samples and aurostibite is next in abundance. The major gold minerals are probably representative of three stages of gold mineralization. The first stage is represented by electrum, which is partly to completely replaced by Sb-rich mineralization forming aurostibite, and the last stage is native gold, often occurring as rims on one or the other earlier gold mineral. The gold minerals are strongly associated with sulphides in the AD samples (55 to 60 vol.%). At the grind used for the hydroseparation the liberated gold mineral quantity (volume %) is also significant, ranging from 65% for sample MW-1 to 30 to 37% for the AD samples.INTRODUCTIONThe Clarence Stream deposit is located 70 km south-southwest of Fredericton and 25 km northnorthwest of St. George, south-western New Brunswick, near the international boundary with Maine (Fig. 1)."

Jan 1, 2007

By M. Maccagni, J. Nielsen

"Engitec developed the EZINEX® Technology some years ago to recover zinc from oxidized secondary sources. This process works at neutral pH and can take into solution any kind of metal, but iron is rejected and remains in the leach residue. Engitec has also developed the FLUOBORATE System, which is able to recover lead and copper from relevant concentrates. Some iron is leached into solution, but it is controlled through a solution purification bleed treatment. In this paper, we present the two above mentioned technologies. They are very different with regards to the chemical environments and the methods used to control the build-up of iron in solution, but both systems are suitable to treat iron bearing feeds.INTRODUCTIONIn the design of hydrometallurgical processes, the most important issues are the water balance, the filtration and the control of impurities. This is particularly important when the process includes an electrowinning unit. Iron has been one of the most problematic elements to remove, especially in acidic environments.Engitec Technologies has developed several hydrometallurgical processes divided in two different electrolyte lines: the Fluoborate Technology for the recovery of lead and copper from primary and secondary sources and the Ammonium Chloride System based on a chloride electrolyte for the recovery of different non-ferrous metals, among which zinc and lead are the most important. In both cases, iron is present in the feed and needs to be eliminated from the solution. It is not a problem for the quality of the metal produced, but when present in solution, it consumes the basic electrolyte reducing its free concentration which is very important both for both the leaching and electrowinning unit operations. Both process systems are very peculiar, the fluoborate case being much more intriguing."

Jan 1, 2016

By Tian Sugui

By direct aging treated, creep properties measurement and microstructure observation, the influences of the direct aging treatment on the creep behaviors of Hot Continuous Rolled GH4169 superalloy are investigated. Results show that the creep resistance of Hot Continuous Rolled GH4169 superalloy may be obviously improved by directly aged treatment. Under the applied stress of 700MPa at 660, the creep lifetime of the alloy is enhanced to 126h from 60h. During hot continuous rolling, the deformation features of the alloy are the twinning and the double orientations slipping of the dislocation activated within the twinning regions. After direct aging treated, the alloy displays a smaller grain size, and the finer g² phase is dispersedly precipitated in the matrix of the alloy, which is thought to be a main reason of enhancing creep lifetime of the alloy.

Jan 1, 2010

By Walter R. Storms

"INTRODUCTION The New Mexico potash exploration described herein was begun in February 1944 with the object of determining the amount of potash ore in the United States Potash Reserve in Eddy County by exploring the deposit from the surface with vertical drill holes. The work was completed in October of the same year after 16 holes had been drilled on the Reserve and in the immediate vicinity.The Potash Reserve is in secs. 26; 27, 34, and 35, T. 20 S., R. 29 E., Eddy County, N. Mex., about 14 miles northeast of Carlsbad, as shown on figures 1 and 1A, Drilling was done in secs. 26 and 35 of the Reserve, in section 14 to the north, end sections 2 and 56 to the east. All work was done on Governnent-owned, unleased land.The Reserve may be reached from Carlsbad by traveling to the north-east by automobile for about 14 miles on the paved U. S. highway 62. This highway passes through the southern part of the Reserve. Other parts may be reached by a State highway that passes along the eastern side of the area, then by poor dirt roads to various drilling sites. A branch of the Santa Fe Railroad also passes across the southern part of the Reserve enroute from Carlsbad to the plant and mine of the Potash Co. of America, a few miles northeast of the project and 22 miles from Carlsbad."

Aug 1, 1947

By William L. Crentz

In the past, Westmoreland County together with Fayette County produced about one-third of the bituminous coal mined in Pennsylvania. The Pittsburgh bed in Westmoreland County has furnished enormous quantities of coal to the by-product and beehive ovens, gas-manufacturing plants, and general industrial manufacturers over a wide area until about 20 years ago. Little attention was paid to the thinner beds because of the superior quality of the Pittsburgh. The approaching exhaustion of Pittsburgh coal will require accelerated-exploitation of these coals if Westmoreland County is to continue as an important source of bituminous coal, Much of the Pittsburgh coal in Westmoreland County is low-sulfur and requires no mechanical cleaning for the preparation of a metallurgical fuel. Even those areas where the sulfur percentage increased to a maximum of about 2 percent, a relatively easy washing operation usually produced a cleaned coal, which found ready acceptance by the coke industry. Davis reported the remaining recoverable reserves of the .Pittsburgh bed in Westmoreland County to be 255,439,000 tons as of January 1, 1937. Since that date, more than 100,000,000 tons of Pittsburgh coal has been extracted so that the time is not too distant when this important coal bed will be depleted. A study of the Pittsburgh bed in Westmoreland -County has not been made a part of this report as the remaining reserves of the coal can be used in coke making with a, minimum of preparation. The production from the Upper 'Freeport bed will increase as the supply of coal from the Pittsburgh bed diminishes, and as of the present time it supplies a substantial proportion of the county's coal output.

Jan 1, 1951

By R. E. Gilmore

Introduction The Sydney coal-field extends for a distance of thirty miles along the northeastern coast of Cape Breton island. At a central focal point at the tip of the south arm of Sydney harbour, seven miles or so in from the Atlantic ocean, is the city of Sydney, with Port Morien to the southeast and Sydney Mines to the north . Mining centres along the ocean coast between these points include Birchgrove, Reserve, Glace Bay, and Waterford. The field is divided into three districts or 'basins', namely, Morien basin to the south, Glace Bay in the centre, and the Lingan-Sydney Mines basin to the northeast. The eastern and western portions of the latter are known as the Lingan and the Sydney Mines basins, respectively. Six distinct coal seams are described as existing in the Morien basin, nine in the Glace Bay basin, and six in both the Lingan and the Sydney Mines basin. Although known by different names in the several basins, a definite continuity of the seams has been established.

Jan 1, 1933