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By Sutham Niyomwas

Synthesis of alumina-mullite-silicon carbide composite (Al2O3-Al6Si2O13-SiCw) was obtained in situ by carbothermal reduction of a mixture of kaolin and two different silica sources. The carbothermal reduction was carried out in a horizontal tube furnace under flow of argon gas. The standard Gibbs energy minimization method was used to calculate the equilibrium composition of the reacting species. The synthesized products were mixtures of alumina, mullite and silicon carbide in the form of whiskers. The effects of adding two different silica sources of rice husk ash and silica powder to the mixture of kaolin and activated carbon were investigated. XRD and SEM analyses indicate complete reaction of precursors to yield Al2O3- Al6Si2O13-SiC as product powders, with the SiC having whisker morphology.

Jan 1, 2006

By C. C. Anderson

"While conducting investigations in connection with the helium program of the Bureau of Mines, the Cryogenic Laboratory has improved an apparatus for the rapid and accurate determination of the helium content of natural gas and gaseous mixtures derived from that source. The separation of helium is effected by the use of activated coconut charcoal which, when cooled to liquid-air temperatures, absorbs the nitrogen and other constituents of the gas, leaving the helium in a. spectroscopically pure state. This absorptive property of activated charcoal was discovered- by Dewar3/ in 1875. Several years later, while conducting their original researches on helium in natural gas, Cady and McFarland employed the charcoal method for the absorption and removal of the common constituents of natural gas and constructed an efficient apparatus in which this operation could be effected.4/ Shortly after initiating the government's helium activities during the World War period, the Bureau of Mines adopted, with Minor modifications, the Cady and McFarland apparatus and method of analysis. Seibel.5./ described this modified apparatus and method of procedure as part of a publication on helium-bearing natural gas. Subsequently, the Bureau's apparatus for helium analysis has been simplified and improved to facilitate more rapid and positive operation. The apparatus and method of procedure now being used by the Bureau of Mines Cryogenic Laboratory arc described in this paper.The personnel of the Bureau of Mines Cryogenic Laboratory has improved and brought the helium apparatus described herein to its present state of perfection. The writer's contributions have been-of minor importance, and he wishes to give the various members and former members of the laboratory staff full credit for the improvements they have made. He also desires to express his appreciation for suggestions and criticisms offered during the preparation of this paper to the following members of the Petroleum and Natural Gas Division, Bureau of Mines, which now includes the Amarillo Helium Plant and Cryogenic Laboratory: H. A. Cattell, chief engineer; C. W. Seibel, supervising engineer of the Amarillo Helium Plant; W. M. Deaton, chemist-in-charge of the Cryogenic Laboratory; and H. S. Kennedy.The quantitative determination of helium in a gaseous mixture is accomplished by the removal of the other constituents from the sample, either by chemical or physical Means, leaving only the helium which can be measured directly. Chemical methods, when applied to natural gas, require the burning of the hydrocarbons in oxygen, the, absorption of the resulting carbon dioxide in a caustic solution, the removal of the excess oxygen in a suitable solution such as an alkaline pyrogallate, and the elimination of nitrogen by sparking or by combination with hot calcium or magnesium.. Such procedures are very slow and tedious compared with the physical method which employs the absorptive property of activated charcoal to effect the separation of the other constituents from the helium."

Jun 1, 1934

By K. Nong, H. F. Fuls

The quality of Pregnant Leach Solution (PLS) at Skorpion Zinc is of utmost importance for efficient operation of the Solvent Extraction (SX) Plant. Suspended solids in the PLS forms CRUD in the settlers, resulting in reduced zinc transfer capacity and increased impurity carry over to Electrowinning. The Ishigaki Fibre-Wakishimizu filter (fibre media rapid filtration equipment) has been identified as polishing filter that potentially could remove solids from the PLS of Skorpion Zinc. A pilot unit with 20m³/h capacity was tested on site over a period of 9 months under plant operating conditions in the refinery. The FW filter produces a clear filtrate, acceptable for the Solvent Extraction. Turbidity is improved by 72%. Gravimetric analysis indicates a 47% removal of solids. However, the gravimetric method is biased by a co-precipitation of saturated salts during the analysis. Filter media is blinded by the Skorpion Zinc PLS solution, as result of suspended solids and process chemistry. The media could not be regenerated to acceptable conditions. Further testwork to investigate the impact of process solution chemistry modification on blinding is undertaken. Based on the outcome of this investigation a final decision on the FW filter can be taken.

Jan 1, 2007

By A. C. Neiva

An energy-dispersive x-ray fluorescence spectrometer was assembled with the aim of analysing alloys and corrosion products of artistic, ethnological and archaeological pieces. The spectrometer is semiportable and consists basically of an 60kV/1.5mA X-ray tube with W anode and a Si-drift X-ray detector with Peltier cooling, with no need of liquid nitrogen. It was used for the analysis of the alloys and occasional corrosion products of several metallic pre-Hispanic pieces of the Museum of Ethnology and Archaeology of the University of São Paulo. Special care was taken to account for the contribution of spurious radiation from both the Pb primary collimator and the Zr detector collimator. The main components of most alloys were Au, Ag and Cu, but Pb, Ca, Fe and other elements were also identified. The characterization of the alloys and corrosion products is important for the subsequent conservation of the collection.

Jan 1, 2006

By Frank J. Arland

Augered-Cast-in-Place piles have been used successfully for many deep foundation applications. The four case studies discussed herein describe ACIP pile projects where problems developed during ACIP pile installation requiring changes to the method or sequence of installation. The case studies illustrate the importance of understanding existing subsurface conditions and project constraints when considering the use of this pile type. Ground loosening and over-excavation of soil during the augering process, a significant concern for fine to medium sands and non-plastic silts below the water table, can significantly impact adjacent structures. This risk needs to be evaluated during the pile selection process and generally can be mitigated, but not eliminated, by requiring the use of piling equipment with high torque and slow auger rotation speed to advance the auger with minimum amount of rotation. In some applications where high lateral stresses in the soil are present such as at the base of retaining structures, the use of ACIP piles may not be appropriate if structure movement is unacceptable. On the other hand, ACIP piles have been successfully used to support deep foundations in preconsolidated varved deposits where the new structure was designed to accommodate recompression settlement.

Jan 1, 2004

By D Craw, C E. Martin, C Smith, C Rufaut

Wangaloa Coal Mine opened in 1945, and by the time of its closure in 1989, had produced 750 000 tonnes of coal and disturbed an area of 75 ha. The original mining licence required land rehabilitation to exotic forestry, however the current owner, Solid Energy, has worked with Crown Minerals and local councils to write a new rehabilitation objective. The site is now being stabilised and replanted with native species, and may be available for public use before the coal mining licence expires in 2007. Site discharge permits expire in 2017, and by that time, it is anticipated that discharge water chemistry will be similar to background levels. MWH are currently contracted for management of the mine rehabilitation project. The Kaitangata coal unit mined at Wangaloa is sulfurous lignite with associated pyrite. Kaitangata coal contains 3.2 wt per cent sulfur, which is higher than most New Zealand coals. Initial analyses at Wangaloa indicate low pH (2.56.2) values in soil, groundwater and surface waters as a result of acid rock drainage (ARD) processes, leading to increased metal mobility and challenging conditions for vegetation. Pilot studies indicate pinus radiata needles contain up to 67 mg/kg boron, and elevated As, Cu and Zn concentrations in surface waters. The main lake at the site has a pH of approximately 4.9, despite lime dosage in 2002. There is a real need for a complete geochemical model of the Wangaloa coal mine. Such a model could be applied to similar restoration projects, and would assist by pinpointing geochemical processes and toxic metal relationships most harmful to the receiving environments. Using this model, rehabilitation in the future will be targeted and more efficient. This project is part of a larger scheme to characterise and model the Wangaloa mine site restoration, including waters, soil, vegetation, geology and invertebrates.

Jan 1, 2003

By Sangseom Jeong, Moonkyung Chung, Junyoung Ko

"Abstract The plugging effect of open-ended piles in sandy soil is analyzed by full-scale field test and plugging measurement. PLR (plug length ratio) measurement data from 144 field cases are analyzed with pile diameter. Based on the plugging measurements, PLR of open-ended piles which have above 1000mm diameter is predicted to be above 0.9. Through plugging measurements, a new empirical method is suggested for quantifying the plugging effect of open-ended piles. The proposed PLR equation is possible to predict the behavior of soil plug in the preliminary design stage. In addition, in order to investigate the behavior of the soil plug of open-ended pile, field load tests are performed on instrumented three piles driven into sand. It is obtained that the resistance components of open-ended pile are separated by double-walled pile system. It is found that inner shaft capacity is developed nearby pile tip. However, upper soil plug did not influence the inner shaft capacity. Also, it is found that all test piles are floating piles and unplugged condition because the sum of inner shaft capacity and outer shaft capacity is calculated about 58 to 76% of the ultimate bearing capacity.INTRODUCTIONIn Korea, a number of huge construction projects such as harbor terminals, offshore grand bridges, and lifeline systems are progress in urban and costal area. In these areas, steel pipe piles are frequently used to support high-rise buildings and heavy weight structures for ensuring structural safety rather than serviceability limit capacity. Also, steel pipe piles are frequently used in civil engineering structures because they have many advantages such as high-load bearing capacity, light weight and outstanding workability. The mega foundations of grand bridges and high-rise buildings are required in geotechnical engineering. Large diameter driven piles are frequently used in several projects.Many specifications such as API, FHWA and AASHTO have been reported as a design guideline of plugging effect, however , the current design method for plugging effect of steel pipe piles are mainly based on the our knowledge derived from observation of the model test or the small diameter pile load test. Therefore, these specifications have limitation to apply the large diameter steel pipe piles.Much work has been done to study the plugging effect by many researchers. Yamahara (1964) reported that soil plug has been modeled as a thin disk element as shown in Figure 1, since the increment of radial strain of the soil plug can be neglected due to high rigidity of the pile compared to that of the soil plug. Klos and Tejchman (1977) reported that the end bearing capacity of open-ended piles was almost equal to that of a closed-ended pile when penetration depth of pile was above 15times the pile diameters by model tests. Paikowsky and Whitman(1990) reported fundamental studies on mechanism of plugging effect in sand. Paik et al. (2003) reported that empirical relations for plug load capacity, annulus load capacity, and shaft load capacity of open-ended piles are proposed based on the model pile tests. As discussed above, much work has been done in the area of plugging effect. But little work has been done to study the plugging effect by full scale field tests."

Jan 1, 2014

By J T. Woodcock, G J. Sparrow

A sample of pyrrhotite flotation concentrate pulp assaying 15.3 g/t Au, which had been prepared from an old tailing dump, was treated to extract the gold. Examination of the concentrate with an SEM showed that exposed or free native gold, 5- 40 ¦m in diameter, was present but no locked gold was observed. Direct cyanidation of the concentrate to extract the gold showed that the flotation reagents present inhibited gold extraction. A range of pre-treatments was used to overcome these effects. Direct cyanidation for 48 h extracted only 26 per cent of the gold, indicating possible contamination of the gold in the concentrate with flotation reagents. Pre-treatment of the concentrate pulp by aeration for 24 h, or by 72 h aeration with an addition of 3.65 kg/t of sodium sulphite, gave little improvement in gold extraction by subsequent cyanidation. Pre-treatment by filtration, or by aeration with 12.5 L/t 100 volume hydrogen peroxide, followed by cyanidation for 48 h gave gold extractions in the range 67-77 per cent. Combining filtration and an aeration period with hydrogen peroxide addition raised the subsequent cyanidation extraction of gold to 88 per cent, giving a tailing assaying 1.5 g/t Au. Re-cyanidation of some of the dried tailings from the initial tests extracted most of the remaining gold giving a tailing assaying 0.5 g/t Au. This indicated that most of the gold was available for dissolution by cyanide. The poor dissolution of gold by cyanidation of the untreated concentrate was attributed to the presence of flotation reagents. It was shown by UV spectrometry that xanthate-containing compounds were present in the solids fraction of the original pulp and that they were partly removed by pre-treatment. MIBC was also present, and dithiophosphate, which was used in the flotation step, was also probably present. The results indicated that the improvement in gold extraction after filtration and oxidation of the original pulp was due to partial removal of the flotation reagents, and illustrates the detrimental effects that residual flotation reagents can have on the extraction of gold by cyanidation of a flotation concentration.

Jan 1, 1990

By J. R. McVey

A 10-channel automatic data acquisition system has been designed and environmentally packaged for use with underground strain-gage applications and associated instruments. The system uses commercially available components and is assembled in two plastic enclosures. Environmental control is provided through a specially designed (compressed-air) air-conditioning system and water-resistant cabling. Accuracies of 0.01 pct and resolution of 1 µV have been obtained in underground tests.

Jan 1, 1973

By Graham Sim

Agenda ?The Water Challenge ?Examples from Three Case Studies ?Mine Drainage, 99% recovery ?Mine Drainage, 80% recovery ?Road Dust Control ?Technology Development ? Conclusion Global water challenges Assuring sustainable quantity Improving water quality Reducing energy consumption

May 1, 2011

By Yves Prévost, Guy St-Amant, Guillaume Dion

In 2010, the foreseen increase of copper grade in feed concentrate at the Horne Smelter was a significant challenge to maintain a steady copper flow throughout the process. The Horne Smelter process includes a Noranda Reactor, a Noranda Converter, pyro refining vessels and anode furnaces. Of the many challenges involved, improving the single casting wheel performance was one of the key topics. Its reliability had to be improved to meet the new production objectives, as anode copper production was to increase from 170 000 to 225 000 tonnes/year. A multidisciplinary team was dedicated to improve the casting wheel availability. The improvement project allowed pinpointing failure modes and reviewing operational and maintenance practices. The common understanding developed by the team allowed improving small components with a high gain-to-effort ratio. The project allowed reaching operational targets without any significant investment. INTRODUCTION In operation since 1927, the Horne Smelter, located in Rouyn-Noranda, in Quebec, has undergone several technological changes since its original construction. Built to smelt the Horne mine concentrates, the smelter also accepted some local custom feeds from the first years of operation. When the Horne mines stopped production in 1976, the plant became a 100% custom smelter. With the development of the Noranda Reactor (1973) and Noranda Converter (1997), the Horne smelter increased its productivity and improved its environmental performance. Continuous improvement of the Horne process allowed maintaining a high level of flexibility in the operation of the smelter, while improving its overall capacity.

Jan 1, 2019

By Russell J. Gartrell

This report describes the engineering feasibility and economic advantages of using a steep angle conveyance (SAC) system in conjunction with medium and large draglines to transport spoil in a typical Western Coal Mine. The SAC system, including a receiving hopper, a steep angle conveyor and a sticker/spreader, is capable of processing overburden material at the rate of 7,000 tons/hr. The unique feature of this system is the steep angle conveyor which transports the overburden material from the pit bottom to the top of the spoil at angles to 45 degrees. Compared to other means of cross-pit conveyance considered during this study, the SAC system offers the advantage of easier operation, lower conveyance cost and greater mobility. The results of this study have shown that integration of the SAC system into both established and planned new mines would improve the overall mining operation, expand the operating capability of existing equipment and reduce mining end reclamation cost.

Jan 1, 1977

By Steve C. Albrecht

The objective of this study is "to assess the impact of surface mining on soil compaction in the Midwest". The study revolves around a unique field sampling program targeted at four mine sites utilizing four distinct types of soil movement of midwestern prime land. Through the preparation of a final report for use as a guidebook, an assessment is made of the degree to which surface mining operations contribute to the soil compaction problem. The final report is formulated through the use of field study data as well as information gathered in an intense literature review. The final report centers on applying collected data to practical field applications. Soil sampling on the four mine sites centers on a comparison of natural and replaced soils for moist bulk density. This characterization evaluates changes in density and texture throughout the soil profile to a depth of 48 inches. Fertility of the topsoil is also assessed for natural and replaced soils. During field sampling and observations, a base of information has been gathered to compile a case study on each mine site. The report accesses the regulations in the prime farmland areas through the use of a matrix. The regulatory matrix allows easy access of mining personnel to State and Federal regulations.

Jan 1, 1982

By Adriana Gómez

White dross is a result of the aluminum oxidation during its primary production and is mainly composed of metallic aluminum, Al2O3, with minor amounts of AlN and some other oxides. Because of the great variety of phases, the quantitative characterization is complicated. This work shows a quantitative method to determine the main phases of white aluminum drosses by means of X-ray diffraction (the Rietveld method). Nowadays the Rietveld method is maybe the most useful method for obtaining quantitative phases information in multicomponent mixtures, this method permits relatively quick quantitative phase analysis by fitting the calculated X-ray diffraction profile with the observed one. The analysis were done using powder with a grain size less than 45 µm; to obtain the suitable material size the aluminum dross was grounded by ten minutes, several times. The grounded material was screened, and the material smaller than 45 µm was taken to quantitative XRD analysis. Keywords: Rietveld Method, Characterization, Aluminum dross.

Jan 1, 2005

By Philip Weaver

The MIDAS project is funded by the European Commission (DG Research) and began on the 1st November 2013. The project will investigate the environmental impact of deep-sea mineral and energy extraction: specifically, polymetallic sulphides, manganese nodules, cobalt-rich ferromanganese crusts and the potential mining of rare earth elements. As deep-sea mining becomes ever closer, and the International Seabed Authority begins to develop its regulatory framework for exploitation of deep-sea minerals, MIDAS is well timed to provide fundamental scientific information. The MIDAS partnership represents a unique combination of scientists, industry, social scientists, legal experts, nongovernmental organisations and small and medium enterprises. MIDAS is carrying out research into the nature and scales of the potential impacts of mining including 1) physical disturbance of the seabed by mining, the creation of mine tailings; 2) the potential effects of particle-laden plumes in the water column, and 3) the possible toxic chemicals that might be released by the mining process. Key biological unknowns, such as connectivity between populations, impacts of the loss of biological diversity on ecosystem functioning, and how quickly the ecosystems will recover will all be addressed. The plan is to use this information to aid development of recommendations for best practice in the mining industry. A key component is the involvement of industry within the project and through stakeholder engagements to find feasible solutions. The project will work closely with European and international regulatory organisations to take these recommendations forward into legislation. A major element of MIDAS will be to develop methods and technologies for 1) preparing baseline assessments of biodiversity, and 2) monitoring activities remotely in the deep sea during and after exploitation, including ecosystem recovery. To carry out this work MIDAS is conducting a number of research cruises to examine the above issues at potential sites for exploitation of SMS and nodule deposits. This talk will present some of the recent findings of the project.

Sep 1, 2014

By Ray Wood, Rene Sterk, Robin Falconer, Sean Aldrich, Simon Nielsen

"The Chatham Rock Phosphorite project is situated 450 km east of New Zealand at approximately 350 to 450 m water depth. The deposit occurs as a thin layer of phosphatebearing glauconitic sand at the surface of the sea floor and has a thicknesses typically ranging from 0 to 1 m. The sand layer consists of mainly silt and sand-sized sediments, with phosphatised chalk nodules up to 15 cm in diameter. Phosphate nodules were first discovered on the Chatham Rise in the 1950s by a New Zealand Government survey. During the 1960s to 1980s several private and government sponsored cruises explored the Chatham Rise and surrounding seafloor area. A total of 1174 samples were collected over a 600 km2 area with the majority of the samples collected using a pneumatic -or large Van Veen-style grab-sampler.Since acquiring the licence in 2010, Chatham Rock Phosphate Limited has conducted six cruises in two programs in the Project area. A total of 261 samples were collected using a Van Veen grab, box core and grab samples.Sample quality and QA/QC measures varied considerably between the cruises and within each cruise. A critical part of the assessment of the data collected in the Project area was to determine what quality thresholds to use to allow or disallow data to enter into the estimation process. As part of the data verification process, the relative and absolute quality of the data was assessed in as much detail as practically possible. The best samples were those that were collected using the pneumatic grab, sampled the full sand horizon, had a small location survey error and had no other apparent data ambiguities. This paper describes the challenges for mineral resource estimation for an unconventional style of mineralisation using unconventional sampling techniques."

Sep 1, 2014

By S. Ripke

Between 2002 and 2004, the performance of a six million ton per year iron ore beneficiation plant dropped significantly. In a classic case of “who done it,” was it the mine, the concentrator, an ore change, or something else? While average annual final product grade decreased 8% (indicated by an increase in silicate gangue from 2.76% to 2.99%), the weight recovery also decreased by 8% (from 37.92% to 34.79%). This represents a loss of 832,000 tons of iron ore worth about $16 million for the two year period! The concentrator had been optimized to produce a high grade wet concentrate as feed to the dry side of the plant. But, did optimizing an individual unit operation’s grade give the best overall plant performance? In this paper, the investigation and solution to this mystery will be revealed.

Jan 1, 2007

Executive JOHN M. LOVEJOY, Chairman ERLE V. DAVELER G. B. WATERHOUSE WISER JUDSON WILLIAM WRAITH J. V. W. REYNDERS, Consultant Finance HENRY KRUM, Chairman PAUL D. MERICA R. M. ROOSEVELT H. G. MOULTON, Consultant Admissions. RALPH M. ROOSEVELT, Chairman GEORGE D. BARRON, Vice-chairman JOHN L. CHRISTI PHILIP KRAFT W. A. SINSHEIMER

Jan 1, 1936

To improve the air quality in large-opening stone mines by developing better ventilation techniques, including appropriate fan selection in conjunction with air-coursing methods. Background Stone mines are the most common underground large-entry mines in the United States. Data from the Mine Safety and Health Administration (MSHA) for the year 2000 indicate that there were 162 active nonmetal underground mines in the United States, of which 117 were stone mines. Many underground stone mines are drift mines developed from previous quarry operations. Typically, these room-and-pillar mines have entries that are 20 ft or higher and at least 40 ft wide. These large dimensions lead to a very small ventilating pressure loss, even when significant air quantities move through the mine. This is especially true of drift mine operations where ventilating pressure losses of <0.25 in w.g. are common. Underground stone mines with shafts that are<200 ft deep typically have ventilating pressure losses that are <2 in w.g. The pressure losses through these mines are much lower than those of a typical coal mine or deep metal/nonmetal mine. Therefore, the ventilation techniques and principles are quite different. In addition, because of new MSHA regulations that limit the concentration of diesel particulate matter, these mines may need to greatly increase their ventilation airflow. Therefore, large-opening mines need a fan that can move large air quantities and operate at low static pressures. There are three fan types for mine ventilation: centrifugal, axial vane, and propeller. Centrifugal fans are uncommon in underground stone mines as they are often associated with mines requiring the highest of ventilation pressures. Axial vane fans are widely used in all types of mining operations. They are the most common fan type currently found in underground large-opening stone mines. However, they typically do not operate at low static pressures with high efficiency. Propeller fans are currently uncommon in underground stone mines. They are designed for low static pressures and large air quantities at higher efficiency. This fan type best suits the ventilation needs in large-opening stone mines?they produce large air quantities at low pressure losses. Mines with air shafts<100 ft long and at least 12 ft in diameter have fairly low mine static pressures and may also benefit from propeller fans.

Dec 1, 2002

China has made great progress in thick coal seam mining, commonly characterized by longwall top-coal caving mining and single-pass longwall mining with a large cutting height. At present, the maximum mining thickness of longwall top-coal caving reaches 20 m while that of single-pass longwall mining approaches 8.8 m. The top-coal caving–related technologies have significantly improved the mining efficiency of thick coal seams and have also made a great contribution to the centralized underground mining of coal. Thus, the number of underground coal mines is greatly reduced in China. However, due to the increase of the mining height and the changes in mining operations, the overburden movement caused by the mining of thick coal seams is more intense, and the influence scope is larger, which brings a series of new problems on ground control of longwall faces. In order to enhance ground control and improve the mining efficiency of thick coal seams

Jul 28, 2020