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By Yue-yuan Li

China has abundant magnesite resource, but the low-grade and powder ores have always been rejected, which influences the comprehensive utilization of resource and often causes circumstance problems. The present work investigated the preparation of magnesia whisker using magnesite tailings as starting materials by preparation magnesium carbonate whisker as precursor firstly in the route of calcination, hydration, carbonation and pyrolysis, follows by second calcination of the precursor. The influence of pyrolysis conditions and additives on morphology of magnesium carbonate crystal as well as the influence of calcination conditions on morphology of magnesia whisker was investigated. The results showed that thermal decomposition products was MgCO3?3H2O. Magnesium carbonate whisker with length of 10~60 µm and the length-to-diameter ratio of 10~20 was prepared when soluble magnesium salt was added. While temperature was elevated at 1°C?min-1, magnesia whisker with length of 10~60µm was obtained.

Jan 1, 2010

By David O. DeGagné

While mine backfill plants are becoming increasingly more automated and instrumented, especially with paste fill operations, underground backfill distribution systems have hardly changed over the years. While fill properties are appropriately measured in the preparation plants, as backfill enters the mine borehole, the technology for control, data gathering and reporting is somewhat lacking. Mines typically experience problems with borehole and pipeline plugging, pipeline bursting, bulkhead failure and exposed fill sloughing. With adequate instrumentation of the backfill system it is possible to obtain a complete, continuous and detailed picture of the entire filling operation from preparation to post-pour. Good data will, over time, provide the basis for needed improvements of backfill systems and will be essential to safer, more efficient and less costly fill practices. This paper will review the areas of the filling operations where monitoring would prove critical to eliminate failures such as pipelines, bulkheads, fill exposures, stope walls, etc. The types of monitoring systems currently available will be reviewed and potential areas for development will be highlighted.

May 1, 2001

By A. W. Hall

A nuclear method was developed for continuously and automatically deter-mining the moisture content of coal flowing through a bin. Fast neutrons from a 1 curie americium-beryllium source penetrate the coal, are thermalized (slowed down) by hydrogen in the moisture, and are counted by a thermal neutron detector. The difference between the number of these thermal neutrons and those thermalized by dry coal (in a reference drum) is a measure of the moisture content of the coal. A materials handling system was developed and in tests at a commercial coal preparation plant, moisture in coal was monitored continuously within 0.2 percent of values determined by conventional means. The meter responded rapidly to change in moisture content, making it adaptable to automatic process control, and was operated for 1 year without malfunction or recalibration. Shielding of the source by the coal kept the neutron flux level at the bin wall less than 1 milliroentgen per hour, a safe level for personnel.

Jan 1, 1973

By J. A. López-Molina, S. García, V. Castellanos-Pedroza

"Grouting aims to reduce the permeability of rock mass below a predetermined value and has been widely used in rock engineering field for a long time. However, the injection procedure needs several empirical decision makings and it is rather difficult to reliably confirm the achievement of improvement, because the grout penetration process is not sufficiently clarified. This investigation proposes a neuronal method of defining spatial distribution of rock hydraulic properties and a fuzzy scheme for estimating their relation with the grout penetration (consumption, localization and filling material). The intelligent method stands as a tool for helping in harmonizing the sealing activities and the medium conditions. The virtual simulation of grouting strategies embraces geology, hydraulic and rock characteristics and the filling process. Important aspects as different pressure injection levels and fracturing systems can be holistically studied using the intelligent environment, resulting in an advantageous, economic, flexible and interactive tool for planning better this critical activity.INTRODUCTION Grouting is a very common method of sealing rock and repairing concrete structures (Butron et al., 2010) and its use in engineering of dam-foundation and tunneling has been documented as very successful (Yang, 2004). Generally speaking, to achieve the closing purpose, boreholes are drilled into the rock mass and grout is injected (under pre-selected pressure) until the fractures around the borehole are filled. The complete filling of these fractures is possible if they are connected to each other in such a way that the remaining water and air can be displaced outside the designed grouting zone (Houlsby, 1990; Kutzner, 1996). Water testing is necessary for evaluating seepage potential and for determining whether grouting is necessary or practical. Regardless of the main reason for the investigations, design of a program for water testing for grouting should consider the type of structure to be built, the geologic conditions at the site and the level of seepage control desired. As information gathered the report must content the fracture openness, number and connectivity, exploratory drill holes orientations, materials situation and a panorama of rock-mass state (quality)."

Jan 1, 2015

Located in Timmins, Ontario the Porcupine Joint Venture, a pooling of assets between two existing operations (the Dome Operation of Placer Dome (CLA) and the Hoyle Pond Operation of Kinross Gold Corporation) came about on July 1st, 2002; Placer being the manager of the Joint Venture with 51% ownership and Kinross with 49%. The formation of the Joint Venture was the realization of the dream of many who could envision the benefits of the whole area being operated as one entity ? the combination of the majority of assets in the Porcupine Camp into one venture containing tremendous synergistic potential of manpower, infrastructure, land tenure and exploration development. The name Porcupine in the gold mining industry brings with it the legacy of world class gold mines; the Hollinger, McIntyre and Dome with a proud tradition of excellence. The name Porcupine brings with it the legacy of over twenty individual mining companies in operation at any one time, producing over 65 million ounces of gold.

May 1, 2003

By Jaeheon Lee, Junmo Ahn, Jiajia Wu

In this project, low grade copper ore samples were obtained from two mining sites in the US, and they were chalcopyrite-rich (sample A) and conichalcite-rich (sample B) ore. Copper grades were 0.6% and 0.4% for the two samples, A and B, respectively. Leaching experiments were conducted by bottle roll tests for 24 hours, and various lixiviant systems were applied. Methanesulfonic acid (MSA) and glycine were used as alternative lixiviants to sulfuric acid. Oxidants including ferric ion and hydrogen peroxide were tested. The results showed the copper extraction of sample A increased after adding 1 g/L ferric ion in sulfuric acid and MSA solution, from 20% to 36%, but further increase was not observed with higher ferric ion concentration. The copper recovery increased significantly with H2O2 concentration, and over 80% copper recovery was obtained with 10% H2O2. For sample B, the copper dissolution kinetics were relatively fast and reached the maximum value in five hours. Around 60% copper were extracted in sulfuric acid and MSA solution. Copper recovery slightly increased after adding ferric ion and H2O2. Glycine is a weaker lixiviant for both samples, the copper extractions were 36% and 4% respectively. INTRODUCTION Chalcopyrite is the most abundant copper sulfide mineral on earth, and it is one of the most refractory copper minerals regarding chemical processing. The declining copper grade and depletion of copper oxide deposits stimulate the development of hydrometallurgical process to extract copper from chalcopyrite. The dissolution of chalcopyrite by ferric ion is normally illustrated as Equation (1) and (2) (Dutrizac & MacDonald, 1974): CuFeS2 + 4Fe3+ → Cu2+ + 5Fe2+ + 2S0 (1) CuFeS2 + 4Fe3+ + 3O2 + 2H2O → Cu2+ + 5Fe2+ + 2H2SO4 (2) However, slow kinetics are usually observed from chalcopyrite leaching at ambient temperature and pressure. Researchers attribute the slow kinetics to passivation during chalcopyrite dissolution, and different passivation products are also proposed (Klauber, 2008). In recent years, many efforts have made to develop new methods to extract copper from chalcopyrite, such as utilizing bacteria or stronger oxidant (Zhao et al., 2015; Ruiz-Sánchez & Lapidus, 2017).

Jan 1, 2019

A combined reflection seismic and magnetic survey off the south coast of New South Wales has revealed six distinct reflection horizons within the Lower Triassic-Upper Permian sequence, and has enabled the upper part of the lllawarra Coal Measures to be mapped in considerable detail. Large magnetic anomalies in the eastern half of the survey area appear to originate in the Gerringong Volcanic Sequence which forms the magnetic basement in the survey. Small residual anomalies in the western half of the area can be correlated with small scale faulting and folding in the upper part of the llawarra Coal Measures, as revealed by the seismic reflection survey.A synclinal axis striking at approximately 55° has been mapped near the western margin of the survey area, and areas of faulting and folding have been outlined by combined analysis of seismic and magnetic results.

Jan 1, 1970

By Klaus Hasselwander

Fluctuating SO2 gas streams represent a difficult task for designers of SO2 removal systems (with respect to designing the plant), but in spite of the designers great efforts to solve the problems, the operation of such plants requires much care and attention. A fluctuating gas flow usually results from metallurgical smelting processes. Both gas composition and gas flow rate may vary. The first part of this paper outlines some existing technical solutions and presents the Pros and Cons of the different solutions. These solutions outline are: - Sulphuric acid plants operated with a preheater permanent in operation - Sulphuric acid plants with concentration increase of SO2 gas either using regenerative SO2 removal or cryogenic partial condensation of the SO2 - Sulphuric acid plants with additional burning of sulfur to increase SO2 content - Single-stage sulphuric acid plants followed by a tail gas system (which is) designed for periods of low SO2 input In the second part, this paper describes some existing technical solutions for removal of SO2 at low concentrations (i. e. less than 0.1 - 2 %-by volume), which could be used as tail gas treatment system for acid plants. While selecting an appropriate solution, special attention should be given to operating costs, which usually to a large extend depends on the type of absorption agent and the costs for disposal of the sulfur compound produced.

Jan 1, 2009

By H. S. Benson

This report documents, from concept through field testing, the pan scraper Wheel Slip Monitor. The function of this device is to instantly warn the scraper operator of wheel slip and thus enable him to take immediate corrective action. Knowledgeable pan scraper people recognize that the preponderance of scraper tire damage and wear occurs during useless wheel slip when the scraper operator attempts to increase machine draft beyond what traction will allow. The resultant shortened tire life has become very expensive. The Wheel Slip Monitor reported here provides the means for relieving the scraper operator of attempting to judge wheel slip on tires he cannot see. Direct and intuitively understandable audible and flashing light warnings tell the scraper operator which wheel is slipping and also indicate the relative magnitude of the slip. Beside the Wheel Slip Monitor's patent utility as a real time operator aid, it has unique potential for application to extended term wheel slip history acquisition under field conditions. This information has never been easily available and it promises practical value in pan scraper management.

Jan 1, 1983

Mining is taking place at increasing depths of cover on the Southern Coalfield beneath predominantly massive sandstone strata. Within the next twenty years, there will be longwall mining at depths greater than 600 m. As the Sydney Metropolitan area continues to expand and as coal mining approaches these urban areas subsidence will continue to become an increasinglY important aspect of coal mining research. Investigations, commenced in the mid 1960's, allow prediction of subsidence in the Southern Coalheld with reasonable confidence. The work is showing that the characteristics of thc subsidence troughs over the deeper mining at Appin differ from the characteristics of mine subsidence at less cover.The longwall mining at Appin Colliery has resulted in a maximum measured subsidenee of 730 mm. The maximum strains were small because of the large radii of curvature of the subsidence profiles. There was no damage to any of the buildings in the township of Appin.

Jan 1, 1982

By K. J. G Hedges

"Once a health based guidance limits for exposure to diesel exhaust have been established, and as part of a multi-disciplinary team, the program for exposure reduction should incorporate the plan-do-check-adjust cycle. Setting a suitably protective (health based) occupational exposure limit (OEL) for diesel particulate matter (DPM) and nitrogen dioxide is a key driver to reduce exposure. It is important to go beyond regulations and reduce exposure to diesel exhaust, DPM, as low as reasonably achievable (ALARA) such as that prescribed under the Australia, Queensland Mining and Quarrying Safety and Health Regulation 2017 where under section 135 Limiting workers exposure, the workers exposure must not exceed the exposure limit applying to the worker for the hazard; and is ALARA. It appears that previously acceptable OELs are no longer safe. Therefore it is important that the internal responsibility system be implemented and the precautionary principle approach be followed, especially as it may be some time before a suitably protective OEL specifically for DPM is in place. One leading multi-national mining company BHP Billiton has acknowledged a significant lag that exists between regulatory action and the level of science that informs health risk. This company is managing exposure to diesel exhaust to as low as technically feasible. This same company that has set an interim target for managing diesel exhaust to 0.03 mg/m3 is achieving these levels which paves the way for other mining companies and general industry including construction. The Occupational Cancer Research Centre 2017 recommends reducing personal exposure to within 0.02 mg/m3 (EC) for underground mining and 0.005 mg/m3 for other workplaces. Controlling DPM is important to prevent cancer however it is also important that that nitrogen dioxide (NO2) be reduced (ALARA) and that careful selection of control technology be considered such as the proper selection of a diesel oxidation catalyst so that the level of NO2 does not in fact increase. The example from BHP Billiton provides a leading practice including using a multi-disciplinary approach and the importance of controlling emission at source and having an auditable diesel emissions based monitoring program in place."

Jan 1, 2019

By William A. Stickney

The zirconium-hafnium separation plant at Albany, Oreg., was the result of a chain of events that started with studies by A. R. Kaufmann at the Massachusetts Institute of Technology. Variations in the listed neutron-absorption cross-section of zirconium caused him to suspect a misprint. As a result of these discrepancies and following his suggestions, Oak Ridge scientists made studies establishing a value of 0.4 barn or lower. This meant that the potential of zirconium for reactor application was greatly enhanced. Since hafnium is invariably associated with zirconium and has a high neutron cross-section, it was necessary that an efficient hafnium-separation method be developed before the superiority of zirconium as a structural material in nuclear reactors could be realized. The Albany plant was built and operated for the Atomic Energy Commission (AEC) under Letter Agreement AT-(11-1) -140, patterned after a plant operated by the Carbide and Carbon Chemicals Corp. at Oak Ridge, Tenn. Construction was begun in April 1951. Hafnium was to be extracted preferentially as hafnium thiocyanate from an aqueous mixture of zirconyl and hafnyl chlorides in hexone (methyl isobutyl ketone) by a liquid-liquid countercurrent system.

Jan 1, 1959

By Daniel Ko, Ian Bell, Shahram Tafazoli, Bahram Sameti, Aylin Azmin

Image-based remote sensing of rock fragmentation in mining and quarry applications essentially treats each rock in the image as a data object in order to determine the rock size distribution. An obvious challenge after rock delineation in a 2D image is the scale of the delineated objects. Conventionally, either objects of known size are placed in the scene or parallel laser pointer are used, both making some assumptions, to calculate scaling factors. These assumptions are applied to the whole scene rather than sensing individual rock attributes.

Jan 1, 2015

By John P. Hager

A special inlet system has been developed for a TOF mass spectrometer that allows the equilibrated high-temperature vapors from an atmospheric-pressure flow reactor to be leaked into the ion source of the mass spectrometer without undergoing any compositional changes. Using this flow reactor - mass spectrometer system and a modified transpiration system (one that allows for the carrier stream to be equilibrated with two different condensed samples) a series of fundamental vapor transport studies were undertaken. The results of these studies are summarized as follows: 1. The vapor species in equilibrium with condensed copper (I) chloride were determined to be Cu3C13, Cu4C14, and Cu5C15. The gas mixture is fifty percent tetramer near the melting point (703°K), with the percentage of tetramer decreasing with increasing temperature. The following thermodynamic results were obtained.

Jan 1, 1977

By John L. White

Vibratory driver/extractors do more than drive and extract sheet piles. I would say more than sixty percent (60%) of the time, vibratory pile driver/extractors are engaged in work that has nothing to do with sheet piles. This is the main reason I refer to this tool as a "driver/extractor", and omit the word "pile". I have spent the last twenty years applying the technology of the vibratory driver/ extractor to all areas of foundation construction. As you will see, the only limits are humankind's ingenuity.

Jan 1, 1997

By D James

Fletcher Challenge Limited through its subsidiary Grampian Mining Co Limited has carried out an ore evaluation of one of New Zealand's largest known deposits of ilmenite located at Barrytown on the West Coast of the South Island, New Zealand. The ilmenite is located in a beach sand environment which has previously been mined for gold. Two analytical techniques were developed to quantify the resource. Considerable difficulty was experienced in this phase of the evaluation due to the presence of major inclusions within the ilmenite grains. Wet and dry concentration circuits, utilising spiral, wet magnet, high tension and plate electrostatic separators have been designed to produce ilmenite from the ore. Studies to utilise the titanium content of the Barrytown ilmenite have been made. Recent work has been directed towards a titanium dioxide pigment process.

Jan 1, 1986

By R. F. Chaiken

The Bureau of Mines has conducted a study of mine fires in the Anthracite Region of Pennsylvania to determine the most effective approaches to fire control in this area. The problems involved in controlling an anthracite fire include the geological and mining conditions in this area, the propagation characteristics of anthracite, the fire control methods available, the hazards associated with these fires, and the mar-ginal effectiveness of past fire control projects. From this genecal background, fire control options were discussed as they apply in ISBO to the Centralia mine fire. Probable effectiveness, feasibility, and costs were assessedv The options evaluated include four excavation plans, flooding, hydraulic flushing, water curtain isolation, mining to construct an underground carrier, burnout control, and relocation of the community. The most advantageous from a technical viewpoint is an excavation method combining complete excavation of the fire zone within the borough with trenching to confine the remaining fire. It appears that for many anthracite fires, as for the Centralia mine fire, there are no available control measures that have a moderate cost, are proven effective, and produce minimal disruption on the surface.

Jan 1, 1983

The need for the hydraulic transportation of coal in the New South Wales coal industry, both from the coal face to the surface and from the coal mine to the consumer or the port for export, is explained. Details of research projects currently in progress and involving the hydraulic transportation of New South Wales coals are given together with information on the hydraulic transportation of coal in the United States of America. The potential of hydraulic transportation as a viable alternative to the proposed expansion and upgrading of the New South Wales railway system to meet the projected New South Wales coal production to the year 2000 is described.

Jan 1, 1980

By Craig T. Jones, Zachary Q. Maassen

"Jet grouting is a method of ground improvement that relies on the erosive capacity of high-speed jets to cut and mix the ground in place with a cementitious grout. A continuous return flow of cuttings, called jet grout backflow or spoils, is expelled to the surface during the grouting process. Data from projects completed in Toronto and Ottawa is presented where BOS Solutions’ services provided significant savings compared to the traditional spoils treatment utilizing vacuum trucks for spoils disposal. These traditional treatment methods are cumbersome and expensive by nature. BOS Solutions provided an alternative solution that is environmentally friendly and capable of handling full flow to process these jet grout spoils utilizing a tank system paired with centrifuges and flocculation additives to remove the ground soils and grout product from the spoils slurry. BOS’ process produced a clean water for reuse in the project while reducing the overall waste volume by producing a dry, stackable solid that could be hauled to a landfill. Benefits observed by using the BOS process were disposal waste volumes decreased over 30% and at least a 19% reduction on disposal costs.SCOPE OF WORKJet grouting is a method of ground improvement that relies on the erosive capacity of high-speed jets to cut and mix the ground in place with a cementitious grout. A continuous return flow of cuttings, called jet grout backflow or spoils, is expelled to the surface during the grouting process. The backflow, or spoils, is a mixture of grout, water and soils. Traditionally, the spoil would be collected in in-ground pits and allowed to solidify for a few days prior to hauling to a final disposal site. For the projects completed in Toronto and Ottawa, the jet grouting work was performed at street level, in high traffic congested areas, presenting the challenge of insufficient space for the contractors to process the jet grout spoils in the traditional way. At first, attempts were made of using vacuum trucks to collect and haul the wet spoils to an off-site location where the spoils would be allowed to solidify. However, this method proved cumbersome and expensive due to the high volumes of spoils generated daily and the high number of vacuum trucks required to support the jet grouting operations, respectively."

Jan 1, 2017

By A. C. Fieldner

This is the tenth annual report of research and technologic work conducted by the Bureau of Mines on the occurrence, properties, mining, preparation, and uses of coal and coal products. These annual reviews are guide's to the current work-and publications of the Bureau but do not replace the more complete reports published under the authorship of the individual investigators on specific problems in Bureau of Mines bulletins, technical papers, reports of investigations, and information circulars and in the technical press. The Annual Report of the Director of the Bureau of Mines to the Secretary of the Interior for the Fiscal Year ended June 30, 1945, summarizes the year's work on coal as follows: Coal and Coal Products The United States maintained its No. 1 industrial position in supplying fuel for war and in preparing for peace through more complete mining, improved preparation and up-grading of coal for special uses, and better utilization of coal in industrial establishments and homes.

Jan 1, 1946