Search Documents

By Jinke Li, Fenghua Wang

"While coal fueling China's economic growth it has already been causing severe pollution and amounts of CO2 emission. How to make deep reductions in carbon emission is not only a huge challenge for the greatest consumer of coal, but also a revolution for China’s coal industry. The paper explores how to shrink CO2 emissions during the lifetime of coal. The paper points out that increase of coal mine efficiency and productivity, green mining, utilization of coal mine methane and environment-friendly disposal of coal gangue can reduce CO2 during coal mining; coal preparation and coal by wire can decrease CO2 during coal preparation and transportation; improving combustion efficiency, CO2 capture and storage (CCS) and coal transformation can lessen CO2 during coal utilization. The paper also points out that Circular Economy Park is a practical way to develop a low carbon economy for coal industry. An econometric model for total coal industry and each sector are constructed to measure carbon emissions based on CO2 equivalent emissions, then with detailed calculations, based on potential greenhouse-gas emission's reduction, a most likely low carbon roadmap of China's coal industry is depicted with scenario analysis method.Introduction Global warming poses a profound threat to humanity and the natural world and is one of the most serious challenges humankind has ever faced. According to the 2007 Fourth Assessment Report by the Intergovernmental Panel on Climate Change (IPCC), global surface temperature increased 273.89 ± 273.33K during the 20th century (IPCC 2007). Increasing concentrations of greenhouse gases have caused most of the observed temperature increase since the middle of the 20th century (United States National Academy of Sciences 2008), and CO2 is the most important cause of global warming. In 2005, CO2 contributed 76% of global greenhouse gas emissions, CH4 contributed approximately 16%, N2O contributed approximately 6% and the combined F-gases contributed approximately 2% (IEA 2010). Among the many human activities that produce greenhouse gases, energy use is by far the largest source of emissions. Since 1870, CO2 emissions from fuel combustion have risen exponentially (IEA 2009). Of the three types of fossil fuels - coal, natural gas and petroleum - coal constituted only a quarter of the world total primary energy consumption in 2007. The situation is even more critical in China than in the rest of the world, as energy-intensive industrial production is growing rapidly, and large coal reserves exist in combination with limited reserves of other energy sources. The development and production of the coal industry provide stability in China's economic growth. There are more than 7000 coal enterprises in China; the coal enterprises are the main contributor to China's ""economic miracle""."

Jan 1, 2017

By J. Weyer

"Colored gemstones are most often mined in small scale artisanal mining operations. Sri Lanka is well known as source for precious stones since thousands of years. Gemstones are mine in small open pits, directly in rivers (river dredging) and in underground mines. Almost all mined deposits are alluvial deposits. PRECIOUS STONES AND DEPOSITS Precious stones from Sri Lanka are well known for thousands of years. Tales and legends from Arabia, India, China and reports from discoverers like Marco Polo describe the fabulous stones from Ceylon which was the name for Sri Lanka before 1972. Already 1000 BC King Salomon got valuable gemstones from the legendary Queen of Sheba on her visit to Jerusalem. Paintings (frescoes) of the “cloud maidens” with huge gemstones can be seen at the “mirror walls” of the Sigiriya rock fortress - one of the eight World Heritages Sites of Sri Lanka.And even today some of the most valuable and most desired gemstones come from Sri Lanka. The term “Ceylon Sapphire” stands for an excellent royal blue color of high quality corundum from Sri Lanka. Reason enough to look a bit closer how these gemstones are mined. Sri Lanka has rich gemstone deposits which are mined underground, in small open pits or directly within a river. Some of the primary deposits in magmatic and metamorphic rock are also known, but most gemstones are mined in secondary alluvial deposits. Gem bearing deposits can be found in a band from NW to SE. Highly probable deposits and main mining areas can be found around Ratnapura – the city of gems, down to the coast (Matale) and up to the region around Elahera. These secondary deposits are mostly thin layers of gravel and sand, so called “illam”. The depth can vary between some dm to 10 25 m or even almost 40 m. But the average depth is about 12 m. Gemstone mining is controlled, licensed and regulated by a special authority – the National Gem and Jewelry Authority - which was founded in 1993. Another task of this authority is the promotion and development of the gemstone industry and the control of import and export of gemstones. Any violence of the NGJA law can lead to a fine or even up to 5 years imprisonment. To increase the confidence in the gemstone industry the Authority offers a unique service to foreigners. All bought gemstones can be tested free of charge in certain laboratories in Ratnapura and Colombo. So visitors can be sure they got no imitations, wrong stones or even synthetic stones or glass. It was said that detected synthetic stones will be destroyed and the seller will do all he can to replace the stone with the right stone. Otherwise he will lose his license."

Jan 1, 2016

Pillars in underground limestone mines are required to support the overburden and provide a safe, stable working environment for mining personnel and equipment. Pillar stability was assessed by the National Institute for Occupational Safety and Health in underground limestone mines in the Eastern and Midwestern United States. It was found that current mine layouts have been successful in providing support to the overburden, while a small number of isolated pillar failures were observed. The stable pillar layouts and failed pillars were plotted on a chart that demonstrates the relationship between pillar width-to-height ratio and pillar stress. The results show that pillar failures occurred at the lower range of width-to-height ratios and can occur at relatively low stress levels. Zones indicating the potential risk of pillar instability are shown on the chart, based on hazards associated with the onset of rib spalling, large angular discontinuities and unconfined pillars. The chart can assist limestone mine planners to evaluate potential instability in current or new pillar layouts that are similar to those included on the stability chart.

Jan 1, 2008

By K. L. Williams

The Bureau of Mines tested a prototype tapered-element oscillating microbalance (TEOM) dust monitor for measuring respirable coal mine dust. The monitor uses the inertial behavior of a vibrating element to measure the mass of sampled dust. Tests were performed to determine variability, drift, the effect of humidity, placement of collection filter, and element orientation during analysis, and comparability with gravimetric measurements of respirable coal dust. Variability was about 1.6 µg. Over about 26 h at 46 pct relative humidity, drift was very slightly negative. When the relative humidity was increased to 78 pct, all units showed a total positive change less then 40 µg over about 70h. Filter placement variation on the tapered element resulting from in- consistent sizing of the filter mounting bases caused significant error (up to 0.2 mg). In practice, calibration of the system for each new filter will eliminate that error. Orientation of the element during analysis did not introduce significant error, but care is necessary when mounting the canister that houses the element to avoid damping oscillation of the element. Dust tests were performed in an aerosol chamber using coal dust. Measurements made by the TEOM dust monitor agreed to within 10 pct of simultaneous measurements by gravimetric personal samplers.

Jan 1, 1986

By R. A. Paul

The requirements for water inflow control for the Chicago Intercepting Sewer System are stringent. This posed special problems in grouting the bored and conventionally mined tunnels, shafts and chambers of the system. In adapting conventional grouting techniques to the specific problems encountered in the system's pilot project, numerous field procedures were developed. Careful preand post-grout testing and evaluation identified the most efficient and economical of these procedures. As an example of some of the conclusions reached during the project it was found that the mineralized groundwater in the Chicago area tended to reduce the efficiency of the grout holes, thus limiting their useful life. Pressure washing to remove natural fillings was a critical factor in achieving a permanent grout seal. The value of relatively thin lubricating grout mixes was definitely established. Although not an ideal situation, satisfactory results could be obtained by manifold grouting several grout holes simultaneously if done within specific limits of hole groutability, location and numbers. Caulking proved to be a primary controlling factor in achieving acceptable results. To achieve such a high degree of water inflow control requires close supervision by experienced personnel. "Temporary grouting as a construction expedient" produces seepage conditions which are extremely difficult to treat.

Jan 1, 1974

By Eric Sturel, Ove Arup, Henry Tayler

One Triton Square was originally a six­storey commercial building with a single level basement located within the Regents Place development near Euston, London. The building was a concrete frame, with steel cores at each corner. The floorplate was approximately 72 x 72 m (236 x 236 ft) with a 36 m (118 ft} wide octagonal central atrium. The original building was well suited for extension due to relatively recent construction standards, high original live load allowances, its large central atrium, generous escape stairs provision and extensive record information. Plant space requirements at basement and rooflevel were maintained. The preferred scheme was the addition of three storeys to the existing six-storey structure and an eight-storey partial infill in the central atrium area, with a further allowance for completely filling in one or two of the lower atrium levels. This allowance was included in the design to offer enhanced flexibility to future tenants. It was clear from an early stage that the foundation load demand would increase to serve the enlarged building area, which increased the existing building floorplate by 70% or 130,000 sq ft (12,100 m2) of commercial space. Maintaining the basement headroom and accessibility for servicing plant would also be important.

Jan 1, 2024

The Centenary Luncheon for Past Presidents was held on Thursday, 24 March, 1994 at The President's Room at Gold Reef City, Johannesburg at 12:30. Herewith the proceedings that followed. Dr H. Scot-Russell It is with great pleasure that my fellow Office Bearers and I welcome you, our Past Presidents, to this luncheon to mark the centenary of the SAIMM. Today one hundred years ago, a group of professionals met and agreed to draw up the constitution and by-laws of a society later to be called an Institute. The Presidents of the Institute, of course, become its Past Presidents and help to guide its progress. A number of our sister institutes cannot wait for their Past Presidents to move of their councils, and cannot understand how we can give such free reign to ours! We believe it one of our strengths. The successful cooperation between our Past Presidents and ourselves is due to the personalities of these men. They attend meetings not to ensure that the status quo is maintained, but allow the current Office Bearers freedom to lead the Institute as they think fit. But they are always present to give sound advice, a helping hand, and support to the Institute in every way.

Jan 1, 1994

By A. Singh, R. R. Maclachlan

SYNOPSIS A back-analysis procedure based upon 35 mm photography was developed on a laboratory scale for the pur¬pose of determining the percentage of oversize particles known to be present in heaps of fragmented rock. Eight simple blends of crushed stone containing varying percentages of oversize on a 1:40 modelled scale were examined. Simulated test conditions for the following were subjected to the photographic study: (1) a bench heap, (2) the surface exposure of a partially excavated heap, (3) a gravity-sorted surface as occurs on an apron dump, and (4) four quadrant views of an incrementally built conical heap of rock fragments. The best back-analysis determinations were obtained from (4), the cone, over all eight blends of fragments. The mean error was within -0,16 per cent of the true value, with a range of ± 1,872. This was for oversize contents of 5 to 20 per cent where a minimum 25 per cent of the photograph area was processed by digitizer. The worst results were from the apron dump at - 1,462 per cent for a mean error of ± 4,174 per cent. The intermediate results were from the undisturbed bench at -0,186 per cent with a mean error of ±2,862 per cent.

Jan 1, 1989

By A. C. Atenas

The majority of refineries that operate with traditional starting sheet technology ?starting sheet- uses a relatively low current density of 250 A/m2. Industrial tests at high current density with conventional technology were carried out in Refinery of Potrerillos, getting satisfactory results that are similar the results obtained with permanent cathode technology. The series of copper refining electrolyses electrolysis trials were carried out between 300 to 325 A/m2. Electrolysis conditions, in accordance with industrial practice, were kept constant in all sets of experiments and were as follows; 45 g/L Cu 2+, 210 g/L H2SO4, 62 °C, electrolyte circulation of 14-18 L/min. The same Dosing dosing of Additives additives used in permanent cathode technology was required in these tests. In general, only not importantminor operational modifications were necessary in comparison to normal practice in the Refinery to assure the good results. Different quality of starting sheet and anodes were examined. The test included starting sheets from smelter and laminated process. Results indicate that the charge physical quality of the electrodes and the control of the process during the two first days of operation are the keys to get the best results.

Jan 1, 2007

By E. K. Albert

Title IV of the 1977 Surface Mining Control and Reclamation Act (SMCRA) provides for an abandoned mine reclamation fund. This fund, taken from fees collected from operating coal mines, provides capital for the reclamation process. The Act directs the Office of Surface Mining (OSM) to collect the fees based on coal production. Monies from the abandoned mine lands (AML) fund are distributed through two programs. The first provides OSM with capital to use in emergency situations resulting from abandoned mine sites and reclaiming high priority sites in states without established AML programs. The second distributes the money through a state's AML program in the form of grants. To provide for a flexible and customized selection procedure for AML projects, a management information system (MIS) that combines scientific selection procedures is being developed. This system employs objective and subjective methods developed in systems research in recent years. The MIS component is an essential part of any selection process involving large numbers of potential projects. It must contain all the necessary project parameters that can be applied to the selection of projects whether or not they are to be used in the immediate selection criteria. In addition, variable selection criteria will allow ‘what if’ types of inquiries for comparison of differing selections and benefits.

Jan 1, 1990

By G. Brofas

The reforestation potential of bauxite mining spoils by seeding was examined on this research work. The experimental plot was established on the location Strofi Koukouvista 5, Ghiona Mountain. The experiment consists of 3 species (Pinus nigra, Robinia pseudoacacia, and Spartium junceum) with 4 sowing treatments and 2 sowing seasons (autumn and spring). The treatments were: (1) broadcasting; (2) broadcasting and soil cultivation; (3) broadcasting with straw mulching and straw binding with asphalt emulsion; (4) broadcasting with soil cultivation, straw mulching and straw binding with asphalt emulsion. Third year results show that spring is better than autumn as a sowing season. Only the Spartium junceum species were found to germinate and survive in autumn. The results are better for all the species on the spring seeding. The most effective treatments for Robinia pseudoacacia and Pinus nigra are 3 and 4 while for the Spartium junceum even simple broadcasting shows good results although the best ones are achieved with treatments 2, 3 and 4. The paper?s findings show that reforestation by sowing could be effective for some species but further experimentation with other species is recommended. Concerning Robinia pseudoacacia, testing of different seed preparation treatments is needed in order to maximize the germination of seeds.

Jan 1, 2002

By Dan Adams, Thomas Post, Paul Kubera, Mike Preston

Mixing is a common unit operation in the mining industry. Mixers are often used in agitated leach, bio-oxidation, and pressure oxidation. In all of these cases it is important to understand the application and what it requires from a mixer in order to be opti­mized. In the mining industJy, it is obviously important to suspend solids. However, the shear level of each of these three applications is ve1y different. In acid leaching, the mixer needs to suspend solids and produce a good degree of blending. In pressure oxida­tion, the agitator must also disperse air or oxygen by creating fine bubbles. Because of the presence of microorganisms, bio-oxida­tion requires less shear than the other two processes, but the agita­tor must be able to suspend the solids, provide excellent blend­ing/heat tJ·ansfer and distribute the air. Thus, in the mining indus­tiy there is an application spectJ·um that requires different impellers to perfotm different jobs. Specifically, these jobs are blending, solids suspension, gas dispersion, mass transfer and heat transfer. It is important to determine whether the process is mass transfer or kinetic rate limited. Mixers affect a mass transfer limitation but have no affect on the kinetics.

Jan 1, 1998

By NONEn NA

1. Book reviews . Rudiments of mining practice, oy C.E. Gregory.Clausthal-Zellerfeld (West Germany), Trans Tech Publications.OS$24.Reviewer: A.N. BrownProfessor Gregory has had a wide experience of hardrockmetalliferous mining throughout the world, beinga well-known academic who has taught at many universitiesin the Western World. His basic training was obtainedin his native land of Australia. In this publication he identified the need for a basic, simple book on miningpractice to provide new students of mining with a backgroundto their studies. He also designed the book to providea background to persons operating on the fringesof the industry such as students of economics and journalists.The text extends to only some 120 pages, and containsa sufficient number of monochrome sketches, diagrams,and photographs. It is written in a straight-forward, easyto-read style. The book contains an index and elementarytable of conversion from imperial to SI (metric) units,and there is also a glossary of mining terms that mostreaders would find useful.The author has succeeded in keeping the contentssimple, as indicated by the title. However, after each chapter, there are references to further recommendedreading. The book could be useful in the South African context, although the coverage of coal and opencast mining operations is slender.

Jan 1, 1987

Mining and Metallurgical Society of America, 76 Beaver St., New York, N. Y. Percy E. Barbour, Secretary and Treasurer. This Society issues Bulletins each year containing papers presented, and accounts of Society business. The Bulletins each year are collected in a volume as the Proceedings for that, year. In 1931 Bulletins numbered 216 to 222, inclusive, were issued in the Proceedings for that year (vol. 24). In addition to the Bulletins two special volumes have been published: International Control of Minerals, $1; and World Survey of the Zinc Indusry, $2.25. A selected list of paper,,-from the last two volumes of the Proceedings: Vol. 24 (1931) : Bull. 216 The cycles of prices of non-ferrous metals, by L. Vogelstein; 218, Marketing problems, by T. M. McNiece; 222, Copper tariff number (a discussion of the copper tariff by a number of authors). Vol. 23 (1930): Bull. 208 to 215, inclusive: Bull. 208, Some aspects of the copper industry, by L. C. Graton; 209, The ethical question of developing Soviet mines; 213, Legal recognition of geophysical prospecting, by A. H. Rogers; The evolution of the metal cartels, by L., Domeratzky and L. Vogelstein; 214, Geological justification for "exploration permits," by L. C. Graton; 215, The future of nickel, by A. J. Wadhams.

Jan 1, 1933

By L. Byszynski

The results of a three month evaluation of the application of EMEW® technology at the KGHM Glogów II Smelter tank house bleed stream are presented. The current, conven¬tional electrolyte decopperization process has some limitations, including: only a fraction of its production is commercial grade cathode copper, significant operating costs, low current efficiency, low current densities resulting in low copper depletion rate, and arsine gas and sulphuric acid emission. The EMEW® cell technology developed by Electrometals Technologies Ltd. can overcome many of these limitations. Tests were performed on a pilot EMEW® installation comprising 30 cells at ambient temperature on electrolyte bleed, using current densities between 100 and 600 A/m2 , with copper concentrations between 45 and <1g/dm3. Results showed that a high grade copper can be obtained to the level of 7 g/dm3 of copper concentration in electrolyte. The use of EMEW® technology allows the direct and efficient recovery of over 85% of the copper contained in the bleed electrolyte. Glue & thiourea addition were tested in order to improve the parameters of the copper depletion process. The behavior of Arsenic and Bismuth was observed and a means for their elimination from the system proposed. On-line copper concentration monitoring is proposed to improve control and performance.

Jan 1, 2007

By M Darby, B Burdett, F Lovell

The results of the process control improvement project aimed at improving the quality of Australian Bulk MineralsÆ (ABM) iron ore pellets produced by four vertical shaft furnaces are very positive. These results are achieved through process stabilisation and optimisation, improvement in process monitoring and taking early corrective actions when operating variables were outside the target ranges. A number of benefits are obtained from this project. These benefits include: More consistent and improved pellet quality. The average cold compression strength (CCS) value of pellets produced during the eight-month trial is 260 kg/pellet, which is 16 kg/pellet higher than that produced during the 12 months prior to the trial (244 kg/pellet). Reduction in the heat input by eight per cent, from 727 MJ/tonne to 668 MJ/tonne. Reduction in bentonite rate by six per cent, from 7.1 kg/tonne to 6.7 kg/tonne. Increase in the furnace throughput rate by four per cent and additional production of 10 000 tonnes per annum through process stabilisation. Better understanding of the process behaviour. This knowledge is valuable not only for setting the target operating conditions but also for developing the ABM expert system to control the process.

Jan 1, 2005

By S. Itoh, T. Nagasaka, J. Ono

With respect to the recycling of used lead-batteries, a pure lead is required to prepare a lead-calcium alloy electrode for a new maintenance-free battery. The pure lead can be obtained by means of electrolytic and/or pyrometallurgical refining. In the lead electrorefming, antimony is concentrated in anode slime. From the viewpoint of the recycling and recovery of metal values from used lead-batteries, especially from anode slime, oxidation experiments were conducted for pure liquid antimony in the temperature range between 973 and 1373 K to elucidate the oxidation kinetics and mechanism. Furthermore, since lead anode slime generally consists of antimony, lead and bismuth, experiments have been also carried out using antimony-lead-bismuth alloy. The equation relating to the mass transfer characteristics in the gas phase was then applied to analyze the oxidation kinetics. As a result, it was found that the anode slime treatment, that is, an oxidation of antimony concentrated in anode slime followed by vaporization as antimony oxide Sb406, should be operated with higher oxygen partial pressure and sufficient amount of gas flow rate at lower temperature around 1073 K. The feasibility of the oxidation treatment for anode slime has been also discussed.

Jan 1, 2004

The tungsten carbide insert bit has probably advanced blasthole drilling more than any other single improvement. Tungsten carbide inserts have longer life, maintain sharper edges, and penetrate faster than hardened steel edge bits. Before the tungsten carbide hit appeared, all-steel bits were used. Even with the new bits, blasthole drilling costs vary with the type of equipment used and its condition; the hole&apos;s length and diameter; the rock&apos;s texture, hardness, and nature; the operator efficiency. To help reduce drilling costs, the operator should be familiar with the use and care of drill bits. This article provides information about tungsten carbide rock bits used for percussion drilling. Consideration of tungsten carbide rock bits includes looking at bit materials [ ] as well as bit operation and maintenance. Two basic tungsten carbide rock hits are the button bit and the four-wing carbide insert bit. Three common hit-to-drill-steel connections are the bottom drive, tapered drive, and shoulder drive. Bottom drive bits arc typically used for singlepass or longhole drilling, with all percussion drills from handheld sinkers to heavy track drills. Tapered socket bits are available with shallow or deep carhide inserts, for the lowest cost depending on the rock type being drilled. Shoulder drive bits are available in all-steel or carbide insert design.

Jan 12, 1981

By J. Borlee, F. Sorrentino, A. Fleischanderl, M. Gimenez, W. Gebert, U. Gennari

Large quantities of solid by-products are generated by the steel industry and other important activity sectors in Europe (power plants, car dismantling companies, urban incinerators) with no or very limited potential for direct recovery. In the frame of a multi¬national project supported by the European Union, a consortium has been created to develop a treatment process able to turn these by-products into valuable metallic and mineral products. VAI has been responsible for the design, erection and start-up of the pilot plant for the new metallurgical process and for the execution of the test campaigns, with the targets defined together with the partners. Up to now, 9 campaigns comprising 60 heats have been performed successfully. By-products from C-Steel and stainless steel plants, as well as fly ash and auto shredder residues, have been used and defined products such as hydraulic binders for cement, metallurgical powders for De-S practice and recycled metal phase have been produced. The mineral products were positively assessed under industrial conditions. Results from cement tests and secondary metallurgy are reported, as well as a detailed characterization. The economic value of the products, credits from avoiding dumping and significant savings on CO2 emissions make the new process economically very attractive.

Jan 1, 2004

By Philippe Dumont

Presentation of the project Underground civil works to be performed They include two single track running tunnels and a service tunnel of a length of fifty kilometers . Many cross adits (180 adits) : to link the tunnels (53 cross passages), to relieve air super pressure from one tunnel to the other (87 piston ducts), to install technical adits (40 electrical rooms). Two cross-overs located at one third of the whole length, allow trains to shunt from one tunnel to the other so as to ensure one way traffic in case of emergency. Pumping stations allow water to be collected at the lowest point and pumped out. 1 Main features of the tunnels 1.1 The service tunnel This 4.8 m inner diameter gallery allows During civil works - front probing operations of the geological layers encountered (front and vertical probes). - lateral soil grouting that may be necessary to facilitate the boring of the two running tunnels . During operations - Maintenance and safety vehicles traffic - Fresh air supply to running tunnels - Fire protection and drainage system - Electricity supply and control and communication. The service tunnel has been bored with a 5.72 meter external diameter Robbins TBM for the undersea section, and a MITSUBISHI TBM for the land section.

Jan 1, 1991