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By S. Sinha, S. Ganguly

"In an opencast mine explosives are used for fragmentation of rock. Inefficient use of explosive energy in an opencast operation produces excessive ground vibration, which is measured by peak particle velocity (PPV). To mitigate ground vibration, it is essential to develop a model to predict PPV. At present empirical models are used. These models are based on only a few input variables, hence they fail to take into account the effects of the myriad factors that cause ground vibration. Due to lack of explicit knowledge about the complex mine blasting system the scope of application of mathematical and statistical modeling techniques is limited. The artificial neural network (ANN) technique is a learning algorithm that can remove some of these limitations and can be applied to predict PPV. In this paper an ANN model is developed for prediction of blast vibration using 248 data records collected from three coal mines with diverse geomining conditions. The correlation coefficient between measured PPV and model output was found to be 0.96 and the average error percentage 11.85. The ANN model output was compared with the output of three empirical models that are widely used for prediction of PPV. The correlation coefficient between the PPV predicted by an empirical model and measured PPV data was 0.63 and the relative error percentage 38.47. This result demonstrates the superiority of the ANN model compared to empirical blast models. By using site-specific structural discontinuities as input the model performance can be further improved. Sensitivity analysis and 3D plotting were used to gain further knowledge about blast-induced ground vibration. IntroductionIn an opencast coal mine explosives are used for fragmentation of coal and overburden. If the explosive energy is not fully utilized it causes blast-induced ground vibration, which may damage nearby structures. Ground vibration is expressed as peak particle velocity (PPV). During different stages of mine planning and operation, it is necessary to use a ground vibration prediction model for blasthole design. Selection of the modelling technique is crucial. Mathematical and statistical modelling techniques have limited application because of the lack of explicit knowledge about the complex mine blasting system. Vogiatzi (2002) highlighted the problem of multicollinearity in case of statistical modeling techniques. Mutalib et al. (2013) stated that mathematical models are unable to capture the nonlinear relationship between several blasting-related parameters due to the complexity of the model input data. However, the difficulty involved in modelling complex blast vibration problems can be removed by adopting an alternative soft computing modelling approach. One of the soft computing techniques is the artificial neural network (ANN). Ragam and Nimaje (2018) developed an ANN model for predicting PPV using six input variables. Kosti et al. (2013) stated that the conventional predictors fail to provide acceptable prediction accuracy. They showed that a neural network model with four mine blast parameters as input could make significantly more accurate on-site predictions. Sayadi et al., (2013), using a database from Teheran Cement Company limestone mines, found that a neural network resulted in maximum accuracy and minimum error. Khandelwal and Singh (2009) developed an ANN model using 150 data records from an Indian coal mine with site-specific rock characteristics and geomining setting. Khandewal and Singh (2007) built a ground vibration prediction model for a magnesite mine using four prediction variables with 20 data records. Kamali and Ataei (2010) predicted PPV in the structure of the Karoun III power plant and dam using an ANN. El Hafiz et al. (2010) evaluated ground vibration predictors using data from a single-station seismograph at a limestone quarry in Egypt."

Feb 1, 2019

By Oliver Q. Leone

Three electrorefining cells were designed to investigate various factors associated with the electrorefining of reject - grade titanium sponge . Operation of the cells provided information on cell design as well as on how design and operating variables affected the quality of the titanium product . A sodium chloride - titanium chloride electrolyte was used , and the electrolyte chambers had capacities ranging from 400 to 3,500 pounds of molten salt . Major factors investigated were electrolyte composition , temperature and useful life , effect of various cathode shapes and materials of construction , methods for removing cathode deposits , effect of current density and cell potential , and the mechanics of deposit growth and crystal morphology . One of the cells was in intermittent operation over a 4 - year period and produced 2 tons of refined titanium . A product with a hardness of 80 or less Bhn (Brinell hardness number ) was consistently and easily obtained . Some metal with a hardness of less than 60 Bhn was produced . In one of the cells in which the electrolyte was held at operating temperature with an internal heater an ac input of 25 kw maintained 3,500 pounds of electrolyte at 850 ° C , but with an external heater 35 kw was required to maintain 400 pounds at 850° C.

Jan 1, 1964

By Alexandre de Freitas Gomes de Mendonça, Leonardo José Silva de Oliveira, Rodrigo Seara Martins, Rodrigo Madrona Dias

No lingotamento contínuo, o pó fluxante é responsável pela formação de uma escória líquida no molde que formará um filme de escória entre a placa de cobre e a pele solidificada. As principais funções do filme são lubrificar e moderar o fluxo térmico no molde. Em particular, para aços com tendência ao agarramento, objetiva-se uma escória que potencialize uma extração térmica mais intensa em relação às escórias aplicadas em aços com tendência à depressão. O índice de basicidade do pó fluxante é o parâmetro que afeta diretamente a resistência térmica do filme de escória e, por consequência, a espessura da pele solidificada na saída do molde. Com o trabalho investigativo das melhores práticas, reduziu-se o índice de basicidade em 16,8% dos pós fluxantes aplicados em aços ultra baixo carbono obtendo um aumento de até 10,1% no fluxo de calor no molde. Além do aumento na espessura da pele solidificada, esse resultado também influenciou na estabilidade do nível de aço do molde e na qualidade superficial de placa.

Oct 1, 2019

By L. I. C. Fernandez, E. B. Ferreira Filho, L. G. Pedroti, L. G. Justino, W. E. H. Fernandes, R. C. S. S. Alvarenga

More and more industries have been concerned with the disposal of the wastes generated in their production processes, once this generates a positive impact, both visual and economic enterprise, no more needing to have resources for transport and final disposal of wastes. In this context, and seen the importance of the Portland cement a sa building material, which aims the creation of an ecological cement from the mix of two wastes, the grits, which is a waste generated in pulp production, and the granite beneficiation waste. It proceeded initially with the chemical and physical descriptions of the wastes. Five mixtures, varying the percentages of the wastes and the preparation method of the raw materials, were prepared. After,the blends were sintered in a muffle furnace at 1300 °C for 15 min, forming new compounds that were compared with national cements, according to the Brazilian technical standards. It was concluded that the sintering of the product obtained satisfactory results, presenting good binder characteristics, however, some parameters were outside the limits for common Portland cements such as rapid setting time, large expandability and low compressive strength.

Mar 1, 2017

By V. L. Eardley-Wilmot

Introduction We are all familiar with the bright and attractive colours of the roofs of our suburban houses and country cottages, but few of us fully appreciate the complex and highly technical nature of the business which produces these roofings. Roofing granules consist of small broken particles of certain types of rocks, burned clay products, or slag. They are used either in their natural state or artificially coloured and are affixed onto one surface of asphalt sheeting. Their main functions are to protect the roof against external fire hazard, prolong its life, and enable it to withstand extremes of weather over a period of years without deteriorating. Pleasing designs and colours are added attractions. The reverse, or inner side, of the sheeting is coated with a film of talc or fine mica to prevent it sticking when rolled up for convenience of handling for transport. The finished sheets or strips are cut into a variety of shapes for roofing shingles, or for sidings which resemble rows of bricks separated by mortar. In Canada, the consumption of roofing granules has increased fourfold in the past decade and indications are that the industry will continue to expand. At present, fourteen plants are engaged in manufacturing granule-coated roofings, but, apart from a relatively small output of natural granules by two producers in British Columbia, only one eastern producer makes both natural and coloured granules in Canada, and these only for its own use. The annual consumption is now over 77,000 tons of roofing granules valued at more than $1,600,000, but about 62 per cent of the tonnage is imported. It is thus apparent that the production of Canadian-made granules, both natural and coloured, could be considerably increased. This paper is presented in order to give an outline of the industry and at the same time to point out its difficulties and pitfalls.

Jan 1, 1946

By T. Beamish, I. Vasilev, T. Nikolov, E. Marinov, D. Kirilov, P. Barrios

In April 2005, Umicore Copper de-merged from Umicore Group and created a new independent Copper company called Cumerio. As a separate company, Cumerio is a major European copper smelter and refinery and a leading producer of copper products such as wire rod, billets, cakes and specialty rod with a total production capacity of copper products in excess of 500,000 tpy with production plants in Belgium, Italy and Bulgaria. The Pirdop Smelter is the only state-of the-art smelter in South East Europe and it makes Pirdop the natural hub for the copper industry in the region. In order to be competitive in the international market the main challenges facing Cumerio are to maintain its low cost structure and to achieve higher production volumes while reducing its impact to the environment and striving for continuous improvement of the production process. Cumerio's state-of-the-art smelting facility in Pirdop has recently increased the anode production capacity to 250,000 tpy by the installation of the third evaporative cooler on the converters section that allows operating with three-hot converters. In April 2007 a general shut-down for repair and modification on the Flash Smelting Furnace and Waste Heat Boiler is envisaged. At this time a revamp of one of the existing Sulphuric Acid Plants is planned, resulting in a further copper capacity increase to 275,000 tpy with modest Capex. In 2005 Cumerio received from the Bulgarian Ministry of Environment and Water the Complex Permit under the EU IPPC criteria. Accordingly an Environmental Compliance Program was defined targeting a large reduction in the secondary emissions. The system will be commissioned in May 2007. In order to better integrate the smelter and refinery in Pirdop and to respond to the growing demand for cathodes in the region, a new state-of-the-art Electrolytic Refinery with an installed capacity of 180,000 tpy will replace the existing refinery. The new refinery is expected to be fully operational as from early 2008. This paper describes the challenges and the projects.

Jan 1, 2007

By F. Lynwood Garrison

Except in the old Catalan forge, or its modifications, attempts to make iron and steel directly from ore in a practical and economical manner have failed so frequently and completely that such schemes are looked upon with justifiable distrust. Without exception, all have failed from one cause or another, although in some instances every indication of a practical success was manifest in the beginning. It is, therefore, necessary to carefully examine and consider every detail affecting the process, or more properly, furnace, under consideration. This I have done to the best of my ability during a long visit to Russia last summer, and after satisfactorily observing the practical success of the furnace in the iron works of Count Stroganoff at Dobriansky in the Government of Perm, I decided to investigate as completely as possible the history of similar furnaces in Finland and Russia. These data, sifted and verified with the greatest possible care, form the substance of the present paper.* An illustration on page 321 of Percy's Iron and Steel shows the old type of Osmundssmide or harkugnar, which has been in use in Northern Europe since pagan times. Fig. 1 shows a furnace of this kind. It should, perhaps, more properly be called a high-bloomary furnace or forge, the Swedish word hark meaning bloom or loupe. It was with this type of furnace that Mr. Husgafvel began his experiments at Porsaskoski in 1875. Attempts to obtain better results with larger furnaces of this type were failures, as every bloom or loupe obtained necessitated blowing out the furnace with a consequent large waste of fuel. A larger furnace of course increased this waste with no corresponding advantage. A movable hearth of threeeighth inch iron, lined with a mixture of clay, quartz and lime, was next tried, but in consequence of the frequent repairs of this lining,

Jan 1, 1888

By Basil B. Zavoico

PRODUCTION of crude it in the United States during 1939 totaled about 1.255,776,000 barrels, an average of 3,440,482 barrels per day, 3.41 per cent above the 1938 output of 1,214,355,000 barrels but 1.83 per cent below the record pro¬duction of 1,279,160,000 barrels, in 1937. However only the two-week shutdown of oil fields in the Southwestern States in August and September prevented the domestic crude production from establishing an all-time record in 1939. Demand for all petroleum products for the first ten months of 1939 showed an increase of 7.04 per cent over the similar period of 1938. Domestic demand for all petroleum products was particularly benefited by the increasing industrial activity, advancing 8.37 per cent above the like period of the preceding year equivalent to a volume increment of 256,810 barrels per day; with motor-fuel demand gaining 5.83 per cent and demand for all fuel oils gaining 12.15 per cent over the corresponding period of 1938. The export demand for the first ten months of 1939 was slightly below the export movements during the same period of 1938, declining 0.56 per cent. The European war was a major factor in 1939 for the petroleum industry in the United States, even if, at the end of the year, the war had not yet resulted in the expected large shipments to England and France.

Jan 1, 1940

By W Frint

An area in Southwestern Wyoming is rapidly becoming the soda ash capitol of the world. Starting only 20 years ago from a unique deposit of trona, the out-put has rapidly increased until now about half of the soda ash produced in the United States comes from this area. Chemically, soda ash is sodium carbonate, a large tonnage, widely used alkali. The largest single industrial use is in glass manufacture, where 25 tons of soda ash are used in producing 100 tons of glass. Other big users are the detergent and chemical industries. The trona deposits in the Green River basin of Wyoming, were formed about 75 million years ago as part of a geologic period when an ancient lake alternately went through periods of being a large fresh water or smaller brine lake. Today these deposits lie from 800 to 3000 feet below the surface in a semi-arid, almost desert region just west of the Rocky Mountain Continental Divide at an elevation of 6200 feet. In this area there is a prevailing westerly breeze and almost every afternoon the velocity reaches very windy conditions. Rainfall is minimal, being only 6-8 inches of moisture per year with an evaporation rate exceeding 24-inches. Most of the moisture comes in winter snows or summer thunderstorms. Temperatures are low with below zero weather dur¬ing most of the winter and early morning frost is not uncommon during the summer months. There are many trona beds varying in thickness from a few inches up to 15 feet. The deposits now being mined vary from 8 to 10 feet in thickness. The ore is mined by driving tunnels either via conventional explosives or with continuous boring machines. It is transported to the shafts via conveyor belts

Jan 1, 1972

By B Chapman, R Nievergelt, J Hill

A major component of Sydney’s new South West Rail Link project is the Hume Highway Underpass (HHU), an 80 m long twin track mined tunnel excavated at a depth of just 5 m below the pavement of the Hume Highway; one of Australia’s busiest road corridors.In order to ensure a safe and efficient construction of the underpass without disruption to the Hume Highway traffic, design of the HHU required specific focus on the prediction and control of ground movements. This paper describes the design and construction solutions adopted in response to these challenging constraints. The paper also provides discussion on the observed behaviour of the underpass during construction and the results of a back analysis that was undertaken during construction.CITATION:Hill, J, Nievergelt, R and Chapman, B, 2014. Design and construction of Sydney’s South West Rail Link Hume Highway Underpass, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 375–386 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By George S. Rice

"The emission of hydrocarbon gases from coal beds and contiguous strata causes many accidents in coal—mine workings, the number of fatalities so caused being second only to those due to falls of roof. Gases tend to increase in amount with depth of coal mining, hence the danger of explosion is increased with depth. The pressure of the gas in virgin—coal areas at a distance from mine workings likewise tends to increase with depth from the surface, probably due to corresponding increase in hydraulic head and possibly, when the gas is held in nonporous formations, to greater ground pressure. The rise in gas pressure with depth under usual conditions is shown in wells drilled from the surface and in some coal fields in drill holes into the face of workings; however, under normal conditions of coal formation gas does not issue into workings under high pressure because the coal and adjacent strata have many bedding and joint planes which allow the gas to escape freely at the face of the workings. The rare occurrence of instantaneous outbursts of gas, with violent effects referred to later, constitute the exception.Variations of volume and pressure of fire-damp or methane found in different coal beds by wells at a distance from mine workings, are analogous to variations in volume and pressure of natural gas found in different gas and oil sands, although in general the pressure tends to increase with the depth. Sometimes, however, in tight sands higher in the formation the pressure of gas therein is abnormally high, and on drilling the well deeper gas in the lower strata may be found at lower pressure."

Jun 1, 1934

By W. S. Landers

Nine high-volatile bituminous Utah coals were carbonized singly and in blends with low-and medium-volatile bituminous coals. Of the 9 coals, 2 are in commercial use as the base coals in blends that produce industrially accept-able metallurgical coke, while 7 are regarded as weakly coking and are not used commercially in coking blends. The carbonization tests were made in a la-inch diameter, cylindrical retort, using 50-pound charges. Sunnyside coal blended with autogenous char generally produced larger and stronger coke than was yielded by straight Sunnyside coal. The volatile matter of the char and the concentration of the char in the blend appear to be important parameters influencing coke size and strength. A blend of 10 per-cent autogenous char of 7.2-percent volatile matter with Sunnyside coal yielded coke that was larger, stronger, and of higher apparent specific gravity than coke produced from an industrial coke oven blend consisting of 15 percent medium-volatile coal and 85 percent Sunnyside coal.

Jan 1, 1967

By Sydney H. Ball

I. INTRODUCTION. DURING the past 50 years the attention of mining-men has been turned to Africa, and within the past decade prospecting-expeditions sent into Central Africa have resulted in the opening-up of several mines. Having recently spent two years in the Belgian Congo for the Société Internationale Forestiere et Miniere du Congo, it is our purpose to outline briefly the mining-conditions in that part of Central Africa. Before it became, in 1908, a Belgian colony, this region was known as the Congo Free State. II. LOCATION AND AREA. The Belgian Congo lies in southwestern Central Africa, west of the continental divide, is illustrated in Fig. 1. It has a coastline of but 20 miles on the Atlantic, but widens rapidly eastward to points 5° north and 14° south of the equator. Its area is 908,000 sq. miles, which is almost one-quarter that of the United States and Alaska, or more than one and one-half times that of Alaska. Stated in other terms, its area is nearly one-third that of the United States, exclusive of Alaska and the insular possessions, or more than that of all the United States east of the Mississippi river. III. TOPOGRAPHY AND DRAINAGE. From north to south, Africa is made up of three topographic elements: 1, the Atlas mountains, a highly-accentuated region

Apr 1, 1910

By J. A. Kost

The contract objective was to evaluate the effectiveness of available dust-control technology for double-drum shearers. Eight underground surveys were conducted to evaluate drum design, drum spray nozzle locations, ranging-arm sprays, water quantity, wetting agents, and cutting techniques. The final report is made up of eight dust-control technique reports, each discussing, details of the individual mine surveys.

Jan 1, 1985

By Chunlin Chen

Nickel-sulfide minerals are normally associated with copper and iron sulfides and often contain a minor amount of valuable metals such as cobalt and detrimental impurities such as arsenic. Metal losses in slag vary from process to process during the pyrometallurgical production of nickel and, depend on the feed composition, slag chemistry and operating conditions. Maximiz the metal recovery is one of major considerations to optimize operating condition for nickel smelting/ converting processes. At the same time, the deportment of minor elements between various phases during nickel smelting is of great importance by smelter operators. The Multi-Phase Equilibrium (MPE) is a thermodynamic package developed by CSIRO for simulating reactions between phases in multi-component and multi-phase systems [1]. Over the years the capability of the MPE model has been extended to cover the behavior of a large number of elements in high temperature systems. The sulfide smelting module of the MPE, which covers the minor elements such as As, Bi, Sb, Pb, Se, Te, Sn, Co and Zn, is capable of modeling the deportment of major and minor elements between various phases during nickel smelting. In this article the application of the MPE model in modelling the nickel smelting process is presented. The modelling results on the majors and minors are compared with the plant data. The deportment behaviour of arsenic in nickel smelting was analysed and the impact of slag chemistry on slag properties was modelled. These results can assist process metallurgists in exploring the optimum fluxing strategy for smooth operation and the potential practices for improving arsenic removal.

By L. Micale

In May of 1986, the Arizona Legislature passed comprehensive environ-mental legislation called the Environmental Quality Act (the Act). The Act focuses on ground water protection and addresses drinking water quality, aquifer protection standards, requirements to apply technology to reduce discharges, and a state Superfund program.

Jan 1, 1988

By Thomas M. Barczak

This U.S. Bureau of Mines (USBM) report evaluates the load supporting characteristics of grout columns used as point supports for mine subsidence abatement. The cone-shaped columns were constructed with sodium silicate and cementitious grout in both wet and dry environments. The scope of work included the testing of seven full-scale grout columns in the USBM's Mine Roof Simulator from which the load-deformation and failure characteristics were determined. The performances of grout columns are analyzed with respect to (1) the amount of roof contact established during column construction, (2) shape effects produced by the truncated cone geometry, (3) size effects in reference to grout strength and full-scale column capacity, (4) the effect of wet environments on grout strength, (5) the effect of the sodium silicate on the grout strength and full-scale column behavior, and (6) the stiffness of the grout column. Limited tests were also conducted on cylindrical columns constructed in fabric bags. Recommendations for point support construction using sodium silicate technology and the need for additional research to develop improved containment devices for column construction are addressed in the report.

Jan 1, 2010

By Cris Sideco

This paper describes the concentration processes of the Sullivan. Concentrator, including crushing , transportation, sink-float, grinding , flotation and dewatering. Handling of hot muck has had a deleterious effect on most of the processes, resulting in significant operating problems and poorer metallurgy. These problems are described -in detail. THE SULLIVAN CONCENTRATOR is situated in Kimberley, high up in the Purcell Range of the Selkirk Mountains, at an elevation of 3,600 feet, approximately 4 miles from the Sullivan Mine (see Fig. 1). The original plant went on stream on August 23, 1923 at a designed capacity of 2,500 tons per day. This has been increased in stages to its present rated capacity of 11,000 tons per day. The latest stage was in 1949, when several major projects, including the underground crushing plant, the sink-float plant and the installation of a rod mill, were completed. Some 112,800,000 tons of ore have been treated in this concentrator to November 1975. The plant started on a 48-hour/ week schedule, but was reduced to 44 hours/week in October 1946 and down to 40 hours/week by the end of 1949. Except for a 6-month period in 1952 when the mill operated continuously, the 40-hour/week, Monday to Friday schedule was in effect.

Jan 1, 1977

By A Penney, M J. Pascoe, R M. Stephenson

The empirical McCracken and Stacey stability and risk assessment method has been in use for more than 20 years to assess geotechnical stability issues for raise bored shafts. The methodology has been applied with various levels of success. Increasingly, trends in mining and civil tunnelling have been towards larger diameter, single pass, raise bored shafts to rapidly provide means of ventilation, material movement (ore passes), or emergency egress. Identifying and assessing potentially problematic zones before raise boring commences can allow for appropriate risk-based decisions on construction, or to investigate alternative solutions. The implementation of a proactive solution to raising through an identified weak zone is preferred to the application of an engineered solution to an area subjected to substantial instability or failure. Methods for investigating potentially problematic areas are discussed in this paper based on AMC’s benchmarking data. Proactive investigation programmes resulting from these investigations are also discussed. Previous publications discussing the benchmarking data have concentrated on Australian case studies. Increased efforts and recent updates have been made to expand the database to include international case studies. This has provided further refinement of lower bound ‘raise bore rock quality index’ (QR) values, and various rock mass parameters for stability assessments. CITATION:Penney, A, Stephenson, R M and Pascoe, M J, 2018. Raise bore stability and risk assessment empirical database update, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 434–445 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By M. King Hubbert

"The present large-scale use of energy and power by the human species represents a unique event in the billions of years of geologic history. Furthermore, in magnitude, most of the development has occurred during the present century. In the United States, the peak in the rate of petroleum production occurred in 1970 and that for natural gas is imminent. The peak in the world production of crude oil is expected to occur at about the year 2000 and that for coal production at about 2150 or 2200. For other sources of energy and power, water power, geothermal power and tidal power are inadequate to replace power from fossil fuels. Nuclear power, based on the breeder reactor and utilizing lowgrade deposits of uranium and thorium, has a larger potential than the fossil fuels, but it also constitutes a large perpetual hazard. The largest source of energy available to the earth is solar radiation. This source has a life-expectancy of a geologic time scale, is nonpolluting and is larger in magnitude than any likely requirements by the human s pecies. In consequence of the large supplies of available energy, the period since 1800 has been one of an unprecedented exponential industrial growth. This also has been accompanied by a world-wide ecological disturbance, including that of the human population. It can easily be seen that such a period of growth must be ephemeral in character and, in fact, is now almost over. One aspect of this transition from a state of exponential growth to a state of nongrowth is the present alarm over an ""energy crisis."" Actually, the world's present problems are by no means unmanageable in terms of present biological and technological knowledge. The real crisis confronting us is, therefore, not an energy crisis but a cultural crisis. During the last two centuries, we have evalved what amounts to an exponential- growth culture, with institutions based on the premise of an indefinite continuation of exponential growth. One of the principal consequences of the cessation of exponential growth will be an inevitable revision of some of the tenets of that culture."

Jan 1, 1973