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By H. R. Shell

Fluorphlogopite mica was synthesized from inexpensive and abundant olivine, clay, feldspar, and sand (plus K2SiF6). The raw materials were melted in crucibles and in an internal resistance electric furnace. The melts yielded >95 percent mica. The major difficulty encountered was incomplete settling of the highly dispersed ferroalloy. This problem was not completely solved. Reducing agents tried in melts of 300 to 400 pounds were carbon, silicon, and silicon carbide. Carbon slowly reduced the iron of the raw materials, with much fuming. Silicon apparently was oxidized ahead of the melting and was ineffective under the conditions obtained. By far the best reducing agent was silicon carbide. With silicon carbide, fuming did not occur and ionic iron content of the mica flake approached 0 percent. However, even with SiC, the highly dispersed globular iron did not completely separate from the mica portion. The fluorphlogopite made during this investigation should be suitable for metallurgical use. A byproduct ferroalloy containing about 5 percent nickel, 3 to 5 percent chromium, and some cobalt was obtained. Because of the highly dispersed metallic ferroalloy, the mica was not deemed suitable for electrical or electronic uses.

Jan 1, 1962

By N. Charue

An international prediction event was carried out within the framework of a 30-pile testing program organized in a sandy soil in Belgium (Limelette). That program called upon sev­eral testing methods: static load tests, Statnamic testing, and dynamic testing. This paper provides a summary of received predictions and results obtained from the static pile load tests, which were carried up to failure of the instrumented piles. The comparison between predictions is made using load-settlement curves with reference to the results of the static load tests. The predictions are based on a geotechnical approach using an extensive soil investigation program and a dynamic approach using the dynamic load test data.

Jan 1, 2002

By Constantin D. Pitis

Similarly to notions of constant capital/expenses in business or magnetization power for electric motors an energetic base load (E0) is always necessary to set up a mining process. Denominated as ?non-productive energy? or base load, (E0) is a constant component of the entire energy consumption of the process, while another component the ?productive energy? (Ep) is variable, being function of the production/throughput (M). By using these new concepts, the author creates an energetic model proposing a new method of assessing changes in mining processes (throughput) that can reveal possible energy savings (DSM component) or energy losses. Proposed mathematical model of assessing (E0) and energy savings by using ?Marginal Energy Usage Index? (MEUI) enables creation of historical benchmarks and direct on line energetic (efficiency) assessment of mining processes and/or equipments. The paper analyses the case of assessing possible energy savings that can be obtained by: ?? Improving efficiencies of various equipments (by retrofit) ? reducing E0 ?? Improving the process control or other process changes ? reducing Ep ?? Monitoring persistence of the adopted Energy Conservation Measures (ECMs). For the new plant design, the proposed method enables prediction of Customer Baseline in various mine/process configurations. The method could become part of a ?preventive action? in design process by offering a reliable tool of assessing additional financial effort (Incremental cost) when choosing various higher efficiency equipments and/or processes.

Oct 1, 2009

By Jiwei Duan

The energy transferred from a hammer to the pile top is considered as the effective energy in this paper. The effective energy is related to the pile dimensions, soil and pile-soil interface properties. This relation may be expressed as an equation based on the dimensionless theory. The relationship between pile capacity and effective energy was studied by performing a series of wave equation analyses using a commercial software called GRLWEAP (Wave Equation Analysis Program) by GRL Engineers, Inc. The results show that the pile capacity increases with the blow count when the effective energy is constant, however, it has a little change as the blow count is over 100 blows per foot. The pile capacity decreases as the ratio of pile penetration depth to pile diameter increases if the effective energy is constant. The pile capacity will increase as the pile diameter and wall thickness increases if the effective energy is constant. The pile stickout (pile length above the ground surface) does not have a significant effect on the effective energy and may be neglected. Curves for pile capacity versus effective energy are presented to be used for preliminary hammer selection according to effective energy and hammer efficiency. Finally, a case from PDA testing was studied. Measurements of the effective energy and pile capacity by CAPWAP were presented and compared with the results by GRLWEAP.

Jan 1, 2006

By N. Som

The pile capacity in cohesive and granular soils depends on a number of parameters. The values of these parameters as recommended by Indian Standard Code of Practice vary over wide ranges. A designer often finds it difficult to select appropriate values of these parameters for realistic estimate of a pile capacity. The present paper makes a critical review of the values of the parameters given in Indian Standard Code of Practice and suggests a realistic approach to selecting them in the light of recent research.

Jan 1, 1996

By A. Bascetin

Waste materials caused by mining activities are an important environmental problem. Paste technology is a good alternative for waste management because it has many benefits in the aspects of environment, cost and safety. Disposal of process wastes in paste form is an attractive option for waste management, as it eliminates or reduces the risks associated with conventional methods. Due to the geotechnical characteristics of the paste, it is very similar to soil materials. So determining the geotechnical properties of the paste material is essential to durability of the paste. The some important geotechnical properties are compressive strength, porosity, shear strength, hydraulic conductivity, water content, consolidation, etc. In this study, the important parameters and the relation between them were investigated and obtained some results which will affect for optimum design of waste management.

Jan 1, 2012

Detailed investigation was carried out on the dephosphorization of a number of phosphorus-rich manganese or samples of India by leaching with dilute sulphuric acid. Various process parameters like concentration of acid, liquid-solid ratio, temperature of leaching, time of leaching, and particle size of the ore were studied in detail for the three samples of manganese ore from central India, and optimum values were worked out on a laboratory scale. Preliminary studies show that certain ores which are not easily amemlible to appreciable dephosphorization by leaching with dilute sulphuric acid can be made amenable by :roasting to 700-900°C before leaching.

Jan 1, 1974

By T. Hudaverdi

Control of the particle size distribution of a muckpile after blasting is always an important subject for mining industry. Blasting has a significant impact on downstream processes such as loading, crushing and grinding. Improvement of blasting results provides increase in loader and excavator productivity due to increased diggability capacity, and increased bucket and truck fill factors. Suitable and uniform particle size distribution results increase in crusher and mill throughput and decrease in energy consumption in size reduction process. Digital image analysis technique has been used for many years in mining industry in order to determine blast fragmentation. The images of muckpile surface can be used to determine the mean fragment size (x50). The source of digital images can also be haul truck, leach pile, waste dump, stockpile, and conveyor belt. The screening that is conventional method to measure blast fragmentation is time consuming and expensive. Digital image analysis is a cost effective and faster method (1).

Jan 1, 2012

By Andy Alder

The Docklands Light Railway (DLR) Extension to Woolwich Arsenal provides a much-needed public transport link to this area of London. The project includes construction of 5.3mID running tunnels under the River Thames, in ground conditions that proved challenging for the Earth Pressure Balance Tunnel Boring Machine (TBM). The project also includes cut and cover tunnel approaches, an underground station, and an emergency shaft on the bank of the river. Major challenges have included tunneling under sensitive infrastructure, and working adjacent to existing operational railways at Woolwich Arsenal. This paper will describe the design and construction of the project and how these challenges were overcome.

Jan 1, 2008

By Peter Duniam, Stephen John Brace

2000 HIGH-TECH SEMINAR Blasting Technology, Instrumentation and Explosives Applications Orlando,Florida,USA July24-27,200O. Objectives:- After completing this session 1. Explain safety issues 2. Do simple initiation design 3. Describe how the system works 4. Demonstrate scanning, hookup, testing and firing 5. Describe hot to do a post blast check 6. Explain how to treat misfired detonators

Jan 1, 2000

By Zhouhua Jinag

The attempt has been made to manufacture high nitrogen austenitic stainless steels by pressurized electro-slag remelting furnace with maximum nitrogen pressure of 7MPa. To obtain high nitrogen content in steels, the compound electrodes with different nitrogen sources (FeCrN, Si3N4) were prepared. Using the Si3N4 as the nitrogen alloying source, the silicon contents in ingots were prone to be out of the specification range, and the electric current fluctuated greatly and the surface qualities of the ingots were poor. The surface qualities of the ingots were improved using FeCrN as nitrogen alloying source. The sound and compact macrostructure ingot with the maximum nitrogen above 1.0wt% could be obtained. A series of high nitrogen austenitic stainless steels have been successfully developed by this method. The mechanical and pitting corrosion resistance properties of high nitrogen austenitic stainless steels were investigated. The results show that the steels exhibit excellent mechanical and pitting corrosion resistance properties.

Jan 1, 2009

Laboratory and pilot plant investigations aimed at recovering gold as an electroformed sheet from gold eluate and gold leach solutions and slurries are discussed. The electrolytic test work undertaken makes use of high surface area electrodes, in particular nickel-chrome foam metal and activated carbon, as well as ultrasonic activation. The process involves initial gold electrowinning (or adsorption onto activated carbon), followed by gold electroforming, both operations being carried out in a specially designed reactor. The pilot plant work mainly involved the treatment of gold eluate solutions from a South African gold mine containing 600 mg/L Au: some tests were also carried out on gold leach solutions containing 6 mg/L Au. In the former case, very efficient gold extraction onto the foam metal cathode was achieved using electrolysis combined with ultrasonics. The polarity of the gold-loaded cathode was then reversed and, using a replacement electroforming electrolyte, gold was electroformed in situ onto a polished stainless steel mandrel, from which gold sheet was subsequently removed. In the case of leach solutions, pilot plant tests confirmed laboratory findings that in the presence of calcium (resulting from the lime used during the leaching process) no electrowinning is possible. Laboratory tests showed, however, that when sodium (in the form of NaOH or Na2CO3) is added to the leach solution, electrowinning can indeed take place. Alternatively, if a special activated carbon electrode is used (without current), the non-ionic calcium aurocyanide complex is adsorbed on to the activated carbon. When a gold-loaded activated carbon electrode is made anodic in a gold electroforming electrolyte, gold electroforming is feasible, although the efficiency is very low. The possible implications of these developments for gold recovery are further examined.

Jan 1, 2007

By K. Boakye

This paper presents the results of a review of historic blast design practices at the Dragon Products Company, LLC (Dragon) Quarry Operation, along with the results of two different blast design vibration monitoring programs. A blast pattern design modification was initiated to determine if production volume per shot could be increased and highwall instability could be decreased. A vibration monitoring program was undertaken to investigate peak particle velocity (PPV) and relate the data to the blastability of the jointed onsite rock mass, utilizing the relationship between PPV and dynamic stress and strain. The Dragon Quarry Operation has historically used a 6-in. diameter, 14-ft by 14-ft production blast pattern, with blast holes loaded manually using cartridge style explosive products. In 2011, Quarry Operations introduced a 6-in diameter, 16-ft by 16-ft production blasting pattern, using pre-mixed, truck-loaded, bulk emulsion/ammonium nitrate/fuel oil (ANFO) blends. This paper summarizes the results of the blast design modifications, the results of the vibration monitoring data, and describes how production blasting and excavation at the Dragon Quarry has benefited from such modifications.

Feb 27, 2013

By Bengt L. Stillborg

INTRODUCTION This paper summarizes the result of a two and a half year research program. The objective of the research was to develop a fundamental understanding of the Rib-in-Roc method. Through the development of a new model technology, namely three-dimensional physical models which powerfully exploit the results of dimensional analysis Stillborg, Stephansson and Swan (1), it has been possible to establish the contribution to both permanent and immediate stabilization of a large underground opening pre-reinforced by the Rib-in-Roc method. Using the results from these physical models and earlier work by Stillborg and Stephansson (2) and Åkesson (3), a conceptual synthesis is given in this paper so demonstrating the Rib-in-Roc method to be a practical working system of pre-reinforcement. DESCRIPTION OF THE RIB-IN-ROC METHOD To give the reader an idea of how this method of pre-reinforcement is performed, a short description will be given, Figure 1. Before any full-scale excavation takes place an entry is made in the host rock and rib raises are driven around the proposed opening. These raises are made at a spacing that is dependent upon rock quality; an opening in poor rock needs more ribs per length of opening. As the ribs are driven they are used as a site from which very competent rock bolting can be done. As a rib is excavated it is filled with reinforced concrete. Finally after having in this way reinforced the zone around the proposed opening, (a reinforced arch is formed) the displacements are automatically controlled as the opening is being excavated. Using this method openings with a span of 50-60 meters (160-200 ft) and a height of 60-80 meters (200-260 ft) are likely to be realised.

Jan 1, 1979

The rapid advance in the adaptation of scientific knowledge to the treatment of ores, resulting in improved chemical and metallurgical processes, has enormously increased the possibility of working lodes profitably, which a few years ago were passed over as unpayable. By the discovery of chlorination, and later of "Cyanidation," by the highly improved methods of concentration, and by the rapid advance in our knowledge of smelting (for which we are greatly indebted to Americanmetallurgists), and by the gradual replacement of scientifing principles and enlightened management, for rule-of-thumb methods formerly in vogue, many large low grade bodies have been opened, and are now paying dividends, which were,twenty years ago, looked upon as hopelessly unpayable. It has been more especially in these large low grade ore bodies, that modern methods have been benefical; for small lodes must be rich to pay at all, as they cannot be worked on the same gigantic scale, but even in these a percentage of metal is saved which formerly was absolutely lost.To make these large deposits remunerative it is, however necessary to try and find the point of greatest economic advantage, to handle the ore in vast quantities, to erect huge plats to treat it, to substitute automatic appliances for hand labour as far as possible, and to combine several processes supplementary to one another, so that ore which is not amenable to one process, shall be saved, by another; and by doing...

Jan 1, 1901

By Heiner J. Sander

Stanford University operates the National Research Facility which is located at the Stanford Linear Accelerator Center (SLAC) in Menlo Park, California. In order to improve and allow for enhanced experiments, the current facilities required expansion. A1500 foot long tunnel (20 ft wide by 21 ft high) and a 220 foot long underground cavern (49 ft wide by 32 ft high) were excavated through the Ladera Sandstone formation which is an intermediate geo-material with week rock properties. The overburden between surface and crown of the structures varies from 10 to 80 feet. The underground structures were excavated according to the principles of the NATM (New Austrian Tunnel Method). This paper addresses the challenges that were encountered during the construction phase of the project and how construction issues were resolved mutually by the owner, engineer and contractor. The implementation of geotechnical instrumentation, recorded data and interpretations, soil conditions and behavior encountered during construction are also presented.

Jan 1, 2008

By Roozbeh Afzali

Designing an appropriate tunnel blasting pattern reduces the cost of rock breakage and subsequent operations such as loading, haulage and support of tunnels. For that reason, we developed a software that designs tunnel blasting patterns. Using this software, three different tunnel blast design models based on parallel hole cut, namely, Swedish, Konya and Energy Balance, were investigated and compared for a virtual tunnel. Accordingly, blasting patterns were designed, for different cross sections. The trend of parameters such as specific charge and specific drilling as functions of tunnel cross-section was determined for each model. Our results show that, in general, The Swedish model gives lower specific charge and specific drilling compared to other models.

Jan 1, 2008

G. R. Compton (Gold Mines of Kalgoorlie (Australia) Ltd., Fimiston, W. A.) : In congratulating Mr. Hooker upon his resume of Mr Parry's paper I have in mind the fact that he carried out the research into pipe pressures. Hydraulic filling as practised in Kalgoorlie has created world wide interest, with these pressures and percolation being vital points.Early in the 1950s, representatives of the Kolar field were conduGted over the local mines where stopes at depths below 2,000 ft were being filled. The problems of pipe pressures were their main consideration since depths of up to 10,000 ft were envisaged.Mr Krishnaiah and Mr Murthy from the same field are with us today and perhaps we may hear of their experiences with depths of 6,000 ft and long lateral lines.J. Holly (Lake View and Star Ltd., Fimiston, W.A.): There is one phase, which I would like to mention myself, that has been very evident in Kalgoorlie operations. That is, we do not get the percolation properties that are obtained on many other fields in the world, and our tendency here has been to assess the quality of our fill more by its settling rate, i.e. the rate at which we can draw off clear water at the surface of the filling levels, rather than the rate that this water percolates down through the fill before it consolidates.We are tending now to measure the quality of our fill as a settling rate rather than as a percolation rate.Americans talk about percolation rates being the important property: If anyone has any experience on operating with fills with different percolation rates, I think their views would be very interesting to the meeting art this stage. Mr ...

Jan 1, 1965

By J. E. Conley

Available statistics show that the demands of the American chemical industry for sodium sulphate have been increasing slightly in recent years. The supply from domestic sources, particularly In the form of byproduct salt cake from the acid manufacturers, has been tending to decrease due to the growing manufacture of synthetic acid. Both hydrochloric and nitric acids are being synthesized from their elements. The natural result has been that a smaller amount of salt cake is available. Simultaneously, the expansion of the Kraft paper industry, especially in the South, has brought about greater demand for sodium sulphate in that section. This dean is being met by domestic byproduct salt cake, by imported German sodium sulphate made from potash waste liquors, and by favorable situated domestic deposits of Glauber salts and tile anhydrous salt, thenardite. No shortage of natural sodium sulphate exists in the United States, but usually such deposits occur in semiarid regions far removed from transportation facilities and from markets. Moreover, the major portion of the natural deposits is Glauber salt or mirabilite (Na2SO4 ? 10H20), which must be dried or dehydrated in order to meet consumer requirements. The water of hydration represents, roughly, 55 percent of tae total weight of the crude salts and therefore has a very important influence on transportation costs. In marry instances the cost of getting, even the dehydrated product to market is the deciding economic factor. Therefore, the recovery oil production of anhydrous sodium sulphate from plant-.waste liquors or from natural brines of suitable composition might be economically feasible. The U.S. Bureau of Mines, at its nonmetallic Minerals Experiment Station, New Brunswick, N. J., has, for a number of rears, been investigating the commercial possibilities of treating the complex saline mineral polyhalite (K2SO4?NgSO4?2CaSO4?2H20) for the recovery of potash and magnesia. Certain proposed processes (1, 2, 3, 4)4/ yield waste liquors that contain the bulk of the magnesium and sulphate originally combined as magnesium sulphate in the polyhalite molecule. Sodium chloride In limited concentrations is also present, as extensive beds of salt occur in strata overlying the polyhalite deposits. A typical waste liquor would contain:

Jan 1, 1936

By Greaves M. C

X-ray fluorescence spectroscopy used for the analysis of mill samples results in improved control of flotation concentrators.Techniques and equipment for sampling pulp streams, filtration and drying, grinding, briquetting and X-ray fluorescence analysis of samples have been developed.The current methods in use permit the analysis for lead and zinc in six pulp samples within 30 min total elapsed from the start of sampling. The X-ray method gives a precision at least equal to the former routine wet-way assay methods.The equipment is used also for pilot plant control, as a means of solving complicated analytical problems and in the rapid qualitative analysis of exploration samples.INTRODUCTIONIn milling and concentrating operations, classical methods for the assay of lead and zinc have been mainly of use for accounting purposes and for the post-mortem examination of plant operations, but have been of little value for rapid mill control. Where attempts have been made to apply these methods to control assaying, it has been necessary to modify the procedures and introduce short cuts which have tended to reduce their reliability.Even with these shortened procedures, the time taken to obtain a limited amount of information rendered them of little value for the control of milling operations where sudden, large fluctuations can occur. In recent years, a number of new and rapid analytical techniques, based on physical rather than chemical principles, have been introduced.These include direct reading emission spectroscopy, x-ray fluorescence spectroscopy and atomic absorptionspectroscopy.

Jan 1, 1964