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By Thomas Schwind, Pamela S. Moran

For short tunnels, a reinforced cast-in-place lining is not economical and shotcreteis a logical substitution. In the past, reinforced shotcrete linings have been constructed with lattice girders and welded wire fabric. For the Russia Wharf Tunnel in Boston, MA, the Contractor, with the help of the Dr. G. Sauer Corporation offered the MBTA a VECP to substitute the reinforced cast-in-place concrete lining with a steel fiber reinforced shotcrete lining. The challenge was to adequately model the ductility of the steel fiber reinforced shotcrete and to test the shotcrete prior to and during construction to assure quality control. To our knowledge, this type of numerical simulation has not been used on any other tunnels in the US.

Jan 1, 2005

By G. R. Addie

"In February, 1975, the President of Georgia Iron Works Company, Mr. Tom Hagler decided to build a new hydraulic laboratory to water performance test all of the companies' centrifugal slurry pumps.Equipment procurement started in March, 1975, by ordering of a mini computer data acquisition system.Work commenced on the lab in July, 1976, by erection of a Butler Building and the laying down of a 20,000 gallon concrete sump.By late October, a facility compromising two water test loops of 8"" and 18"" pipe diameter was in operation carrying out head quantity and suction performance tests on pumps up to 16"" in size.In August of the following year, an 8"" diameter pipe slurry loop was installed to enable pipe friction and deposition velocity of a slurry to be measured in an 8"" inside diameter pipe.With the encouragement of Reserve Mining in Minnesota and IMCC in Florida, this was followed in March, 1978, by the addition of over 300 feet of 18"" diameter pipe to make up an 18"" diameter pipe slurry system complete with head loss and deposition velocity observation sections.The office and shop areas of the lab were again expanded in April, 1978, to provide further expansion to the test sections and staff facilities."

Jan 1, 1980

By Richard C. Moore

The U.S. Bureau of Mines contracted a study to review the air and water monitoring requirements of five Federal environmental acts (the Federal Water Pollution Control Act, the Safe Drinking Water Act, the Clean Air Act, the Surface Mining Control and Reclamation Act, and the Resource Conservation and Recovery Act) and to compile information on the currently available monitoring instruments. A literature review of the acts and their associated regulations was conducted to determine applicability to the mining industry as well as any air and water monitoring requirements. In addition, an industry search and literature review was performed to assess the instrumentation available to comply with the monitoring regulations. Based on this research, the instruments are classified by general applicability to air, surface water, or ground water monitoring, then catalogued by monitoring parameters. A discussion is provided on recommended and innovative monitoring techniques.

Jan 1, 1981

By Herrmann Flor

In steelmaking process, where up to 70% of variable cost of finished product is already incurred, energy and refractory costs account for 45-50% of the cost of production of crude steel and contribute significantly to the carbon footprint of the end product. Any attempt to control and reduce these costs will automatically lead to more competiveness and reduced carbon emissions. Leading the technology for ECOPLANT (characterized by the fact that the economic and ecological benefits are integral part of our products), SMS has developed innovative solutions which can be applied to both new and existing plants alike. This paper reviews one of the electrical and automation concepts. Tackling the secondary gas cleaning system and hence being applicable to almost all steel plants, the X-Pact® Gas Cleaning Assistant optimizes the control of individual dampers based on modelling of fluid resistances of ductwork in gas cleaning system. It guarantees the best dust removal from work place at minimum energy consumption.

Oct 30, 2017

By B. H. Bergstrom

The Gaudin-Meloy1 size distribution equation requires the evaluation of two constants, xo and r. The common log-log representation of a screen analysis as cumulative weight percentage passing versus size, readily yields the required constants as illustrated for curves A and B in Fig. 1. The 100% passing (y = 1.0) size is simply x,. If the straight portion of the curve be extrapolated to the 100% passing (y=1.0) abscissa, the intercept is the Schuhmann size modulus, k. The ratio of xo to the size modulus, k, is r as shown: The Gaudin-Meloy equation requires that the slope, a, of the size distribution approach unity in the finer sizes, as is the case for curves A and B. Often distributions are better characterized by slopes other than unity. The schuhmann2 equation is able to represent these distributions if the upper portions of the curves are ignored. Empirically, the Gaudin-Meloy equation can be modified to yield slopes other than unity by writing it as Here, a is the familiar Schuhmann slope, and xo is the 100% passing size. The value of r is still given by Eq. 2. Eq. 4 with its easily determined constants is more versatile than either the Schuhmann or the Gaudin-Meloy equations, since a wide variety of size distributions can be closely described. It is easier to fit than the Rosin-Rammler3 equation, and has the advantage that the top size, x,, is finite. REFERENCES A. M. Gaudin and T. P. Meloy: Model and a Comminution Distribution Equation for Single Fracture, AIME Transactions, 1962, Vol. 223, pp. 40 to 43. R. Schumann, Jr.: principles of comminution, I., size Distribution and Surface Calculations, AIME Technical Publication No. 1187, 1940. P. Rosin and E. Rammler: The Laws coverning the Fineness of Powdered Coal, J. Inst. Fuel, 1933. Vol. 7, p. 29.

Jan 1, 1967

By R. N. Powell

The Pipeline ore body was discovered in March 1991. The construction of the new mine and mill did not start until early March of 1996. Upon completion of permitting and corporate project approval, the 289 million USD project was “fast tracked”. The commissioning began 11 months after start of construction and the project ended 40 million USD under the budget figure. The objective of this paper is to review and highlight the Pipeline Project history from discovery, design, lawsuits, permitting, and re-design through to current - 1998operating practices. Particular emphasis will review the process design, design mistakes, and design successes. The paper will review project history, feasibility, design concepts, operator training, construction, financial and the current operation. Additional discussion will review what design features worked and which did not work within the process plant.

Jan 1, 1999

By M. King Hubbert

In 1856 Henry Darcy described in an appendix to his book, Les Fontaines Publiques de la Ville de Dijon, a series of experiments on the downward flow of water through filter sands, whereby it was established that the rate of flow is given by the equation: q= - K(h2- h2)/I1 in which q is the volume of water crossing unit area in unit time, I is the thickness of the sand, h1 and h2 the heights above a reference level of the water in manometers terminated above and below the sand, respectively, and K a factor of proportionality. This relationship, appropriately, soon became known as Darcy's law. Subsequently many separate attempts have been made to give Darcy's empirical expression a more general physical fornzulation, with the result that .so many mutually inconsistent expressions of what is purported to he Darcy's law have appeared in published literature that sight has often been lost of Darcy's own work and of its significance. In the present paper, therefore, it shall be our purpose to reinform ourselves upon what Darcy himself did, and then to determine the meaning of his results when expressed explicitly in terms of the pertinent physical variables involved. This will be done first by the empirical method used by Darcy himself, and then by direct derivation from the Navier-Stokes equation of motion of viscous fluids. We find in this manner that: q = (N4(p/p)[g - (l/p) gradPI = WE, is a physical expression for Darcy's law, which is valid for liquids generally, and for gases at pressures higher than about 20 atmospheres. Here N is a shape factor and d a characteristic length of the pore structure of the solid, p and IL are the density and viscosity of the fluid, a = (Nd2)(pip) is the volume conductivity of the system, and E = [g - (l/p) grad p] is the impelling force per unit mass acting upon the fluid. It is found also that Darcy's law is valid only for flow velocities such that the inertial forces are negligible as compared with those arising from viscosity. In general, three-dimensional space there exist two superposed physical fields: a field of force of charucteristic vector E, and a field of flow of vector q. The force field is more general than the flow field since it has values in all space capable of being occupied by the fluid. So long as the fluid density is constant or is a function of the pressure only, curl E = 0, E = - grad F where F = gz + dp/p The field of flow, independently of the force field, must satisfy the conservation of mom, leading to the equation of continuity div pq = — f ap/at , where f is the porosity, und t is the time. For steady rnotion ap/at = 0. and div pq = 0 .

Jan 1, 1957

By G. Tiravanti

A recurrent concern in mining operations is how to deal with the large volumes of fresh water used which in turn generates large volumes of effluents that have to be treated. Water treatment can focus in one of two main strategies: treat the effluent as it is produced, or use a simulation tool to optimize water use in the process and reduce volume of effluents, contaminants concentrations, operational costs, and so on. This article shows a successful tool developed in Matlab-Simulink® that allows modelling a mining process and simulating potential improvements to evaluate the results. This tool has been proven in Cu-Mo operations and recently it has been used in poly-metallic operations. This article reviews the 4 Key Steps required to achieve our goals: a) Elaboration and verification of the mining Operation?s Block Diagram, based on a field survey; b)Model construction and input flows and qualities in selected streams; c)Model Validation and Simulation of new alternatives like recirculation, changes in reagents and dosage, partial treatment, flows merges/separation, and others; d)Development of the Optimal Solution which consists on determining the CAPEX and OPEX.

Feb 27, 2013

The individual or company director who ignores his or her obligations under the Resource Management Act 1991 and under the proposed hazardous substances legislation, ignores them at their peril. Two recent cases in Canada and the United Kingdom concerning environmental offences under similar legislation illustrate the risks well.

Jan 1, 1993

By A Tawadrous, P D. Katsabanis, S Kim

A series of small scale tests, have been performed to establish the effect of powder factor and initiation timing on the grindability of rocks. The blasts were performed in high quality granite blocks, which were cut from stone prepared by dimensional stone quarry operations. Three different types of granite, Barre, Stanstead and Laurentian, were tested. The charge consisted of detonating cord placed in five holes with water as a coupling medium, or concentrated charges of equal mass of high exolosive, fully stemmed or air decked. Powder factor was varied from 0.39 to 1.17 kg/m3. Charges were detonated simultaneously or with a small delay and in some experiments, detonation waves collided in the middle of each borehole. All fragments were collected and screened, and drop weight impact tests were performed on selected size fractions, using different levels of impact energy, to calculate the resistance of the rock to impact breakage. The work index of some of the blasted samples was measured using standard Bond mill grindability tests. The experiments generally showed increased softening of the rock with powder factor, manifested by the increasing initial slope of the relationship between t10 and impact energy. The rate of change of the initial slope decreased with increasing powder factor. Changes in the work index were small and consistent in trend with the results of the single fragment impact characterization tests. Charge configuration, timing as well as in-hole collisions of detonation waves affected the initial fragmentation but had little effect on the impact breakage of the samples.

Jan 1, 2009

CONTENTS PAGE Bronze Bearing Metals. By G. H. CLAMER 1729 Pennsylvania Railroad Anti-friction and Bell Metals. By F. M. WARING . . 1733 The Tin-plate Industry. By D. M. BUCK. Discussed by G. H. CLAMER, J. W. RICHARDS 1735 The Aluminum Bronze Industry. By W. M. CORSE 1738 Bronzes, Bearing Metals, and Solders. By G. K. BURGESS and R. W. WOODWARD. Discussed by G. H. CLAMER, R. T. ROBERTS 1742 Babbitts and Solder. By G. W. THOMPSON 1751 The Cadmium Supply Of the United States. By C. E. SIEBENTHAL. Discussed by M. L. LISSBERGER, C. W. HILL, F.- F. COLCORD . . .. . . . . 1752 Solder, Its Use and Abuse. By M. L. LISSBERGER 1759

Jan 12, 1918

The Kaiser Aluminum and Chemical Corp. announced plans to raise June ingot prices by 4 cents to 57 cents per pound. Producers? April value for 99.5 percent unalloyed aluminum ingot was at 53 cents per pound. Domestic merchants last month were quoting the metal at 48-49 cents per pound. Primary aluminum producers began restarting production facilities following the settlement of the coal strike. Noranda Aluminum Inc. recalled workers to prepare potlines for production at its plant at New Madrid, Mo., which had closed February 14, 1978 due to the shortage of coal. Eastalco Aluminum Co. resumed full capacity production at its Frederick, Md. smelter where production had been cut by 30 percent. Anaconda Aluminum Co. resumed full capacity production at its Sebree, Ky. smelter.

Jan 1, 1978

By S. M. Spottiswoode

Crush pillars are widely used in mine workings on the Merensky Reef in the Bushveld Complex to prevent panel collapses. Crush pillars are expected to fail as or soon after they emerge from the face and failure should occur non-violently. Unfortunately, violent failure occurs frequently and is said to be the main cause of seismicity associated with mining of the Merensky Reef. Recent work by Napier, Malan, and du Plessis has shown that limitequilibrium quasi-static models are able to simulate pillar failure using three states of strength of rock in pillars, namely intact, residual after failure, and decayed strength after later time-dependent (viscous) weakening. We have previously introduced an additional state of strength to account for the dynamic failure that results in seismic events, and found that this approach could be used to generate synthetic seismic catalogues similar to observed seismicity for deep-level gold mines, where seismicity takes place mostly on advancing faces. The less brittle seam material of the Merensky Reef, compared to the brittle quartzites and lavas of the Witwatersrand reefs, results in little or no face bursting and is modelled with an assumed plastic strain of some 0.005 over an effective stope width of 2 m before failure. When this plastic yield is surpassed, we allow the reef to fail ?seismically?. We show that synthetic seismic catalogues modelled in this way have some of the features of observed seismicity. Analysis is greatly facilitated using our custom-built software that reads the mine?s survey data into a database and presents results in an interactive graphical form.

Jan 1, 2014

By I M. Turnbull

QMAP (the Quarter Million Mapping Programme, 1:250 000 scale) is a geological mapping programme which will build a digital geological database of the whole country and publish maps and books to document it. The programme was established in 1993, following a recommendation by a review panel appointed by the Ministry of Research, Science & Technology, and is funded by the government, from the Public Good Science Fund. The relevance and fundamental value of QMAP lies in the greatly improved geological knowledge it will provide for researchers and other end-users of geological information.   QMAP research involves assessment of previous work, field and laboratory investigations in key areas, and data storage, manipulation and publication using Geographic Information Systems (GIS) computer technology. The QMAP digital database of New Zealand geology will be completed by 2006, as will the series of 21 full colour printed geological maps and accompanying explanatory texts. Two are already completed and published (Kaitaia and Dunedin), and six other projects are well advanced.   QMAP information will also be available in digital form. Next year we hope to expand the scope of the programme to cover the reconciling and linking of many other earth science databases to QMAP, because we believe this will create a powerful research tool. The intention is to develop internet access to the databases, to make the information publicly available.

Jan 1, 1997

In blasting large tonnages of ore or material, the economy of the operation 'depends mainly on the mine manager's judgment in placing the holes to the best possible advantage and in determining the most effective size of hole to suit the conditions and requirements.The placing of holes is often looked upon as a problem involving so many uncertain factors that the application of simple mathematics is impossible. The uncertain factors arise when dealing with strata of different character, in hardness toughness and resistance to shearing.A study of the practice at many mines where all types of strata from hard ore to relatively soft overburden, and even coal, is being mined, suggests that the problem is not as complex as generally believed. There is, without doubt, some uniformity in the amount of burden given to holes of equivalent dimensions, regardless of the material being mined. The reason is simple. With too great a burden hard rock will not break out and soft rock will "bull". The nature of the strata is taken care of by the strength, quantity and distribution of the explosive charge and, to some extent, the spacing of the holes.It is because burdens are uniform in all classes of strata met with in mining, that a formula can be used to design blast hole layouts.The formula introduced in this paper is empirical as it is based on prevailing practice. It has been tested and proved remarkably accurate against every example available to the writer. Many thousands of blast holes, at many different mines, are represented by the examples given in the attached tables; to give further examples would only mean, unnecessary repetition. At the Mount Morgan Mine...

Jan 1, 1952

Since mid-July, most domestic producers have been marketing 99.5 percent unalloyed aluminum ingot at 53-57 cents per pound. Dealers in the United States have recently quoted ingot at 52.3-52.8 cents. On October 2, London Metal Exchange will trade aluminum, selling contracts on a cash and a 3-month basis. New York dealers were quoting August ingot at 52.3 52.8 cents. The Bonneville Power Administration announced that, effective December 20. 1978, electric power rates charged primary aluminum producers in the Pacific Northwest would be increased The increase (equivalent to about 4 cents per pound of aluminum produced) will raise the average rate to about 8.7 mills per kw-hr compared to 3.2 mills per kw-hr.

Jan 1, 1978

By Bin Tang, Suping Yao

In the last decade, the copper industry in China has developed rapidly and attracted the world’s attention. The production capacity of refined copper has grown remarkably from 4.578 million tons in 2010 up to 9.029 million tons in 2018, accounting for about 40% of the global refined copper production. And now, China has become the biggest refined copper producer in the world. This paper summarizes the application of modern copper metallurgical technologies such as Outotec flash smelting/converting technology, Cyclone smelting technology, TSL (ISA/Ausmelt) smelting/converting technology, Jinfeng side blown smelting and Baiyin side blown smelting technology, Chifeng side blown smelting and continuous top blown converting technology, SKS bottom blowing technology, Dongying two-step smelting technology, copper electrorefining with high current density, etc. in China’s copper industry, analyzes and compares the characteristics of those technologies and presents the great efforts of China’s copper smelters in adapting to the increasingly strict emission standards and improving economic benefits of copper smelters. INTRODUCTION China has been the biggest refined copper producer in the world for many years. China produced million tons of refined copper in 2018, accounting for 40% of the copper smelting production in the world, and of which, roughly, 70% of the copper concentrate was imported, mainly from Chile, Peru and Australia. ICSG (International Copper Study Group, 2017) shows clearly the position of top 20 countries of copper production and copper mine production (Figures 1 and 2). Blast Furnaces, Reverb Furnaces and Electric Furnaces dominated China Copper Smelting for quite long time till 1980s. The first modern copper smelting technology (flash copper smelting) was introduced into China in 1980s, then followed by Noranda, Ausmelt and ISA. Since then, China copper smelting technology stepped into modern time. Since 2000, old processes (Blast Furnace, Reverb Furnaces and Electric Furnaces) were phased out and replaced by modern smelting technologies. China Copper Production has been increasing dramatically (Figure 3).

Jan 1, 2019

By Anderson Ayres Bittencourt

O monitoramento de sistemas e ativos de automação sempre existiu de forma rudimentar e descentralizada. A análise desses dados tanto quanto sua obtenção é um desafio para as empresas atuais. Foi a partir deste princípio que nosso projeto foi desenvolvido.Este trabalho tem como objetivo demonstrar a solução de Monitoramento online e preditivo implementada na ArcelorMittal Aços Planos da América do Sul, onde desde o início de sua implementação pudemos capturar benefícios operacionais, melhoria dos processos, otimização, eliminação e/ou diminuição de indisponibilidade de plantas, entre diversos outros retornos que serão apresentados.

Oct 30, 2017

By Thomas Barkley

Mining tradition holds that a parallel round underground can not be any deeper than it’s smallest face dimension. ln other words, a mine using a 12’ (3.7 m) high by 24’ (7.3 m) wide room and pillar mine, the deepest pull that can be achieved is plus or minus 12’ (3.7 m). After experience with decking of rounds in a 12’ (3.7 m) diameter shaft to achieve more than 12’ (3.7 m) advance per round, the concept of deepening the pull on horizontal parallel rounds seemed to be a feasible concept. Tests were conducted in a conventional room and pillar metal mine with a round size of 12’ (3.7 m) high by 24’(7.3 m) wide. Standard rounds were drilled with a 16’ (4.9 m) steel as parallel rounds to an average depth of 14.5’ (4.4 m). The average depth of pull on these rounds was about 13’ (4.0 m). Using the available drilling equipment, 20’ (6.1 m) drill steel was used to drill holes to an average depth of 18’ (5.5 m). Five rounds were drilled and shot with a resulting aven$e pull of 16.2’ (4.9 m) or 90 % of drilled depth. Rounds were designed with decked bum cuts to maximize depth of pull in the cut area An innovative method of de&mining drilling accuraq was used to estimate it’s effect on depth of pull in the rounds. This method used a standard automatic 35-mm camera and scaling to determine the average drill deviation for many of the holes in the rounds.

Jan 1, 2000

What is a nugget effect? In the early development of geostatistics, the term ?nugget effect? was coined for the apparent discontinuity at the beginning of many semivariogram graphs. This name was chosen to reflect the large differences found between neighbouring samples in ?nuggety? mineralizations such as Wits gold reefs. Geostatistical theory assumes that the difference between a sampled value and a potential repeat sample at the same location is actually zero. Included in this ?nugget effect? would be true variation between contiguous samples due to the nature of the mineralization, micro-fracturing, nugget or crystal size, and so on. Also included in the nugget effect would be any ?random? sampling variation which might occur due to the method in which the sample was taken, the adequacy of the sample size, the assaying process, etc. Arguments were put forward that ?sampling errors? actually exist at zero distance. Some geostatistical schools actually maintain that the ?nugget effect? is all sampling error. This would imply that ?perfect? sampling would eliminate the nugget effect entirely. There is now a dichotomy both in the geostatistical world and in the software packages provided for geostatistical analyses. It may seem academic to argue over whether the semivariogram model should take a value of zero, a value equal to the nugget effect, or a partial value at distance zero. However, the decision can have a profound effect on both the estimated resource and in our confidence on that resource. Whereas most geostatistical texts define the semivariogram model as taking the value of zero at zero distance, others imply that the full nugget effect should be used at zero distance. For example: ?The nugget effect refers to the nonzero intercept of the variogram and is an overall estimate of error caused by measurement inaccuracy and environmental variability occurring at fine enough scales to be unresolved by the sampling interval3 ?Christensen4 has shown that the ?nugget effect?, or non-zero variance at the origin of the sernivariogram, can be reproduced by a measurement error model ?The nugget effect is considered random noise and may represent short-scale variability, measurement error, sample rate, etc.5. In many training texts and Web courses, the definition of the semivariogram is ambiguous as the formulae for semivariogram models is not actually specified at zero distance6,7,8.

Jan 1, 2010