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By A. M. Neale

Kriel Colliery has experienced some sub-standard blast results on the overburden. Blast results are considered poor when the fragmentation is too big, back break into the new highwall, capping is experienced and/or excess overburden material is thrown into the void. Poor blasting leads to lower productivity, equipment breakdowns, and poor drilling and blasting results on the adjacent blast, contamination of coal or loss of coal. A simulation was developed in Microsoft Excel to model blasting results while changing various parameters. From the simulation results, it could be seen that a change of blast design could be beneficial. As an example, smaller drilling patterns were simulated (10 m x10 m to 8 m x8 m, and 8 m x8 m to 7 m x7 m in Pit 5 and Pit 6 respectively) in combination with changes in explosives (P700 emulsion vs. ANFO) and drill bit diameter (311 mm vs. 251 mm). The results show that each of the options has a specific scenario that will be most beneficial to the mine. These results are quite specific and subject to variable inputs. The purpose of the example is to demonstrate how the simulation can be used as a tool to asses blast design variations.

Jan 1, 2010

By J. Kempken, R. Degel, J. Kunze, R. König

The FeNi technology is currently dominated by high-power submerged arc furnaces, often designed as smelter as "two-inline-solution". To achieve the intended high efficiency, state-of-the-art design in good correlation with ores and reductants and an integrated layout of the whole plant is of great importance. An introduction will be given to general aspects in the production FeNi, plus a detailed overview of design principles for large FeNi smelters and finally some examples of innovations and research projects concerning Fe-Ni.

Jan 1, 2007

By Frank B. Fulkerson

A study was made of scrap iron and steel in the South Central States in order to determine trends in processing, shipment, and consumption of this important commodity. These data were derived in part from statistical sources and in part by visits to scrap yards and steel mills. Trends in the industry were reviewed. Dealers in 1963 supplied 1.8 million tons of iron and steel scrap to steel mills and foundries in the south-central area, compared with 2.1 million tons in 1955. Most of the scrap was processed and shipped within 200 to 300 miles of consuming centers. Exports provide a principal outlet for dealers along the gulf coast. Most of the scrap that fills these orders is loaded onto freight cars at yards in Texas and Louisiana and -is shipped to ports for direct transfer from railroad car to ship. The tonnage exported varies greatly from year to year. The largest scrap operations are in or near large cities which are heavy scrap generating areas, steel mill sites, or port cities for export of scrap. A tentative analysis indicates that the short-run supply of prepared scrap is inelastic to price changes; therefore, buyers probably arc in a strong bargaining position at times of declining demand. One technological development in the iron and steel scrap industry is the use of large presses which can take complete automobiles with frames, wheels, springs, and other heavy parts still intact and reduce them to bundles. At Houston, Tex., and Kansas City, Mo., shredding plants are in operation that reduce car bodies and other light scrap into flat pieces 4 to 6 inches in size.

Jan 1, 1966

By Nino Catalano

The combination of two top levels of cross-lot braces designed and installed to act as a truss, and vertical post-tensioning of the panels allow the unbraced excavation of a 36' span. Philosophy of Excavation Support System The excavation of interest is for the cut-and-cover box sections of the southern approach to the Third Harbor Tunnel, which is part of the Central Artery/Tunnel project in Boston, Massachusetts. The 60' deep excavation is located very close to an existing building which is supported by piles, as shown in Figure 1. Therefore, it was necessary to minimize ground movement which may damage the building.

Jan 1, 1994

By R. E. Heithecker, D. B. Taliaferro

"INTRODUCTION Recovery of core specimens from subsurface formations and their subsequent analysis are important aids in efficient development and operation of oil and gas fields. Gore specimens first were obtained mainly for the geologic information they revealed; now they are analyzed to determine many of the physical characteristics and conditions of the subsurface formations as well. Cores recovered from the producing formations may be analyzed for porosity, permeability, oil content, ""connate"" water content, and other physical and chemical properties of the formation, all to the end of furnishing enough data for making reliable estimates of the quantity and avail¬ability of oil and as within a reservoir and in devising efficient means for their withdrawal.Examination of bottom-hole samples of oil gives valuable information concerning the amount of gas in solution in the oil within the reservoir and the resultant shrinkage of the oil when the gas is released. Producing characteristics of reservoirs nay be determined by means of subsurface pressure and temperature gages and measurements male at the wellhead; however, unless reliable core analyses are available, these data have only limited use in any quantitative study of reserves. In such a study the quantity of oil, gas, and water contained in a unit volume of the reservoir formation is extremely important. Although reliable methods of analyzing cores have been developed and the data thus obtained are valuable, their applications become more limited or reservoirs at higher temperatures and pressures are discovered. This condition results almost entirely from the fact that in recovering a core from a formation of high pressure and temperature by present methods a large part of the fluid content of the core is lost or contaminated to an unknown extent. For a number of years most petroleum engineers have held that if this loss and contamination of the fluid content of a core were eliminated, the value of core analyses would be increased greatly."

Nov 1, 1939

By J. T. Dunham

Zirconium has possible use in industry where severe corrosion conditions are encountered because it resists attack from a variety of corrosive environments. However, very little experimental testing has been done to evaluate the corrosion behavior of zirconium when simultaneously subjected to high tensile stresses and exposed to corrosive environments. This investigation was initiated for an evaluation test, but was limited to environments consisting of ferric chloride solutions which were known to attack zirconium and were shown to promote stress-corrosion cracking in preliminary tests. Tests for cracking susceptibility were conducted by the Bureau of Mines to show the effect of stress, solution concentration, air aeration of solution, and the method of mechanical processing. Tensile stress was applied to the specimens by a constant-load method which proved more reliable than a constant-strain method.

Jan 1, 1961

By S. M. Shelton

Ferrograde manganese ore or its equivalent is essential to the manufacture of every ton of steel produced; although it is well-known that there are largo deposits of low-grade ore in the United States, production of substantial amounts of ferrograde material from domestic sources presents a problem that becomes more and more critical as the stock piled ore is depleted through inability to obtain adequate supplies from foreign sources. Consequently, a program of laboratory and pilot-plant investigations designed to solve the problem of obtaining a domestic supply of manganese has been undertaken by the Metallurgical Division, Bureau of Mines. This paper is one of a new series that will include reports of results obtained in the various investigations conducted under the manganese program. The scope of the program and the organization that was set up to direct and supervise the work were discussed in the foreword of the first paper of this series, Report of Investigations 3506, Manganese Investigations 1. Concentration of Manganese Ores from the Drum Mountain District, Utah, by S. R. Zimmerley, J. D. Vincent, and C. H. Schack. Other reports will be published as the work progresses.

Jan 1, 1942

By V. L. Gravitis

Radioisotope X -ray techniques of analysis for nickel have been tested in laboratory and plant trials. In the laboratory tests. a comparison was made of radioisotope and conventional analyses for nickel in solid s samples taken from streams of a nickel concentrator. Coefficients of variation of 1.7% for feed and concentrate samples , and equal to 10% for final tailing samples, were obtained. Continuous determination of nickel in final tailing slurries was demonstrated in a trial lasting 20 days at a nickel concentrator (Western Mining Corporation), nickel being determined with a standard error of 0.036% Ni in the slurry solids within the range of 0.24 to 0.68% Ni. This error, obtained by comparison of on-stream probe analyses with assays of samples taken from the stream, includes errors in sampling and assay by conventional techniques.

Jan 1, 1977

By JO. E. SHERID

THE Dawson coal-mines are owned and operated by the Stag Canon Fuel Co., of which Dr. James Douglas is President and E. L. Carpenter general manager. The property is situated in Colfax county, N. M., and the openings now in operation are in townships 28 and 29 N. R. 20 E., and township 28 N. R. 21 E., shown in Fig. 1. The mines are part of the southern end of the Raton coal-field, which extends north into Colorado and embraces many coal-camps of the Trinidad section. II. GEOLOGY. Geologically, the coal-measures, commonly known as the Laranmie series of the Cretaceous system, have a thickness of about 800 ft. in the vicinity of Dawson. The coal makes an excellent coke, and, according to some authorities, its coking properties are clue to the action of intruded sheets and sills of igneous rock, the sheets occasionally thickening into masses resembling laccoliths, at such places making nearer approach to the coal and sometimes producing small areas of natural coke. There are but few dikes through¬out the entire southern portion of the field and little or no faulting along the dikes. In some parts of this great coal-field the intrusive sheets are far removed in the green shales below the coal-measures, and are so much altered as to be difficult of identification. There is but little disturbance of the strata through¬out the Raton coal-field in as far as it extends into New Mexico. There are two workable seams in the coal-measures, and two or three smaller coal-seams, ranging from 1 to 2.5 ft. in thick-

Jun 1, 1909

By Joo Hyun Park, Hyun-Sik Park

"Gold is one of the most valuable and precious metals. But, the extraction efficiency of gold from natural resources is very low and labor-intensive due to very low concentration of gold, i.e.,1–5 ppm, which means that gold extraction processes produce extensive amounts of tailings. The gold content in printed circuit boards (PCB) from waste mobile phones is about 100 to 400 ppm, which is enormously greater than the concentration found in natural ores. Consequently, processes for recycling waste PCB and gold mine tailings become of increasing importance to maintain a sustainable society. As processing these waste materials by pyrometallurgical methods has become more economically attractive, understanding the thermodynamic behavior of gold in smelting slags under oxidizing and reducing conditions has become increasingly important. Therefore, in this study, the effects of slag chemistry, oxygen potential and temperature on gold solubility in smelting slags are discussed. From the results presented, the predominant species of gold is strongly dependent on the basicity of slag. Furthermore, more basic slags showed higher solubility of gold at a given oxygen partial pressure, and more oxidizing atmospheres enhanced the dissolution of gold to the molten slag phase. As a consequence, careful control of the slag composition during pyro-processing of gold-containing waste materials is required to maximize gold recovery. INTRODUCTIONGold has good physicochemical properties. Thus, it plays an increasingly important role in industrial applications. For example, over 300 tons of gold are used annually in electronic components (Hageluken &Corti, 2010).However, 75% of all gold ever produced has been extracted since 1910 and gold reserves in the world are becoming rapidly depleted (Louis & Pluchery, 2012).The cost of gold production and its price in the market have increased rapidly during last 20 years as shown in Figure 1, and interest in the recycling of gold-containing materials has naturally increased.The wastes from electronic equipment (e-wastes) contain large amounts of precious metals compared to their own respective ores, and therefore such wastes may be considered as a secondary source of valuable metals. For instance, the concentration of gold in natural ore is commonly 0.5–15 g/ton-ore (0.5–15 ppm), while its concentration in electronic circuit boards is over 10 times higher, typically being about 150 ppm in expansion cards and over 10,000 ppm in central processing units(Barbieri et al., 2010).Also, gold mine tailings are discharged after the flotation process as slurry form then stored near the operating plants (approx. 100 ton per day in one Korean gold mine). Gold mine tailings contain gold at about 1–2 g/ton. This is the reason why Au-containing materials such as e-wastes and mining wastes are highly important sources of gold (Yamasue et al., 2009)."

Jan 1, 2017

By Raymond E. Healy

Mercurian e1ectrum (Au-Ag-Hg alloy) is the principal Au-bearing phase in the massive sulphide ores at Trout Lake, Manitoba. The average composition of this phase (in wt %) is 49.2 % Ag. 38.7 % Au and 11.0 % Hg, with ranges of 17.34 to 76.47 % Ag, 1.62 to 79.86 % Au and 1.29 to 30.87 % Hg. Compositional variation reflects solid solution in the a-phase of the Ag-Au-Hg system. Backscatter electron imagery reveals systematic zoning and suggests a general crystallization sequence from metamorphic pore fluids of progressively Ag-rich compositions. Investigation of the occurrence of gold in mill products demonstrates that mercurian electrum accounts for over 90 % of the Au in Trout Lake ore. I Invisible" gold in pyrite (x = 0.72 ppm Au) and arsenopyrite (x 30.2 ppm Au) is confirmed by SIMS analyses, and accounts for 7-10 % of the Au in the ore, and 35 % of the Au lost to the tailings. The remaining 65 % of the Au lost to the tailings consists principally of mercurian electrum locked with pyrite. No significant losses of mercurian electrum in the size range amenable to flotation and/or regrinding is indicated.

Jan 1, 1989

By C. M. Kleemann

The paper describes the present milling practice at Western Mining Corporation Limited's new nickel mine at Kambalda in Western Australia. It details the crushing, autogenous grinding, flotation and spray drying circuits for the production of a nickel concentrate. It also indicates some of the metallurgical problems which have been encountered in concentrating this ore.

Jan 1, 1973

By C. E. Smith, R. J. Inglis, M. I. Brittan, J. H. Schoeman

"AbstractA number of plant-scale cyanidation tests were carried out in an attempt to uncover the causes of fluctuations in gold recovery efficiency. Computer analysis of the results verified that the treatment of reclaimed waste rock material along with normal run-of-mine ore was having an adverse effect on metallurgical efficiency. Mineralogical examinations showed that the free gold particles in the dump material were heavily tarnished or coated (predominantly by hydrated iron oxide), accounting for the lower recoveries. The indications were that the effect could be counteracted somewhat by using higher than normal cyanide and lime reagent concentrations and adequate leaching times. Analysis of the results showed further that leach pulp density was an important operating parameter affecting extraction efficiency. A variable activation energy leaching model provided an extremely good characterization of individual batch leach runs.IntroductionFLUCTUATING METALLURGICAL EFFICIENCY at the gold concentrator of the S.A. Land and Exploration Company Limited (""Sallies"") prompted some plant-scale cyanide leach studies in an endeavour to uncover the causes of the variations in gold recovery."

Jan 1, 1977

Airy kind of a power system is a complicated network of various electrical components, such as cables, transformers, electric machines, circuit breakers, etc. For a system to work continuously and efficiently, each of the components has to be in perfect operating condition. The failure of any of these components can cause serious interruption of the supply and may in several cases involve a lot of precious time and labor in removing and replacing the damaged equipment it may also give rise to dangerous overvoltages on the system, thereby causing a safety hazard. Any piece of electrical equipment can have two likely modes of failure. The first would be the degradation of solid insulation material due to overheating, mechanical damage or a combination of the two, In this mode of failure it is possible that If the insulation damage is not an instantaneous phenomenon (a cable damaged by severe mechanical, Stress) that a detectable leakage current will do lop prior to the faint. The fault would probably he a result of heating and deterioration of the insulation by the leakage current.

Jan 1, 1975

By G. Atesok

Turkey?s EU affairs started in 1963 with the Ankara Treaty. On 31 December 1995 the Customs Union between Turkey and the European Union came into effect. In order to achieve the Copenhagen Criteria?s, Turkey, made laws parallel to the Framework Programs. On 3 October 2005, with the confirmation of ?Membership Framework Document? the negotiation process of Turkey has started. Coal had important role in the industrialization of EU and it is directly related to Energy and Environmental subjects. In this point many restriction became with the some protocols, in last decades. European Union composed Energy and Coal Policy, therefore engaged to reduce the emissions, and made new regulations. This regulations concern Turkey?s energy future, since large; but low quality of lignite reserves of Turkey, it is expected to have some difficulties with Union?s Environmental Legislation during Turkey?s congruity process. With the last natural gas import agreements of Turkey, the production and consumption of coal sunk in last seven years. However, considering environmental sustainability, the role of coal in energy production will rise up in the coming future. In this paper, in terms of Turkey Energy Sector, production and consumption problems of coal discussed and evaluated considering EU?s coal, energy and environmental rudiments.

Jan 1, 2014

By M. Z. Naghadehi, E. Emami, J. Sattarvand, R. Battulwar

In this paper, a methodology for a computerised recognition of joint sets on 3D point cloud models of rock masses is presented. The process starts with classifying joints on a 3D rock mass surface through training a deep network architecture and validated using manually labeled datasets. Then, individual joint surfaces are identified using the Density-Based Scan with Noise (DBSCAN) clustering algorithm. Subsequently, the orientations of the identified joint surfaces are computed by fitting least-square planes using the Random Sample Consensus (RANSAC). Finally, the joint planes are classified into different joint sets, and the dip direction and dip angle for each set are calculated. The performance of the proposed methodology has been evaluated using a case study. The results show that the presented procedure is fast, accurate, and robust.

Sep 1, 2021

By P. Holman

I would like to start this paper by looking back about twenty years to see where we have been in the mining industry. We will also look forward a bit and talk about what lies ahead. Here is what has happened to the world economy since the 1970s. Economic growth was strong in the early 70s, but slipped into a recession in the middle of the decade. Then, after a fairly decent recovery recession struck again in the early 80s and since then growth has been rather sporadic. All in all, it has been a real roller coaster ride. There will continue to be plenty of ups and downs in the world economy in the future.

Jan 1, 1993

By Paulo Eduardo Melo da Cunha

Com um cenário de constante mudança na área e logística, uma demanda cada vez maior por transporte rápido, eficiente e a baixo custo, muito se tem exigido dos gestores de logística na solução, otimização e implementação de soluções criativas para desatar o nó logístico existente hoje no país. A falta de infra-estrutura tanto interna, quanto externa tem dificultado o trabalho e comprometido os resultados globais das empresas. Muitos trabalhos já foram realizados, mas as constantes mudanças, aumento dos volumes transportados em cada modal, a falta de planejamento governamental, tem exigido novas formas de trabalhar. Um relacionamento mais próximo dos fornecedores de transporte, com grande envolvimento dos clientes e áreas comerciais é fundamental para os bons resultados e é desta forma que buscamos otimizar o fluxo ferroviário para a região da grande BH.

Jul 29, 2018

By G. M. Ritcey

The recovery of copper from low-grade solutions res ulting from dump leaching is well known, whereas the recovery from highly concentrated copper solutions has not been practiced. This paper discusses the use of Ashland Chemical's Kelex 100, a substituted quinoline, for the recovery of copper from solutions resulting from leaching copper-nickel concentrates. A flow sheet is described, and an economic comparison shows Kelex 100 to be superior to either the LIX 64N or LIX 70 reagents of General Mills for the recovery of copper.

Jan 1, 1973

By Liu Jin

"In order to reduce the dosage costs and increase the economic benefits of a full floating process in a low grade complex multi-metals W-Mo ore, based on the study of the magnetic characteristics of the main gangue minerals, a joint process by magnetic separation and floatation technology is adopted. The first step of the flowsheet is to recover magnetite by magnetic separation, then remove the magnetic gangues by high gradient magnetic separation (HGMS) and finally recycle the W-Mo from the magnetically separated tailings by flotation. Results of the lab experiment show that in comparison with the full flotation process, the floatation feed tonnage of the combined flowsheet are only 46%. The grade and the recovery of Mo in the rough Mo-Bi concentrate is similar with the original one while the WO3 in the tungsten rough concentrate is increased from 3.85% to 6.64%. The dosage costs are reduced by 53%. The new process can significantly improve the plant economically. INTRODUCTION With the continuous exploitation of scheelite resources, the easily obtained resource is gradually depleting. The ""lean, fine and complex"" scheelite resource has become the main research object of tungsten beneficiation (Lou et al., 2010) (Xiao et al., 2013). The passive situation of tungsten beneficiation can be reversed by enhancing technological innovation and investment in science and technology, changing the business philosophy and mode of production, optimizing the process structure and process conditions, improving various technical indexes and reducing production costs of reagents, which will maximize economic benefits (Jiang et al., 2012 ) (Zhu et al., 2016). A polymetallic deposit of tungsten molybdenum bismuth original process adopts a full flotation process. With the expansion of stope mining, the content of valuable metals in the ore continues to decrease, resulting in a high cost per ton of concentrate produced and a low output value (Li et al., 2015)."

Jan 1, 2018