Search Documents

This paper forms part of a series of papers relating to the Melbourne Underground Rail Loop and presented to the Fourth Australian Tunnelling Conference in Melbourne, March 1981. The Design of Electrical and Mechanical Services in Museum Station and adjacent Running Tunnels and their relation to Rail.wruy Operation through the Loop are described. The descriptions, while specific to Muscrio Station, are generally representative of those being provided at Parliament and Flagstaff Stations. The Museum Station comprises some 6500 square metres of platform and track area, 5000 square metres of booking hall concourse and entrances and 1200 square metres of offices and plant rooms. The Mechanical and Ilectrical Services for this complex are .imilar in many aspects to those of a large !.gr.hrise city building, but in general the i::;ign is directed more strongly towards :.arety, durability and reliability, and subject to many restraints imposed by L'mitations of space and accessability.

Jan 1, 1981

By Douglas Brand

"The data that many mineral processing plants make use of, is provided by samples taken from sampling systems which are inadequately designed or improperly maintained, and therefore cause detrimental effects to plant operations, production planning and metallurgical accounting! Poorly designed or maintained sampling systems will likely produce low probability samples which give the operator a false sense of security of the product and the process. If data is the basis for action (Flintoff, 1992, p.2), then using the resulting suspect or bad assays by operators, control systems, or metallurgist and administration personnel will act and make decisions which may adversely affect the profitability of a processing plant. Here we will discuss some of the fundamental sampling problems, propagation of errors and a method to estimate what impact this has on an operations Net Smelter Return.INTRODUCTIONIn order to control a mineral processing plant at its best potential, it is necessary to obtain the best possible measurement results of the metal or mineral in question. The sample which is delivered to a measuring instrument, or lab, needs to be of the highest probability to be able to achieve this. This paper will discuss the effects of sampling errors on grade / recovery and grade / Net Smelter Return (NSR) and provide a method to estimate the monetary advantages of using probabilistic sampling in a processing plant.REVIEW OF SAMPLINGSampling, by definition, is the removal of a small representative portion from a total consignment, or flow, for the purpose of accounting or process control.• A sample can only be considered representative, if each and every increment collected, in each of the sampling stages, is representative.• Each particle of the sampling lot must have the same probability of being included in the final sample.• If both of the above conditions are met, then the final sample will be representative of the complete sampling lot.It is commonly known that in order to take truly representative and probabilistic sample, best practices indicate that:• The total stream should be sampled.• The sample cutter should intersect the sample at right angles to the flow.• The sample cutter should travel through the stream at a linear and constant speed and the speed deviations should be less than 5%."

Jan 1, 2016

By H. O. Lien

Among the known iron deposits in Canada, many are of low grade and require beneficiation to produce an acceptable blast-furnace feed. Some of the deposits have never been considered for commercial exploitation due to the lack of a suitable concentrating process. A number of deposits of this type are located in Northern Ontario. The problem in upgrading these deposits is three fold. Firstly, the iron occurs as a mixture of magnetite and hematite. Secondly, the grain size of the material can be fine to very fine. Thirdly, the complex mixture of gangue minerals, which consists invariably of silica, flaky silicates and carbonates, slimes excessively on fine grinding. Algoma's efforts to concentrate these iron-bearing materials culminated in the development of a "Selective Flocculation and Desliming Process" employing slimes removal as the sole beneficiation technique. The process was applied successfully in the laboratory using two stages of grinding and a total of seven deslimings. Prior to the removal of slimes, the iron-bearing fines were selectively flocculated from a thoroughly dispersed pulp using a modified starch as flocculant, Sodium silicate was employed as dispersant. An attempt was made to optimize some of the process variables using material from one specific iron formation near the town of Geraldton in Northern Ontario. The preparation of the starch proved most critical. This matter, and the method used to evaluate the degree of breakdown of the starch molecule, are therefore discussed in some detail.

Jan 1, 1978

By George T. Motock

The author prepared the following report as the result of a trip to Germany in the summer of 1945 for the Technical Industrial Intelligence Commitee Subcommittee on Metals and Minerals. The purpose of this committee, which functions under the Joint Intelligence Committee of the Joint Chiefs of Staff of the United States Armed Forces and of which the Bureau of Mines

Jan 1, 1946

The paper describes the propensity of tin to form intermetallic compounds with microalloying elements such as Nb, Ti and aluminium, which are commonly used as additions to achieve particular combination of strength and toughness. Two series of alloys were prepared by arc melting under an argon atmosphere. Each series was based on Fe, Sn and A1 with either Nb or Ti additions. The microstructures were studied using scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy and microprobe analysis. It was found that the level of Nb addition has an effect on the formation of Sn-rich compounds. For small Nb additions, no Sn containing compounds were found, whereas in higher Nb alloy, a Laves phase (FezNb, hexagonal, a = 0.4830 nm and c = 0.7879 nm) containing about 1 at % Sn was found. A FezNb3 phase (cubic, a = 1.1261 nm) associated with the formation of alumina was also found but did not contain tin. No Sn containing compounds were found with Ti additions. The experimental observations have been compared with thermodynamic calculations performed using MTDATA.

Jan 1, 1999

By Rollie P. Dobyns

The K.M.A. reservoir was discovered to be oil bearing at a depth of 3,719 feet on March 11, 1931. Extensive development, however, was not begun immediately, because the discovery well had a low initial daily oil production, and market conditions for oil were unfavorable. Development of the field progressed slowly for the next 6.5 years. In the latter part of 1937, a wildcat well approximately 2 miles southwest of the discovery well was drilled on a magnetometer high and completed with an initial flowing production of 2,018 barrels of 430 A.P.I.-gravity oil in 12 hours. Rapid development of the southwestern part of the K.M.A. field was begun immediately and continued until over 700 wells were drilled and approximately 12,500 acres proved oil productive. Because of the large size of the entire K.M.A. field, this report is limited in scope to the southwestern part only, and the discussion that follows pertains to this area only. The closing date for production statistics is August 1, 1949. The K.M.A.? structure is a complex anticline having a maximum closure of 250 feet, and the K.M.A. formation is composed of sediments that grade from limestone through sandy lime and limy sand to sandstone with thin streaks of shale. Two "distinct members of the K.M.A. formation, zone I and zone II, are oil productive. Core analyses indicate the average porosity to be 16.5 percent for zone I and 16.1 percent for zone II. A relationship was established from core data, which showed the correlative permeabilities to be 42.1 millidarcys for zone I and 39.5 millidarcys for zone II, whereas the arithmetical averages of the permeabilities were 84 millidarcys for zone I and 216 millidarcys for zone II. Connate-water saturations were 17.5 percent for zone I and 20.0 percent for zone II. The porosity-saturation method, using a thickness-correction factor, was employed to calculate the volume of 168.1 million barrels of stock-tank oil initially in place in the reservoir. Analyses of the reservoir oil indicate that, although the initial reservoir pressure was 1,750 p.s.i., the original reservoir oil was saturated to only 1,300 p.s.i., at which pressure 1 barrel of stock-tank oil contained 525 cubic feet of ea~ in solution.

Jan 1, 1952

By R. H. Lien

The Bureau of Mines, U. S. Department of the Interior, is investigating chemical and biological decontamination of complex wastewaters such as tailings pond water containing 280 ppm CN and 5 ppm Se as well as significant concentrations of arsenic, copper, iron, silver, and zinc. The most effective chemical procedure involves cyanide oxidation using hydrogen peroxide or sodium hypochlorite followed by selenium reduction using ferrous hydroxide. The effluent contains <l ppm CN and 20 ppb Se; concentrations of other major contaminants meet EPA drinking water standards. Preliminary research indicates that biological cyanide oxidation is possible even in highly alkaline solutions (pH 10.5) containing high cyanide concentrations; indigenous bacteria destroyed 85 pet of the cyanide. Exploratory research shows that other bacteria removed up to 79 pet of the selenium from chemically oxidized, low-cyanide water. These promising results may lead to a final processing scheme that involves a combination of chemical and biological techniques.

Jan 1, 1990

By C. A. Kumke

The Korean crisis and the cessation of Russian manganese-ore shipments to the United States in 1950 reemphasized the almost total dependence of the domestic steel industry on foreign supplies for metallurgical-grade manganese ore. In this emergency, Congress authorized the Bureau of Mines to undertake experimental mine and process development work on the known large reserves of low-grade manganese ore in the Artillery Mountains region in Mohave County, Ariz. The objective of the work was to obtain the basic mining and metallurgical data needed to make specific plans for initiating exploitation of the deposits within 3 years if high-grade foreign ore could not be obtained during the emergency. The manganese deposits of the Artillery Mountains region are in an area of about 25 square miles on the north side of the Bill Williams River in southern Mohave County. Lasky, of the Federal Geological Survey, has estimated reserves at 175 million tons of manganiferous material assaying 3.5 to 4 percent Mn. Although the man¬ganese occurs in various Tertiary and Quaternary formations as both bedded and fissure vein deposits, the more important syngenetic deposits are found in upper and lower manganiferous zones in the sedimentary beds of playa and alluvial fan origin that constitute the Chapin Wash formation.

Jan 1, 1957

By Manuel Gomez

The Bureau of Mines used data from 31 core samples to develop prediction equations for evaluating chemical and carbonization properties of six seam units in a lignite deposit approximately 2 miles wide and 8 miles long in the Wilcox Formation of central Texas. Statistical response surfaces, based on core analyses, were computed for 14 parameters indicative of lignite quality. These computed surfaces, and their mathematical equations, can be used to predict values of the selected properties of the lignite seams at any desired surface coordinate position between core hole locations. The wide range of application shown by this study indicates that the methods of statistical regression analysis may be useful to evaluate large deposits of lignite or higher rank coal.

Jan 1, 1969

In the course of an investigation of the influence of bismuth on copper carried out some years ago, (1) the author found that phosphorus exerted a beneficial effect on bismuth-copper alloys of low bismuth and oxygen content by neutralizing the embrittling effect of the bismuth. In the intervening years, a further examination of bismuth-phosphorus-copper alloys has been canied out and the influence of other elements and combinations of elements on copper containing bismuth has been studied.The results recorded in the present paper are part of this investigation.MATERIALSAll the alloys were made from high-grade copper (KS.A. wire-bar) of the following composition: copper 99&#183;95%, oxygen 0,040&apos;%, iron 0&#183;0015%, sulphur less than 0-001%, bismuth less than (j&gt;&apos;OOl%, other elements each less than O&#183; 0010/&lt;-. The bar was hot rolled and cold drawn to strip which was cut into short lengths and cleaned in nitric acid ready for melting.A piece of this &apos;strip was drawn to wire 0&#183;08 in. diam., annealed at 5000 C, and measured for electrical conductivity as a check on purity. The result was 101&#183;5% of the I.E&apos;.C. standard.In making the alloys, phosphorus was added as 14% phosphor-copper, bismuth as 17% bismuth-copper, and the other constituents either as copper alloys or as elements of a high degree of purity.PREPARATIQN OF STRIPSThe charges were melted in plumbago crucibles (Morgan salamander brand) in an oil-fired furnace, Le;, in the manner commonly adopted in industrial practice. The copper was first melted under charcoal, well stirred with a chaned stick, and the necessary alloying elements added and stirred in with the stick. The weight of a charge varied according to requirements but generally was about 4 lb. The charges were poured into slightly tapered brass moulds heated to about 1000 C and dressed with a mixture of mineral oil and tallow. They were not only poured under charcoal through the burning mould dressing but also- through a ring of flame produced by burning kerosene on asbestos cord wrapped round the top of the mould. Experiments carried out with plain copper proved that by this means oxygen could be excluded from the stream of metal. The billets were 7&#183;5 in. long x O&#183;83 in. diam. x 1&#183;3 lb. weight.The billets were cropped about 1 in. from the top, cleaned in nitric acid, and measured for density by the usual method of weighing in air and -in water. As these measurements were required only as a check on casting, technique a high degree of accuracy was not essential (accuracy = -+ 0&#183;2%).

Jan 1, 1942

By Beatryz C. Mendes, Márcio Sampaio S. Moreira, Rita de C. S. S. Alvarenga, Juliano Correa

Over the last decades, modern technology to build wood structures have been substantially developed. Building solutions for floor systems of wood-concrete mixed T-beams with wood web and concrete flange stand out among these technologies. This work describes an experimental investigation of the performance of bond connectors made of round steel bars for wood-concrete mixed elements. Symmetric three-member specimens were built. The middle member was made of concrete and the other two were made of wood. The first kind of connector consisted of steel bar designed as straight pins with head, normally driven through the wood. The second kind consisted of arc-shaped connectors directly embedded into the wood or bonded using epoxy adhesive. The specimens were then tested in compression. The compressive strength and the force-displacement curve were obtained, in order to evaluate the failure mode and obtain the stiffness in the ultimate (Ku) and serviceability (Ks) limit states. The stiffness values were calculated in the interval corresponding to the secant straight line between, respectively, 10–40 and 10–70% of the ultimate strength. The obtained results indicate high strength and ductile failure mode for all of the cases. Bond stiffness gains were verified when using the arch-shaped connectors.

Mar 1, 2017

By N. de Koker, Y Jooste, J. Gerber

This paper presents a novel application of the boundary element method for numerical modelling of the seismic activity and hazard that is associated with the shaft pillar extraction at Bambanani mine in South Africa. In the numerical model, the tabular mining excavations are represented by displacement discontinuity elements, and to accommodate crush, shear, and fault slip seismic events, the numerical model is populated with additional displacement discontinuity elements that represent modelled crush- and shear-type failures in the rockmass. Crush-type failures are evaluated by applying the limit equilibrium method and a Hoek-Brown strength criterion, and shear-type failures are evaluated by applying a Coulomb-friction strength criteria to Ortleppshear and geological features. In this paper, the modelling results are presented as time history analyses of modelled potency from 1 January 2010 to 30 June 2022 and normalised exceedance rates for different mining periods using an upper-truncated power law. The normalised exceedance rates of seismic events that have moment magnitude Mw ≥ 1.0 are lowest for the initial mining period (26 events per year) and highest for the final mining period (218 events per year). The relative errors of the modelled potency and normalised exceedance rates are typically less than 10% or 15%, which suggests that the modelling methodology is appropriate for medium- and longer-term forecasting of seismic activity and hazard, as presented in this paper. Shorter-term forecasting is not considered in this paper.

Nov 24, 2025

By Animesh Jha

Univariant diagrams are constructed for the reduction of nickel and cobalt oxide and sulphide minerals. The results from the carbothermic and hydrogen reduction of sulphide minerals are compared. The importance role of lime and calcium sulphate in controlling the emission of sulphurous- gases during reduction reaction is also explained. The mechanism of carbothermic reduction of nickel sulphide is explained by examining the sulphur exchange and reduction reactions. The phase equilibrium relationships that determine the formation of multicomponent liquid are characterised. Also the governing equilibria for inert atmosphere calcination- roasting of nickel and cobalt sulphide minerals are also described for the metallization of nickel and cobalt.

Jan 1, 1993

By Christopher J. Farrow

This paper describes the grinding circuits installed at two remote sites in northern Canada. One is Cominco&apos;s Polaris Project at Little Cornwallis Island; a barge-mounted lead/zinc concentrator. The other is Echo Bay Mines&apos; Lupin Project at Contwoyto Lake, 400 km northeast of Yellowknife, a gold mine, all components of which had to be flown to the site. Logistics and considerations of operating and maintenance presented challenges which were met by innovative design. The evolution of the grinding circuits is discussed. Both plants are operating at design throughput.

Jan 1, 1983

By Mirko Jurkovic, Thomas Hueper, Jens Kempken

The high competition scenario pushes the steel producers business. Zero defect requirements from customers force the operators for additional efforts in process control and quality management. PQA® has been developed as an advanced process and quality management assurance solution. It is focusing on the analysis of process data, equipment information, inline quality measurement devices and trend analysis. The paper describes the structure of the advanced process and quality management assurance solution PQA®; it gives insights on the expert know-how, process and quality evaluation and points out the benefits like cost reduction, improvement yield and customer satisfaction increase.

Oct 1, 2019

By A. E. Dwight, A. F. Berndt

Binary and ternary alloys of uranium with transition metals were prepared with U2X stoichiometry. The compounds U2Tc, U2Rh, U2Os, and U2lr were formed by peritectic or peritectoid transformations, and were shown to be isostructural with U2Ru. The lattice constants are presented. Miscibility relationships obtained from the study of ternary alloys are graphically summarized in terms of an area-of-stability plot. The compound U2Re is not isostructural with either U2Ru or U2Mo. A series of compounds with stoichiometry U2X has been prepared in which X is technetium, rhodium, rhenium, osmium, or iridium. The only other U2X compounds, for which X is related to the above transition metals by proximity in the periodic table, are U2Mo and U2Ru. The structure of U2Mo is the tetragonal C11b type (MoSi2 type)1 and U2Ru is monoclinic, with a new structure type.&apos; This investigation was undertaken to determine if any of the above compounds are isostructural with either U2Ru or U2Mo and to find the range of occurrence of these phases. EXPERIMENTAL Alloys were prepared from stoichiometric amounts of electrolytic uranium (99.99 pet pure) and transition metals of 99.5 pet purity (98+ pet pure Tc), by arc melting on a water-cooled copper hearth under an Ar-He atmosphere. Weight losses were negligible. The buttons were homogenized at temperatures between 700o and 800°C (900°C for U2Tc) in evacuated capsules and air-cooled. The X-ray powder specimens were annealed briefly at the temperature of homogenization. Except in the case of the technetium alloy, metallographic examination was used to determine the number of phases present. The radiation hazard involved in handling technetium precluded the use of metallography to examine U2Tc. The temperature and mode of formation of the U2X phases were determined by heating the metallographic specimens to successively higher temperatures, until examination indicated the presence of chilled liquid or a peritectoid transformation. RESULTS The U2X compounds investigated were found to be formed under the following conditions: UzTc unknown U2Ru peritectic 897o ± 3°C U2Rh peritectoid 755o ± 5°C U2Re peritectoid3 below 750°C Uas peritectic4 920°C U2Ir peritectoid 775o ± 5oC Debye-Scherrer patterns for the above U2X phases were made with CuKa radiation (nickel filter). The similarities in the positions and intensities of the strongest lines in the front-reflection region strongly suggested that U2Tc, U2Ru, U2Rh, U2Os, and U21r are isostructural with only minor differences in the unit-cell dimensions. The known lattice constants and intensities of the Debye-Scherrer rings for U2RU2 were used as a guide in order to index the low-angle X-ray reflections of the U2TC, U2Rh, U2Os, and U2Ir powder patterns. Approximate lattice constants for these compounds were thus obtained and were used along with the intensities observed for U2Ru to index the strongest lines in the back-reflection regions. A sin2 2? correction term was included and the lattice constants were refined and standard deviations estimated by least squares. Comparison of observed and calculated values of Q(= 4 sin2?/?2) used in these calculations are given in Table I. In each case when the positions of lines could not be resolved on the films they were not measured. The final lattice constants, with their standard deviations, are given in Table 11, along with the unit-cell volume and X-ray density. The values of the atomic volume5 of the transition ele-

Jan 1, 1965

By D Kilkenny

This paper discusses the use of a mechanised shaft sinking machine Herrenknecht Vertical Shaft Sinking Machine (VSM) – to conduct the 93 m presink for the Wira Hoisting Shaft at the Prominent Hill Mine in South Australia. This technology has been widely used in the global construction industry, however, this was the first time it had been used in Australia and the second time in a mining application. The non-entry shaft sinking system eliminates risks associated with a traditional manual method and allows all shaft construction operation to take place from surface. The geology in the upper 100 m at the Prominent Hill mine is conducive to mechanical excavation, with expected rock strengths below 130 MPa. This enabled an alternative shaft construction methodology to be considered. The Herrenknecht VSM system was selected due to its extensive work history and demonstrated performance in similar ground conditions. In collaboration with the operations and design team, the shaft collar and surface configuration were modified to suit the requirements of the VSM, additional equipment, and loading jacks that support the pre-cast lining. Dedicated concrete moulds were designed in Germany and built in Italy. The concrete segments were cast in Adelaide and road freighted to site. This paper outlines each stage of the presink – refurbishment, transportation, logistics, establishment, operation and demobilisation. Selecting this shaft presink excavation methodology, delivered through positive collaboration and communication despite some challenges, shows the benefit to the mining industry of applying new technology and innovation to improve safety and productivity.

Mar 29, 2023

By M. Jorgensen, I. Markland, D. Shuck

"The McLaughlin Mine owned by Homestake Mining Company is located 70 miles northeast of San Francisco in California's coastal range. The mine began operations in February of 1985. The mill currently processes 3,000 short-ton per day of sulfide ore that has an average grade of 0.15 ounces of gold per ton, plus another 3,000 tons per day in a newly completed oxide circuit. Annual production from the mine totals over 200,000 ounces.The sulfide ore extraction process involves three basic steps, grinding, oxidation of sulfide minerals in an autoclave, and cyanide leaching for recovery of gold in a carbon-in-pulp circuit. This process, which incorporates a new technology where oxidation of sulfide minerals is conducted prior to cyanide leaching to facilitate gold recovery, was successful from start-up. However, limitation in the grinding mills initially limited sulfide tonnage throughput.This paper discusses modifications made in the grinding circuit, both mechanical and operational, to resolve it deficiency. The SAG mill, in particular, was unable to achieve design tonnage initially and proved to be most troublesome. Complications occurred due to the hardness and variability of ore being processed, short component life, and a lifter /liner arrangement that had to be tailored to the particular circumstances at McLaughlin. IntroductionHomestake Mining Company's McLaughlin Mill, located in northern California, was designed to process a refractory gold ore at a rate of 3,000 tpd to render the ore amenable to cyanidation. Seven years transpired between discovery of the near-surface ore body in 1978 and the February, 1985 plant start-up. Development of the McLaughlin mill and open pit gold mine hinged on the use of autoclave technology to achieve design recoveries."

Jan 1, 1991

By Yimin Zhu, Dezhou Wei, Haijun Liang, Zhifu Zhou

It has been fairly well established by many experiments that Thiobacillus ferrooxidans (T. ferrooxidans), also named Acidithiobacillus ferrooxidans(Kelly and Wood, 2000),can depress the floatability of pyrite. However, the mechanisms governing the process have not been known completely. In the present investigation, wettability and electrokinetic studies were carried out to examine the surface chemical changes on pyrite before and after interaction with T. ferrooxidans or its secretions. Attachment of T. ferrooxidans to pyrite was observed using a scanning electron microscope. The results of experiments showed that, under certain conditions, T. ferrooxidans and its secretions would obviously change the surface electricity of pyrite and result in the iso-electric point of pyrite shifting notably. However, the surface wettability of pyrite hardly changed and its hydrophobicity increased little after interaction with T. ferrooxidans and its secretions. Based on the results of the present investigation it can be reasoned that the depression of floatability of pyrite is due to the reduction of surface free energy, rather than the increase of surface hydrophilicity of pyrite. The decrease of surface free energy weakens the attachment of collector to pyrite; during the process bacterial protein plays the most important role and the bacterial chemotaxis strengthens the effect.

Jan 1, 2003

By Bryan Ulrich

On March 20, 2014, the ?Roundtable Discussion on Innovations in Heap Leaching and Mine Waste Management? was hosted by Knight Piésold and Co. at the Red Lion Hotel in Elko, NV. This topic is timely, and formed something of a lead into the inaugural ?Workshop on Innovations in Waste Rock, Tails and Heap Leach Management.? That workshop, which grew from the 2013 Elko Roundtable, was held on the University of Nevada, Reno (UNR) campus on May 19, 2014. The workshop was hosted by UNR and the University of British Columbia. Knight Piésold?s local representatives, Bryan Ulrich and Logan Jensen, were joined by Tom Kerr, president of Knight Piésold?s, U.S. practice; Rick Frechette, senior vice president, environmental services and Jeff Coffin, geotechnical engineer, from the Denver, CO office for the roundtable event. The event played host to about two dozen attendees from several western states.