Search Documents

By J. E. Udd

A core sample for this study was taken from the sulphide ore of the Geco Mine. The subsequent research was based on the assumption that a part of the scattering of strength-grade data could be correlated with variations in the chemical and/or mineralogical compositions of the samples. The results demonstrate clear relationships between strengths in tension and compression and the zinc-iron contents of the rocks.

Jan 1, 1977

By R. S. Bigelow

Part 1.- Metal Mines Early experiments with mechanical loaders in metal mines were confined largely to machines of the shovelling type and generally air-operated. Although the first application of the scraper to metal mines dates back to 1910, it was not until about twelve years ago that it came to be used extensively. Generally, the scraper gives better results in metal mines than in coal mines, as degradation due to soft bottom and breakage are not factors, but it has a wide range of application and is successfully used in the mining of salt, potash, gypsum, zinc, copper, and a variety of ores, from soft material to hard chunky ore which settles compactly. Today, the scraper has replaced to a large extent the shovelling type of machine in metal mines. Scrapers have offered an inexpensive solution for the mucking problem and are now employed in most mining districts throughout the world. They are operated by labourers of all colours and degrees of skill. Each installation, however, requires individual study on the part of the mine mechanical department to determine the type of scraper, horsepower of hoist, and most economical speed of rope, as well as method of rope rigging. Unfortunately, the scraper has no power to select pay ore from waste and its suitability for use under circumstances which might require sorting of the ore can only be decided by a weighing of the economic factors involved

Jan 1, 1931

By J. Pepin

When using alternating current submerged arc welding (SAW) to produce pipes from microalloyed linepipe steels, it is critical to balance penetration depth and deposition rates, in order to minimize the number of weld passes while still maintaining good heat affected zone (HAZ) microstructures and properties. A series of bead-on-plate (BOP) submerged arc welds were performed on X70 steel, using different waveform variable settings (i.e., balance, offset and frequency). Weld bead cross-section profile deposition and penetration areas were measured, and both Vickers hardness and Charpy V-notch impact testing were performed. Both single electrode and tandem electrode welds were evaluated.

Jan 1, 2011

By Han Xing, Cui Jianzhong, Qin Ke, Shao Bo, Zhang Haitao

In this paper, a new approach that uses hot-top DC casting process to producing multi-alloy ingots is present. The different type and size of composite and coated ingots (4045/3004/4045 three-layer composite ingots with section 630mm by 1500mm and 4045/3003 coasted ingot with F140mm/F110mm in diameter) are cast by this approach. The macro-morphologies and microstructures of the composite ingots, the temperature distribution and the element distribution in the interface zone were investigated, also and the interface bonding strength was measured. Results show that the solid supporting layer formed on the cooling plates plays a key role in the casting process of composite ingots. The solid supporting layer can prevent the blending of two melts by resisting the impact of alloy melt, which ensures the stable casting process and casting high quality composite ingots, because the contact height is increased using hot-top DC casting. In addition, fabrication and properties of 4045/3004/4045 three-layer composite ingots with section 630mm by 1500mm are reported in detail.

Jan 1, 2015

By C. Horstmann, D. Andreo, G. Barthold

"The concept of large single line grinding circuits provides a valid answer in project feasibility studies by reducing capital investment requirements compared to parallel lines for the same plant throughput rates. The benefits of this concept are reflected as well on the operational aspects, in terms of higher and greater process stability, and reduced operational costs mainly due to the associated lower maintenance expenditures. However, concerns exist in the minerals industry on whether large single line grinding could reduce the overall concentrator plant availability. The mechanical design and integrity, the mill and gearless mill drive integration, as well as assets management aspects of this type of equipment are the key to guarantee successful availability records. Together with an overview of the added value provided by large single line grinding circuits, this paper focuses on risk mitigation strategies during mill and gearless mill drive integration, as well as on the design of the equipment itself, for the key aspects which could put at risk the operations availability.INTRODUCTIONDespite a large long term demand for commodities, the mining industry has never faced complex challenges as it is doing today. Decreasing high-quality and accessible deposits, declining ore grades in existing mines, shortages of electrical energy (e.g. in Chile) and an aging workforce are the most significant among the megatrends affecting our industry. In addition to this, flat underlying commodity prices and high price volatility are currently posing strong requirements to miners when entering into the process of approving investments.Nowadays to get projects financially approved (optimizations, expansions, new plants), capital expenditure has to be reduced, as observed up to 30% compared to the last decade, and at the same time the plant design has to be such to demonstrate that operating costs will also be significantly lower than in the past.When it comes to the concentrator plant, the concept of large single line grinding circuits provides a valid answer in project feasibility studies by significantly reducing the capital investment requirements compared to parallel lines for the same plant throughput rates. The benefits of this concept are reflected as well on the operational costs, in terms of higher and greater process stability and reduced maintenance expenditures."

Jan 1, 2016

By W. H. White, A. J. Sinclair

"Unaltered biotites from three samples of monzonite and gabbro from the Copper Mountain stock and a single sample from a pegmatic biotite-chalcopyrite vein cutting the Triassic Wolf Creek formation have a mean K-A age of 193±7 m.y. These data support a suggestion based on geological evidence that Copper Mountain ore deposits are related genetically to the Copper Mountain stock.A cogenetic mineral pair (biotite and clinopyroxene) from a sample of sericitized and chloritized monzonite of the Copper Mountain stock have identical K-A ages of 150 m.y., which probably represents a time of wide-spread, post-ore, hydrothermal alteration. This alteration is believed to be related genetically to a group of post-ore intrusions known as the ""mine dykes,"" suggesting that they also have an age of 150 m.y."

Jan 1, 1968

By L. Hutton, S. W. Colley

"The release of soluble salts of base metals from acid mine pits and in the waste water from metal refiners is an avoidable source local pollution and contamination. Tightening of the regulations controlling natural resource extraction and industrial wastewater discharge is mandating the removal and recovery of metals from waste streams, and the remediation of contaminated sites. There is an economic incentive in recovering the valuable copper and nickel, as the value of the recovered metal can offset remediation costs and for high flow waste streams can be a source of income. Extraction of metals from waste streams by conventional Ion Exchange and chelation resins is widely practised, but has limitations on applicability in complex and dilute feeds due to the structure and properties of polymeric resin beads. Composite Advanced Ion Exchange (AIX) materials have been developed for the recovery and purification of base metals from base metal mining and metal processing industries. A silica-composite based resin has been developed for the selective extraction of copper from high iron containing feeds. This resin can be eluted with sulfuric acid yielding a copper stream suitable for return to solvent extraction or to electrowinning. We describe the development and application of the resin and process to two acid mine drain feeds of varying copper and iron concentrations, and show that the copper concentration can be considerably upgraded even at small scale with a final metal content of >95% copper.INTRODUCTIONWaste water with high sulphate concentrations, low pH and containing complex and variable mixtures of metals is an inevitable product in the mining, extraction and metal refining industries. One problematical water source is Acid Mine Drainage (AMD) which in addition to the metals of interest also contains a wide range of contaminating elements. Purge streams from metal refining are less complex in composition but contain significant quantities of the value metals. The typical treatment of such waste streams is treatment with lime to increase the pH of the water, precipitating the dissolved metals and sulphate as a sludge of mixed metal oxides/hydroxides and sulphates. The process is effective in producing a water stream that can be safely discharged but if there are significant concentrations of value metals such as copper, nickel, zinc then there can be a considerable loss of metal value."

Jan 1, 2016

By C. R. van Staal, L. R. Fyffe, J. A. Winchester

"The geochemical characteristics of Early Paleozoic volcanic rocks are used to establish the following tectono-volcanic regimes in the northeastern mainland Appalachians: foreland continental rift volcanics; fore-arc ophiolites; island-arc volcanics; back-arc ophiolites; and back-arc ensialic volcanics. A Late Precambrian calc-alkaline magmatic arc bounds the Early Paleozoic volcanics to the southeast.The Precambrian calc-alkaline volcanics of the Caledonian Highlands, primitive Cambro-Ordovician oceanic-arc volcanics of the Eastern Townships, and within-plate Ordovician volcanics of the Miramichi Highlands can be related to a progressive change in mode of subduction from compressional Andean-type in the Late Proterozoic to extensional Western Pacific-type in the Early Paleozoic. The development of marginal oceanic basins in the Paleozoic created a more favourable environment for volcanogenic sulphide deposition, particularly in back-arc areas.The influence of tectonic setting is reflected in the distribution, size and metal ratios of the massive sulphide deposits associated with the volcanic rocks; deposits within intra-oceanic arcs in the Eastern Townships of Quebec average two million tonnes grading 2.2% Cu, 4.0% Zn, and 0.6% Pb, whereas those within a back-arc, ensialic rift near Bathurst, New Brunswick, average nine million tonnes grading 0.6% Cu, 5.4% Zn, and 2.2% Pb."

Jan 1, 1990

By K. Howard Poulsen

Shear zones are tabular tructures which tend to occur either discordantly within, or concordantly along the margins of, competent rock masse uch as plutons, sill or flows. They contain deformed equivalents of their host rock and are common sites for gold mineralization localized in tructure oriented y tematically relative to the shear zones and internal linear fabric. Apan from genetic implications, hear zone analysis proves useful in exploration for this type of deposit because the zones are generally wider and more continuous than associated mineralization and because there is an element of predictability to mineralization geometry (i.e. vein orientation. plunge).

Jan 1, 1986

By Guocheng Pan

"Although many factors play roles in the estimation of recoverable reserves, smoothing effect and conditional bias are considered major geostatistical issues in the estimation. This paper introduces measures for smoothing effect and conditional bias, and provides insights into their relation to the estimation of recoverable reserves. Both smoothing effect and conditional bias are intrinsic to the information effect and kriging estimators. For a given level of drilling information, however, it is possible to identify the optimal search radius that minimizes conditional bias. Furthermore, it is also feasible to define variance correction factor for reduction of the smoothing effect from exploration block models. Both of these components are key to the accurate estimation of recoverable reserves. IntroductionThe accurate estimation of recoverable reserves is critical to decision making in different phases of feasibility study and mine planning. Much attention for improving the methodology of estimation has been focussed on the effect of the change-of-support (Parker, 1980; Dagdelen, 1996). For example, it is essential to make a volume- variance correction to the estimate of multiple indicator kriging (Hoerger, 1992). When the size of block, b, in the geostatistical model differs from that of selective mining unit (SMU), v, a volume-variance correction is warranted for the prediction of recoverable reserves.Most mining plans and decisions are made prior to the availability of high density blast-hole samples. In most mining operations, the true SMU grade Zv is unknown at the time of selection. Instead, the selection is based on the estimate Z v**derived from high density blast-hole samples within the deposit G. Nevertheless, the estimate Z v * of recoverable reserves in the stage of mine planning is derived from exploration data. At the end, the production result must be reconciled to the estimate Z v * . In other words, the selection is based on Z v** from blast-hole samples, while the final production figures are reconciled to Z v * from exploration drilling. For a given preselected cutoff grade z0, the actual mining panels will consist of the units having the estimated grade Z v** =z0 rather than the true grade Zv =z0. The difference between Z v** and Zv is usually of less concern."

Jan 1, 1998

By Ho-Sung Yoon, Jyothi Rajesh Kumar, Chul-Joo Kim, Sung-Don Kim

A recovery process for rare earths (REs) such as dysprosium and neodymium from the leach liquor of permanent magnet scrap (PMS) was developed. The two hydrometallurgical routes namely liquid-liquid extraction (solvent extraction) and selective stripping were implemented. The present study deals with the separation and recovery process development by using organo-phosphorous based extractant di-(2-ethylhexyl phosphoric acid (D2EHPA) as reagent for REs processing. Initial studies considered the influence of time on the extraction process, as well as pH and extractant concentration effects. This suggested the aqueous mechanism and separation factors played a role in process during development. McCabe-Thiele diagrams for extraction isotherms were developed. Counter current extraction (CCE) using various phase ratios influenced metals separation. Maximum loading capacity of the D2EHPA was determined. The loaded organic generated by the CCE process was water washed followed by a scrubbing process to remove the other metal ion from targeted metal. Finally, a stripping process was tested using various mineral acids.

Jan 1, 2015

By Z. Y. Liu

A local additional potential model (LAPM) was developed to illustrate the role of strain rate in stress corrosion cracking (SCC) of pipelines. According to LAPM, both density and mobility of the local active spots on the steel surface, i.e., dislocation emergence points, increase linearly with strain rate. Generation of such active spots introduces an additional negative potential locally, affecting the electrochemical reaction and, consequently, the susceptibility of the steel to SCC. Electrochemical corrosion measurements, slow strain rate tests and electrochemical hydrogen permeation test were combined to demonstrate the validity of LAPM to illustrate pipeline SCC in an acidic soil solution. It is found that a maximum of the SCC susceptibility occurs at strain rate of 10-6 s1, which is associated with an enhanced hydrogen evolution due to the local additional potential (LAP) effect.

Jan 1, 2010

By B. F. Osborne

"A new sensor cannot be considered in isolation from the process in which it is utilized. This paper, describing an on-stream particle size analyzer, therefore gives considerable emphasis to the slurry handling techniques employed to ensure that the instrument is presented with a representative sample. A new sampler is described, which continuously abstracts a small, representative sample from a closed pipeline containing a flowing slurry. This sample is then diluted, thoroughly mixed and pumped to a head tank, from where a continuous stream is fed at a constant rate to the size analyzer. Data are presented to show that particle size segregation is minimal throughout this sampling and sample preparation. A continuous particle size analyzer based on a separation principle is described, and the basic parameters of size distributions, and how they relate to this particular instrument, are considered. Typical results are given. An electronic system is presented which accepts the basic sensor outputs, and converts these to a particle size signal suitable for process control. Finally, the use of an inplant computer to process the sensor signals to obtain a particle size signal is briefly considered."

Jan 1, 1972

By Keith Jones, Largo Albert

"Decelerometer testing of a rigid guide system in a mine shaft pro vides usefuI information to operating and maintenance people. High acceleration/deceleration rates can lead to high maintenance costs to bath conveyances and shaft and can also present an operating risk . Possible disastrous results in the shaft have been avoided by restricting the maximum conveyance speed until the shaft and/ or conveyance problems have been solved.The test instrument is a valuable aid especially during commissioning or updating of a hoisting installation. High acceleration/deceleration rates also lead to reduced hoist rope life. During the past fourteen years, a total of 15,000,000 feet of testing was performed in 74 assorted shaft compartments.Based on this experience, it is possible to establish acceptable conveyance maximum speeds provided that all other conditions in the shaft compartment are normal. The body of the paper will present examples of several tests made under actual operating conditions.IntroductionMore and more mine operators are recognizing the real value in the use of the decelerometer for determining the state of shaft guide alignment in their shaft compartments , not only during the initial mine start-up periods, but also on a regular basis while the mine is in production.Decelerometer testing, is a technique in which an accelerometer , commonly known as a decelerometer, is used for measuring conveyance acceleration/deceleration in a lateral plane. lts purpose is to determine the severity of shock loads produced by misaligned shaft guides. Testing is performed by mounting the instrument on the conveyance and operating the conveyance (empty and loaded) at various speeds up to and including full speed . However, full speed may not be attained due to conditions indicated by the tests. These conditions may present an operating risk to the plant."

Jan 1, 1984

By J. R. Jutras, C. Brissette, J. Champagne

"Pure cadmium sulphide was leached by the action of the bacterium Thiobacillus thiooxidans in the presence of finely divided sulphur. The influence of time, temperature, pH and concentration of inoculum on the extent of the cadmium extraction was studied. Under optimum conditions, up to 72 per cent of the cadmium could be dissolved over a six-week period. A cursory study of the role played by elemental sulphur seems to indicate that its presence is essential but that the sul1>huric acid produced through its oxidation is a minor factor in the cadmium extraction."

Jan 1, 1971

By S. R. Steinacker, H. Schnideritsch, J. Antrekowitsch

Primary copper industry flue dust plays an increasingly important role in the creation of matte and slag. From a thermodynamic point of view, the chemically formed section of fine particles play a techno-logically interesting role in comparison to the mechanical carry-over. Here, the volatilization and the sub-sequent condensation in the off gas system lead to a characteristic distribution of the contained elements which are represented by various compounds of desired metals like zinc and lead. On the contrary, certain undesired components such as arsenic, bismuth and cadmium accumulate within the product as well. This paper describes existing models and theories concerning the formation of flue dust in the copper smelting process and presents a thorough investigation of the physico-chemical fundamentals by verifying assump-tions with thermodynamic calculations. By fully understanding the formation patterns at different stages and temperatures within the process, better knowledge for flue dust in the first step of the pyrometallurgi-cal copper smelting can be obtained - hence leading to new ideas and incentives for the following stages in the copper production cycle.

Jan 1, 2015

By H. P. Kang, Y. J. Feng

The hard roof in underground coal mines is generally considered as a main cause that induces disasters in working faces and entries, such as rock burst and windblast. Hydraulic fracturing technology is an effective approach to weaken hard roof to reduce ground pressure and control rock burst. The state and achievements associated with hydraulic fracturing technology applied in Chinese coal mines are summarized in this paper. Theories related to hydraulic fracturing are of the essence in fracture design to determine the fracture initiation and propagation pressure and predict the geometry and the characteristics of hydraulically induced fractures. Initially, theory of elasticity was employed to determine the breakdown pressure for a vertical borehole where the rock medium is assumed to be elastic. However, porosity and pore fluid have an influence on the borehole breakdown pressure, and then the poroelasticity theory was applied. Arbitrary deviated boreholes in practice are rather common and the maximum tensile stress criterion was employed to determine borehole breakdown pressure. The effect of natural crack in the rock medium on the initiation pressure has been taken into consideration through fracture mechanics. Meanwhile, considerable achievements have been made on hydraulic fracturing tools and equipment, and a set of mature hydraulic fracturing technologies for hard roof control are available. Some comprehensive investigations on the hydraulic fracturing for hard roof weakening are presented, and successful field applications in the Jincheng and Luan coal mining districts are introduced. Finally, the unsolved problems related to hydraulic fracturing are also put forward.

Jan 1, 2015

By B. K. Choi, S. H. Kang, G. E. Kim, K. B. Kim, S. Noh, T. K. Kim, H. J. Jin

Oxide dispersion strengthened (ODS) steel is being considered as an in-core structural material of future nuclear reactor systems because of its excellent creep and irradiation resistance on the basis of uniformly distributed nano-oxide particles with a high density, which is extremely stable at high temperature in a ferritic/martensitic matrix. Up to now, ODS steels have been intensively studied and developed to apply these materials to the in-core structural component of future nuclear systems. The primary activity is to develop high strength advanced ODS steel, fabrication technology for the structural components and key joining technology for the component fabrication. As a result, a Fe-10Cr-1Mo alloy with a superior creep resistance at high temperatures has been developed. An optimized fabrication process of this alloy system has been established through various process conditions in mechanical alloying, hot/cold working, and heat treatment processes. Joining technology for the ODS steel components is also being developed using solid-state welding such as magnetic pulse welding, friction stir welding and diffusion boding. These R&D activities will contribute to the realization of ODS materials for future nuclear reactor system applications.

Jan 1, 2015

By Guangdong Institute of Resources Comprehensive Utilization, Y. H. Tang, H. X. Hu, T. S. Dong, Z. H. Zhang

"A world class rare metals ore deposit in Africa belongs to a massive granite type poly-metallic pyrochlore-niobium resource. Successful project development in realizing the resource is vital to Africa’s economy and pyrochlore processing technology.The ore properties are quite complex due to the presence of varieties of valuable minerals, fine dissemination and intimate association of minerals and the relative abundance of easy-floatable minerals. The separation of pyrochlore from zircon, calcite and mica is generally considered difficult. Whilst studies have previously been conducted by several independent institutions overseas, no satisfactory process has yet been developed to date for the ore deposit—possibly due to the process designed being too complex; high cost of regents; lower performance.Based on process mineralogy study and extensive testwork, the authors have in recent years developed a new technology—“De-slime—Iron-rejection—Zircon (with calcite) and Calcite reverse flotation—Pyrochlore flotation”. The flow-sheet is characterized by ?1prior removal of slimes and iron minerals; ?2 Zircon (with calcite) and Calcite reverse flotation; and ?3Pyrochlore flotation applying new type of chelating collector GYX3 developed by GZRINM in conjunction with selected regulators and depressants.The process involved in the new technology is simple to implement and facilitates stable operation; the flotation reagent regime is easily adaptable; the cost of main reagent is lower largely because it is easy to manufacture and is environmental friendly. Laboratory test results demonstrated that, for raw ore assaying 0.35% Nb2O5, 0.03% Ta2O5 and 0.45% ZrO2, pyrochlore concentrate grade of >35% Nb2O5 could be obtained with >74% recovery. Meanwhile, the Ta2O5 content in pyrochlore concentrate could be recycled, and ZrO2 recovery >50% could be achieved in zircon concentrate assaying ZrO2>63%—significantly improving the technical-economic indicator. These results were verified in pilot trials of 1.44t/d throughput. The paper presents the new technology in whole, summarizes the key factors affecting its performance and discusses in simple terms the mechanism of separation."

Jan 1, 2016

By S. G. Coultis

Turner Valley is in the foothills of the Rocky mountains, at an altitude of 4,000 feet, and is 42 miles south west of Calgary. The present producing area is 8 miles long by 1 1/2 miles wide, while drilling is being carried on over an area of 10 miles by 2 miles . There are 32 wells producing, 26 wells drilling, and 17 wells shut down, making a total of 75 wells, which range in depth from 2,160 feet to 5,900 feet, varying according toa the well location on the anticline centre wells being shallower than those located on the flank. The first indication of possible production in this field was a gas seepage on the banks of Sheep river, in what is now the Royalite plant yard (Figure 1). Geologically, this seepage proved to be located on an anticline running through the valley in a southwesterly direction. The Calgary Petroleum Products Company was formed in 1912, and under the direction of Mr. A. W. Dingman, President, and associates, the first well was drilled. Production was obtained in this well. Gas was found in several horizons from 884 feet to 3,960 feet, and oil at 1,557, 2,718 and 3,839 feet. In May, 1914, oil was struck at a depth of 3,839 feet, this being a light straw-coloured oil of 60 gravity, which was blown spraying from the well accompanied by three to four million feet of gas. The latter contained some 200 grains of hydrogen sulphide per 100 cu. ft., giving it the disagreeable odour so well known in Turner Valley gas. This strike caused considerable excitement and started the famous 1914 boom, when some 400 oil companies were formed. The well referred to produced from two to five barrels of 60 gravity oil per day, and 4,000,000 cu. ft. of gas. The oil was used in the crude form in cars and trucks.

Jan 1, 1929