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By P. Keating, J. Goutier, J. Ayer

"New, high-resolution geophysical surveys were undertaken over parts of the Abitibi Subprovince, Canada, to help with geological mapping and to promote mineral exploration. Gravity surveys in the Rouyn-Noranda and Matagami areas (Québec) allowed better 3-D mapping of important geological structures, and a multiscale edge analysis of ground gravity data over the Blake River Group confirms that major faults behave at depth as predicted by surface geology. Airborne gravimetry west of Matagami (Québec) helped to identify a new trend south of Lake Grasset that is almost perpendicular to the assumed geological trend of the area. Electromagnetic (EM) surveys, flown in the Chibougamau (Québec) and Bartlett Dome (Ontario) areas, allowed new conductors to be identified at greater depths than were achievable with previously used EM systems. Airborne magnetic surveys were flown in the Burntbush area (Ontario), and other available high-resolution magnetic data were compiled to produce a continuous and homogenous magnetic grid of the Abitibi region.The resulting compilation map clearly shows the locations of dikes, faults, and shears zones, and reveals some fault extensions in areas of extensive overburden. This grid also allows the computation of enhanced maps, such as vertical derivative and tilt maps (e.g., a tilt map shows subtle magnetic features in the Blake River Group that are difficult to see in the total magnetic field or its first derivative). Results from these new surveys show there is considerable value in (1) resurveying areas covered by older surveys, and (2) recompiling data sets from these older surveys."

Jan 1, 2012

Ecological Fuel from High-Sulfur-Content Coal

Sep 13, 2010

By M. Bilal Khan

Thermal stress relief by means of a typical heat treatment cycle (660oC for one hr) is compared with the one achieved through vibratory stress relief at resonant and multiple resonant frequencies for the D-406 HSLA material. Our analysis of the data is based on the microhardness profiles measured for the entire length of scales, namely, base metal, heat affected zone (HAZ) and the weld bead itself. The profiles obtained using the two techniques mimic each other, for an equivalent 70% stress relief level. The data are further qualified by impact testing wherein the zone of interest is projected in the retention groove to provide impact by the pendulum striker in the Charpy mode. Higher equivalent energy absorption in the treated specimens confirms the efficacy of the vibratory method. The present work rectifies earlier anomaly where heat treatment has been reported at 310oC for the same material.

Jan 1, 2009

By Donald Leroux, Ralph Dahlke, Dave Scott, Finch. James A., Cesar O. Gomez

"The efficiency of the flotation process depends on how effectively air is dispersed into small bubbles. Bubble surface area flux - the surface area of bubbles per unit time per unit cross-section area of a cell - is emerging as the parameter to characterize gas dispersion. One of the approaches proposed to measure bubble surface area flux in industrial cells is based on the measurement of two variables: gas velocity and gas holdup, using separate sensors. Plant testing of the gas velocity sensor gave evidence of a series of operational problems which may be necessary to correct before attempting to characterize gas dispersion. Problems such as uneven air distribution within a cell and along a bank, faulty air and slurry valves detected during attempts to redistribute air, and poor control of pulp level and gas flow became evident. Detection of these problems from gas velocity measurements is illustrated.INTRODUCTIONBubble surface area flux is considered a key variable in the optimization of flotation circuit performance (Gorain et al., 1997; 1998). The Mineral Processing Group at McGill University has devised and developed a method for estimating bubble surface area flux in industrial flotation cells (Finch et al., 1999). The method is based on measuring gas holdup and superficial gas velocity using two separate sensors and applying drift flux analysis to estimate bubble size (Dobby et al., 1988; Banisi and Finch, 1994). With bubble size and superficial gas velocity known bubble surface area flux can be calculated.This method was selected by Noranda to characterize gas dispersion in cells as part of a program to model and optimize flotation circuit performance. However, initial testing at Brunswick Mine with the gas velocity sensor provided some unexpected results indicating operational problems and equipment malfunctions that needed to be addressed before systematic measurement of gas dispersion could be initiated.The subject of this communication is to illustrate the detection of these problems from gas velocity measurements. The line 3 Zn Cleaner circuit comprising four stages of Denver DR cells was the main subject of analysis, including the effect of correcting these problems on the metallurgical performance of the Zn 3rd cleaner bank of ten DRl 00 cells."

Jan 1, 2001

By J. E. Crawshaw

"The few previous observations of the effect of turbulence on limits of inflammability have been made on a small scale in turbulence produced either by a fan or by movement of the mixture.By a suitable amount of turbulence from a fan the lower limit of methane was 5 per cent as compared with 5 per cent observed for quiescent mixtures in the same vessel.3 With a streaming movement of the gas mixture within the range of speed from 35 to 65 centimeters per second (69 to 128 feet a minute) the lower limit was approximately 5 percent,4 For a quiescent mixture of ethane the lower limit was 3.10 per cent ethane, but with fan running at a moderate speed a 3 per cent mixture exploded.5The object of the tests herein reported was (1) to determine the lower limit of natural gas in a mixture of natural gas and air Which would be ignited and propagate violently when the turbulence was produced by explosives fired from a cannon into the mixture; (2) to observe the behavior when the mixture contained less than this low limit; and (3) to determine how turbulence produced by a fan affects thin limit.Four series of tests were run, three of which were to determine the effect of different sources of ignition: Tests with (1) an electric igniter; (2) 3F black blasting powder stemmed with 2 pounds of dry fire clay stemming used to ignite the mixture, and (3) 40 per cent straight nitroglycerin dynamite unstemmed. The fourth was made to study the effect of turbulence produced by a two-speed electric fan, using an electric igniter as the source of ignition.In both series of tests with explosives, charges of 50 and 200 were used to determine the effect of increased quantity of explosives on the lower limit of natural gas."

Jul 1, 1930

By Andrew L. Peterson

CATOH Inc. of Weedsport, New York recently completed a very challenging Bored-In Pile project which features unique construction techniques in the installation and load testing of 45 and 100 ton capacity piles. The bored-in piles were installed on a twenty-nine million dollar New York State Department of Transportation project which began in the fall of 1995 and ended in March of 1997. The project included the construction of 5 new bridges to alleviate a very congested traffic network which had come to be known as the "Octopus" in the small city of Ithaca, New York. CATOH Inc. was awarded the piling contract by general contractor Santaro Industries in the fall of 1995. Piling installation work was completed in March of 1997. BACKGROUND The project is located at the southern tip of Cayuga Lake which lies in the heart of Upstate New York's Finger Lakes Region. This region is popular not only for wine making and vacationing, but also for its impressive geological history. The glacial activities that helped to form the deep valleys of this scenic area are also responsible for creating challenging underground conditions for deep foundations work. CATOH developed two pile designs to accommodate differing site conditions on the project. Internally reinforced piles were developed for use in the center of the valley and externally reinforced piles were developed for locations close to the valley wall.

Jan 1, 1997

By Rony Yupanqui C

El presente trabajo señala el proyecto de remediación de los relaves mineros realizado en la relavera Ticapampa, ubicado en el Distrito de Ticapampa – Huaráz, región Ancash, con el objetivo de remediar los relaves de TICAPAMPA depositados por más de 30 años y que contaminan al río Santa, fuente principal de irrigación del Valle del Callejón de Huaylas. El proyecto comprende la extracción de contaminantes del pasivo ambiental de Ticapampa a través de la flotación de los sulfuros de fierro, y la obtención de un material inerte (con bajo contenido de sulfuros contaminantes) para la fabricación de productos cerámicos por medio de resinas recientemente desarrolladas.

Sep 12, 2011

By Clarke DS

The igneous intrusions in SE Papua New Guinea are part of a sub-volcanic to plutonic, high-K calc-alkaline to shoshonitic suite. High-K andesitic to dacitic intrusives on Misima and Woodlark Islands, and shoshonitic intrusives in Milne Bay and the eastern Owen Stanley Ranges are related to late Cenozoic andesitic volcanism. Both suites are associated with epithermal Au-Ag deposits and weak porphyry Cu-Au mineralisation. All significant alluvial and lode gold occurrences in the region are spatially related to intrusions. Intrusions in the D'Entrecasteaux Islands and near Mt Suckling are core plutons related to basement doming, and appear to have no association with either volcanism or hydrothermal mineralisation. The core plutons are not petrochemi:ally distinct from the volcano-re:-ed Intrusions.

Jan 1, 1991

By X. Goso

Laboratory-scale tests were conducted at Mintek for the production of titanium powder from particulate Kroll sponge by the hydrogenation-dehydrogenation (HDH) process. The aim of this work was to produce titanium powder for powder metallurgical consolidations. The work involved the production of titanium powder at optimized conditions, which included hydrogenation in a horizontal tube furnace at 600°C for 2 hours, milling using planetary and roller mills, and dehydrogenation in a vacuumed retort fitted in a muffle furnace running at 700°C for 36 hours. The titanium powder produced in this project matched the elemental specifications of commercially available titanium powder, except for high carbon content. Nevertheless, the powder has been tested further in mechanical alloying and has been found suitable for the production of powder metallurgical compacts. Keywords Powder metallurgy, titanium components, HDH process, ball milling.

Jan 1, 2011

By Chris Uys, Johan Labuschagne

Sishen Iron Ore Mine, located in the Northern Cape, is an open cast mine excavating approximately 100 million tons rock to produce 25 million tons of high grade haematite ore per annum. The size of the pit is approximately 12 km ‘1.5 km ‘150 metres. The final depth is planned to be around 350 metres. It is hard rock mining operation employing the conventional truck and shovel method. Mining benches are twelve and a half metres in height and are divided into blasting blocks, each consisting of approximately 300 000 tons of material.

Jan 1, 1997

By Sri C. Sawmliana, P. Pall Roy

Damage to underground roof and pillars in blasting gallery (BG) panels has been an increasingly important area of study in recent years due to the invention of new explosives and cord systems which has led to the modification and alteration of the design aspects developed by Charbonnage de France (CdF). According to extensive mine experiments conducted by Indian and foreign experts, it has been established that the induced peak particle velocity (PPV) is predominantly related to the emanated seismic energy of a source and the distance from the source. With that concept in mind, nearly 160 experimental blasts were carried out in four BG panels in India under varying geomining conditions. Based on the results obtained thus far, the authors have established predictor equations correlating explosive energy (in Joules) and distance from the shot to that of induced peak particle velocity received at the sensor point. Good correlation was obtained between the actual and the predicted values. It is realized that this equation may be used as an efficient tool to determine the size limit of blasts in BG panels so that the induced particle velocity does not create damage in underground workings as per the established Blast Damage Index (BDI) and other available safety norms.

Jan 1, 2004

The paper outlines the development of a solvent extraction process for the recovery of scandium, yttrium, thorium, and heavy lanthanides from waste sulphate liquor at the Port Pirie uranium treatment plant. A summary is given of known solvents for these elements, including the recently developed alkyl-phosphoric acid esters which are applicable to sulphate solutions.A kerosene solution of di- (2'-ethylhexyl) phosphoric acid (EHPA) has been suggested by some workers as a suitable solvent for fractionation of the lanthanides. Experimental work with this solvent showed that it could be used for initial recovery of the above elements from low concentrations in the complex sulphate liquor. In particular, scandium could be recovered as a high grade product by extraction with 0·lM EHPA, followed by a purification strip with 9N sulphuric acid, and final stripping of scandium with sodium hydroxide solution.To enable alkaline stripping to be used successfully, the kerosene solution of the reagent was modified by the addition of a small proportion of nonanol. Experimental work included laboratory scale batch tests and small pilot scale continuous tests.A proposed extension of the process for the separate recovery of individual heavy lanthanides, yttrium, and thorium is described.INTRODUCTIONAt the Port Pirie uranium treatment plant of the South Australian Government, large volumes of "barren liquor", free from 'uranium, are at present run to waste. This "barren liquor" results from sulphuric acid leaching of Radium,Hill uranium concentrate, followed by separation of solid residues and removal of uranium from the clear solution by ion exchange. The mineral davidite, from which the uranium is derived, contains other potentially valuable components, notably vanadium, chromium, thorium, yttrium, scandium, and the lanthanides. These constituents are...

Jan 1, 1961

By J. Kim, H. Cho

The objective of the experiment was to investigate the efficiency of hindered-settling column in recovering carbon from anthracite. Two types of Korean anthracites were prepared for feed materials. Each sample was crushed and classified by size, and washability analyses were performed. Separation efficiency was evaluated under various operating conditions using a laboratory scale hindered settling column. Results showed that the carbon recovery was higher for the smaller sizes, but the purity of the product was better for the larger sizes. In, overall, 2-0.21mm particles of 40-45 % ash could be processed into about 20 % ash products.

Jan 1, 2002

By Thomas Leonard Watson

Jan 1, 1906

By Leonello Sciacca

Deepening of harbours has become a priority, necessary to the ongoing operation of the wharves in the face of deeper draft merchant vessels and cruise ships. It is now standard practice in many areas to provide for harbours to be dredged to significant depths below mean sea level, in the order of 12.00 m (39 ft) for existing berths and 15.00 m (49 ft) for new wharf construction. The Ravenna Port Authority initiated a project to deepen the harbour bottom at selected wharves to a depth of 12.00 m (39 ft). In preference to reconstruction of the wharves with longer and heavier sheet piling or other equally disruptive reconstruction, they identified the structural reinforcement of the existing wharves by means of deep underwater tie rods as a possible alternative cost-effective solution. Having defined the design concept, effort was concentrated on developing the required technology. A technique, already in use for the installation of tie rods by means of robotics, was identified as potentially suitable for underwater use. It was decided to carry out the fine tuning and the evolution of the technology for a marine environment of the robot unit and of the related remote control software that controls the installation of the tie rods. An experimental test site was set up to refine the drilling, installation, grouting, monitoring and testing of underwater tie rods. The purpose was to confirm the feasibility of the proposed solution and the reliability of these tie rods for use in the reinforcement and construction of wharves. The paper also discusses the theoretical and experimental study of underwater tie rods dealing with the theoretical analysis of the interaction between tie rod and soil, aimed at identifying the correlation between the forces of applied traction and the corresponding measured elongations. A series of tests were carried out with positive results, both at the operating load of 300 kN (67 kips) and at the nominal maximum load of 630 kN (142 kips). The tests were carried out on seven tie rods, of which three were installed at a depth of 5.00 m (16 ft), principally to test the reliability of the operating and remote control systems in the presence of a significant hydrostatic pressure, and four were placed at a depth of 8.00 m (26 ft) to check the load bearing capability of the tie rods positioned at the depth called for by the current project.

Jan 1, 2011

By Sachihiko Tokunaga, Hirofumi Taguchi, Kenji Maruyama, Hidenori Takahashi, Yoshiyuki Morikawa

"Abstract The present study proposed a new liquefaction countermeasure to improve sandy ground and conducted a trial execution. The new method is a floating-type and lattice-shaped cement treatment method, where cement-treated soil is not fixed to a non-liquefiable stratum. A fixed structure such as treated soil should be formed at the side of the floating-type treated soil to reduce its lateral displacement. In the study, one-dimensional dynamic response analyses were first conducted to confirm the mechanism of the new method. Then, a series of centrifuge model tests were performed to demonstrate the effect under a stress condition at the prototype scale. The analyses and model tests confirmed the effect of the liquefaction countermeasure. Finally, trial executions were carried out to confirm high-quality vertical execution.INTRODUCTIONLiquefaction induced by an earthquake generates sand boiling and ground settlement. Other problems have also been reported, including a decrease in bearing capacity and an increase in the horizontal earth pressure against retaining walls. To prevent these problems caused by liquefaction of the ground, various countermeasures have been proposed, such as cement deep mixing and high-pressure jet mixing methods. These methods have the big advantage of being applicable to ground that contains soil with a fine-grain fraction. Furthermore, the unnecessary displacement caused by the construction can be reduced. In Japan, a lattice-shaped cement-treatment method has frequently been used at many construction sites to prevent liquefaction, where cement-treated piles are intersected to form a lattice, as shown in Fig. 1. The lattice-shaped walls can reduce the shear stress generated by an earthquake, restricting the liquefaction at that location. However, the construction cost of the cement treatment is relatively high compared to other methods such as the sand compaction pile (SCP) method, and needs to be reduced. In particular, the cost of the high-pressure jet mixing method, which can be applied to the liquefiable ground under existing structures, is significantly high. Therefore, decreasing the total volume of the cement treatment is necessary to reduce the construction cost."

Jan 1, 2014

By A. Redman

Aquatic organisms are sensitive to free cyanide (HCN) though the presence of certain metals that can form stable complexes and thereby reducing both the amount of bioavailable cyanide. Recent work has suggested that consideration of HCN rather than total cyanide can provide the basis for water quality criteria. Cyanide is often present in complex effluents that affect speciation and bioavailability. We have developed a model to predict the speciation of cyanide in complex effluents and have shown that this model can predict the toxicity of metal-cyanide complexes in terms of HCN. This study evaluated available cyanide toxicity exposures with this model to assess the role of water chemistry (e.g., metal-cyanide interactions) on the observed. Toxicity endpoints based on total cyanide ranged over several orders of magnitude for a variety of metal-cyanide mixtures. However, predicted HCN concentrations among these same tests described the observed toxicity data to within a factor of 2. Aquatic toxicity can be well described using HCN though in certain metal-cyanide mixtures toxicity was jointly described by HCN and elevated levels of bioavailable metals. This work was performed in support of an industry-sponsored reassessment (Gensemer et al 2006) of the U.S. EPA water quality criteria for cyanide (EPA 1985) using free cyanide as the basis for the re-calculation. The work presented in this manuscript presents technical support for using free cyanide as the preferred basis for this recalculation.

Jan 1, 2011

Seam correlation in the central Rapahoe Sector (Greymouth Coalfield) can be enhanced by detailed lithostratigraphy and chronostratigraphy. Rewanui Coal Measures are overlain comformably by lacustrine, deltaic and fluvial strata, and this upper contact can be located using lithological and geophysical log character. The Cretaceous-Tertiary Boundary (KTB) occurs near the top of Rewanui Coal Measures and has been identified palynologically in 16 drillholes. The Rapahoe Sector can be subdivided into two palynostratigraphic domains which adjoin along a basement normal fault which was downthrown to the north during coal measure deposition. The KTB provides an isochronous surface which is independent of the lithostratigraphic datum. Using the KTB as a datum, the æUpperÆ, æMainÆ and æSubmainÆ seams can be reliably correlated throughout the southern and central Rapahoe Sector. Similarly, the æSubmainÆ seam can be correlated with æcÆ seam of the Strongman Mine area, though other Strongman seams are absent from the central and southern Rapahoe Sector.

Jan 1, 1996

By ALICE V. Petar

Thallium is one of the rare metals that has come into commercial use within recent years . Its comparative scarcity , combined with a resemblance to the common metal lead , have retarded the development of uses for thallium . Although production is still measured in pounds rather than in tons , it is now finding application in a number of fields . Perhaps the earliest commercial use of thallium was as a constituent of optical glass of higher refractive power than similar glasses containing lead . One of the later applications to attract attention was the use of the oxysulphide in a sensitive electrical device similar to the selenium cell . The " Thalofide " cell , which was patented in 1919 , constituted for a time the most important outlet for thallium. During the next few years the limited use of thallium and its salts in other fields was insufficient to absorb an annual production of a few hundred pounds , and the price dropped from $ 16 or $18 per pound in 1922 to $ 5 per pound in 1924 . Beginning in 1925 several new uses were developed , especially as a poison for rodents and ants , and as a result the demand for thallium increased sufficiently to cause a recovery in price to the present level of from $12 to $15 per pound .

Jun 1, 1931

The development of Western Mining Corporation's first commercial gold heap leaching operation is described. The laboratory testwork requirements for determining the amenability of ore to heap leaching techniques is discussed. Heap construction and operating practices are described; and production statistics and operating parameters are presented. It is shown that for a specific low grade gold ore a treatment cost optimization can be performed. Taking cognizance of the ore grade, percentage gold recovery, operating costs, and the gold sale price, it can be determined whether Carbon-In-Pulp (C-I-P) or Heap Leaching should be employed as the extraction process. The examples presented in this paper refer specifically to Kambalda and should not be used in themselves as generalities.

Jan 1, 1987