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By M. H. B. Nasseri

Barre granite?s samples have been tested for fracture toughness under mode I along two different directions with respect to microstructural fabrics were investigated. 3D objects counter algorithm technique is applied on micro CT images to identify physical properties such as crack induced porosity, crack density, generated total surface area and contribution of individual mineral grains within the damaged zone.The result obtained justifies very well the fracture toughness anisotropy in Barre granite, and explains the difference in the structure of the damage zone evolving as a result of test crack interacting with pre-existing microstructural fabrics. The present study has potential application in the fields of rock mass stability, oil reservoir stimulation, rock fragmentation and damage in blasting and emplacement of dykes.

May 1, 2009

WITH the exception of the deposits of the Milburn Cement Co near Dunedin, Wilson's Portland Cement Co., on the Mahurangi River (a short distance north of Auckland), and those of the New Zealand Portland Cement Co., at Limestone Island, the cement. Tesources of New Zealand remain practically undeveloped. The Milburn Company utilizes a mixture of limestone and mud for the manufacture of cement, while Wilson's and the New Zealand Portland Cement companies both have the advantage of a natural cement stock which requires but small additions of highgrade limestone to give the mixture required. The plant and deposits of the New Zealand Portland Cement Co are located in Whangarei Harbour, some six miles from thetownship of Whangarei. The works and dwelling-houses are situated on Limestone Island, which, with an area of 92 acres, and rising to a height of 212 ft., supplies the bulk of the raw material required. In addition to the island, the company possesses a high-grade limestone area of, roughly, four acres, situated on the mainland, 11 miles to the south. A better location for a cement works could not well have been chosen. On the east side of the island there is a deep channel, which never shows less than 18 ft. of water alongside the company's...

Jan 1, 1912

By Andre L. De Vegt, Cees J. N. Buisman

"For the past eight years Paques has been engaged in the development and installation of treatment systems based on biotechnological processes to remove sulfur compounds from water, air and gaseous streams. Metal and sulfate can be removed from mine waters using two biological steps:1. Sulfate reducing bacteria convert sulfate to hydrogen sulfide (H2S). The H2S reacts with the dissolved metals to form insoluble metal sulfide precipitates.2. Sulfide oxidizing bacteria convert excess H2S to elemental sulfur.Paques has designed and installed a groundwater treatment system for the Budelco zinc refinery in the Netherlands to remove metals and sulfate as described above. The system has been operating since May 1992 treating a flow of 5000 m3/d. A test program, utilizing a large scale pilot plant, will commence in November 1995 at a copper mine in the U.S.A. to remediate groundwater contaminated with sulfate and heavy metals. Biological reactor performance and selective metal recovery will be studied. Sulfur dioxide (S02) can be removed from fluegas using a combination of scrubber technology and the two biological steps. The end product is elemental sulfur. A commercial size biological desulfurization plant has been in operation since July 1994 treating 50,000 Nm3/h of fluegas. Sulfide can be removed from mining waters or anaerobic wetlands using a THIOPAQ® Sulfide Oxidizing reactor.lntroductionSulfur can be present in various water and gaseous streams in a mining operation. In many cases the sulfur compounds have to be removed because of toxicity, corrosive properties and contribution to acid rain. Mine waters can contain dissolved heavy metals. An efficient way to remove dissolved metals removal is the precipitation as metal sulfides. Paques has developed and installed treatment systems based on biotechnological processes to remove sulfur compounds from water, air and gaseous streams. These treatment systems biologically convert sulfate to hydrogen sulfide (H2S) which can be used in heavy metal precipitation. Excess H2S is biologically converted to elemental sulfur. This paper provides an overview of these newly developed biotechnological treatment systems."

Jan 1, 1997

By S. J. Oosthuizen

This article explores the Fray Farthing Chen (FFC) Cambridge process, a novel method for the electrochemical deoxidation of metal oxides in molten salt, discovered at the University of Cambridge in 1997. The process was hailed as a highly promising, potentially low cost, novel method for the production of titanium metal direct from its oxides. The article should inform researchers in the field of some of the challenges in the commercialization of a novel, high profile process involving multiple stakeholders. The author, former senior process engineer at British Titanium Plc, the company originally tasked with commercializing titanium production via the FFC Cambridge process, reviews the latest literature and discusses past and present progress in the pursuit of low cost titanium metal via this process. Topics explored include the history of the process, attempts at commercialization, NASA?s alternative application, and present status of the process. Keywords FFC Cambridge, titanium, molten salt.

Jan 1, 2011

Standards And Laboratory Monitoring In Gold Assay Key Components Of Best Practice

Jan 1, 2005

By S. J. Boone, A. Poschmann, C. Pound, A. Pace

San Diego’s Stadium Conglomerate consists of poorly cemented cobbles, gravel, sand, silt and clay. Conventional laboratory and in-situ testing is not suitable for characterizing its engineering properties. Although the formation is often considered a “rock” its behavior is more readily modeled using soil mechanics. Static and seismic design of a tunnel for the Mission Valley East light rail extension required that the stress-strain characteristics of the ground be identified over a broad strain range. Geophysical methods and field plate load testing were used to develop a full non-linear stress-strain model of the expected ground behavior. Quantification of the coarse material distribution was also required for selection of tunneling methods and construction considerations.

Jan 1, 2001

By Grant Loveday, Vincent Dieudonné, Andrew Jonkers

Bateman Minerals & Metals supplies the APIC Technologies which include the under-bed air-pulsed APIC jig and related technologies such as the JigScan controller and advanced mathematical models of the jig process. Bateman have developed a methodology for predicting process performance for jigs from simplified testing and modelling, based on batch equipment matched to industrial designs. Batch tests conducted on laboratory scale air-pulsed jigs can process small batches of material, such as those obtained from drill core samples. The novelty comes from using an advanced jig process model, ASTRAD, to link the results of batch and continuous jigs. The batch jig presented as a novelty in this paper has been designed to be hydraulically equivalent to the full-scale APIC Jig, allowing the generation of equivalent pulse shapes and using JigScan controller. Lump and fine ferrous ore material have been separated in this unit and any feed >1mm can be tested and extracted. The global test procedure and further modelling focus on the stratification of material, with emphasis on key aspects such as pulse shape, feed characteristics and residence time. The splitting of rejects from concentrates is itself more difficult to reproduce in batch jigging, however the ASTRAD model includes a separation imperfection module, and the APIC Technologies have extraction systems adapted to each type of material. Air pulsed batch jigs are available in several locations and are relocatable. They have been used to treat samples from Australia, South Africa and India as part of studies into ore processing using jigs. Each test layer is available for various physical testing procedures (density and chemical analyses). Test-work is performed on a case by case basis, and analysed using an advanced model ?now available over the internet. Some fundamentals of air-pulsed jigging are recapped along with some of the features of APIC jigs. The process of designing a ?hydraulically equivalent? batch jig test is then described. Some results from jigging tests are presented plus the results of the ASTRAD advanced jig model, which was first developed at the JKMRC with ferrous ores and coal and is now being supported and further developed and utilised by Bateman.

Jan 1, 2006

By H. Pei

PZH (Pan Zhi Hua) Iron and Steel (Group) Corporation, the biggest steel company in southwest China, has been using titanium-vanadium-magnetite as the main raw materials for blast furnace iron making processing for over 30 years. One of the problems that has a negative affect on the blast furnace operation is slag foaming. Based on the chemical components of the blast furnace slag-bearing higher TiO2, the foaming properties were studied. The TiO2content, which is calculated according to the total titanium content in all the forms of titanium compound in the slag, in this research is 30% weight per cent. Different forms of titanium compounds have different actions on the slag foaming behaviour that depends on the reduction condition in the blast furnace. The relationships among slag foaming performance and the binary alkalinity of the slag, the content of CaF2, MnO in slag, and the amount of gas injected in slag are investigated. The results show CaF2 and MnO have a stronger anti-foaming affect on the slag, even in the lower percentage. The way to measure high TiO2slag foaming performance and how to eliminate foamy slag are also discussed. Keywords: blast furnace slag bearing TiO2, foamy slag, foaming performance

Jan 1, 2004

By G. O. Oniyide, H. Yilmaz

The South African platinum mines in the Bushveld Complex (BC) have unique features that distinguish them from the gold mines. They have a higher horizontal stress closer to the surface, lower occurrence of seismic activity (caused mainly by pillar failure), and are sited in an area of high geothermal gradient. One of the future challenges of platinum mining is the increasing temperatures as the mining depth increases. High temperatures invariably bring about higher ventilation costs and require different approaches to human factors and ergonomics. Excavation stability would also be another area of concern due to increasing stresses. In this investigation, the effect of temperature on the physical and chemical properties of selected Bushveld rocks (chromitite, pyroxenite, norite, leuconorite, gabbronorite, mottled anorthosite, varitextured anorthosite, granite, and granofels) was studied by means of optical microscopy and scanning electron microscopy using energy-dispersive Xray spectrometry (SEM-EDX). The rock specimens were heated in a temperature-controlled oven a rate of 2°C /min to 50°C, 100°C, and 140°C and kept at temperature for five consecutive days. Samples were allowed to cool to ambient temperature (approximately 20°C) before image capturing. Micrographs of the specimens were taken before and after heat treatment. All the SEM samples were also subjected to heating and cooling on alternate days for ten days in order to observe the effect of repeated heating and cooling on the rocks. The results of the optical microscopy analyses showed minor physical changes in the rocks. The SEM images revealed that cracks initiating at lower temperatures extend with increasing temperature. The chemical analyses showed that the temperature range considered in this research is not high enough to induce changes in the chemical composition of rock samples.

Jan 1, 2016

By F. E. Joyce

This paper describes the development of a process for producing manganese and iron pellet concentrates from low-grade manganiferous iron ores of the Cuyuna range by a two-stage sulfatization-reduction roast. First, the manganese minerals (7.5 percent manganese) were converted to water-soluble manganese sulfate by roasting in sulfur oxide gases at 700° C, then, the hematitic iron minerals (31 percent iron) in the hot sulfatized are were reduced to magnetite with simulated reformed natural gas in the temperature range of 350° to 425° C. Batch tests were made in a 3-inch-ID by 6-inch-long, gas-heated, stainless steel retort, and continuous countercurrent experiments were performed in a 2-inch-ID by 10-foot-long, electrically heated shaft furnace. Manganese sulfate was removed from the roasted product by leaching with water, and over 90 percent of the manganese was recovered in an oxide product (65 percent manganese) obtained by precipitation, drying, and thelmal decomposition of the sulfate. An iron oxide concentrate (60 percent iron) with an iron recovery of 75 percent was obtained from the water-insoluble residue by magnetic separation.

Jan 1, 1973

By W. C. Lacy

Stratabound copper ore bodies in thick Proterozoic metamorphosed sedimentary and volcanic rocks at the Tong Kuang Yu Mine in southern Shanxi Province of China were considered as possibly being amenable to block cave mining. Initial evaluation of caving characteristics was based upon old calyx drilling records, limited underground mining experience and geological mapping, a few diamond drill holes and measurements in surface subsidence features. Classification and mapping distribution of rock quality types aided in mine design, prediction of fragment sizing and explosive requirements, cave assist and ground support requirements. Comparison is made between early feasibility predictions and actual mine experience.

Jan 1, 1989

By Francis Kendorski

The Skyline #3 Mine of Canyon Fuel Company in Utah was planning longwall mine development adjacent to and downdip of older mine workings known to be flooded. Barrier pillar geometries and widths were proposed by mining company personnel. Hydraulic conductivity testing suggested that the general characteristics of the local coal seam, dikes, and faults are only weakly conductive and that leakage through the barriers, if any, would be minor. The mechanical performance of the proposed barrier pillar design was evaluated according to (1) published empirical design methods and (2) numerical stress modeling. Comparison of the proposed design, with the range of barrier widths derived from the empirical methods, served as a first-order check on the adequacy of the proposed design. Numerical modeling was used to evaluate conditions site-specific to the Skyline #3 Mine and barrier geometry. Models were developed to quantify the relationship between barrier width and the abutment stresses onto the future workings. The models were also used to estimate the stress distribution within the barrier pillars. The hydraulic performance of the proposed barrier pillar design was evaluated according to (1) published empirical design methods for hydraulic impoundments, (2) empirical method estimates of seepage through coal barrier pillars, (3) numerical hydrogeologic flow modeling, and (4) numerical strain modeling. Using the techniques described above, and based on relevant industry experience, underground observations, knowledge of local geologic conditions, hydrogeologic measurements, and analytical results, the level of geomechanical risk associated with the barrier design as proposed was considered low and the level of hydraulic risk was considered moderate. The largest uncertainty that remained was the possibility that unfavorable geologic structures, such as faults and dikes, would act as conduits for leakage of impounded water into the new workings. Although the study indicated only minor steady-state leakage would occur through a small number of known structures, the presence and full leakage potential of threatening structures in the barrier could not be reliably known until the barrier was mined. One longwall panel has been completed adjacent to the barrier with no evidence of water flow even in fractured zones. Thus, as predicted by the modeling and analysis, it appears that abutment stresses imparted on the barrier during mining did not substantially alter the natural hydrogeologic characteristics, or leakage potential, of the barrier. The longwall coal mine water-barrier pillar design and performance are considered a success.

Jan 1, 2007

By C. Ringas

Pipelines are used extensively in industry to convey various products. Internal corrosion of pipelines can lead to perforation and leakage of the product. A growing problem, not often accurately recognized, is internal corrosion of pipelines caused by bacteria. Microbiologically-induced corrosion (MIC) refers to corrosion caused by a variety of micro-organisms. This form of corrosion is not widely recognized in many industries, although it is widespread and causes many corrosion problems in pipelines, both internal and external. Sulphate-reducing bacteria (SRB) are responsible for the bulk of the corrosion problems caused by MIC. Corrosion caused by SRB is found extensively in water pipelines conveying raw, potable and waste water, as well as in pipelines conveying slurries. This problem also occurs in pipelines conveying crude oil. This paper describes internal corrosion problems of slurry pipelines caused by bacteria and outlines mitigation methods to improve slurry pipeline integrity, thereby extending the life of such pipeline

Jan 1, 2007

By K. G. Thorne, L. J. Cabri, L. R. Fyffe, D. R. Lentz, D. Hoy

"Mineralization at the Main zone of the Clarence Stream gold deposit in southwestern New Brunswick occurs within a parallel series of quartz veins that occupy a NE-trending, steeply north-dipping, brittle-ductile shear zone related to the nearby terrane-bounding Sawyer Brook fault. This deformation zone cuts volcaniclastic sedimentary and volcanic rocks of the Silurian Waweig Formation, and is intruded by mantle-derived East Branch Brook gabbroic dikes and a number of felsic dikes. Intermittent shear-zone reactivation during local magmatic activity induced heterogeneous deformation and alteration of the country rocks and dikes. The terminal phase of shearing is associated with narrow pegmatite-aplite dikes that grade laterally into granophyric granite, and into an auriferous quartz vein. Gold, aurostibite, and gold-antimony intergrowths, predominantly with vein quartz, are associated with a low ƒO2 sulfide mineral assemblage (pyrrhotite, arsenopyrite, and berthierite) that has a sulfur isotopic signature consistent with a magmatic source. Gold saturation and deposition occurred episodically between 300° and 360°C at low activity of sulfur, predominantly in response to pressure reduction during brittle failure combined with the effects of decreasing temperature and sulfidation reactions during fluid-wall-rock interaction. Geochronological studies demonstrate that the timing of the emplacement of the pegmatite-aplite dikes and associated auriferous veins overlap with that of the Early Devonian Magaguadavic granite. Moreover, the composition of the dikes is consistent with their derivation from this granite as late fractionates. The Main zone of the Clarence Stream deposit is therefore interpreted to be intrusion-related, with the Magaguadavic granite being the ultimate source of the gold-bearing fluids. La minéralisation de la zone principale du gisement aurifère de Clarence Stream dans le sud-ouest du Nouveau Brunswick occupe une série de veines de quartz parallèles dans une zone de cisaillement fragile-ductile de direction NE et à pendage abrupt vers le nord apparentée à la faille de Sawyer Brook avoisinante qui délimite deux terranes. Cette zone de déformation recoupe les roches volcaniclastiques et volcaniques de la Formation de Waweig d’âge Silurien et est recoupée par les dykes de gabbro d’East Branch Brook, d’origine mantellique, ainsi que par divers dykes felsiques. La réactivation intermittente de la zone de cisaillement durant l’activité magmatique locale a entraîné la déformation et l’altération hétérogènes des dykes et de l’encaissant. La phase finale du cisaillement est associée à de minces dykes d’aplite-pegmatite qui passent latéralement à des granites granophyriques, puis à des veines de quartz aurifères. L’or, l’aurostibite et les intercroissances d’or et d’antimoine principalement associées aux veines de quartz sont associés à un assemblage minéral de sulfures à faible ƒO2 (pyrrhotite, arsénopyrite et berthierite) présentant une signature isotopique du souffre compatible avec une source magmatique. La saturation en or et la précipitation a eu lieu épisodiquement entre 300° et 350°C dans des conditions de faible activité de souffre, principalement en réponse à la baisse de pression durant la rupture fragile ainsi qu’aux effets de la baisse de température et aux réactions de sulfuration durant l’interaction entre le fluide et l’encaissant. Les études géochronologiques indiquent que l’âge de la mise en place des dykes de pegmatite-aplite et des veines aurifères qui leur sont associées coïncide avec le granite de Magaguadavic, d’âge Dévonien Précoce. De plus, la composition des dykes est compatible avec une origine provenant de ce granite sous la forme de phases fractionnées tardives. Le gisement principale (Main zone) de Clarence Stream est ainsi considéré comme étant associé aux intrusions, le granite de Magaguadavic étant la source ultime des fluides aurifères."

Jan 1, 2008

By Ludger Suarez-Burgoa

At the Porce III Underground Powerhouse Complex in Colombia, the observational method (Peck, 1969), was used to provide information to an underground wedge and a 2D Finite Element Method numerical models, both used to estimate the mechanical behavior of the hoisting rock mass. The observation process consisted in collecting fault events in the field and in interpreting Multiple Point Borehole Extensometers and Surface Convergence Displacement Points readings. The calibrated models were employed to predict the behavior of the pillars formed between the machine and transformer caverns. The observational method is an important activity during excavation of large openings and provides arguments to understand the rock mass mechanical behavior.

Jan 1, 2008

THE Synthetic Liquid Fuels Act. (30 U.S.C., 321-325, and amendments) became law April 5, 1944, and a period of intensive research and development in this field was begun by the Bureau of Mines. As part of this program, bulletins were published on pressure hydrogenation.3 the Fischer-Tropsch synthesis,4 anal oil shale.5 The Bureau also has published a short bibliography on coal gasification,6 mostly of a theoretical nature. Because coal gasification is prerequisite to either the Fischer-Tropsch or coal-hydrogenation processes, publishing this sizable collection of technical information in this form will be valuable. The material will be presented in three parts, as follows: I. United States Patents. II. United Kingdom Patents. III. Other Foreign Patents. The domestic patents for this bulletin were collected between 1953 and 1955.

Jan 1, 1960

By Y. M. Chen, H. L. Zhang, W. U. Bing, C. Q. Zhou

Multiphase flow in the widely used Vanyukov furnace was numerically studied. An unsteady three-dimensional and three-phase flow model was firstly built using the computational fluid dynamics (CFD) software ANSYS FLUENT®, and then solved with the volume of fluid (VOF) and k - ??model. The results showed that the proposed model could be used to predict the multiphase movement, the slag/air fluctuation, the vortex formation, and effects of structural and operational parameters. By fast Fourier transform (FFT), the dominant frequency of density with time signal was calculated as 0.29 Hz. The analysis of different injection flow rates of enriched air indicated that this variable has a major effect on the mean slag velocity. The peak mean velocity increased from 2.17 to 4.99 m/s while the flow rate of enriched air varied from 70 to 160 m/s. The proposed model provides a method to optimize the furnace structure and operating conditions for the best furnace performance and lowest energy consumption.

Jan 1, 2015

By Scales PJ, Ralston J

Fine coal particles have been examined with respect to dustiness and its connection with various physical and chemical properties. It appears that a given coal will tend to be dusty ifthe moisture content is low and if the inert maceral content and overall rank are high. The hydrophobicity ofa coking coal (Young-Wallsend) and a steaming coal (Blair Athol) was examined in detail by a dynamic contact angle technique. The YoungWallsend coal had a higher contact angle, on average, than the Blair Athol sample. This result has important implications for dust suppression and associated processes.

Jan 1, 1986

By H. F. Letient, D. C. Johnson

At the 25th Annual B.C. Mine Reclamation Symposium in September 2001, Huckleberry Mines Limited received the Jake MacDonald Reclamation Award for its exemplary mine waste management plan, conceived to prevent the onset of acid rock drainage (ARD) and facilitate reclamation of the site. The mine is an excellent example of a total mine waste management plan, with all materials scheduled in detail for the life of the mine. The filling plan for the waste management facility takes into consideration the requirement for permanently flooding the potentially acid-generating rock. From an acid generation point of view, the tailings fall in the zone of potentially acid-generating material. To avoid long-term ARD concerns, it is planned to float pyrite out of the tailings toward the end of the mine life, thereby generating a non-potentially acid-generating tailings stream which will be used to cap the deposited mine waste. The pyrite-rich tailings will be discharged into the deeper portion of the impoundment. On closure, a permanent water cover will be maintained over the mine waste. Only beaches of non-potentially acid-generating tailings will remain exposed. Mining will be phased to also allow one of the pits to provide storage for potentially acid-generating rock and to be flooded at the end of mine life.

Jan 1, 2004

Komatsu America International has introduced two new hydraulic excavators. They can work in congested and confined areas. The tight tail swing radius of the PC128US-2 and PC22-8USLC-2 enables the excavators to minimize the work space. The units can operate in confined work settings that are inaccessible or counterproductive to traditional machines. Even the door is designed for tight working conditions. A convex door slides open along the exterior curve of the cab, rather than swinging out on hinges past tracks. And the excavators’ tight tail swing design allows them to load within the track width of the machine.

Jan 1, 2000