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By I. Westermann, K. Marthinsen, M. S. Remøe

"Al-Mg-Si alloys often add small additions of e.g. Mn or Cr, to form dispersoids, which may act as nucleation sites for Mg2Si particles after homogenization. The purpose is to ensure a high density of uniformly distributed small ?’-particles, which can be dissolved during further processing prior to the final age hardening step. However, their density and spatial distribution are critically dependent on the homogenization procedure. It is therefore important to have a robust and reliable method for assessing their spatial distribution. In the present work an existing methodology for assessing spatial uniformity, the Global Shannon Entropy (GSE), has been implemented and evaluated for different dispersoid structures characterized by scanning electron microscopy. This metric is highly dependent on the parameters used, but by careful selection of adequate parameters, it can be effective in detecting non-uniformity. An important weakness with the GSE was identified, and a modification to improve on the ability to differentiate degrees of non-uniformity is suggested. To evaluate the proposed methodology, the effect of heating rate on dispersoid precipitation behaviour during homogenisation of four Al-Mg-Si alloys with different Mn/Cr-content has been investigated. The metric with the new term has demonstrated promising results, and improved the ability to differentiate degrees of spatial uniformity.INTRODUCTION Al-Mg-Si series alloys are the most common aluminium extrusion alloys and are attractive for applications in a range of sectors (e.g. construction, automotive and recently also in consumer electronics), due to their generally good combination of strength, ductility and corrosion resistance. However, their extrudability and end properties depend critically on the alloy chemistry as well as prior processing conditions. Coarse ß-AlFeSi or Mg2Si-particles typically have a detrimental effect on extrudability, while small dispersoid particles may affect recrystallization, grain growth and precipitation of Mg and Si. The strengthening potential in the final age hardening step depends strongly on the amount of Mg and Si in solid solution after extrusion. The manner in which these particles are spatially distributed will decide whether the final product will exhibit uniform properties, and the number density and sizes will determine the extent of the effect. As such, these are important characteristics."

Jan 1, 2018

By Y. W. Pan, Y. R. Liu

The disturbed natural rock mass tends to equilibrium state accompanying with non-equilibrium evolution process which has significant influence on the long-term stability of engineering structure. The deformation development in the non-equilibrium evolution is determined by two intrinsic processes, trend to equilibrium and damage development, which can be illustrated by evolution of excavated tunnel. Thus the creep and damage must be taken into account in study of non-equilibrium evolution process. Within Rice’s irreversible thermodynamics with internal state variable (ISV), the conjugate force function which equals to zero is a convex surface which divide the stress space into two parts, called equilibrium and nonequilibrium stress space respectively. The concept of effective stress of non-equilibrium has been proposed, in which the stress difference (d - d ) are the effective driving forces of non-equilibrium evolution process with hardening and damage effective. The formulations of inelastic strain rate and energy dissipation rate have been recast in the form of effective stresses. The inelastic complementary energy (ICE) is proposed to measure intensity of non-equilibrium evolution of material system. The specific equations of conjugated forces and kinetic equations of internal state variables are presented. The ICE and rate of energy dissipation are all calculated to be used to evaluate long-term stability of geo-engineering. The results show that rate of energy dissipation may be more convenience and flexible than ICE for internal state variable constitutive equation of rock mass.

Jan 1, 2015

By A. B. Baldwin

"Uranium and thorium mineralization occurs at several localities in eastern Quebec along the north shore of the Gulf of St. Lawrence. The main occurrences are near Sept-Iles, Baie Johan Beetz, Romaine and St-Augustin river. Mineralization occurs mainly as disseminated uraninite, uranothorite, uranothorianite, monazite and minor zircon and allanite. Yellow to orange oxidation products are observed along fracture planes of the uranium-bearing deposits to a depth of a few feet. Magnetite, biotite and smoky quartz have a distinct tendency to accompany the radioactive minerals. The host rocks include white to pink pegmatite, pink granite and also, in the case of the Romaine and St-Augustin River occurrences, cream to grey plagioclase-rich, well foliated paragneiss and migmatite. Radioactivity near secondary structures, such as fractures and joint planes, indicates some reconstitution of radioactive minerals.The North Shore of Quebec is the northeast extension of the Grenville sub-province. It is also a uranium-thorium metallogenic province."

Jan 1, 1970

By S. R. L. Harding

"Introduction0N MAY 2th, 1953, Socony Seaboard Pembina No. 1 well, located 70 miles west-southwest of Edmonton, was completed as a producer of high-gravity oil from the Cretaceous Cardinm sand. This event is possibly the most significant in the development of the oil industry in Western Canada since the Devonian discovery at Leduc in 1947. The result of the Pembina discovery and the follow-up drilling has been a tremendous increase in interest in the Cardium formation.Descriptions of the Cardium formation, as it occurs in the 'Central Foothills' and in the 'Southern British Columbia Foothills' have been presented by R. E. Folinsbee (9)-and C. R. Stelck (21), respectively. The purpose of this paper is to discuss the more regional aspects of the subject.The name Cardium was first used .as a stratigraphic term in 1863. Dr. James Hector ( l2), geologist attached to Captain John Palliser's exploratory expedition, gave the name 'Cardium to the whole section of marine Cretaceous beds exposed along the Bow river west of Calgary."

Jan 1, 1955

By S. A. Pence, A. I. McCallum, V. de Korompay

"Special salt protection rings containing a water-swell• able, polymeric sealant are in successful operation in Canadian potash shafts. Installed above the Prairie Evaporite salt formation at a depth of 3,000 feet, the sealant is preventing formation water migration into the salt and pressure build-up on the concrete lining of both production and service shafts. The salt protection rings are not under the hydrostatic pressure of the formation water.The chemical sealant in use has the unique property of imbibing water and swelling. •Therefore, any water at• tempting to flow by the seal ring actually produces a tighter seal.The purpose of this paper is to discuss the sealant and its properties and uses. Installation of the material and its operation in two Canadian mine shafts is described."

Jan 1, 1971

By D. Van Tonder

ABSTRACT The comparative economics of ion exchange and direct precipitation have been analyzed by developing indicative CAPEX/OPEX models for typical alkaline leach uranium circuits. An agitated tank ore leach application is considered, comparing resin-in-pulp and direct precipitation as recovery options. Capital and operating cost estimates are derived from rates and factors used in recent studies and projects. The analysis showed the main economic drivers to be the ore grade and resin loading. The resin loading is impacted by the prevalence of competing ions, especially chloride. At resin-in-pulp solution chloride concentrations below 3 g/L and uranium grade below 640 g/t U3O8, resin-in-pulp is more economical, whereas at chloride concentrations above 3 g/L, direct precipitation is more economical.

Jan 1, 2012

By R. S. Fitzpatrick, P. Hegarty

"Gravity separation is a key technology in the recovery of a range of mineral ores including coal, tin, tungsten and tantalum. One of the problems associated with gravity concentration is that recovery is traditionally lower than for other separation techniques such as the flotation of base metals. Any improvements in recovery will, therefore, have a significant effect on the economics of operations of this type. More accurate, robust modelling of gravity separators is one means of achieving greater recoveries. Furthermore, better modelling can lead to more informed equipment selection and process design for potential economic deposits.Previous models for gravity separation equipment have typically relied on simple metal mass balances from samples of the separated products. However, with advances in technology there is a ready availability of analytical instruments for the automated quantitative determination of mineralogy. Instruments such as the Mineral Liberation Analyser and QEMSCAN make it possible to estimate particle size and density (related to mineral liberation and association) which are the primary factors in gravity separation. Models produced using quantitative mineralogy of feed streams will be potentially superior to those produced historically.This paper describes test work undertaken on a wet shaking table using a synthetic ore. The objective of this test work was to develop a model to predict the effect of changes in feed ore characteristics on shaking table performance by measuring quantitatively the mineralogy of the feed material. Particles were divided into size/density classes based on the results of QEMSCAN analyses.It was found that it was possible to use data from QEMSCAN to predict the recovery of size/density classes and to predict the effect of changes in the relative abundances of these classes on the separation. This model can potentially be used to adjust operating variables to maximise grade and recovery by monitoring the input feed. Care was needed when utilising QEMSCAN data to ensure representivity."

Jan 1, 2016

By J. Stiksma, K. Buban, J. Oftsie, R. Kalanchey, S. Sadykov, E. McConaghy

The Kazakhmys zinc refinery in Balkhash, Kazakhstan, which employs the Dynatec Zinc Pressure Leach Process, officially launched autoclave operations on December 27, 2003. The Kazakhmys plant is the world's first greenfields zinc refinery based on Dynatec's two-stage pressure leach technology. Production of zinc was realized on February 9, 2004, when the first cathode was stripped. Currently the plant start-up is ongoing, with progression to two-stage zinc pressure leach operation and ramp-up to full design capacity continuing through 2004.

Jan 1, 2004

By Hyung Sup Choi

The preparation of high-purity zirconyl compounds was studied in order to develop an economical process for obtaining pure zirconium via the caustic fritting of zircon sand. The direct dissolution of caustic frits with concentrated hydrochloric or nitric acid at 80c. followed by the addition of a small amount of acidified gelatin, gave high-purity zirconyl chloride or nitrate. The addition of a small amount of gelatin caused a mutual flocculation between colloidal silica and gelatin. The precipitation of this silica floc markedly lowered the content of silica in the product. The silica content of the compounds (or solution) so produced, generally less than 100 ppm., was sufficiently low for tributyl phosphate extraction for nitrate solutions. It was found that the degree of purification de-pends not only on the procedures employed but also on the nature of the frit itself. Silica was more effectively eliminated from the fritted product produced at higher temperatures, and less silica was present in the com-pound prepared from the frit produced in a shorter heating time. In order to ascertain the nature of the

Jan 1, 1965

By G H. Reavely, The University of Western Ontario Department of Geology

The lower Middle Devonian Sylvania Sandstone occurs in the sub-surface in the western part of Mal-den township, Essex county, Ontario. The formation is composed of well rounded, frosted quartz grains with a silica content varying from 42 to 93 per cent and the grains are cemented by carbonate, constituting up to 57 per cent of the rock. This sand-stone is not a homogeneous bed but is divided by strata rich in carbon-ate cement. The thickness of the Sylvania in Malden township varies up to a known maximum thickness of 88 feet. The lower contact with the chert-bearing Bois Blanc formation is sharp but the upper contact with the Amherstburg formation (Detroit River group) exists as a transition by a gradual downward increase in quartz grains. The Sylvania would seem to outcrop in the lake bottom near the mouth of the Detroit River dipping to the north along a broad anticline the axis of which follows the Detroit River. Just south of Amherstburg, a local east-west trending

Jan 1, 1961

By Brian Hart, Zhe Chen, Liuyin Xia, Mana Pourdasht, Stamen Dimov

"Gold losses related to carbonaceous matter (CM) during processing are a significant problem in the gold processing industry. Inherent CM in gold ores can behave similarly to activated carbon in its ability to adsorb gold cyanide. This phenomenon is termed preg-robbing as the surface adsorbed gold cannot, for the most part, be recovered. Research has identified that gold adsorption by inherent CM is linked to the specific surface area, pore structure, degree of C disorder and surface functional groups. One of the strategies to inhibit CM preg-robbing prior to leaching is a chemical oxidation; a process linked to modification of the surface functionality. In this study, the variability in gold cyanide adsorption due to oxidation with different reagents has been investigated. Variability in gold cyanide adsorption by CM is examined in relation to structural and surface modifications using TOF-SIMS, XPS and Raman spectroscopy.INTRODUCTION A major obstacle for effective gold recovery during carbon in leach (CIL) or carbon in pulp (CIP) processes carbonaceous gold ores is the presence of carbonaceous matter (c-matter) which has the ability to adsorb, or preg-rob gold from the cyanide leach solution. It can be responsible for poor recoveries as the carbonaceous materials (CMs) within the ore competes with activated carbon used during the leaching and adsorption phase of processing (Cay, 2014). Preg-robbing capacity can vary significantly with mild preg-robbing ores showing absorption capacities of less than 1 g Au/t ore, while severe preg-robbing ores may have CM with the capacity to preg-rob more than 500 g Au/t ore (Dunne, 2007). Research by a number of groups have shown that the degree of C disorder has some influence on the ability of the carbonaceous material to adsorb Au(CN)2- (Miller et al, 2005, Helm et al, 2009, Hart et al, 2010). It is also apparent the adsorption characteristics of carbonaceous material is affected by changes in surface chemistry (Dimov, 2016). Various treatment including; flotation to remove the carbonaceous material (Wills, 2010), addition of surface blinding agents (for example kerosene) to passivate or blanket the carbon surfaces (Dimov, 2016), addition of strong adsorbents (eg. activated carbon or resin) to compete with the carbonaceous material and passivation or surface coating by oxidation (pressure, roasting, chlorination and biological oxidation), have been employed prior to leaching in an attempt to minimize the gold losses (Dunne, 2013)."

Jan 1, 2017

By I. V. Kojo

Continuous development of technologies has been self-explanatory for Outokumpu Technology's engineers for decades. The aim in the development has always been the improvement of profitability of the copper production but also the sustainability of the processing i.e. high copper recovery, low external fossil based energy utilization, high emission captures and of course low operation and investment costs. Outokumpu Technology's long-term view of the development is a change towards continuous processes and elimination of number of unit operations in smelting i.e. elimination of possible sources of emissions. Outokumpu blister smelting processes i.e. Outokumpu Direct-to-Blister Flash Smelting and Kennecott-Outokumpu Flash Converting have shown excellent operational results during the years of operation and it is expected that soon more than 10 % of the world primary copper is produced by these technologies. The paper will give some background of this development trend.

Jan 1, 2007

By G. Avramovic-Cingara

Grain boundary characteristics and microstructural evolution are analyzed in a comparative study using orientation imaging microscopy (OIM/SEM) and transmission electron microscopy (TEM/SAD). The subgrain sizes and misorientations were determined by the OIM for aluminum deformed in torsion to equivalent strains between 0.2 and 4 over the temperature ranges of300-600°C and strain rates 0.01-1 s". The OIM gives clearer evidence of boundaries with high misorientation than does TEM, but it overestimates their frequency b y missing boundaries less than 1 0. T EM more clearly reveals low-angle arrays of widely spaced dislocations resulting in finer subgrain sizes than those indicated by OIM. The evidence supports a mechanism combining dynamic recovery (DRY), deformation band formation with permanent boundaries and geometric dynamic recrystallization (gDRX) in contrast to the hypothesis known as continuous dynamic recrystallization (cDRX).

Jan 1, 2004

By Long Han, Beijing General Research Institute of Mining and Metallurgy, Yu Xie, Yunhai Zhang, Yangge Zhu, University of Science and Technology Beijing, Yanbo Shang, Xingrong Zhang

"The first-principles method was employed to study the adsorption of hydroxyl calcium (CaOH+) and hydroxyl (OH-) on hematite and quartz surfaces. The calculation results suggested that OH- preferred to interact with the active Fe sites on the hematite surface, whereas OH- adsorbed on the quartz surface by weak hydrogen bond. Though CaOH+ could easily adsorb on the hematite and quartz surfaces by the formation of Ca-O bond, the covalence formed on the quartz surface was apparently stronger than that on the hematite surface, meaning a stronger and more stable adsorption. CaOH+ adsorbed on quartz surface was mainly through the interaction of O-2p and Ca-3d states, and this interaction on hematite surface was weaker.INTRODUCTIONIron Increase and Silicon Reduction Technology (Yu & Duan, 2002) of hematite is mainly through the reverse flotation (silica is floated away from the iron concentrate). There are two ways to achieve this (Houot, 1983). One is to collect quartz by cationic collector directly; the other is to activate quartz by lime and then collect it by anionic collector. There are two main different views with respect to the mechanism of quartz activation: mono-hydroxyl compound theory (Fuerstenau, Rice & Somasundaran, 1965; Fuerstenau & Palmer, 1976) and surface hydroxyl precipitation theory (Hu & Wang, 1988; Wang & Hu, 1990). The former indicated the formation of the mono-hydroxyl complex is one of the two criteria of quartz flotation. The later theory, on the other hand, suggested that surface precipitation is the adsorption of active species of metallic ion on quartz surface. However, most of those researches are based on the solution chemistry of flotation and little is done at the microscopic level.In this paper, by the help of first-principles calculations, the adsorption models, bonding conditions, Mulliken charge populations and adsorption energies of hydroxyl and calcium hydroxyl ions (OH- and CaOH+) on hematite (001) and quartz (100) surfaces were investigated to find out the lime activation of quartz at atomic level, which is significant for the researches of quartz activation theoretically and practically."

Jan 1, 2016

"THE Canadian Advisory Committee on Coal Research, which is commonly known as CACCR, has been in existence for the past five years and has held annual meetings during that period. This Committee is comprised of representatives from: the Mines Branch, Fuels and Mining Practice Division, Ottawa; the Geological Survey of Canada; the Dominion Coal Board; and the Provincial Research Councils and Foundations. It embraces all coal research in Canada that is sponsored, for the most part, by Government funds.To bring the country's coal research activities to the notice of the Canadian coal industry, the Coal Research Committee of the Coal Division, C.I.M., passed a resolution at the 1964 business meeting in favour of recommending the publication of an annual research report prepared by the CACCR. The first such report was published in the September, 1964, issue of the C.I.M. Bulletin; the second appeared in the November, 1965, issue of the same publication."

Jan 1, 1966

By J. E. Danoczi

Shore Gold Inc. (Shore) is presently designing a diamond processing plant for the Star and the Orion South kimberlite deposits in the Fort à la Corne (FalC) area in central Saskatchewan. The first step in the plant is diamond liberation and occurs in the comminution section. Diamond liberation is the process of breaking up the kimberlite rock, as gently as possible so as not to damage the diamonds. Autogenous grinding mills (AG mills) use a combination of impact crushing, abrasion and attrition to break up the kimberlite. The forces that occur during the actions of abrasion and attrition cause the kimberlites to break up preferentially along lines of weaknesses which offers a ?diamond friendly? method of comminution. Hard competent kimberlite is commonly found in the diatreme zone as well as the root zone of the volcanic pipe and is the source of kimberlite for most of the Southern African diamond mines. Softer kimberlite is typically found in and around the crater area of a volcanic pipe and it is this kimberlite that makes up the majority of kimberlite for both the Star and Orion South deposits. These softer kimberlites can be readily broken up using abrasion and attrition imparted by AG mills. In order for Shore to benefit from the softer kimberlite found in the Star - Orion South diamond project, two large (10.97 m diameter x 7.10 m long) AG mills were designed for the comminution section based on extensive test work and simulations by Metso Minerals (Metso).

Jan 1, 2012

By S. R. McCutcheon, D. R. Lentz

"Abstract - The 12.1 Mt Brunswick No. 6 Zn-Pb-Cu-Ag massive sulfide deposit (New Brunswick, Canada) lies between two subaqueous felsic volcanic formations near the base of the Middle Ordovician Tetagouche Group. The footwall comprises rhyodacitic pyroclastic rocks (Nepisiguit Falls Formation), whereas the hanging wall comprises a sequence of rhyolitic flows, breccias, and hyaloclastites (Flat Landing Brook Formation), with an age difference of less than 3 m.y. The Brunswick No. 6 deposit is a proximal autochthonous deposit with a well-zoned massive sulfide body and a basal Cu zone that, at depth, develops into a stockwork stringer sulfide (feeder) system. The massive sulfides are capped sharply by a layered magnetite-chert unit that extends regionally beyond the deposit. The deposit has a keel shape (sheath) formed by the F1F2 interference pattern. The heterogeneous ductile deformation and upper greenschist-grade regional metamorphism has transposed many of the epigenetic stockwork structures and alteration within the host sequence. Hydrothermal alteration is much more extensive, both vertically and laterally, in the footwall (a few 100 m) than in the hanging wall (<100 m). Anomalies farther up in the hanging wall sequence seem to be associated with independent alteration systems related to the rhyolite domes. The least-altered footwall units exhibit keratophyric alteration (albite or adularia) and weak Mg enrichment (chlorite). More intense micaceous (sericite and Mg-rich chlorite) alteration occurs around the footwall sequence. The transposed stockwork stringer sulfides are typically composed of Fe-rich chlorite (± sericite, ± silica) with pyrite, pyrrhotite, chalcopyrite, arsenopyrite, and sphalerite. The (Fe2O3T+MgO)/(Na2O+K2O) and base metal alteration indices are the best practical lithogeochemical vectoring tools at this deposit. Sommaire - Le gîte de 12.1 Mt de sulfures massifs de Zn-Pb-Cu-Ag Brunswick No.6 est localisé entre deux formations volcaniques felsiques sous-marines situées près de la base du Groupe de Tetagouche d’âge Ordovicien Moyen. Le mur consiste en roches pyroclastiques rhyodacitiques (Formation de Nepisiguit Falls) tandis que le toit consiste en une séquence de coulées, de brèches et d’hyaloclastites de composition rhyolitique (Formation de Flat Landing Brook); la différence d’âge entre les deux est de moins de 3 m.y. Le gisement Brunswick No. 6 est un gîte autochtone proximal comprenant un corps de sulfures massifs clairement zoné ainsi qu’une zone cuprifère basale qui passe progressivement à un stockwork de filonnets de sulfure en profondeur (feeder). Les sulfures massifs sont abruptement surmontés d’une unité laminaire de chert et de magnétite dont l’extension par delà le gisement est régionale. Le gisement affecte la forme d’une quille (fourreau) résultant d’un patron d’interférence F1F2. Plusieurs des structures épigénétiques du stockwork et des patrons d’altération de l’encaissant ont été transposés par la déformation ductile hétérogène ainsi que par le métamorphisme régional au faciès des schistes verts. L’altération hydrothermale est beaucoup plus importante, tant verticalement qu’horizontalement, dans le mur (quelques 100 m) que dans le toit (<100 m). Les anomalies situées plus haut dans le mur semblent être reliées à des systèmes d’altération indépendants associés aux dômes de rhyolite. Les unités les moins altérées du mur une altération kératophyrique (en albite ou en adulaire) ainsi qu’un faible enrichissement en Mg (chlorite). Une altération en mica (séricite et chlorite magnésienne) plus intense est présente autour de la séquence du mur. Les sulfures du stockwork de filonnets transposés consistent typiquement en chlorite ferrifère (± séricite, ± silice) accompagnée de pyrite, de pyrrhotite, de chalcopyrite, d’arsénopyrite et de sphalérite. L’indice d’altération (Fe2O3T+MgO)/(Na2O+K2O) et l’indice des métaux usuels sont les outils d’exploration les plus appropriés dans ce gisement."

Jan 1, 2006

By G. A. Gross

DURING the past 5 years a large amount of money and effort has been expended in exploration of iron-formations and in testing their suitability for beneficiation. Beds of ferruginous material are numerous and widely distributed in the Precambrian rocks of Canada and practically all of the known iron ranges or belts have been examined to a limited degree at least in an effort to evaluate their potential as sources of iron ore. A number of favorable beds have been selected for mining on completion of surface sampling, diamond drilling, extensive metallurgical testing and economic studies, and many other ranges are being studied. There are still a great many iron-formations that have not been evaluated by modern concentration methods and their regional extent is not fully known. The iron-formations are easily located by airborne or ground magnetic surveys but the main task in finding a mineable ore-body of this type amounts to locating a bed sufficiently large for mining which consists of material that can be concentrated economically by modern beneficiating methods. The ease with which an iron-formation can be concentrated to give a marketable ore depends primarily

Jan 1, 1961

By A. Hayatdavoudi, K. G. Sawant, F. Boukadi

"In this work, we found that contact between shale and water results in development of micro fractures. Based on results of experiments on Pierre shale, we conclude that appearance of micro fractures begin with saturation of capillaries, ionic and diffusive transport of water into the shale clays and once capillaries are saturated, the cause of micro fracture propagation is the conversion of ionic activity/exchange to excess pressure that did not exist before fracking. Based on these findings, the spread of micro fractures appear to be a time-dependent phenomenon which has not been addressed in the existing macro/micro fracture models.INTRODUCTIONShale has often been involved as a hazard in drilling operations. This hazard can be defined as “destabilization” of shale. When contacted with water-based drilling fluids, some shales readily swell and sometimes, cause the wellbore to cave-in, slough, wash-out, close, and pack-off, impeding the drilling by sticking the drill-pipe. However, once drilling reaches the desired depth or length, the casing is set, cemented, and perforated, and then actually we wish to initiate fractures and destabilize the shale formation, using hydraulic fracturing.Clays constitute a major portion of minerals in shale. These clays contain a large amount of free energy which is the main factor for “slick” water adsorption/absorption. In fact, the reason for using “surfactants” in hydraulic fracturing fluids is to make the penetration of the fluid into the capillaries much easier, thus water meets with less resistance to enter the small capillaries. Also, the result of high capillary suction pressure is due to small Angstrom size capillaries, smaller pores and presence of ions and hydrateable metal atoms. The free energy is thus, related to all the above mentioned and other affects. Capillary pressure, osmotic pressure and other pressures are responsible for creating the micro-fractures in shale, thus, increasing the network of micro-fractures which leads to more gas production. The objective of this study is to evaluate the pressures of the individual ions which are released by the diffusing “slick” water into shale. These pressures would be added to the above mentioned capillary pressure, osmotic pressure, bacterially-induced pressures, chemically-induced reaction pressure, pressure due to exchangeable ion-transport, pressure due to release of free energy of solvation and eventually to the pore pressure as suggested by Terzaghi’s equation."

Jan 1, 2015

By G. A. Witwicki

"The Thyssen Mining Group of Companies has successfully applied ground freezing technology to numerous projects throughout Europe and North America for over 100 years. Recently, the aspect of data acquisition and data verification has received greater focus.Thyssen Mining has been engaged in several relatively deep shaft sinking projects over the past five (5) years, all of which have required ground freezing to successfully sink through water bearing rock. To safely and economically sink through a quantity of water similar to Saskatchewan’s Potash Mines, it is imperative to understand freeze wall thickness and growth rate.Critical to understanding freeze wall thickness and growth rate, is the collection of accurate data as well as the interpretation of those data. The data can then be utilized to gain a better understanding of the freeze wall growth rate in active projects as well as to provide data to be utilized in modeling for future projects.This paper elaborates on the installation and operation of the data acquisition system utilized at the Newmont Leeville project, Nevada’s first frozen shaft project. In addition, this paper elaborates on the methodology developed by Thyssen Mining to manipulate the freeze wall data derived through the data acquisition system.The successful incorporation of the new system of collection and analysis of freeze wall data for the Leeville Project has given Thyssen Mining a high degree of confidence in the understanding, as well as prediction, of the ground conditions during shaft sinking.This paper will include:•,A brief description of ground freezing and its objective;•,An overview of previous data acquisition methods employed;•,Current data acquisition methods;•,Installation requirements; and,•,Data manipulation and presentation methods."

Jan 1, 2015