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By L. Dufourm

This paper presents a review of plant layout considerations incorporated into recent designs of SAG/Ball mill circuits for two medium sized concentrators. The plant layouts presented and the design concepts discussed, relate to smaller SAG circuits, but can equally apply to larger milling circuits. Included are design concepts and ideas introduced by the various project teams, and the focus is on the primary factors of any layout design which are safety, constructability, operability, and capital cost.

Jan 1, 2012

By Wayne D. Goodfellow, William M. Luff, Steven J. Juras

Brunswick No. 12 is a vent-proximal massive sulfide deposit that formed above a feeder pipe with associated hydrothermal alteration. Because of the replacement of bedded sulfides deposited above the hydrothermal vent, individual sulfide lenses show the following vertical and lateral zoning outward from the vent complex: massive pyrite-pyrrhotite-ehalcopyrite core interlayered pyrite-sphalerite-galena (pb-Zn ore zone) - bedded pyrite. The feeder zone which underlies the Cu-rich core consists of an anastomosing network of pyrite-pyrrhotite-chalcopyritequartz veins with variable and generally minor contents of ferroan carbonate, Fe-rich chlorite, sphalerite, galena and arsenopyrite. Hydrothermal alteration of felsic igneous rocks hosting and adjacent to the feeder pipe is represented by an inner zone (zone I) characterized by sulfide stringers, Fe-rich chlorite, muscovite, quartz, and ferroan carbonate that formed at the expense of feldspars and what was probably glass; outer zones (II and III) are represented by Mg-rich chlorite and muscovite formation, and the albitization and silicification of K-feldspar. Accompanying these alteration trends is a marked decrease of Na + Ca, and an increase in Fe + Mg + C03 in zone I, and increases in Mg + Na in the outer zones. The classic zoning of metals within the sulfide lenses, the formation of a feeder pipe below the vent-proximal sulfide core, and the hydrothermal alteration of felsic volcanic rocks cut by the feeder pipe all support a vent-proximal origin for the Brunswick No. 12 deposit. Furthermore, restriction of sulfide stringer mineralization to the footwall sequence, the folding of the stringer zone by an F, fold, and the difficulty of long distance mass transfer of metals from the sulfides into the host rocks all argue against a tectonic origin for the stringer zone. All of the evidence indicates that the feeder pipe formed during the ore forming hydrothermal event, but has been distorted and in some areas detached from the overlying massive sulfides during subsequent deformation.

Jan 1, 1992

By R. S. James, D. C. Peck, P. T. Chubb

"The East Bull Lake gabbro-anorthosite intrusion is one of several Early Proterozoic layered mafic intrusions occurring along the Southern Province - Superior Province boundary in the Elliot Lake - Sudbury region, Ontario. The base of the East Bull Lake intrusion comprises abundant plagioclase cumulates (Leucogabbronorite Zone) hosting two distinct styles of sulfide mineralization: (1) disseminated magmatic sulfides, and (2) disseminated to massive, structurally controlled sulfides. Both types of mineralization are enriched in Pd, Pt, Au, Cu and Ni. The host rocks to the sulfide mineralization display a range of interesting features including nodular textures, dendriticpegmatitic mafic pods, inclusion-rich zones (pyroxenite, anorthosite and granitic inclusions) and magmatic breccias. Disseminated chalcopyrite, pyrrhotite and pentlandite occur in concentrations of up to 100/0 within erratically distributed gossan pods near the base of the intrusion. The sulfides were originally precipitated from intercumulus liquids, but were subsequently recrystallized and locally remobilized along fractures during the major period of metamorphism and deformation that affected the East Bull Lake intrusion. The base- and precious-metal tenor of the structurally controlled sulfides can be explained by extensive remobilization and reconcentration of the pre-existing magmatic sulfides in the vicinity of a major shear zone. Both styles of sulfide mineralization locally contain ppm abundances of POE + Au and are generally Pd- and Cu-rich, although both display large variations in Pd:Pt and Cu:Ni ratios. The magmatic sulfides are more strongly enriched in POE and contain up to 1470 ppm Pd in 100% sulfide. Several factors, including source characteristics, magmatic processes (crustal assimilation, fractional crystallization) and post-magmatic interaction with hydrous fluid, have influenced the present distribution of POE, Cu and Ni in the East Bull Lake intrusion.The magmatic sulfide occurrences from the East Bull Lake intrusion compare favorably with marginal-type deposits from rift-related intrusions (Noril'sk-Talnakh region, Siberia; Duluth Complex, U.S.A.) in terms of their distribution, but are most similar to reef-type POE deposits with respect to their base- and precious-metal geochemistry. The combination of high POE tenors and large tonnages that is observed for the POE-Cu-Ni mineralization from the East Bull Lake intrusion suggests that a good potential exists for the presence of economic concentrations of Pd, Pt, Au, Cu and Ni in the intrusion. On a global scale, the East Bull Lake intrusion is part of a suite of Early Proterozoic plutons, many of which contain significant volumes of stratiform and/or marginaltype POE-Cu-Ni mineralization. The East Bull Lake intrusion is also one of the oldest mineralized intrusions derived from a sub-Superior Province mantle source region that has given rise to several significant magmatic POE-Cu-Ni deposits during the period 2.5 Ga to 1.1 Ga."

Jan 1, 1993

By K. G. Chipman

The Geological Survey is the oldest map making department in the Canadian Government service, and when organized in 1842, one of the first principles to be recognized was the absolute necessity of having good maps. The primary purpose of the Survey has always been geology; but because a graphic representation by means of maps makes the written report .more readily intelligible; because the correlation of known geological facts is often difficult or nearly impossible unless they can be represented on a map; and, because the public demand information shown in this way, the Geological Survey must continue to supply maps; and the supplying of these maps must be considered as an essential part of the work of the Survey. It is a commonly recognized principle of pedagogics that an appeal to the eye is quicker than one to the ear; that children (and others) learn more quickly when a thing is presented to them through the eye rather than through the ear. The application of this principle to the work of the Geological Survey is that, to a large number of people, the message of a map is more quickly grasped, is more readily intelligible, and is in many ways of more interest and value than is the same information in a report. I do not mean that the maps are of more importance than the reports.

Jan 1, 1924

By Leiting Yue, Peng Ren, Yu Shen, Zhihong Liu, Haibao Shao, Longgong Xia, Feng Yu

The Kennecott-Outotec Flash Converting technology has been proven as an advanced and mature process in 5 individual plants during the past 2 decades. High grade copper matte (65–72%) produced in the flash smelting, or other smelting technologies is granulated to 3-5mm granules in a water torrent, and further crushed to fine powder (≈50µm) and dried to contain less than 0.3% H2O. Oxygen enriched air, together with fine copper matte powder and lime flux are injected into the reaction shaft by a matte burner. The copper making and slag making reactions will happen in very short time and distance during the particle falling and settling. However, industrial practice has found negative effects caused by sodium contamination. Na is introduced in the copper matte granulating process, and appears as Na2SO4 on particle surface. When Na content was high, scaling problems in the boiler will be worse, and the processing air will be blocked by the growing accretion around the matte burner, and as-produced blister copper is always high in S and O. In this present study, an industrial matte sample was used in the experimental work. Na was introduced into the matte powder by Na2SO4 solution soaking. The burning behaviour of the doped copper matte powder has been investigated as a function of the impurity concentration and processing temperature. Morphology and composition of these samples explained how Na2SO4 converts and reacts in the oxidizing atmosphere, and how they or their converting species influence the burning behaviour of matte particles. Cross-sections of as-prepared samples were analyzed with SEM-EDS, and the reaction mechanism has been carefully interpreted. Results from the present study can benefit both academic and industrial people. INTRODUCTION "Flash Converting" technology was developed jointly by Kennecott Utah Copper Smelter and Outotec (Finland) OY in 1992. The first industrialization of the technology was in Utah Smelter in 1995. Since 2006, it has been successfully applied in Xiangguang Copper, Tongling Jinguan Copper Branch, Fangchengang Jinchuan Copper, and Ningde Southeast Copper. The technology has also been further developed in those smelters. At present, roughly 2 million tons blister copper is produced annually through the Kennecott-Outotec Flash Converting technology, accounting for more than 10% of global primary copper production. The technology has advantages of high efficiency, high sulfur capture rate, good in environmental issues, mature equipment supporting, high automatic control level, low comprehensive energy consumption and flexible connection with the smelting unit, which make the technology to be one of the best choices in investing a new large-scale copper smelter or updating an old copper project in the world.

Jan 1, 2019

By P. I. Laforest, M. S. Moats

"Antimony in smelted copper anodes has been shown to cause problems in electrorefining including brittleness of starter sheets. In order to improve deposit properties, a study was conducted examining the effect of anode chemistry on cathode ductility and electrolyte chemistry. Two industrial anodes with different molar ratios of As/(Sb+Bi) were used in laboratory electrorefining experiments with commercial electrolyte, and the addition of commercial glue and Avitone. The ductility of 21-hr copper deposits was evaluated by a 180° bend test. X-ray diffraction (XRD) and metallography were performed on unbent specimens to characterize the deposit structure. Increasing the anode As/(Sb+Bi) molar ratio from 0.54 to 3.8 resulted in an increase, on average, from four to eight bends to failure in cathode material produced. Significantly lower concentration of antimony (V) in the electrolyte was detected when operating with the higher molar ratio anode. The presence of (111) and (200) planes was noted in cathode material produced from the higher molar ratio anode suggesting that mixed growth character could be responsible for the observed increase in bend test results. The ductility of the starter sheet materials was improved by a higher anode molar ratio.INTRODUCTIONThe presence of antimony in copper electrorefining electrolyte has been reported to cause problems in cathode production (Hiskey, 2012; Peng, Zheng & Chen, 2012; Wang, Chen, Zhou-Lan & Lian-Sheng, 2006; Wang, Chen, Zhou-Lan, Wang, Xiao & Zhang, 2010; Wang, Chen, Zhou-Lan, Wang, Xiao & Tang, 2011; Wesstrom, 2014). To better understand the impact of antimony, laboratory scale electrorefining experiments were conducted using industrial inputs (anodes, cathodes and electrolyte). The influences of anode chemistry on the valences of antimony and arsenic in the electrolyte were monitored and correlated to physical cathode characteristics, such as a bend test to failure and crystallographic orientation.Commercially, starter sheets are produced by electrorefining impure cast copper anodes onto titanium blanks. The starter sheets are then hung in an electrorefining or electrowinning cell using loops of bent starter sheet material. These loops, in the absence of sufficient ductility, fail resulting in cathodes falling into the electrolysis cells. It is thought that the reduction in ductility can be related to anode composition; in particular, the molar ratio of arsenic to antimony plus bismuth As/(Sb+Bi). It has been stated that maintaining this ratio above 2:1 results in numerous improvements to electrorefining operations (Baltazar, Claessens & Thiriar, 1987; Kamath, Mitra, Radhakrishnan & Shetty, 2003; Krusmark, Young & Faro, 1995; Noguchi, Itoh & Nakamura, 1995; Wenzl, 2008)."

Jan 1, 2016

By Rodrigo Madariaga, Tracy T. Morris

The practice of stripping copper starter sheets from titanium blanks to be used in a conventional electrolytic tankhouse has been around since the advent of Electrometallurgy. Historically it has been done manually, utilizing many people to produce in some cases thousands of starter sheets per day. Some other conventional tankhouses have successfully converted to using mechanical means to strip starter sheets or have made the switch to permanent cathodes and although robotics have been around for quite some time they have not been used to strip starter sheets until recently. The Amarillo Copper Refinery began using robotics to strip several years ago and the details to how this came about and how the robots work will be described. INTRODUCTION ASARCO LLC (Asarco) was organized in 1899 as the American Smelting and Refining Company. Originally a consolidation of several lead-silver smelting companies, it evolved over the years into an integrated producer of primary non-ferrous metals, including copper, lead and zinc and associated co- products (Marcosson, 1949). Grupo México, S.A.B. de C.V acquired Asarco in 1999. Today, Asarco is a vertically integrated producer of primary refined copper and associated co-products such as gold, silver, molybdenum, selenium and tellurium. Asarco operates three open-pit mines and mills and two solvent extraction-electrowinning (SX-EW) plants all in Arizona plus a copper smelter in Arizona and a copper refinery in Texas. Figure 1 illustrates how the copper metal comes out of the ground at the mine and ends up as a refined product at the refinery The copper refinery in Texas is known as the Amarillo Copper Refinery (ACR) and is located in Amarillo, Texas. It was built in 1975 to replace 3 other aging refineries and was designed to produce 550,000 tons (500,000 MT) of refined copper per year using conventional starter sheet technology. At the time it was commissioned it was the largest tankhouse in the world at just under 1/2 miles long under one roof.

Jan 1, 2019

By J. E. Rowland

NIOCALITE is a new mineral species which has been identified in rock from the Oka district, Quebec. It occurs as prismatic crystals up to l 0 mm. in length and I mm. in width, in coarse, white, crystalline calcite with associated apatite, diopside, biotite, pyrochlore, and niobian perovskite. The crystals of niocalite are light yellow in col-our and have a vitreous lustre. The optical properties of niocalite (I) are as follows: Biaxial negative -2V = 56° a = 1.700, [ ] = 1.730 Birefringence y -a = 0.030 Optic orientation: X = b, Z/\c 12°, Y , /\a = 32° The specific gravity is 3.32 and the hardness is approximately 6 (Mohs scale). A detailed analysis performed on 2.4 gm. of hand-picked material reveals that niocalite is essentially a calcium niobium silicate. Table I gives the result of the analysis. Crystals of niocalite, apparently suitable for X-ray diffraction work, were selected, and single crystal photographs were obtained using both Weissenberg and Precession cameras. Initial difficulties were encountered in interpreting these films, and in correlating the crystal data with the optical data. The in-consistencies were explained by the fact that every grain examined was twinned to some extent.

Jan 1, 1957

By R. C. Wallace

Introduction At a time when the mineral-bearing areas in Manitoba are being fi very keenly explored because of the major developments which are now taking place in that Province, it may be timely to give an analysis of the mineralization in the two major types of deposits, with a view particularly to assist in the intensive prospecting to which the mineral-bearing areas in the Province are now to be subjected. As is already well known, there are two principal types of mineral deposits in the territory- copper-zinc and gold; and attention will be confined almost exclusively in this paper to these two types, with some indication of such modifications of the main types as may be found to be of economic value. The details of the paper are drawn from what is yet a small part of the area of the Province available for prospecting. Enough is now known of the types of mineral deposits which are described in the following pages to justify the expectation that these types may serve as criteria in the search in the newer districts. Doubtless new types will also be found as investigations proceed.

Jan 1, 1928

By H. A. Kee

In the mining industry, as in other business, one of the more satisfactory results of sincere but cheerful effort lies in the proper completion of undertakings and problems, which, to be successful, must continually hold the interest of all concerned in the work. In most undertakings, genuine interest and satisfaction is largely dependent on the proper appraisal of opportunities presented, and the opportunity to associate ourselves with sinking operations at McIntyre central shaft, from the surface to a depth of 4,133 feet, was genuinely appreciated. This opportunity was made possible by the previous persistent and successful leadership of Mr. J. P. Bickell, President, with the assistance of his associates, and of the general manager, Mr. R.J. Ennis, in the development of the McIntyre Porcupine mine, and I beg to state that any success in this sinking operation was very largely due to the congenial co-operation and splendid workmanship of Captain Martin C. Horne, his shift bosses, leaders, and all those who worked with us . Our slogan throughout was " Safety First for Pleasant and Efficient Workmanship," and this general policy made it possible to sink and timber 2.,123 feet during the first year without a serious accident.

Jan 1, 1928

By Charles "Chick" Rodgers, Anthony Sarion

"With declining feed grade and increased production targets, it became necessary to upgrade Key Lake's eight stage counter current decantation (CCD) circuit. Following laboratory trials, mill operations recognized that dilution of the feed slurry and buffering of the feed density variations would improve thickener throughput. Plant testing resulted in the installation of Outokumpu's Supaflo ""Floe-Miser"" system. The circuit's flowsheet, instrumentation and control strategy were also upgraded along with the thickener feedwell modifications. The paper will also discuss these modifications and the implementation of the current control strategy.IntroductionCameco Corporation's Key Lake operation is the largest single uranium producer in the world. Current production is fourteen million pounds of uranium oxide (U 308) per year. It is owned 2/3 by Cameco and 1/3 by Uranerz Exploration and Mining with Cameco as the operator.The mine is 570 kilometres north of Saskatoon on the southern edge of the Athabasca basin. Access to the mine is by an all-weather road and a private airstrip.Process DescriptionThe Key Lake milling process consists of five individual plants: crushing and grinding; leaching and counter current decantation (CCD); solvent extraction; yellowcake precipitation and ammonium sulphate crystallization; and bulk neutralization (Figure 1 -Simplified Mill Flowsheet). A detailed mill flowsheet can be found in the appendix."

Jan 1, 1998

By J. D. Stewart

One of the first important questions that should be settled on the opening of a mine or the development of a new deep is the system of haulage to be used, since the layout of the haulage-ways at the pit bottom, or, in case of a slope mine, the arrangement of the surface works, depends largely upon the type selected. Should it later become desirable to install a system of haulage of a type other than that for which the mine roadways were originally laid out, considerable difficulty would likely be encountered in its installation and with the result that it would in all probability be most unsatisfactory and expensive in its operations. It therefore becomes very necessary that full consideration be given the haulage problem at an early date in order that the type best suited to the mine conditions and the required outputs can be intelligently planned for. It is sometimes found, however, that no matter how well the mining engineer explores the seam to be developed, or how accurately he anticipates its eccentricities, there will still remain some unrevealed or unsuspected conditions, or shall we say obstacles, placed by Nature to prevent the too easy winning of her treasures and incidentally to frustrate or modify the application of the plan so painstakingly laid down on paper, and to adversely affect the cost estimate.

Jan 1, 1928

By W. Dan Hausel

"Hundreds of diamonds have been found in the United States. The majority of the discoveries occurred during the 19th century as a by-product of placer gold mining. Most of these early diamond finds have no known source, and in many cases are situated in areas unfavorable for diamond exploration based on current models that require kimberlite or lamproite to be emplaced in a stable Archean craton or Proterozoic craton margin.Diamonds have also been recovered in situ from lamproite at Murfreesburo, Arkansas, from kimberlite in the Lake Ellen region of Michigan, and in several kimberlites in the Colorado–Wyoming State Line district. Unverifed reports also suggest that diamonds may have been recovered from other related intrusions at a number of localities in the United States.IntroductionTo date, diamonds have been recovered in situ from kimberlite in the Colorado–Wyoming State Line district and from a kimberlite in Michigan. Additionally, diamonds have been recovered from lamproites in Arkansas. Diamonds have also been reported from kimberlite in Kansas, and from peridotite in New York and Maryland. However, these latter reports have not been verified."

Jan 1, 1995

By Brien A. Perry, Art Wiebert

"Many organizations which have implemented Total Quality Management (TQM) are finding that the process has either stalled or is not working so well as originally envisioned. This can be particularly evident in an engineering environment where the uniqueness of engineers and their particular culture has not been adequately considered. Winning the commitment of a highly educated group ojprojemnnJJ1s to the TQM concepts, which are often initially 5W2 as too simplistic poses special challenges.Successful TQM implementations are found among technical groups where employees have significant input into creating the new work culture, feel empowered to make changes and are well trained in teamwork. A coach who is knowledgeable in implementation problems can, when working closely with the technical teams, help them circumvent obstacles and guide them successfully through the difficult early phases. The remaining key ingredient for success is supportive management which leads the change and is both informed and appreciative of the accomplishment being made.This Paper is based on first-hand experience with common problems and results encountered in implementing TQM in an engineering environment. Described in the paper are ways of avoiding these problems through awareness of the unique nature of engineering groups, implementation planning, just-in-time training and coaching people in the TQM process. The paper concludes with a focus on the opportunities and results from a successful implementation. These opportunities and results include the benefits each engineer can realize through process thinking, empowerment and teamwork."

Jan 1, 1995

By L. Klatzel-Mudry, D. J. Nikols, J. D. Hughes

"The Geological Survey of Canada Paper 88-21, A Standardized Coal Resource/Reserve Reporting System for Canada, is referenced by National Instrument 43-101 for the preparation of resource and reserve estimates on coal deposits. However, for all disclosure of mineral resources or mineral reserves for coal, issuers are required by NI 43-101 to use the equivalent mineral resource or mineral reserve categories set out in the CIM Definition Standards and not the categories set out in Paper 88-21. “Because the framework is based on Canadian deposits and their tectonic regimes, the Canadian Securities Administrators believe it is not reasonable to apply Paper 88-21 to foreign coal properties. The “Resource Links” at the end of this volume provide website links to guidance documents for preparing coal resource and reserve estimates in Australia, South Africa, and the USA.”This report discusses definitions, concepts and parameters used to determine coal resource and reserve quantities, and provides a framework to facilitate consistent categorization of coal quantities found within various depositional and tectonic regimes in Canada.Coal deposits, or portions thereof, are first categorized in terms of their geological complexity <Geology Type), and probable recovery method (Deposit Type). Methods for determining quantification parameters including seam thickness, areal extent and bulk density are outlined for each geology/deposit category. Within each geology/deposit category, coal resources are further divided, based on their assurance of existence, into measured, indicated, inferred and speculative subdivisions and, according to their feasibility of exploitation, into immediate and future interest subdivisions. Coal reserves within each geology/deposit category are subdivided according to whether they are within or outside active mining areas, and may be reported on in place, recoverable and saleable bases.A wide cross-section of the coal industry in Canada contributed to the development of this reporting system. To ensure that the parameters and concepts expressed in the system continue to reflect technological and economic realities in the future, the Coal Association of Canada has established a committee to facilitate periodic reviews."

Jan 1, 2003

By Christian M. Bauer

Modern surface mines are among the world&apos;s largest single consumers of diesel fuel. A typical mine site can consume in excess of 200 million liters of diesel fuel per year. Delivered diesel fuel is not necessarily clean. Depending on the mode of transportation, handling practices and local climate, incoming bulk fuel can contain up to 20 mg/L suspended solid contaminants and also significant quantities of free water, which can amount to substantial quantities ? for a typical mine site 200 to 400 kg of dirt per year. Standard on-board fuel filters are not designed to handle high levels of contamination, and most engine manufacturers have specific fuel cleanliness requirements to ensure reliable engine operation. New developments in fuel injector technology, such as high pressure, common rail injectors require even cleaner fuel. In order to ensure reliable operation, it is therefore recommended to control particulate contamination throughout the entire Diesel supply chain - from the bulk storage on mine sites to the injection systems on-board through the use of particulate filtration and liquid coalescence technologies. In this work, the author introduces a comprehensive approach to contamination control for the entire fuel supply chain, and discusses the benefits of using advanced filtration and separation technologies, with a particular focus on the requirements of modern high pressure, common rail (HPCR) fuel injection systems.

Nov 1, 2011

By Steve R. McCutcheon, Cees R. Van Staal, John P. Langton, Leslie R. Fyffe

Abstract -The volcanic-dominated Tetagouche Group in northern New Brunswick contains numerous massive-sulfide deposits and intimately associated metalliferous sediments. The massive sulfides are generally hosted by Llanvirnian-Llandeilian volcaniclastic sedimentary rocks of the Nepisiguit Falls, Patrick Brook, and Boucher Brook formations. These formations are intercalated or closely associated with rhyolitic-dacitic flows and/or domes, and minor continental tholeiites of the Flat Landing Brook Formation. Pyroclastic rocks are relatively scarce in the silicic volcanic complex. Tuffites and epiclastic sandstones, of the Nepisiguit Falls and Patrick Brook formations, respective­ ly, generally occur along the fringes of the silicic volcanic complex. The flows and tuffites are intruded by quartz- and feldspar-phyric rhyolite (porphyry) dykes, sills, and domes. Although the volume of the silicic volcanic complex is large, evidence for a previously proposed collapsed-caldera model is lacking. On the basis of host-rock type and stratigraphic position, the sediment-hosted massive sulfides have been divided into three groups: the Brunswick-, Caribou- and Halfmile Lake-type deposits. Syngenetic feeder pipes and asociated alteration zones are generally not present beneath the Caribou- and the Halfmile Lake-type deposits and, if present at all, are poorly developed underneath the Brunswick-type.

Jan 1, 1992

By M. Pötsch, W. Schubert

"The kinematic analysis of rock blocks is one part of a block stability assessment. It provides information about a block’s movability, i.e. if a block can detach from the adjacent rock mass and move towards the free space. This paper introduces an analytical method for the analysis of pure rotations of arbitrary finite polyhedral blocks. It enables the engineer to judge a block’s rotatability about a corner or an edge. The method is presented using a graphical and computational method. The application of the method is illustrated with an example. INTRODUCTIONThe kinematic analysis of rock blocks deals with the determination of the movability of blocks. Established methods typically cover: (a) translational motion (John 1968, Markland 1972, Londe et al. 1969, 1970, Goodman & Shi 1985, Warburton 1981) and (b) the specific rotational cases Toppling (Goodman & Bray 1977) and Slumping (Kieffer 1998). Mauldon & Goodman (1990, 1996) and Tonon (1998) introduced rotational kinematic analyses for three-joint pyramids and tetrahedral blocks extending Goodman & Shi’s block theory.All mentioned methods are subject to assumptions that limit the applicability to engineering problems. For example, the kinematic test of daylighting joints or intersections inherently assumes a finite block, which only can be proved by the finiteness theorem (Goodman & Shi 1985). Daylighting of an intersection or plane is not a sufficient condition for removability. Goodman & Shi’s and Warburton’s methods are limited to translational block motion. The methods for block rotations so far address tetrahedral blocks only. They also address only pure rotational modes and neglect the general motion of a rigid body. This paper introduces an analytical method for the analysis of the kinematic rotatability of finite rock blocks. It extends Mauldon's and Tonon's theory of rotatability of tetrahedra to arbitrary polyhedral blocks. A graphical method using the stereographic projection and a computational method are presented."

Jan 1, 2015

By K. M. Wild, C. D. Martin, F. Amann

Peak laboratory strength data obtained from low permeability clay shales/rocks often display a bilinear or non-linear failure envelope. In many of these tests pore pressures are not measured because of issues associated with back-saturation prior to confined compressive loading. In such tests the effective state of stress at failure remains unknown and provides room for speculation. The non-linear shape of the failure envelope may have several reasons including the influence of capillary forces or the tendency of a saturated clay shale to dilate as the confining stress is changed. The former stems from sample preservation, preparation or core unloading effects and represents a partly saturated state (i.e., not representative for the in-situ state); the latter represents the response of a saturated material. This contribution discusses these issues based on a data set obtained from Opalinus Clay specimens, and concludes that without a careful back-saturation processes knowledge of the underpinning reasons for the non-linear failure envelope cannot be obtained.

Jan 1, 2015

By B. W. Snyder

INTRODUCTORY THE earliest known case of transmission of natural gas by pipe lines was early in the Christian era when the Chinese used bamboo pipes to transport natural gas from surface seepages to heat brine for the recovery of salt. Since that time many materials have been used as conduits-hollow wooden legs, wood stave pipe, day tile, cast iron, and, finally -since about 130 years ago - steel pipe. Even then, this new material came into use rather . slowly for, as recently as 80 years ago, wood pipe was still being used. However, as techniques were developed to take advantage of the properties of steel, this material gradually replaced all ethers for the transportation of gas for longer and longer distances at ever increasing pressures. In 1912, one of the longest pipe lines of its size at that time was built-this was a 16-inch line bringing gas from Bow Island to Calgary, a distance of 170 miles. We have been able to find records of only two ether such lines at that time-one a 185-mile 16-inch line from Vivian, Louisiana, to Little Rock, Arkansas, completed in the summer of 1911, the ether a 280-mile line from West Virginia to Toledo, Ohio. This last ? mentioned line was reported in a magazine article of September, 1912, but no indication was given of its size on completion date. It is apparent, therefore, that modern high pressure transmission of natural gas is a technique less than forty years old.

Jan 1, 1951