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By R. I. Grauch, Michael D. Glascock, Chen Nansheng, Jr Coveney, James B. Murowchick

"Unusually rich molybdenum ores (cutoff grade = 4.10/0 Mo) hosted by Lower Cambrian black shales have been mined since 1985 near Zunyi in the province of Guizhou in China. Similar ores were once worked for Mo and Ni near Dayong in the province of Hunan. In both mining areas, mineralization occurs in Lower Cambrian black shale (Niutitang Formation and stratigraphic equivalents) as a single sulfide bed or lens with exposed thicknesses up to 15 cm and reported thicknesses up to 35 cm. In addition to high Mo values (4% to 7%), ore samples contain up to 7% Ni, 2% Zn, 2.5% As, and several hundred ppb Au and Pt-group elements, but the precious metals have never been recovered from the ores. Sporadic occurrences of Mo-Ni sulfide ore beds are found in at least five provinces stretching approximately 1600 Ian from Yunnan to Zhejiang. None of the Mo-Ni ore-bed occurrences has any obvious connection with mafic or ultramafic source rocks. Similar occurrences containing elevated values for Ni, Mo, and PGE exist in Devonian black shale in the Yukon. Future exploration for Pt, Au, Mo, and Ni deposits should consider this previously unknown type of sediment-hosted mineral deposit.Sommaire - Des minerais anormalement riches en molybdène (teneur-limite = 4.1% Mo) provenant de schistes argileux noirs du Cambrien Inferieur ont été exploites depuis 1985 près de Zunyi dans la province de Guizhou en Chine. Des minerais semblables ont déjà été traire pour Mo et Ni près de Dayong dans la province de Hunan. Dans ces deux régions minières, la minéralisation se présente dans le schiste argileux noir du Cambrien Inferieur (Formation Niutitang et équivalents stratigraphiques) sous forme de couche ou lentille unique de sulfures avec des épaisseurs exposées de plus de 15 cm et des épaisseurs rapport6es de plus de 35 cm. En plus des fortes teneurs en Mo (4%-7%), des échantillons du minerai contiennent jusqu’ à 7% de Ni, 2% de Zn, 2.5% d'As, et plusieurs centaines de ppb d'or et d'éléments du groupe du platine; toutefois, les métaux précieux n'ont jamais été récupérés des minerais. Des présences sporadiques sous forme de couches de minerai sulfure de Mo-Ni se retrouvent dans pas moins de cinq provinces s'etendant sur 1600 km de Yunnan a Zhijiang. Aucune de ces présences de minerais, sous forme de couches, ne semble associée a des roches du type mafique ou ultramafique. Des présences similaires contenant des teneurs élevées en Ni, Mo et EOP se retrouvent dans le schiste argileux noir Devonien du Yukon. L'exploration future pour des gisements de Pt, Au, Mo et Ni doit prendre en considération ce type de gisement encore inconnu précédemment."

Jan 1, 1992

By R. F. Tylecote

"The closure of the iron and steel making plant at Consett in Durham in 1980 marked the end of an era-a long era in the world's iron and steel making history. Iron had been smelted in the Tyne-Wear area of the United Kingdom since before the Roman period, but apart from evidence of smithing in the Roman period, the historical evidence for iron production on a large scale dates from the 14th century.The paper describes sites in the area that first worked the bloomery process and then, in the 16th century, as did most of Europe, graduated to the blast furnace process. The main emphasis is on the early introduction of coal to iron making at the end of the 18th century and the use of the steam engine to render integrated sites possible.IntroductionIron has been smelted in the Tyne-Wear area of the United Kingdom since before the Roman period, but apart from clear evidence of smithing in the Roman period, the historical evidence for iron production on a large scale dates from the 14th century. Like many other countries, the United Kingdom benefitted from the visits of foreign observers, such as Jars, Svedenstierna, de la Houliere and Dufrenoy, who left detailed records. In modern times, information gained from excavations of iron and steel making sites has supplemented the historical record.Natural ResourcesUp to the end of the 19th century, the industry was wholly dependent on its own resources. Iron ore, limestone, wood, coal and water power were all found a short distance away from the main valleys of the Tyne and Wear. The main sources of iron ore were the coal measures, with rider ores from the lead vein s in Alston and Weardale, and carbonate ores from shale horizons in the Carboniferous limestone. Good coking coal was available from West Durham and reasonable coal from the Tyne valley and Northumberland limestone. Limestone was plentiful."

Jan 1, 1983

By D. C. Carter

"The Nova Scotia Department of Mines and Energy located a drillhole at Riverside Corner, Hants County, Nova Scotia, to examine the stratigraphy, structure and potash potential of the Kennetcook River gravity low. This evaporite-related gravity anomaly is one of the largest virtually unexplored gravity anomalies in Nova Scotia. The drillhole intersected a structurally complex sequence o flower Windsor Group ('B' Subzone) evaporites. Downhole geophysical wireline logs were used, in conjunction with detailed lithological descriptions, to interpret the structure and stratigraphy of the sequence. Similar application of total gamma ray, density, caliper and neutron-neutron log responses allows stratigraphic correlation of Windsor Group carbonate marker units separated by up to 35 km in Cape Breton. This work confirms the value of downhole geophysical logs as a tool in the exploration of evaporite deposits regardless of the presence or absence of high quality core. INTRODUCTIONThe exploration methodology for evaporite (specifically salt/potash) deposits in eastern Canada (and worldwide) is relatively simple: identify a negative gravity anomaly within a favourable geological setting, Windsor/Cordroy Group sediments in eastern Canada, and drill it (Anderle, 1980). Although this is an obvious oversimplification of the necessary expertise in the planning and complet ion of an exploration program, those familiar with potash exploration drilling can attest to the risks and expense, in terms of time and problems , associated with the location and drilling of diamond-drill wildcat holes. Potash exploration programs in eastern Canada, their results and inherent difficulties, have been documented by Anderle et al. (1979), Cooper (1981), Dekker (1982), Carter and Boehner (1986), Carter (1988) and Carter and Anderle (in prep .).Downhole geophysical wireline logs have become an important tool in the stratigraphic and structural interpretation of evaporite sequences in eastern Canada and, in many cases, represent the only information recovered or the only information available due to the drilling method (rotary) and/or the long term instability of evaporite cores. This paper documents examples of downhole geophysical log responses which, combined with detailed lithological examination of drill core, or in the absence of core, are used in the interpretation of the complex lithology and structure of a deformed evaporite deposit. Geological and geophysical data from the Nova Scotia Department of Mines and Energy (NSDME) Riverside Corner 85-1 drillhole are presented here as a partial case history and prime example of the use of this method to interpret the complex structure of an evaporite deposit. Drilling of NSDME Riverside Comer 85-1 was conducted in late 1985and early 1986by the Department (Carter and Boehner, 1986) under a program to assess the potash potential of selected areas of the province as part of the Canada-Nova Scotia Mineral Development Agreement 1985-89. A reinterpretation of a portion of the available data from two exploration drilling projects on Cape Breton Island in the Canso-Bras d'Or area is also presented (see inset, Fig. I). Several drillholes have intersected the Windsor Group evaporite sequence in these areas and the available geophysical logs are a valuable tool in the interpretation of the structure of the deposits. However, no attempt has been made to present or discuss the detailed geological investigation and comparison of these two deposits. They are presented here as an example of the reinterpretation of existing data and their application to stratigraphic correlation and structural interpretation of complex evaporite deposits. Further work is necessary to document the stratigraphic and structural correlation of these two areas."

Jan 1, 1989

By W. H. Gross

To pollute means to make impure or unclean. We tend to forget that man defecates, urinates, sweats, expectorates and exhales and in himself is a beastly little pollutor-but then so is Mother Nature! The object of this paper is to try to put what man and nature do into perspective. The facts indicate that although man may sweat a little, Ms. Nature is by for the greatest pollutor of all.

Jan 1, 1979

By C. J. Newman, D. J. Kemp, R. M. Sweetin

"The smelter is described by area; feed preparation, continuous furnace line, gas handling and auxiliary systems, blister refining, Hazelett casting of thin anodes, and scrap remelting. Early smelter campaign data is presented and compared to design. Some modifications to the basic design of the furnaces and gas trains are indicated, with their respective impacts on improving smelter performance.Plant compactness, the use of jumbo tanks, and a highly automated electrode handling system are featured in the refinery description, with brief coverage of the liberator and slimes leaching sections. Early experience in refining thin regular Hazelett anodes, and submersible pump recovery of raw slimes are relayed, together with automatic stripping from titanium blanks.Refinery tonnages and operating parameters are given showing the relatively trouble-free attainment of refinery design performance.IntroductionPrevious papers and articles ( 1), (2) ,(3 ) have described the metallurgical facilities serving the copper-zinc-silver Kidd Creek orebody located near Timmins, Ontario. For convenience a brief review of their mid-1983 operating status is presented.The concentrator, originally designed for 9,000 short tons, was commissioned in late 1966. It can now comfortably process over 13,000 metric tonnes per day largely as a result of the addition of a fourth circuit in 1978."

Jan 1, 1984

By P. Diehl, M. David

"As shortage in the supply of mineral commodities become more probable, there is an increasing need for reliable and comparable reserve/resource data. It is therefore necessary to standardize the traditional classification procedure by quantifying the three basic criteria in resource evaluation: economic feasibility, geologic assurance and recovery. For the portion of fairly well documented deposits and as far as their geologic parameters are concerned, geostatistical methods can considerably improve the quality of ore classification. In respect of economic feasibility and recovery, approved geostatistical methods can be introduced directly into the classification procedure. The concept of geologic assurance, however, requires a new interpretation in terms of geostatistical error spread. As the ""risk"" in estimating an ore parameter is also a function of the respective block size, it is reasonable to define not only upper limits for the risk intervals for each class of uncertainty, but also block dimensions which reflect the typical stage of planning associated with the different ore categories. An algorithm has been developed to block out areas inside a mine or a large panel which satisfies the constraints of an ore category in respect of the risk intervals of a parameter and in respect of their size. The method has been computerized and is demonstrated on a massive copper-nickel deposit.IntroductionFacing an uncertain future with respect to the demand and supply of mineral commodities, both governmental authorities and the mining industries show an increasing interest in a useful framework for the assessment and classification of the remaining mineral resources"". This is reflected by the recently published appraisal and classification scheme of the United Nations as well as by the new or revised classification systems of the USA; Canada or Australia. Moreover there are various classification schemes which are currently discussed in major mining companies."

Jan 1, 1982

By M. J. Gole, R. E. T. Hill, S. J. Barnes

"The Agnew (also known as the Perseverance) nickel deposit and its northern extension, the Rocky's Reward deposit, form one of the world's largest accumulations of nickel sulphides hosted by komatiites. Agnew was previously classified as an ""intrusive dunite-associated"" deposit . It has now been shown that the sulphides are hosted by komatiite flows which underlie an adcumulate-textured dunite body that crystallized in a large lava channel.The rocks of the mine area have been subjected to a metamorphic temperature of550°C and pressure of up to 3 kb. The komatiites have mostly been reconstituted to olivine-amphibole chlorite assemblages. There is a zoned sequence of enstatite-, anthophylite-, talc- and antigorite-bearing assemblages inwards from the western margin of the ultramatic reflecting variations in the CO/HP ratio of metamorphic fluids.Facing directions are determined from variations in the proportions of metamorphic minerals and in rock compositions which reflect asymmetric layering in the flows . Olivine-sulphides matrix ore is hosted in a single 50 m thick, east-facing flow that is overlain by flows containing massive sulphides. Much of the massive sulphide has been physically remobilized into fold noses, faults and shear zones. Chemical diffusion of ore components has upgraded a sulphide-rich metasedimentary unit where it is in structural contact with massive ore.To the north, the mineralized flow sequence is separated from a stratigraphically higher komatiite sequence, the Perseverance ultramafic complex, by approximately 150 m of felsic meta volcanic and meta sedimentary rocks. Southward, the Perseverance ultramafic grades laterally into an olivine adcumulate body and its lower contact cuts progressively down stratigraphy until it lies directly on top of olivine-sulphide ore of the mineralized flow sequence. This discordant contact is interpreted as the base of a thermal erosion channel formed by a voluminous komatiite lava flow. This contact greatly influenced later deformation of the mineralized flow sequence."

Jan 1, 1989

By Lloyd H. Yeomans

"This paper will cover recent developments in conveyor applications with specific reference to capacities, bell speeds and distances. It will also discuss certain unique arrangements of horizontal, curved and loop belt systems. In addition, the recent changes in safety factors resulting from new conveyor construction methods will be reviewed.IntroductionConveyor belt systems are currently undergoing dramatic changes. Their use is being extended to providing a viable means for the transportation of bulk material over longer and longer distances.In this paper, a brief account of the historical development' of the belt is outlined, demonstrating how conveyor technology has adapted to changing market demands.Today, energy and environmental requirements are providing what may even be greater challenges. The ability of the belt conveyor to transport material and meet those requirements, places it in the position of replacing many conventional means of bulk material transportation.The paper also outlines some of the progress which has been recently made in this regard and includes a broad approach to the subject of belt design and application.Recent design developments have greatly extended the potential of conveyor belt systems to include applications thought impossible just a few years ago.Graphically illustrating the potential of this new technology IS a belting system currently operating in New Caledonia. Built in 1970, the system has an incredible centre distance of 43,000 ft, or about eight miles.Not to be outdone, the British Coal Board is currently constructing a belt system with a centre distance of 49,000 ft and a speed of 1,650 feet-per-minute. This system is expected to be completed in 1986.These innovative advances contrast dramatically to the conveyor belt's beginnings in the early industrial revolution. Oliver Evans, writing in the 1795 edition of 'Miller's Guide' defined the conveyor belt as a ""broad endless strap of thin pliant leather or canvas, revolving on two pulleys in a case or trough.""Obviously, the conveyor belt has come a long way since those early days."

Jan 1, 1983

By Teresa Sikora

For over 40 years the Institute of Innovative Technology EMAG has specialized in the development of systems and equipment for laboratory and on-line monitoring of coal quality parameters, as well as the implementation of these systems and devices in mines and power stations. Some of these systems, based on advanced radiation detection techniques such as ?-ray backscattering (ALFA-06 and ALFA -06/T systems) or dual energy ?-ray transmission measurement (ALFA-06/2E ash meter), and also the ALFA-06/3E system applying microwave technology for the measurement of moisture, have had numerous applications in Poland. At present, over 100 systems and devices are used in Polish hard and brown coal mines. For over 10 years, EMAG has been specializing in the development of systems and devices, based on natural gamma measurement technology. An on-line ash meter, RODOS and RODOS Ex, based on measurement of natural gamma radioactivity of coal, has been developed and put into operation. This technique has been also used in developing the portable ash meter WALKER and laboratory analyzer GAMMA NATURA. The paper briefly presents features of the above-mentioned devices, their limits and their obtained accuracy, but in particular refers to the laboratory analyzer, GAMMA NATURA, as the first such device in the world, and presents the results of ash and moisture content measurement in hard, brown coals and potassium salts. The possible applications and advantages of the device in coal mines are discussed. The paper also presents the implementation results of the portable ash meter, WALKER, and the on-line ash meter, RODOS, that is used underground in coal mines.

Aug 1, 2013

By William W. Shilts

"In carrying out a geotechnical survey of a proposed gas pipeline route from the Arctic Islands south to Longlac, Ontario, the Polar Gas Consortium contracted the drilling of several hundred 2- to 2D-m-deep boreholes in drift and bedrock. Samples from these holes were made available to the Geological Survey of Canada, where they were subjected to stratigraphic and trace-element geochemical analyses. The geochemical characteristics of the clay and sand-sized heavy mineral fractions of till samples from these boreholes have been summarized in a series of geochemical profiles.From the proposed pipeline terminus at Longlac northward to the vicinity of God's River in Manitoba, tills contain significant amounts of Paleozoic carbonate rocks and Proterozoic sedimentary rocks derived from the Hudson Bay basin and lowlands. Within this section, two sites were enriched in base metals, indicating the possibility of local mineralization of possible economic interest.From God's River northward to Seal River, Manitoba, no evidence of local mineralization was noted. The heavy mineral fractions of the tills are universally enriched in Mn-rich siderite thought to originate on or in the Paleozoic section of the Hudson Bay lowlands.From Seal River northward to Thelon River, near Baker Lake, tills contain only components originating west of the Hudson Bay sedimentary basin. Near the Keewatin-Manitoba border, all till is enriched in uranium, which probably originates in the ""young"" porphyritic granites underlying much of the region, and produces a distinctive airborne radiometric anomaly.At the Thelon River, multiple till sections are variously enriched in Cr, Ni, U, Cu and Mo in the vicinity of a distinctive aeromagnetic anomaly.From Thelon River northward, several coincident zones of chromium and uranium enrichment are found where the line of boreholes crosses east-west-striking belts of volcanic, ultramafic and sedimentary rocks of the Prince Albert Group.The results of this study indicate that till tends to have characteristic element associations or concentrations over each of several broad regions along the pipeline route. These are related both to large-scale bedrock associations and to largescale effects of glacial dispersal. In addition, the samples, collected more or less at random with respect to local bedrock geology, have intersected several small-scale geochemical anomalies that appear to be related to zones of mineralization of possible economic interest."

Jan 1, 1980

By Roy O. Ifill, W. Charle Cooper, Alan H. Clark

"A detailed study of the compositional relationships of the Uand Th-bearing minerals in Elliot Lake uranium ores has been conducted, particularly with regard to uranothorite, which clearly plays a critical role in hydrometallurgical processing. Application of the rotating disc progressive-leaching technique to individual mineral grains and intergrowths of known compositions has defined for the first time the solubilization behaviour ofthe minerals in question.In descending order of leachability, regardless of leaching conditions, the phases are: uranothorite, uraninite, and monazite. Inclusions of secondary uranothorite enhance the dissolution kinetics of uraninite, which exhibits a complex dissolution mode. U-rich uranothorite dissolves more readily than Th-rich. Monazite is soluble in HJ)04 and HCI solutions only at temperatures exceeding 85°C. Consequently, it is deduced that the 15% to 20% of thorium not leached from the ore is lost both as monazite and as uranothorite inclusions locked in monazite which persists to the tailings. INTRODUCTIONThe importance of precise information on the mineralogy of ore and gangue constituents for the optimization of metal recovery in hydrometa Uurgical processing has been recognized for some years (e.g. Burkin, 1969), and numerous investigations integrating mineralogical studies and experimental leaching have been reported for ores of gold, nickel, copper and uranium (see summary by Henley, 1983). The complex mineralogy of uranium ores hosted by Precambrian pyritiferous, quartz-pebble, conglomerates has prompted particular attention in this regard (e.g. Liebenberg, 1956; Liebenberg and Taverner, 1958; Feather and Snegg, 1978). In the great majority of documented studies, however, petrographic examination has been followed by bulk leaching, an approach which, although providing valuable information, does not permit precise definition of the evolution of mineral dissolution processes. The authors contend that experimentation involving the step-by-step leaching and mineralogical study of ores is more likely to reveal the actual dissolution events which control the release of metals and, hence, may better define the optimal conditions for hydrometallurgical processing. Such studies (e.g. Hausen, 1983; Horlick et al., 1981) in addition lend themselves to the prediction of changes in the leaching behaviour of ores in which one or more mineralogical feature is subject to modification, a common characteristic of mineral deposits."

Jan 1, 1989

By John Drew Ridge

"Over the years, ore geologists have made innumerable observations as to the relationships of certain kinds of ore deposits to particular types of rocks and to the types of primary and secondary structures that these rocks contain. On the basis of these, the places in which to look for new are deposits are more clearly defined than they would be in an exploration program based largely or solely on concepts of ore genesis. This paper discusses the affinity of certain rock types and structures for such ore deposits as: (1) tin-tungsten associated with granitoid rocks; (2) lead-zinc of simple mineralogy in carbonate rocks; (3) massive base-metal sulphides in sedimentary or volcanic rocks; (4) massive base-metal sulphides and oxides at, or near, contacts with igneous rocks; (5) gold or gold-uranium in, or adjacent to, conglomerates; (6) shale- or sandstone-hosted copper; and (7) porphyry coppers. Additional varieties could be considered, but it appears that these examples are sufficient to demonstrate the validity of the suggestion that the use of observational characteristics is far more useful in mineral exploration than that of theories of ore genesis.As by-products of the theory of plate tectonics, many concepts have been put forward to explain how ore deposits of different kinds have been formed. Most, if not all, of these theories seem to be as valid as present-day information permits. However, do these ideas add to the ability of the ore geologist to find ore deposits? I doubt it, and offer reasons as to why I think so.To produce maximum results in any exploration program, the one that makes the greatest use of information produced about the geologic environment of the area being investigated is the one that will provide the greatest return in deposits found for the sponsors of the program. Such exploration is best designated as total exploration, and it certainly is the most effective way of uncovering such new deposits as may exist in the area being studied in particular and of adding to the sum total of nonfuel minerals deposits available to the industrial world in general."

Jan 1, 1983

By M. Massinaei

Recently constructed circuits have included multiple stages of columns in a variety of applications, from roughing to cleaning. The Miduk copper concentrator (in south-eastern Iran) is one of the unique mineral processing plants which use column flotation cells as rougher. As the bulk of final concentrate is produced by rougher columns, optimized metallurgical performance of these cells is crucial. This paper will present the study and optimization of, a froth washing system of columns. For this purpose, the cross-sectional area of orifices was increased and their orientation altered. Concentrate assay for copper and silica, in addition to bias rate were found to be the assessment criteria. Modification of the wash water system resulted in increasing the purity of rougher and final concentrate. Negative bias and short-circuiting of wash water into the concentrate launder were the main causes of improper froth zone washing in the former system.

Jan 1, 2007

By Himmelman. Nicholas P.

In this paper, the hardware foundations and data collection methods of a real time collision avoidance system for electric surface mining rope shovels are described. The primary goal of the system is to help a shovel operator avoid accidentally colliding the shovel?s dipper with either a nearby haul truck or the shovel?s tracks. To achieve this goal, the system requires complete and precise knowledge of the shovel?s geometry and movement, as well as the location of any nearby haul trucks. This paper describes the subsystems created to acquire this necessary information. This system is unique in that all of its components are mounted solely on the shovel and that it is designed to be easily retrofitted to a shovel without significant modifications.

Oct 1, 2009

By Eric L. Hoffman

Sample preparation technology changes Rock Soil Vegetation Analytical Innovation Assay or Geochem Choice of Digestions Choice of analytical method Whats new in analytical technology? Innovations in surface Geochemical Methods Hydrogeochemistry Biogeochemistry Soil Gas Hydrocarbons (SGH) Selective Extractions Glacial Environment Arid Environment

May 1, 2008

By David R. Winfield

I would like to thank you for spending the time with me today to review the FLIR PathFindIR thermal imaging camera system: It is truly an innovative safety system that has the added benefit of offering increased efficiency Our company the Winsted Group, specializes in mobile video systems that are fully customizable to address standard and unique operational requirements in a variety of industries from heavy equipment cameras to police and military digital recording systems, high end video camera systems are a hallmark of Winsted?s product line. The use of thermal imaging camera systems to enhance mobile safety is a relatively new concept as it relates to their use in both transportation and heavy equipment operation. This technology, like so many before it, has been adopted for civilian use from its military roots. The identification of enemy combatants through their heat signature has given our troops a decisive edge in military operations in total darkness Likewise, the ability to discern people and objects that give off heat is a significant step forward in collision and accident avoidance. The PathFindIR camera system that I am demonstrating today is so advanced that it cannot be exported outside of continental North America without a US government approved export license I would like to commence my presentation with a short video clip that discusses the technology associated with the FLIR PathFindIR Thermal Imaging camera systems. The video demonstrates the operational effectiveness of thermal imaging camera systems installed on a vehicle operating on the roadway at night, of course there are definite parallels to use in a mining environment, primarily the fact that lighting is limited and the chance for vision limiting dust is ever present. We are, of course more concerned with personnel safety in our mines than encountering wildlife on the roadside. From the same perspective, the transport driver is just as concerned with encountering a stalled vehicle as our mine truck operators are with other mine traffic.

Feb 1, 2008

By Fan Delian, Ye Jie, Lui Tiebing

The lower and the upper parts of the Doushantuo Fonnation, Hubei Province, China, contain silicate-type K-rich beds (illite and feldspar), and intraclastic phosphorites, as well as Ag-V and V deposits in a "Black Shale Series". The K-rich beds fonned in an anoxic basin whereas the phosphorites fonned in a more oxic and higher energy depositional environment. The Black Shale Series occurs in the lower and upper parts of the Doushantuo Fonnation; that in the upper part consists of black illite shale and dark gray dolostone, and contains Se-rich Ag and V deposits. These deposits are of more industrial significance than the previously discovered Ni-Mo polyelement sulfide deposits which occur in the Lower Cambrian Black Shales Series of South China. Studies of lithotype, sedimentary sequence, and geochemistry of the Doushantuo Fonnation have led to more attention being focused on the uppennost Black Shale Series and its Ag-V and V deposits. There are three ore types: black, Ag-V-rich, illite shale; black, V-rich, illite shale; and dark gray, Ag-Vrich, fmely crystalline dolostone. The first two ore types contain 3070 to 5% Corg and the last, 1.25%. The Ag-bearing minerals are naumannite, argyrodite, aguilarite, acanthite, and native silver that occur as inclusions in pyrite associated with barite. Vanadium substitutes for AI in illite and is also related to organic-matter contents. Because (1) the pre-Sinian Kongling Group contains one to three times greater than the Clark Ag value; (2) black, illite shale has a negative Ce anomaly; and (3) there are large occurrences of black, K-rich, tuffaceous, fme siltstone, the sources of Ag are thought to include subaerial and submarine volcanic materials. It is proposed that Ag, V, and Se were absorbed by clay particles and organic matter during syngenetic deposition in an anoxic environment; Ag subsequently was reconcentrated into sulfides and selenides, whereas V was incorporated structurally into illite during early and late diagenesis. These types of Black Shale Series-hosted Ag-V and V deposits are, therefore, considered to be sedimentary-diagenetic in origin.

Jan 1, 1992

By A. G. Slade

"This paper deals with the direct application of rock mechanics in the underground mines at the Sudbury Operations of Falconbridge Nickel Mines Ltd. It covers mining methods, the use of photoelastic models, the fore-casting of rock strains and their elimination, closure methods and other common methods of ground control.INTRODUCTIONROCK MECHANICS IS A STUDY IN ROCK BEHAVIOUR and, although it is being termed a new science, it has been practiced since the industry began. Every person involved with rock excavations, from the mine superintendent to the stope driller, is actually practising rock mechanics. They probably call it by another name -experience, and applications of this knowledge are in evidence throughout the Falconbridge operations. Only in recent years have formal rock mechanics studies been employed to provide technical assistance to the mine operators in their primary objective of producing ore safely."

Jan 1, 1968

By Cale J. Dubois

At Cameco Corporations' Cigar Lake Project, large excavations are developed on the 480 Level and 500 Level must remain stable for at least 15 years to host underground processing infrastructure. Following the successful dewatering of the mine in October 2009, subsequent internal rockmechanics investigations augmented by third party technical investigations; determined that to keep the back of the Water Flush Crusher/Run-of-Mine (WFC/ROMs) excavation stable; required a rehabilitation strategy to mitigate deterioration/deformation of the WFC walls and intersection pillars. The mechanism of failure propagating the movement of the excavation walls is understood to be controlled by the presence of a dominant E-W striking and steeply dipping foliation within a relatively weak and mildly altered rockmass sub-parallel in strike with 14 meters high walls and an intersection span approaching 15 meters. The application of open and resourceful communications between site mining engineers, geologists, contract mining staff, construction management experts, corporate mining and civil engineers, and third party technical experts resulted in a multi-faceted short-term ground support strategy consisting of standard bolting and screening, deep-seated modified-strand cable bolts coupled with heavy gauge mesh straps, rockmass reconditioning using low-pressure grout injection, and horizontal cable-lacing for the intersection pillars applied in lifts using a top-down methodology. The intention of the short-term strategy was to stabilize the excavation so that a long-term structural steel support installation - consisting of composite concrete walls, and arch support applied to the side walls and crown of the back - could be constructed safely. This paper summarizes the evolution of the short and long-term ground support strategy and criteria for the WFC/ROMs excavation developed using elements of civil, mining and hydrogeologic design.

Nov 1, 2011

By John D. Smith, Robert J. Mitchell

"There is a world-wide trend toward underground bulk mining methods employing hydraulically placed backfill. This trend is recent and therefore there is little in the literature to assist an operator in the design of backfill properties, the design of drainage facilities, the calculation of the operating forces on a bulkhead, and the control procedures considered necessary before, during and after pouring. This paper presents recommended procedures that are based on over to years of experience in the various aspects of backfilling large openings. Free-draining timber or concrete block bulkheads are shown to be a viable alternative to massive reinforced concrete bulkheads for the containment of backfill pours. Hydrostatic pressures cannot develop in backfills provided adquate drainage facilities are installed.IntroductionThe increasingly adverse relationship between mining costs and mineral values has led mining companies to develop more productive, lower-cost, bulk mining methods. This has led to the increasing use of large, more or less continuous, hydraulically placed backfill pours to enable the recovery of a higher proportion of pillar ore. The success of any bulk mining method depends on the degree of stability maintained during the stoping operations with reference to the mining rate, the performance of the backfill with respect to the per cent extraction of pillar ore, and the control of the mine structure with respect to safety and productivity. One such method has been previously described(I) where a steeply dipping orebody is being mined with a sub-level method that employs large, hydraulically placed tailings pours for delayed pillar recovery. The paper describes the rock mechanics analysis undertaken to establish the stope and pillar geometry and the approach taken to establish backfill strength requirements to prevent dilution during pillar recovery. Production with this method started in 1970 and because few, if any, large bulk pours had previously been used in- this way (judging by the lack of information in the literature), design data and criteria were needed for several aspects of the work. Methods to establish backfill quantities and pertinent ""in-place"" fill properties are described in 2, 3 and 4 in the list of references. Results of field measurements taken to establish fill pressures for bulkhead design purposes are described in 5 and 6. Laboratory large-scale model tests undertaken to confirm a fill strength design equation, which takes into account fill arching, have recently been completed. A paper describing these tests and the results will be forthcoming in the near future."

Jan 1, 1982