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By W. Zieman

"The low consumption of reagents can probably be attributed to a good clean type of ore. The cyanide level is kept at 0. 8 lb/ ton of solution and the lime at 1. 8 to 1.9 lb per ton of solution (pH 12. 2 to 12 .3). Experience in cutting down the lime level in half produced troubles in the presses, in the refinery and resulted in higher cyanide consumption. Finally the residue increased under these conditions, High lime always seems to prevent the trouble from occurring.A survey at one mine of the taxable work, performed in the mine shops for use in the mine, showed that under the new regulations, this had increased some 30 times what it was before the new rules came into effect on June 14, 1963.A water softener idea is incorporated at Lamaque with the crude addition of 100 lb of lime per shift to a spare agitator to precipitate the bicarbonates as carbonates from the water before it enters the mill. The lime titration of the softened water is about 0,2 to 0.3 lb per ton of solution (pH 11). This water is used mainly on the filters as washes."

Jan 1, 1964

By H. Fujiwara, T. Ito, T. Mizuguchi, K. Kawasaki

"In this study, we characterize the high-temperature deformation of typical “Class I” solid solution Al-Mg alloys as a superplastic elongation attributable to the solute drag creep of dislocations. The second-phase particles formed by adding Fe or Si as impurity atoms to the Al-Mg alloys impeded the gliding motion of dislocations, thereby decreasing their hot ductility and resulting in cavity formation. High-temperature tensile tests were performed with initial strain rates in the range of 1×10–3 to 1×10–1 s–1 at air temperatures 673–723 K. The dominant high-temperature deformation mechanism in these alloys was the solute drag creep controlled by the interdiffusion of Mg in Al. In this study, the calculation of critical length, defined by the diffusion-based relaxation of the stress concentration region around second-phase particles, is reported using the Needleman–Rice parameter. An analysis of the impact of cavity formation based on a comparison of the Needleman–Rice parameter and second-phase particle size is also reported.INTRODUCTION Aluminum alloys with high specific strengths are utilized as structural materials for transportation machines to minimize their weight, which consequently maximizes fuel efficiency, environment preservation, and so on (Miller et al., 2000; Heinz et al., 2000; Starke & Staley, 1996; Polmear, 1996; Immarigeon et al., 1995; Burger, Gupta, Jeffrey, & Lloyd, 1995; Ye, 2003). Microstructure refinement by severe plastic deformation (SPD) has been performed on a laboratory scale to achieve a higher strength of crystalline materials (Valiev et al., 2006; Song, Ponge, Raabe, Speer, & Matlock, 2006; Beyerlein & Toth, 2009; Sabirov, Murashkin, & Valiev, 2013; Sauvage, Wilde, Divinski, Horita, & Valiev, 2012). At room temperature, grain refinement strengthens the material, as given by the Hall-Petch relationship (Hall, 1951; Petch, 1953); at higher temperatures, superplasticity can be expected (Sherby & Wadsworth, 1989; Edington, Melton, & Cutler, 1979; Furukawa, Horita, Nemoto, & Langdon, 2001; Langdon, 2006). However, the synthesis of large-size materials by SPD processes is not yet feasible."

Jan 1, 2018

By J. Mirza, E. Nicol, J. Lipkowski

Gold passivation in thiosulfate leaching media is a major barrier to its implementation. Addition of Cu (II) into the leaching solution has shown to aid in gold dissolution, but the mechanism by which it acts, and its role in the passive layer, remains unknown. Surface Enhanced Raman Spectroscopy (SERS), in tandem with linear sweep voltammetry, were employed to determine the dependence of leaching currents on mass transport and for fingerprint identification of sulfur species on the surface of gold. SERS leaching experiments were performed using gold nanorod electrodes that showed increased stability compared to other SERS active surfaces.

Jan 1, 2011

By Franc R. Joubin, Donald H. James

"The Property of Rix Athabasca Uranium Mines Limited is in the Beaverlodge area of northwestern Saskatchewan. The mine is 7 miles by road north from the Lake Athabasca port of Bushell which is 250 miles north by aircraft or boat from railhead at Waterways, Alberta.The Rix property is a portion of the former DD 1 concession, obtained in 1949 from the government of Saskatchewan when private prospecting for uranium became permissible. The concession was prospected in detail during the 1950 and 1951 field seasons and a great many radioactive show-ings were discovered. Development and drilling were concentrated in two and later three of these areas, and by late 1952 enough ore had been indicated in the Leonard series and ""Smitty"" zone to justify underground development by adit-drift and shaft respectively.Four hundred feet of drift development on the Leonard No. 1 vein and the sinking of a two-level vertical shaft with related lateral development on the Smitty zone were completed in 1953. In April 1954 the Smitty section was placed in production at a rate averaging 100 tons per day, thereupon becoming the first privately owned post-war uranium producer in Canada. The ore is shipped for processing 12 miles by truck to the mill of Eldorado Mining and Refining Limited.Until recently all of the Company's production was drawn from the Smitty orebody. In April, 1955, ore production commenced from the faulted west extension of the Smitty structure, known as the Rix 62 zone, and from the Leonard No. 1 vein.The Smitty orebody (see Figure 2) is an intensely brecciated lenticular zone bordering both sides of the Smitty fault. The breccia areas are irregularly mineralized with pitchblende, very sparse galena, and pyrite in a gangue of feldspar, chlorite, calcite, and silica, all thoroughly soaked with fine-grained hematite to produce the locally-called ""red alteration"".Tenor of the ore currently being mined is classified information. The average grade estimated, prior to production, was 0.20 per cent (4.0 lbs.) U308 per ton."

Jan 1, 1949

By H. Brodie Hicks

"THE REVIVAL of the Mayo mining camp, with particular reference to the activities of United Keno Hill Mines, Limited, has been one •of the more spectacular and also one of the most important of the post-war developments in the Canadian mining field. The geological location of the camp, coupled with other natural disadvantages, have in the past limited the mining area to small-scale, highgrading operations, but the post-war improvement in metal prices has now broadened the possibilities and has led to the considerable success achieved by United Keno Hill Mines, Limited, and the present boom-type development by a whole host of newcomers to the field.LocationYukon which has an area of 207,000 square miles, is showing ever increasing possibilities as a mineral source of great value and more and more attention is being focussed on the Territory. The accompanying generalized map (Figure 1) shows the main transportation routes and mining districts.The Mayo Mining District comprises roughly the eastern two thirds of Yukon Territory lying north of McMillan river and south of the Peel. The district was one of the first in the Territory in which placer gold was discovered, but the occurrences proved of minor importance. Other minerals reported include ores of tungsten, tin, antimony, and several other metals, but of primary importance have been the ores containing silver-lead-zinc-cadmium now being developed and mined in the Keno area. Similar ores have been found over a very considerable area, extending some 50 miles north, 15 miles east, 30 miles west, and 10 miles south of the townsite of Keno Hills, Keno City, a total area of 2,700 square miles."

Jan 1, 1952

By John Hughes

1. De Beers, Diamonds and Canada 1.1. De Beers was founded long ago (1888, the same time that Canada became a country) in a rural mining village in South Africa. Today, we employ 22,000 people across 19 countries and have 14 mines including open pits, shafts, beach-sands and seabed. 1.2. Last year our sales were US$5.7 billion and our total production amounted to 47 million carats which means a 40% global market share. For the Kyoto buffs in the audience, the company consumes 66 million cubic metres of water per annum, 210 million litres of hydrocarbon fuel and 1,600 GWh of electricity. Stats are good, but aren?t as expressive as a movie. This one is 2 minutes long, which is quicker than I could elaborate. (Video 1 - 2 minutes) 2. De Beers in Botswana is the leading source of diamonds 2.1 Today Botswana is the Jewell in the Crown. There are three big open pits that enjoy economies of scale that make them the lowest cost producers. Last year 60 million tonnes of overburden and 30 million tonnes of ore were moved in Botswana alone. Botswana produced 31 million carats, compared to 14 million carats in South Africa and 2 million very high quality carats inn Namibia. 3. Diamond Mines provide feedstock? ?.to jewellery stores

Apr 1, 2005

By James K. Gowans

"Cominco Ltd's Polaris Mine, located on Little Cornwallis Island, Northwest Territories (latitude 75degrees 30') went into production in late 1981, becoming the world's most northerly base metal mine. The concentrator, powerhouse, shops, offices, dry and warehouse, were uniquely designed and constructed on a 100f t wide by 400 ft long by 65 ft high barge. This process barge was constructed in southern Canada at Trois Rivières, then towed 3,500 miles into the High Arctic Islands and beached on Little Cornwallis Island.The paper deals with the original design philosophy, flowsheet and the initial year's operation of the Polaris process barge.IntroductionTo bring a mining property into production in the Canadian High Arctic, a company must deal with the harsh environment, the short shipping season and the high cost of labour. In trying to minimize the effect of these fact or s, the concept of a barge-mounted process plant was investigated as an alternative to the conventionally built concentrator. Cominco's previous experience gamed at the Black Angel Min e on Greenland's west coast suggested that this would be a practical alternative.The normal shipping season at Little Cornwallis Island is approximately six weeks long, from mid-August to the end of September. All equipment and materials must be delivered during the ""shipping window"". The logistics problems are enormous; if the conventional approach had been used the major process equipment would have been delivered to Little Cornwallis Island at the same time as the completed barge actually was! Construction would also be starting at the start of the worst climatic conditions, the Arctic winter. Nine months' production was gained by opting for the ""barge"" approach."

Jan 1, 1983

By Al Hoffman

During the period May 15 ? 17, 2006 four fatalities occurred at #1 Waste Dump, at Teck Cominco?s Sullivan mine located at the city boundary of Kimberley, British Columbia, Canada. The fatalities occurred in the sump of a water monitoring station. The Chief Inspector of Mines and his staff immediately responded to the incident. The team worked collaboratively with the Teck Ltd. Trail Hazmat team, a consultant group from Rescan Ltd. and other Teck operation and technical staff. Sampling in and around the water monitoring station in the days following the fatalities showed that exposure to a depleted oxygen environment was the immediate cause of the fatalities. The sump located at the base of the shed was hydraulically connected to a French (coarse rock) drain, located at the toe of the covered waste dump. This presentation will briefly review the immediate cause of the accident, the investigation, a brief introduction to the work of the Sullivan Technical panel and the British Columbia government?s response to the incident and the recommendations of the Coroner?s inquest.

May 1, 2010

By Louis Tellier

SIDBEC commenced detailed planning of major capital expenditures to install integrated steelmaking facilities in 1969. Today, less than IO years later, SIDBEC and its subsidiaries have completed major mining, concentrating, pelletizing, direct reduction ? electric furnace steelmaking and continuous casting plants. The total cost of these projects was almost 1 billion dollars. The philosophy behind the project planning and the evolution of management control are explained. These extensive projects were undertaken during a period of exceptional inflation and a disturbed labour climate, but were nevertheless completed with only modest overruns, with good control of timetables and with exceptionally good start-up performance. Project planning, relations with consulting engineers, introduction of new technology, purchasing and field management and cost control are discussed.

Jan 1, 1979

By F. H. Edmunds

I N presenting this paper, the writer wishes to point out some of the difficulties and problems of geological work in that part of Saskatchewan in which outcrops are few. These problems are well known to all geologists who have made investigations in this region, but may not be so well known to those outside. A table of the strata as known in certain areas of Saskatchewan and the adjacent provinces is given, with a brief discussion of some of the formations and beds about which there is little knowledge due to their being deeply buried and not exposed in the region. Comment with regard to possible oil and gas structures is made and some features of the structures in the Battleford and Simpson districts are described. The writer wishes to make acknowledgment to members of the Geological Survey of Canada to whose work in Saskatchewan and the adjacent provinces reference is made, and to others who have made, or are making, valuable contributions to the stratigraphy of Saskatchewan. Mr. G. C. Webb has kindly furnished information regarding and materials taken from a well bored recently in the Paynton district. Special thanks are due to the Simpson Oil and Gas Company for permission to use much valuable information with regard to their wells and for the generous way in which the officials and staff co-operated with the writer. The opportunities the writer has had to visit many parts of the Province have been in connection with investigations for the Provincial Department of Natural Resources and through facilities provided by the Department of Soils of the University of Saskatchewan. To these Departments the writer accords his thanks. For the purposes of this discussion, Central Saskatchewan may be considered as that portion of the Province extending from Township 16, with Regina, Moose Jaw, and Swift Current situated on or near the southern boundary, to Township 48, with Prince Albert and Lloydminster on the northern boundary. This region includes territory underlain by Cretaceous sediments and excludes the southern portion of the Province, where Tertiary beds underlie the surface and are exposed to an extent sufficient to permit a measure of systematic mapping.

Jan 1, 1937

By Erwin L. Zodrow

"IntroductionThrough an extensive coal sampling project in the Sydney coalfield of Nova Scotia during 1981 - 1984 involving a majority of the mineable coals (Zodrow, 1985, Fig. 1), a sizeable inventory on trace, minor and major metals was established. In this paper, results of studying the inventory are summarized, concentrating mainly on the relationship that exists between metal variations and thickness of coal channel samples (i.e. trends) and on explaining the trends in geochemical and sedimentological terms. As an over-all conclusion the Everglades peat of Florida is proposed as a modern-day analogue to Upper Carboniferous peat swamp development that took place in the Sydney Basin.Data InventoryFor this study 17 channel samples were cut , 8 cm to 14 cm channel width and 8 cm to 10 cm depth, from 10 successive coals which in stratigraphically descending order are as follows: Point Aconi (3), overrider Lloyd Cove (2), Lloyd Cove (2), Stubbart (2), Harbour (4), Backpit (I), Phalen (,I), Shoemaker (1) and McAulay (I), where bracketed values signify the number of channel samples cut from a seam (Zodrow, 1985, Fig. I). Each channel sample was subdivided by 15 em incremental length yielding a total sample size of 137 for analysis. By appropriate modern techniques these samples were analyzed to determine concentration levels for 32 chemical elements and ash content, the average results of which are presented in Table 1.Tests were also made for Pd, Pt, Ga, Nb, Cd, Cs, Sm and W but their concentration levels in many instances hovered on the lower detection limits that were used and on this accounts are excluded from discussion. Ashing, when necessary for the determination of concentration levels, was done for 12 hours at a temperature not exceeding 450°C. Concentration levels for the elements are reported in reference to whole-coal or whole-coal equivalents and discussed on this basis. In the course of the analyses, lower detection limits received careful attention."

Jan 1, 1986

By Engineering Staff

"This paper briefly describes the surface mining operations at Smoky River Coal Limited (formerly McIntyre Mines Limited, Coal Division) near Grande Cache, Alberta. Geology, mining methods, equipment, manpower and reclamation and environment topics are discussed. Introduction Smoky River Coal Limited, a wholly-owned subsidiary of McIntyre Mines Limited of Calgary, Alberta, produces a high quality, low sulphur, low volatile bituminous coking coal from its minesite located at west central Alberta, approximately 20 km from the town of Grande Cache and 360 km west of Edmonton (Fig. I). Most of the coal property is contained within a 30 km long by 20 km wide block lying in a northwest-southeast direction in mountainous terrain. Elevations vary from 920 m above sea level ·at the plant·site on the Smoky River to 1,600 mat the upper levels of current and proposed mining operations. A total of 11 coal seams have been identified. Only two seams, No. 4 Seam and No. 10 Seam are currently considered of major commercial value. These seams are recovered by both surface and underground mining. Approximately 650Jo of the plant feed coal is obtained from a conventional shovel/truck surface mine; the balance is mined underground by room-andpillar methods. Background In 1921, McIntyre Mines Limited acquired some 26,300 hectares of coal leases at Smoky River. Since then the leases were explored intermittently by different companies including McIntyre. In the mid-l 960s exploration activities increased and several feasibility studies were completed. Development of the area was undertaken by McIntyre in 1968 and, in August of the same year, a long-term contract was signed with a consortium of Japanese steel mills for delivery of 2 x 106 t of clean coking coal for 15 years commencing in 1970. Production was focussed on underground mining, using longwall methods."

Jan 1, 1985

By Roy EI. Durr, Glen R. Davidge

"This paper presents the results of structural analyses and full-scale destructive tests conducted on liner plate culverts. The purpose of this work was to establish a design method and evaluate the suitability of using these structures in potential roof-fall areas for a rehabilitation application in lower stress and relaxed mining environments. Field evaluation of the design is currently in progress.Theoretical ultimate resistance functions were established for two different culvert shapes and were found to be representative of their experimental behaviour. The ultimate resistance function was used to determine their plastic behaviour to a rapidly increasing deflection condition, to determine the energy absorption capacity of these structures, and to predict their response to impact loading.IntroductionThe Kidd Creek mine of Falconbridge Limited is located justnorth of Timmins, Ontario. The area under rehabilitation for which this program was developed is the 2600 level of the No. I mine. The problem of effectively securing selected drifts at the 2600 level in NO.1 mine, for access to a high-grade ore block, is key to the economics of the operation. Diamond drill test holes had indicated a loosened rock mass above the 2600 level of about 7.5 m thick in response to the extensive mining operation below this level. This level forms the arbitrary boundary between the No. I and No. 2 mines, and has extensive volumes of cemented rock fill below it and largely untouched ore above it to the 2000 level in the North orebody. The walls at that level were showing relaxed ground conditions typical of de-stress: sub-horizontal joints opening up, and peeling.Due to the ground conditions, the consequent safety risks, the high grade of the ore, the potential production delays, and the likelihood of several phases of rehabilitation, regularly used drift rehabilitation employing rock bolts, cable bolting, or shotcrete was not practical. Two options were deemed possible alternatives to suit these conditions, steel sets with blocking and lagging, and liner plate culverts with backfill. Culverts were chosen."

Jan 1, 1995

By Graham Sim

Agenda ?The Water Challenge ?Examples from Three Case Studies ?Mine Drainage, 99% recovery ?Mine Drainage, 80% recovery ?Road Dust Control ?Technology Development ? Conclusion Global water challenges Assuring sustainable quantity Improving water quality Reducing energy consumption

May 1, 2011

By B. Calver, D. J. M. Farnsworth

"As open-pit operations expanded at Pine Point, hydraulic aquifer evaluation was undertaken to establish the criteria necessary for the design of a feasible dewatering system.The extreme climate of this northern location dictated that the ore zone under extraction be rendered as dry as possible to minimize freezing effects. The design and implementation of such a system necessitated detailed hydraulic evaluation, and the problems that occurred are typical of those inherent in open-pit mining operations in northern areas.The paper describes the problem solution as approached from a mine engineering point of view, with particular reference to the practical aspects of operation and installation. The hydrological analysis used is simple and readily applicable to most open-pit dewatering problems."

Jan 1, 1969

By Russell A. Luke

"Modular Mining's computerized LHD position monitoring and dispatching system commenced operation at the De Beers Finsch Mine in mid- J99J. A sophisticated blend of proven and new technologies links the dispatcher at the workstation console on the surface with the LHD operators several hundred metres below. The dispatcher allocates each LHD to a priority tip and loading drive based on instructions provided by the miners and shift bosses underground. LHD operators receive tip and loading drive allocations on the vehicle computer console which communicates data via a Leaky Feeder radio network. The operators interact with the console to notify the dispatcher of delays, breakdowns, and changes in tip and tunnel status. The underground terminal displays allow shift bosses to monitor the progress of the LHDs as they pass infrared beacons (IRs) located in the tips loading drives and rim tunnel main haulage ways. The terminals also provide on-line statistics for the current and previous shifts. Future enhancements include optimized dispatching and interfacing to a PLC system controlling ventilation. Further, token ring-based loop UHF radios are being investigated as an alternative to the Leaky Feeder data radio network. IntroductionFinsch first contacted Modular about an LHD monitoring and dispatching system in late 1988. At that time, Modular declined a request for a formal quotation but agreed to perform an engineering feasibility study. The study was issued in mid-1989 and confirmed Finsch's belief that an underground system could be developed with technology available at that time. A contract for the system was signed the following year and, in May of 1991, the system began operation. By the end of 1991, LHDs on both production levels of the mine were under the control of the system."

Jan 1, 1993

By M. Venkatraman

The limit of Hall - Petch relationship in ultra fine grained steels has been examined based on dislocation pile-up mechanism. When the grain size becomes small the dislocation multiplicity ceases resulting in very low work hardening rate in these materials. An approximate analysis of the theories of hardening indicates that H-P relation is obeyed up to 100nm. It appears that grain refinement is not the suggested approach to improve toughness as well as strength below a critical size.

Jan 1, 2004

By F. Channier

The paper provides the most recent information on the construction of the AP60 phase 1 plant of Jonquiere which is due to be commissioned and started up in the first quarter of 2013. HSE management on site by RTA, and cooperation with local equipment manufacturers and contractors of the Saguenay-Lac Saint Jean region are highlighted in this section. The AP60 phase 1 Jonquiere plant aims to demonstrate of the AP60 technology at an industrial scale and allows the further developments of the AP60 cell. The advantages of the AP60 cell technology in terms of productivity, power consumption and environmental footprint are also briefly presented in the paper.

Jan 1, 2011

By Z. Zhong, Y. J. Hu, D. Elsworth

"A standard triaxial apparatus was set up to perform sliding tests. Slide-hold-slide (SHS) tests, with hold times from 10 to 3000s and at invariant effective confining pressures of 1MPa, incremented to 3MPa and then 5MPa, were conducted on both dry and wet split limestone samples to study the evolution of fracture friction under holding and sliding processes. Limestone fracture shows time-dependent behaviors in SHS tests, friction drops (creep) gradually during hold periods, and recovers (healing) after re-slide. Frictional healing and creep increment are proportional with hold times, while are inversely proportional with effective confining pressures. Moreover, the wet sample displays heavier healing than the dry one, whereas creep increment of the wet sample is lighter than the dry one. We conclude that the evolution of limestone fracture friction is significantly controlled by mechanisms of fluid-rock interactions.INTRODUCTIONThe evolution of the mechanical properties of fractures and faults exerts a critical influence on the behavior of fault zones and on the earthquake cycle. In addition to natural processes, this behavior has broad implications in induced seismicity and influences oil and gas production, the sequestration of carbon dioxide and the disposal of nuclear wastes.Fault friction is typically measured by slide-hold-slide experiments, where fault gouge is deformed at low velocities (<0.1 mms-1) and over small shear offsets (<30 mm) (Dieterich, 1979, 1981; Mair et al., 1999; Marone, 1998, 2004) or alternatively with rotary-shear devices, that enable higher slip velocities over very large shear offsets (Hirose & Shimamoto, 2005; Mizoguchi et al., 2006). Typical experiments (Dieterich, 1972; Marone, 1998; Olsen et al., 1998; Bos & Spiers, 2002; Tenthorey et al., 2003) show significant creep during the holding period and frictional healing (strength gain) upon reloading. Fault creep and healing are often time-dependent with longer hold times typically resulting in greater magnitudes of creep and in strength gains (Tenthorey et al., 2003; Yasuhara et al., 2005; Carpenter et al., 2012). Frictional healing may arise from growth of grain contacts (potentially induced by pressure solution) (Rabinowicz, 1951; Dieterich & Kilgore, 1994; Yasuhara et al., 2005), strengthening of the contacts (correlates with cementation) (Hickman & Evans, 1992; Beeler et al., 1994; Karner et al., 1997; Olsen et al., 1998; Muhuri et al., 2003; Tenthorey et al., 2003; Li et al., 2011) or via other changes in state including changes in porosity and rearrangement of force chains. Experimental evidence (Dieterich, 1979, 1981; Johnson, 1981; Marone & Scholz, 1988; Marone, 1998; Saffer & Marone, 2003; Moore & Lockner, 2007; Ikari et al., 2007; Ikari et al., 2011; Carpenter et al., 2012) quantifies both the mode and magnitude of second-order changes in the velocity-dependent (including velocity- strengthening and weakening) evolution of frictional strength."

Jan 1, 2015

By E. M. Hillary, D. F. Sangster

"Abstract - As a contribution to the World Minerals Geoscience Database Project, an index-level database comprising information on 142 SEDEX Pb-Zn deposits and occurrences was constructed in Microsoft Access 95 format. Although consisting of only basic information, the compilation, with full referencing of all data, is possibly the largest non-corporate SEDEX Pb-Zn database in the world. It thus provides an opportunity to make geoscience queries of SEDEX Pb-Zn deposits on a scale not previously available. This report provides a summary of the results of a few such queries both as a contribution to a better understanding of SEDEX lead-zinc deposits and as a demonstration of what even such a simple database can offer.During the compilation process, it became apparent that SEDEX Pb-Zn deposits could be assigned to one of the following three sub-types: Type 1 (53.5% of total) in which sulfide minerals are the only exhalative components; Type 2 (33.1%) in which the exhalative components are sulfides plus chert, siderite/ankerite, and/or barite; Type 3 (13.4%) which contains any components of Types 1 and 2 plus abundant iron-oxide minerals (commonly magnetite) and/or is associated with iron oxide-rich sedimentary rocks.Highlights of systematic queries of the database reveal that:1. a majority (84%) of the world’s SEDEX Pb-Zn deposits are not underlain by a discordant footwall feeder zone or vent complex;2. 63.6% of deposits occur in Proterozoic strata followed by a second peak in the Devonian (16.8%). Of those in the Proterozoic, 83% of Type 3 deposits occur in the Gondwanaland supercontinent, whereas only 42% of Type 2 and 39% of Type 1 are located in this large paleo-landmass;3. median (Pb+Zn) grades in Types 1 and 2 fall between 9% and 10% with a majority clustering within this range. Type 3 grades, however, range from ~1% to ~20% (Pb+Zn) with a median of 5%; 4. median size of Type 3 deposits is ~33 Mt, whereas Type 1 and 2 median sizes are ~7 Mt and ~8 Mt, respectively.The report concludes with a brief discussion of how an index-level database such as this can be used in conjunction with other, similar databases to reveal interesting and instructive relationships for guiding both research and exploration."

Jan 1, 1998