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By James F. Reynolds

Introduction There are 1.4 Gt (1.5 billion st) of recoverable coal under less than 914 m (3,000 ft) of cover in Colorado in pitching seams. Snowmass Coal Co., in cooperation with the US Department of Energy, introduced the longwall mining method in pitching seams to North America. This venture is a coal mining research program directed toward the profitable production of coal under difficult mining conditions as found in pitching seams of the western US. Snowmass Coal classifies pitching seams into the following categories for longwall on the strike in seams 3 m (10 ft) or less thick: • Flat = 0 to 10°: Normal continuous mines and shuttle cars work efficiently. • Slight = 10° to 22°: The maximum pitch that rubber tired equipment will function. • Moderate = 22° to 40°: The angle of repose of mined coal. • Steep = 40° to 60°: The limit of safe use of this roof support. • Vertical = over 60°. The longwall roof support covered here will work in all pitches except vertical. The shearer and conveyor will work in flat through moderate conditions. Longwalling across strike with this equipment in seam pitch over 60° could be accomplished with an inclined face. Development of the first longwall panel began in 1979 and was completed in 1981. The longwall equipment was installed and mining began on Aug. 11, 1981. Mine Planning and Development The original mine plan took advantage of old works abandoned in the 1960s. The gates were developed on a two-entry system with the entries rising 2° to the strike, allowing water to drain from the face. The mining method was by Alpine F6A road header continuous miners with bridge conveyor type coal transport into 5.4-t (6-st) bottom dump coal cars hauled on 1.1-m (42-in.) gauge track by 7.2-t (8-st) battery locomotives. The initial concept was to haul coal from the longwall by battery locomotive. Lack of discipline, however, was shown in the irregular direction of the gate entries, and local rolls in the coal seams severely limited the capacity of battery locomotives. Current mining law prohibits using an intake escapeway for belts or trolley locomotives. A two-entry system is the simplest method of panel development in a pitching seam. A continuous miner cannot be trammed from one entry to another because of steep "X" cuts. Thus, the development requires a continuous miner in each entry. The configuration of the old mine works resulted in a first panel longwall block of three 108 m x 1.6 km (355 ft x 5,400 ft). In panel development, the use of battery locomotives for coal hauling became evermore costly. When the panels were completed and the setup room finished, the lower gate entry was changed to a belt entry and battery locomotives were abandoned. A new slope was driven and the mine supply system was converted to rubber tire diesel supply. The latest generation of roadheader and standard high powered shuttle car-to-belt system is now used for development. Selection of Longwall Equipment Longwall mining across the strike on pitching seams is currently practiced in many nations. Equipment similar to that used by flat seam longwalls is available for pitching seam use in Great Britian and Germany. Face equipment includes a twin outboard armored face conveyor. It was selected to give maximum retention of coal on the conveyor due to flight rigidity and to prevent coal from sliding down the face and jamming the lower belt gate. Also selected was a 22-mm (0.9-in.) Dowty twin-outboard face conveyor for a 106-m (350-ft) face with a single 112-kw (150-hp) drive

Jan 12, 1983

By Jim Sadowski, Steve Stewart, Bob McMurdy, Martin Nevens

"Mohawk Garnet has been operating a small pilot plant near Sudbury, Ontario for several years attempting to produce commercially viable garnet. The challenges of operating a pilot scale mining, processing, and product handling operation as a full time plant have led Mohawk Garnet to seek a better way. In co-operation with Mohawk Garnet, Outotec (USA) Inc. has taken on the technical and design challenges of increasing garnet product from twenty tonnes per day to two hundred tonnes per day.Outotec performed a comprehensive test and flowsheet development program applying Outotec’s density separators, spirals, flotation, and other technologies to design a successful process for the separation and recovery of the valuable garnet for Mohawk.This paper explores the test program, the process flowsheet development work, plant design and preliminary engineering of a new garnet processing. The various technical challenges, process technologies involved, and design concepts will be discussed.INTRODUCTIONMohawk garnet has been operating a small-scale garnet mine and process plant in Wahnapitae, Ontario near Sudbury.The current operation was intended to be a pilot plant and so only produces 20-25 tonnes of garnet concentrate per day. The garnet is bagged and sold for use as abrasive. The process is inefficient with low yields, poor material handling and very high cost per tonne. Mohawk garnet approached Outotec to help them improve their garnet process and transform themselves into a larger scale and more efficient operation."

Jan 1, 2010

By Russel Delmar

Construction of Ontario Power Generation?s 12.8-m diameter, 10.4-km long water diversion tunnel in Niagara Falls, Ontario, is underway. The tunnel is being excavated by means of a 14.44-m diameter open gripper Tunnel Boring Machine. The tunnel lining is constructed as a two-pass system with the initial lining consisting of rock bolts, mesh, steel channels or ribs, and shotcrete, and the final lining consisting of pre-stressed cast-in-place concrete with a waterproof membrane. This paper describes salient design and construction aspects as follows: ? Regional and Site Geology ? Tunnel Layout and Design ? TBM Tunnelling and Cast-in-place Concrete Lining Construction

Jan 1, 2008

By Warren L. J

The effectiveness of shear-flocculation as a method for upgrading simple mixtures of ultrafine (1-11 \lm) scheelite and garnet was evaluated. Statistical methods were used in the design and analysis of the main test program.The stirrer speed, stirring time, and initial weight ratio were all found to have significant effects on both the recovery and grade of the floes produced. The particle sizes also had an effect on the final grade. There were several important interactions between factors which also affected the results. Optimum conditions for shear-flocculation were established, and under these conditions about 80 per cent of the scheelite could be recovered at a grade which depended on the composition of the starting mixture. Starting with mixtures containing 10 and 50 per cent scheelite, the best final grades were between 20 and 50 per cent and between 70 and 90 per cent respectively, the actual value depending on the particular combination of particle sizes.

Jan 1, 1977

By C. C. Anderson

"While conducting investigations in connection with the helium program of the Bureau of Mines, the Cryogenic Laboratory has improved an apparatus for the rapid and accurate determination of the helium content of natural gas and gaseous mixtures derived from that source. The separation of helium is effected by the use of activated coconut charcoal which, when cooled to liquid-air temperatures, absorbs the nitrogen and other constituents of the gas, leaving the helium in a. spectroscopically pure state. This absorptive property of activated charcoal was discovered- by Dewar3/ in 1875. Several years later, while conducting their original researches on helium in natural gas, Cady and McFarland employed the charcoal method for the absorption and removal of the common constituents of natural gas and constructed an efficient apparatus in which this operation could be effected.4/ Shortly after initiating the government's helium activities during the World War period, the Bureau of Mines adopted, with Minor modifications, the Cady and McFarland apparatus and method of analysis. Seibel.5./ described this modified apparatus and method of procedure as part of a publication on helium-bearing natural gas. Subsequently, the Bureau's apparatus for helium analysis has been simplified and improved to facilitate more rapid and positive operation. The apparatus and method of procedure now being used by the Bureau of Mines Cryogenic Laboratory arc described in this paper.The personnel of the Bureau of Mines Cryogenic Laboratory has improved and brought the helium apparatus described herein to its present state of perfection. The writer's contributions have been-of minor importance, and he wishes to give the various members and former members of the laboratory staff full credit for the improvements they have made. He also desires to express his appreciation for suggestions and criticisms offered during the preparation of this paper to the following members of the Petroleum and Natural Gas Division, Bureau of Mines, which now includes the Amarillo Helium Plant and Cryogenic Laboratory: H. A. Cattell, chief engineer; C. W. Seibel, supervising engineer of the Amarillo Helium Plant; W. M. Deaton, chemist-in-charge of the Cryogenic Laboratory; and H. S. Kennedy.The quantitative determination of helium in a gaseous mixture is accomplished by the removal of the other constituents from the sample, either by chemical or physical Means, leaving only the helium which can be measured directly. Chemical methods, when applied to natural gas, require the burning of the hydrocarbons in oxygen, the, absorption of the resulting carbon dioxide in a caustic solution, the removal of the excess oxygen in a suitable solution such as an alkaline pyrogallate, and the elimination of nitrogen by sparking or by combination with hot calcium or magnesium.. Such procedures are very slow and tedious compared with the physical method which employs the absorptive property of activated charcoal to effect the separation of the other constituents from the helium."

Jun 1, 1934

By Evelynn Stirling

Agenda ? Emissions legislation ? Cummins Tier 4 Technology ? Cummins Experience with Technology ? Operation and Maintenance Impact The Emissions Challenge ? The 2014/5 emissions regulations present the most significant challenge to our customer?s diesel powered equipment design and operation in recent history? ? ?and Cummins has the solution.

Aug 1, 2013

By J. E. Nesset

"I had been requested earlier this year by MetSoc, our sister society of CIM, to contribute a chapter on technical developments in Canadian mineral processing over the past 50 years to their 50th Anniversary volume. Accepting the challenge of assembling such a chapter seemed at first a reasonably straightforward task, until one realises that the list of contributions by Canadians to mineral processing over this period has been more than just significant. It turns out to have been an extraordinarily fertile time for innovation and impact for Canadian-based technology. The list is necessarily a subjective one, however I had no trouble identifying twenty technology developments that are clearly outstanding, and there are undoubtedly others. As much as possible, I approached the individuals themselves who played key roles in each technology and asked that they tell the “story”. Without exception, all who were invited accepted eagerly and delivered more than I had hoped for. The technologies have been grouped into those that are truly Canadian innovations, such as the Knelson gravity concentrator and the McGill gas dispersion sensors in flotation, and technologies where Canadians and Canada played a very significant role in their success and implementation, such as AG/SAG grinding and ion-beam surface analysis. Also included are what may be termed technology transfer initiatives and institutions that have risen to a world class level, such as SGS Lakefield and the Canadian Mineral Processors Society of CIM. The challenge is now for the coming generation to continue this record of innovation and contribution to the industry, and that includes the (mostly) Canadian mining and metallurgical companies who have taken the longer term view and supported many of these initiatives, through their critical early years, with both financing and project sites for these ideas. Let us hope that the current trend of mining company globalization will not dampen their enthusiasm to participate. This plenary presentation will highlight many of these technologies, the individuals behind them, and their significance to the mineral processing industry."

Jan 1, 2012

By J. Kirsch

Keywords: Pyrometallurgy, pneumatic transport, pneumatic transport Dense-phase pneumatic injection has begun to replace more traditional furnace-feeding systems. The paper describes the technology as it is applied to processes where the back pressure at the point of injection is greater than 50 kPaG. It reviews earlier systems of injection and more recent developments that address concerns for instantaneous control in modern smelters. The new technologies fall into two groups, (1) modified pressure-difference control (sub-divided into simple and complex) and (2) mechanical-feeder-based control. Features of current injection systems include feed splitting in two forms, passive and active, and co-current injection.

Jan 1, 2006

By David J. Hoadley

This report describes the development and limited testing of a semi-automatic, raise climber, Compact Service Hoist System designed for stope access in underground metal and nonmetal mines. Demonstrated capabilities of the system include a 1,000-lb payload capacity, control from the traveling cage and from up to three remote stations, operating in vertical or inclined raises 3 ft in diameter and up to 300 ft in length and a travel speed of 50 ft/min. The system has the capability of operating in crooked raises because the conveyance climbs two stationary wire ropes suspended down the raise. The drive unit is electrically powered with power and control signals supplied to the drive unit through an umbilical 'cable also suspended down the raise. The system has been designed for portability, ease of installation and minimum raise development. The hoist has been demonstrated successfully in an above ground test tower. This report provides a detailed description of the hoist design and its demonstrated performance to date.

Jan 1, 1985

By A. D. Storrie

An underground wet shotcrete trial was completed last year to determine the effectiveness of wet shotcrete as an alternative support mechanism to dry shotcrete in the kimberlite environment. The wet shotcrete was manufactured at the underground batch plants, transported to site using an agiecar and transferred to the shotcrete pump. The wet shotcrete is pumped to the nozzle where compressed air at 7 bar and an accelerator, Meyco SA 160, is added and enables the shotcrete to be placed successfully onto the tunnel wall. No tunnel guard was previously placed on the sidewall and hangingwall. Geotechnical testing indicates that the Grace fibre performed extremely well with the energy absorption tests at 7 kg/m3and 8kg/m3where both achieved over the mine requirement of 750joules. The Grace fibre and wet shotcrete mix also achieved a compressive strength in excess of 55 MPa, well above the 45 MPa requirement for Premier Mine. The recommended wet shotcrete mix design is therefore based upon: [Material/ CriteriaQuantity/m3Units ?Lafarge 42.5 Duratech500kg ?Condensed silica fume40kg ?Rayton Sand1.558Ton ?Delvocrete stabilizer 103.6litres ?Glenium 27CH5.4litres ?Meyco TCC 7355litres ?Water230litres ?Meyco SA16025litres ?Fibre8kg ?Cement/Water Ratio2.35? ?Water/Cement Ratio0.43? ?Flow615 mm] If the wet shotcrete system is implemented there is a potential for Premier Mine to make major savings. In South Africa there are two suitable wet shotcrete machines available for the mining industry, the Spreymec, manufactured by Tamrock and the Fermel/Meyco wet shotcrete machine. The Spreymec is a fully imported machine. The Fermel component is manufactured in South Africa and the Meyco shotcrete components are imported and supported by MBT (Master Builder Technologists) in South Africa. The Fermel/Meyco machine is assembled in South Africa. Premier Mine has allocated some R2, 100,000 towards the implementation of the wet shotcrete system. If implementation is successful there should be an internal rate of return gain of 76% with regard to this project.

Jan 1, 2001

By Luis Briceño Arata

El presente texto describe los proyectos mineros desarrollados hasta el año 2000, el cual contempla los siguientes minerales: plata, hierro, fosfato, oro, carbón antracítico y bituminoso, así como las necesidades energéticas, hídricas y posibles fuentes del suministro.

Jan 1, 1975

By J. D. Bardill

"The Stoddard mine, Cheshire County, N. H., was explored by the Bureau of Mines in 1944 as a source of the strategic fluorite. It was reported that the vein persisted in the bottom of old workings and the geology of the immediate area indicated the possibility of finding additional lenses.In its program of exploration of mineral deposits, the Bureau of Nines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts pre¬liminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director.Special acknowledgment is expressed for the cooperation and assistance given by Robert F. Sherwood of the United Feldspar & Minerals Corp.; by McHenry Mosier, chief, College Park Division, Mining Branch, who aided in re¬vising this report; and by J. B. Zadra, chief, College Park Division, Metallurgical Branch, and others of his staff, who assisted in performing the beneficiation tests and analyzing samples. The field work was under the direction of Harry P. Hermance.The property lies on the southern boundary of the town of Westmoreland, Cheshire County, N. H., at approximately 72° 39’ west longitude, 42° 27’ north latitude, in the Keene, N. H. (G.S.) quadrangle.Good gravel roads lead from paved State Highway 63 to the property. A dirt road in fair condition suitable for truck leads to the nine.Dwight H. Smith, Putney, Vt., is the owner and has leased the property to the United Feldspar & Minerals Corp., 10 East 40th Street, New York 16, N. Y.Property titles were not investigated.The fluorite deposits of Cheshire Count', H. H., have been known for many years, being reported by Jackson, (Geology and Mineralogy of New Hampshire, by Charles T, Jackson, 1844) and by Hitchcock, in1878 (Geology of Now Hampshire, vol. 3, 1878, by Charles H. Hitchcock). A large pit on the largest or east vein was mined by Lovat Frazer from about 1908 to 1917, This operation is reported to have produced approximately 3,500 tons of fluorspar. In 1917, the American Steel & Wire Co, took over the mine end is said to have produced 3,500 tons of fluorspar before relinquishing the lease in 1923.From 1935 to 1937 the New Hampshire Fluorspar Cc. operated the Stoddard mine, working chiefly on the most westerly of the three known veins on the property, as well as doing some preliminary work on the small central vein. In 1938, the United Feldspar 6 Minerals Corp. leased the mine, and less than 100 tons of fluorspar was produced from exploration and development work, No mining has been done since that time."

Sep 1, 1946

The need to hoist increasing loads from great depths is leading to the more general adoption of winders of the Koepe and Blair types. The trend has introduced a number of new problems in winding ropes, more particularly in the Koepe system where regular destructive tests during the life of a rope are not possible. Consequently, the importance of introducing non-destructive tests is much greater, especially so in the case of Koepe ropes used for deep winding where there are three major destructive fatiguing influences. These are rotational effects when a vertical rope is changed end-for- end each trip, the much greater range of stress to which the rope is subjected each trip as compared with drum winding, and the destructive effect of a high coefficient of friction between wheel and rope. A plea for a lower coefficient in the interest of better rope and tread life, substantiated by analysis, is made for Koepe winders operating at depth.Co-ordination of rope testing with general hoisting problems is stressed and the active participation of the Wire Rope Committee of the Australian Mineral Industries Research Association Ltd. in the promotion ofthe project is noted.The general introduction of a rope testing programme in Australia, personnel requirements and some local basic research in the subject to cope with future demands are considered.

Jan 1, 1967

Cessation of mining on the Bendigo goldfield makes it evident that, as the older generation fades away, knowledge of the famous Bendigo saddle reefs will be limited in the future by their written records. It is important therefore that the summarised account by D. E. Thomas (1953) in the Geology of Australian Ore Deposits should not be misleading. Fig. 6 in this article is stated to portray a cross section and longitudinal section through a series of gold shoots in the Garden Gully 300 ft. reef. The gold shoot along the capof the saddle reef is represented as extending down the east leg in a series of prongs, with the tips of the prongs about 50 ft. apart. It is the purpose of this note to indicate that this illustration can be suspected to be a diagram of the old stopes instead of a diagram of the distribution of gold in the quartz.The original sketches of Figs. 6 and 7 in Thomas' account were extracted, I believe, from the field note books of H. S. Whitelaw, years after his death in the late twenties. Whitelaw was stationed in the Bendigo office of the Geological Survey of Victoria, carrying out geological surveys of the Bendigo mines. He was there for many years before the Gold Research committee started its investigations in 1916 and he was acutely aware of the problem attached to the distribution of gold in the reefs. He had felt concern that manyauriferous reefs were being mined without adequate study and record and he decided, as he expressed it to me, to pick up what he could as he went along. There can be little doubt that the diagrams of Figs. 6 and 7 are products of this resolve.Opportunities to investigate gold occurrences at Bendigo were limited before 1916 because the field was operated by Manuscript received at The Institute 18th November, 1960.

Jan 1, 1961

By L G. B Wadley

The Australian gold industry has made large steps forward in the last few years. This progress has been driven by improvements in mining and processing technology, the high price of gold and by a favourable legislative, political and taxation environment. This paper concentrates on improvements in gold project development, process engineering and technology as seen by BHP Engineering, Perth, Australia. The paper describes technical aspects of successful gold project development including metallurgical test work, feasibility studies, choice of process flow sheet (gravity, heap leach, carbon in pulp (CIP), carbon in leach (CIL) or other routes). It sets out our views on plant design, plant construction, procurement and project management. A case study for a small plant recently completed in the Philippines is presented as a solution to the problems often encountered in treating quartz vein gold deposits.

Jan 1, 1990

By Luis Briceño Arata

El presente texto señala las posibilidades de evolución cuantitativa de la producción minera del país hasta el año 2000. Para ello, se evaluaron los factores que influyen en la producción, la metolodología de proyección adoptada y así elaborar la producción de elementos estudiados.

Nov 1, 1974

By Lucien Eaton

THE use of filling in mines is less common in the United States than it is in Europe, where in some places it is required by law. In most cases the filling is placed by hand, and the material used for this purpose is the waste from development and that sorted from the ore in the stopes. When these sources provide an insufficient supply, additional rock must be quarried on surface or mined underground, or some other material :st be used. In different parts of the world sand, clay, gravel, culm, nulated slag, mill tailings, and even ashes, have been used as filling material in place of or in conjunction with rock. Of all the materials used for filling the best is probably clean sand. Gravel, finely crushed rock, granulated slag and coarse mill tailings are almost as good, and the methods used for placing and confining sand will apply equally well to any of these. The advantages of sand are its comparatively slight compressibility and the ease, economy and convenience with which it may be placed. On account of the voids, which necessarily occur in fills made of coarse waste, such fills will compress 10 to 25 per cent before they develop their full strength, whereas clean sand seldom compresses more than 5 per cent. Sand is especially desirable when practically complete filling is required, and sand derived from mill tailings, especially when not thoroughly cleaned, has been remarkably effective in sealing off and extinguishing mine fires. When natural sand is available on surface, or when it can be obtained from the mill tailings or tailings dump, the cost of using this material for fill will probably be considerably less than that of rock. In this paper it is not proposed to discuss all methods of filling, butt to describe some of the methods used for placing sand fill and to make a brief comparison of their merits.

Jan 1, 1932

By I. Demers

Doyon mine, Quebec, Canada evaluates the possibility of desulphurizing their tailings to produce material to be used in as cover over the acid generating tailings disposal site. Laboratory tests were conducted and showed that a single-layer cover made of desulphurized tailings placed over reactive tailings can prevent the generation of acid mine drainage. Modelling with the software Vadose/W was undertaken to optimize the design parameters, namely cover thickness, water table position, and residual sulphide content of desulphurized tailings following laboratory work. It was found that the optimal configuration includes a 1 m desulphurized tailings cover containing 0.8%S, with the water table kept at the interface between the reactive tailings and the cover. To maintain the cover performance to reduce oxygen flux towards acid-generating tailings even in the event of a long dry period, a sand layer is suggested to protect the cover from excessive evaporation. It is possible to reach the environmental objective chosen for Doyon mine (10 mol/m2/year) with the protective sand layer, even in extremely dry conditions.

Jan 1, 2008

By W. C. Winegard, A. Galibois, C. J. Beingessner

The effects of solutes on the distribution of two-dimensional configurations of grains in zone-refined tin have been studied. When solutes with partition coefficients (ko) greater than unity are added, three-sided pains become more prevalent and the growth law changes. It is shown by electron-Probe micro-analysis that a solute buildup occurs ahead of a moving grain boundary when ko > 1. It has been found recently1, 2 that solutes with partition coefficients greater than unity have a larger retarding effect on grain growth than solutes with k, less than unity. ko is defined as the ratio of the concentration of solute in the solid to the concentration of solute in the liquid with which the solid is in equilibrium. Niessen and winegard2 have suggested that this effect is probably due to the complex shape changes which occur during the process of grain growth and that no theory based on single boundary motion3-5 can explain the results. They suggested that the dissociation of the unstable fourfold junction was delayed in alloys where ko was greater than 1 because the boundaries at the junction had to move into a region of high solute concentration. If indeed this mechanism were correct, it was felt that not only would the dissociation of fourfold junctions be affected by the solute buildup ahead of the boundaries, but the collapse of three-sided grains would be impaired. These combined effects would naturally lead to a modification in the distribution of the number of sides per grain seen on a two-dimensional section. The present investigation was undertaken to test these hypotheses by examining the grain-growth process in detail. EXPERIMENTS The Distribution of Grain Configurations in Zone-Refined Tin as Seen on a Two-Dimensional Section. Following the method of Bolling and Winegard,6 zone-refined tin was cast into button-shaped specimens and, subsequently, plastically deformed under a drop hammer at room temperature. The resulting flat coin-shaped samples were annealed at 200°C, some for 50 sec and others for 100 sec. The specimens were then examined to determine the distribution of the number of sides per grain, i.e., the num- ber of crystals adjacent to any particular grain in the section. For simplicity, the grains were classified as three-sided, four-sided, and so forth; this concept is schematically illustrated in Fig. 1. As indicated by smith,' it was necessary to examine every grain within an enclosed area to obtain a proper distribution of the relative frequency of each type. The distributions for the two annealing times are illustrated in Fig. 2. The total number of grains examined is also indicated on the figure. It is evi-

Jan 1, 1965

By McIntosh A. H, Torlach J. A

Since the last paper on mining methods was presented to the Annual Conference of the Australasian Institute of Mining and Metallurgy in 1:960, numerous advances have been made in drilling and blasting techniques at Mount Morgan. This paper describes the drilling and blasting methods being employed in the open cut. The change over to track mounted percussion drills for all types of primary drilling is almost complete and new techniques such as detergent drilling and pressure loading of ANFO are being applied successfully.

Jan 1, 1965