Search Documents

By George S. Rice

GROUND movement and subsidence is an important matter from several points of view and it is regrettable that more papers have not been written on this subject in the past year. Damage may be done to surface buildings or to the higher workings of a mine, and a study of the subject gives valuable in- formation on hanging-wall or roof control. The latter objective is strikingly shown in a recent paper presented by Jack Spaulding on Oct. 21, 1937, before the Institution of Mining and Metallurgy, of Great Britain, entitled "Theory and Practice of Ground Control in the Kolar Gold Field, India." All may not agree with some of his theories that were deduced from studies of the many violent rock bursts at depths of 5000 to 7000 ft., but the data obtained are of great value. His theories of symmetrical ring stresses and symmetrical domes which are pictured as perfect are rather hard to understand as such uniformity is un- likely in view of the irregularities in the formation due to folds and fractures of various kinds. All will agree in principle with this idea of domal effects, which have been observed in many countries, but they are generally irregular.

Jan 1, 1938

By John B. Gayle

The coking time has considerable influence on the throughput of a coke oven, and for this reason a large number of papers dealing with the relationship between coking time and the different operating variables have been published. Although all factors known to influence the coking time have been studied, agreement has not been reached on several questions.2/3 Therefore, it appears worthwhile to evaluate any data that become available during investigations of the carbonizing properties of various coals and coal blends. Because it is expected that reports covering several different phases of this problem will be forthcoming as additional data-become available, the following study of the relationship between coking time and bulk density represents a report of progress on the overall investigation of factors influencing the coking time in slot-type ovens. The practice of including coarse coal in the blend going to the ovens to obtain increased bulk densities is well known. Similar increases have been realized by adding small quantities of oil to the coal mix. Although it would appear that such procedures provide inexpensive methods for increasing the capacity of existing coke-oven installations, Ramsburg and McGurl4/ point out that this increase is possible only if the additional coal can be carbonized in the same coking time as regularly employed without using abnormally high flue temperatures. This statement is in substantial-agreement with the position of Auvil and others5/ and implies that any change in bulk density may be accompanied by a corresponding change in coking time. On the other hand, a recent review of proposed methods for calculating the time required for carbonization6/ includes a number of equations that completely ignore the effects of variations in bulk density.

Jan 1, 1954

By A. M. Cann, C. I. Godwin

"The Kemess porphyry copper-molybdenum deposit occurs in the Intermontane Belt of north-central British Columbia. The deposit is in andesitic to basaltic flows and tuffs which may be correlated with the Savage Mountain Formation of the Upper Triassic Takla Group. Most known chalcopyrite and molybdenite is associated closely with a 500-m-diameter zone of intense quartz-sericite-pyrite alteration. A zone of supergene enrichment, up to 30 m thick, underlies a leached capping about 20 m thick. The age of mineralization and the surrounding granodiorite and quartz monzonite pluton is Early Jurassic. K-Ar and Rb-Sr analyses indicate that the mineralization and alteration is slightly younger (l82±6 Ma) than the granitic intrusion (KAr: about 205±6 Ma; Rb-Sr: 190±4 Ma). The low 87Sr/J6Sr initial ratio for the granodiorite is typical of plutons in the Intermontane Belt.IntroductionKemess is a medium to small porphyry copper-molybdenum deposit with significant gold and silver values (Pilcher and McDougall, 1976). This paper describes the lithologies and alteration at this property; geochronology by Rb-Sr and K-Ar methods defines the ages of mineralization and surrounding plutons to be Early Jurassic.The property, located in the Thutade Lake area of northcentral British Columbia (NTS Map 94E; lat. 57°04'N; long. 126°44'W), is about 425 km northwest of Prince George (Fig. 1). Closest road access is 35 km southeast of Kemess. Final access must be by float plane or helicopter. The British Columbia Railway right of way passes 70 km to the southwest of theproperty.A prominent gossan zone at Kemess was staked in 1967 by Kennco Explorations (Western) Ltd. following detection of geochemical anomalies during stream sampling the previous year. During 1968, 1969and 1971, Kennco completed 232 m of X-ray diamond drilling, conducted geological mapping and carried out geochemical sampling of silts and soils (Stevenson, 1969; B.C. Ministry of Energy, Mines and Petroleum Resources, G.E .M., 1969 and 1971). Getty Mines Ltd. optioned Kemess in 1975and 1976. They remapped the area and diamond drilled 12 BQ and NQ holes, totalling 2065 m (B.C. Ministry of Energy, Mines and Petroleum Resources, Expl. B.C., 1975)."

Jan 1, 1980

By Serhan Guner, Sundar Chiluwal

Although significant research has been conducted on helical piles, there is a lack of research and official design provisions on the helical pile-to-pile cap connections. These connections may govern the global response of pile cap systems—especially in tall and light structures where uplift forces dominate the response. To improve future industry practice, the objective of this study is to understand the influence of pile-to-pile cap connections on the global behavior of concrete pile caps and develop recommendations for their efficient design. For this purpose, 108 high- fidelity nonlinear finite element simulations are conducted to quantify the influences of bracket type, embedment depths, longitudinal reinforcement percentages, shear span-to-depth ratios, and loading conditions on the load, deformation, cracking, and failure behavior of concrete pile caps. The results indicate that the design configurations involving single bracket type may result in premature concrete cracking around the anchorage zones with a 25% reduction in the uplift load capacity. The investigations also confirm that high reinforcement percentages and low shear span-to-depth ratios result in higher load resistance in all bracket types, and that the load capacities of the double and studded bracket types are similar. For applications requiring the use of lower embedment depths, it is recommended that either double or studded bracket types be used. The research findings have applicability to both helical and micro piles given that both include similar connection types. INTRODUCTION Tall and light structures may experience significant uplift forces at their foundations due to large overturning moments from wind or other lateral loads. Helical piles (e.g., Fig. 1a) can provide a cost- effective, practical, and resilient solution for resisting significant uplift forces. In order to realize the full potential of helical piles, it is imperative that the helical pile-to-pile cap connections (see Figs. 1b, c and d for examples) are properly designed to resist the applied forces. However, there is a lack of research and associated knowledge on the influence of pile-to-pile cap connection detailing on the global response of pile caps.

Jan 1, 2019

By B. Dubé, R. Friedman, J. Oliver, R. Aubertin, M. Burson, G. Panneton, M. Hamilton, J. Ayer

"Abstract — The Detour Lake gold deposit is located within the northwestern limit of the Archean Abitibi Subprovince of the Superior Province. Mineralized zones are hosted by a sequence of pillowed and massive flows, hyaloclastite units, and altered ultramafic rocks, and are commonly oriented parallel to a series of high-strain zones that are co-planar to the regional-scale Sunday Lake Deformation Zone. Early in its kinematic history, the Sunday Lake Deformation Zone placed older (2.72 Ga) volcanic rocks of the Detour Lake Formation over younger (2.70 Ga) sedimentary rocks of the Caopatina assemblage. Gold mineralization is also parallel to the position of a laterally persistent siliceous rock unit, the 2.725 Ga ‘Chert Marker Horizon.’ The Chert Marker Horizon coincides with the boundary between the mafic-dominated upper Detour Lake Formation and the ultramafic-dominated lower Detour Lake Formation. Stratigraphic and geochronological data suggest that the Chert Marker Horizon is a deformed felsic volcaniclastic unit. At a cut-off of 0.6 g/t Au, the Detour Lake deposit contains 17.26 million ounces of Au within 445.9 million tonnes of rock grading 1.20 g/t Au. Gold occurs in shear-hosted and extensional vein arrays within rocks of the upper and lower Detour Lake Formation and within the Chert Marker Horizon. The Detour Lake deposit has many of the characteristics of a greenstone-hosted, quartz-carbonate vein deposit; its very large size may be attributed to large-scale rheological controls resulting in the formation of dilatant sites in permissive rock units. © 2012 Canadian Institute of Mining, Metallurgy and Petroleum. All rights reserved."

Jan 1, 2012

Currently all engineering schools face a common problem, an ever expanding technological base which must be presented to students within a fixed time period. Traditionally the programmes of study taken by engineering students destined for employment within the mineral industry include formal instruction in aspects of management to an extent greater than that presented in other engineering disciplines. Providing an adequate coverage of an expanding technological base within a fixed time span can lead to a reduction in the time available for 'non-technical' subjects, such as 'management'. This situation calls for periodic review of course contents and allocations of time. Following consultation with an Advisory Committee representing the mineral industry, mining research establishments, and kindred teaching institutions, the University of Melbourne has revised its mining programme. This programme is offered as an example of how aspects of management such as communications, economics, labor

Jan 1, 1980

By Donald E. Ralston, A. T. Yu, Richard P. Killmeyer, Peter Phillips, R. W. Vander Laan, John N. Murphy, John R. Messineo, John Peters

Overview Coal production in the first half of 1982 remained near the high levels begun in mid-1981. Production then fell sharply during the latter part of the year due to recession-weakened demand. Even so, 1982 coal production was estimated at 756 Mt (833.4 million st), a record high that exceeded 1980's previous production record of 752.7 Mt (829.7 million st). Though 1982 coal production was substantially below industry expectations, the attained production represented a modest achievement in view of the recession's severity. In 1982, the gross national product declined 1.8%, its worst performance in 36 years. The recession, along with mild weather, improved energy efficiency, and conservation efforts caused the nation's energy use to drop 4.1%. With the iron and steel, construction, and auto industries experiencing production declines, industrial energy use fell 10.8%. The extent to which the nation's economic slump affected coal markets in 1982 varied: • total domestic coal use declined 3.4%; • exports remained strong for most of the year; • electric utility coal use declined for the first time in 25 years; • coal use at coke plants declined by one-third; and • coal use in other industrial sectors stayed surprisingly near the 1981 level. Coal Use Domestic coal use totaled 641.8 Mt (707.5 million st) in 1982,22 .9 Mt (25.2 million st) below the 1981 level. Nearly all the decline occurred at coke plants where use dropped to 37.1 Mt (40.9 million st) in 1982 from 55.3 Mt (61 million st) in 1981. The decline in all other industrial and electric utility coal markets was only 5.3 Mt (5.8 million st). Residential and commercial coal use increased 635 kt (700,000 st) to 7.3 Mt (8.1 million st) from 6.7 Mt (7.4 million st). Power generation decreased 2.3% in 1982, the first year since 1945 that output failed to increase. The decline was due to a drop in industrial demand. Electricity sales to residential, commercial, and other nonindustrial users increased slightly. But coal's competitive position stayed strong. Power generation from oil and natural gas fell 28.9% and 11.7%, respectively. Power generation from coal declined only 0.9%. Among the primary energy sources, coal fueled 53.2% of US electric power generated in 1982, compared with 52.4% in 1981. In 1982, US steel production declined to 66.1 Mt (72.9 million st), the lowest level in 50 years and down from 109.6 Mt (120.8 million st) in 1981. The reduced steel demand forced 13 coke plants to shut down. Coal Exports Coal exports in 1982 totaled 96.4 Mt (106.3 million st), 5.7 Mt (6.3 million st) less than in 1981. Despite the worldwide recession and above normal coal stockpiles in many countries, exports were higher than many expected. This showed the relatively strong US position in international coal trade. The US continued to export near-record coal tonnages despite increasingly competitive influences. These included an improvement in Australia's labor difficulties, the return of Polish coal to Western European markets, and lower oil prices. In 1982, US port facilities were improved and expanded, and more efficient methods for scheduling foreign vessels were implemented. As a result, high volume coal shipments to US ports were routinely loaded and dispatched unhampered by bottlenecks that plagued East Coast ports in 1981. Appalachian coalfield production declined 1.4% from 1981 output and 3.9% from 1980 output. The interior region of the US showed an increase of 7.8% in production. This was primarily because of a

Jan 5, 1983

By V. E. Housman

EPA's Mining Waste Section within the Office of Solid Waste is continuing to collect and analyze information on mining waste management practices. Starting in 1991, the Mining Waste Section has continued to conduct site visits and prepare case study reports on the waste generation and management practices of operating mines. In choosing sites to study, a reasonable attempt was made to provide diversity in mining commodity types, geographic regions, geology, climate, and environment. To date, EPA has visited the following mines: Asarco Troy (copper) in Montana, Newmont Rain in Nevada (gold), Cyprus Thompson Creek (molybdenum) in Idaho, LTV Steel (iron) in Minnesota, Phelps Dodge Morenci (copper) in Arizona, Doe Run Fletcher (lead) in Missouri, Brewer (gold) in South Carolina, IMC Four Corners (phosphate) .in Florida, Pennzoil Culberson (sulfur) in Texas, Nerco Cripple Creek (gold) in Colorado, Copper Range White Pine (copper) in Michigan, Magma San Manuel (copper) in Arizona, Colosseum (gold) in California, and several gold placer mines in Alaska, including the Valdez Creek Mine. EPA has prepared a case study report on each facility. The mine operators were provided an opportunity to comment on their respective site visit report and their comments have been included in' each respective report. These site visit reports have in turn been incorporated into technical resource documents which provide a detailed description of each mining sector. EPA is currently reviewing the technical resource documents and plans to release the documents in the Spring of 1994.

Jan 1, 1994

By Clyde E. Williams

[As a results of work conducted during the past three years, the Northwest Experiment Station of the Bureau of Mines, in cooperation with the University of Washington at Seattle, Washington, has developed a process for the production of sponge iron. Commercial operation of this process in a 3 to 4-ton scale has been so satisfactory that its use on a large scale (20 to 100 tons per day) can be safely considered. Description of Process. The process consists in passing a mixture of iron ore and coal through a rotating kiln heated at one end to a temperature sufficient to convert iron oxide to metallic iron, discharging, cooling, and separating the sponge iron from the residual coke and silicious material on a magnetic separator. Both the coal and the ore should be crushed to peso as 6-meth scream, tans producing particles finer then 1/12 of an inch. Seventy-five parts of coal or other carbonaceous material arc charged with every 100 parts of ore), This large amount of coal is required in order to supply sufficient carbon to maintain a strongly reducing atmosphere in the charge, but may be reduced to about 65 parts per 100 parts of ore by recovering and using tae carbon that remains in the discharge product. Large-scale operation and refinements in furnace design should lower this ratio to perhaps 56 or 60 parts of coal to 100 parts of ore.]

Jan 1, 1924

By Xie Zhang, Chongyang Zhao, Qingyun Huang, Bing Xie, Xiaopeng Zhen

"Extracting vanadium from vanadium containing hot metal into vanadium slag by BOF is the main vanadium production process in China. In this paper, the influence of Si content in hot metal on the quality of vanadium slag is analyzed. Synthetic vanadium slag with different SiO2 content were melted at 1673 K and then cooled to 303K at the cooling rate of 3?/min. Optical microscopy, SEM, EDS and XRD were used to analyze the mineralogical phases and crystallization behavior of vanadium slag. The results show that vanadium slag mainly contains spinel phase and silicate phase; V is enriched in the spinel phases while Si is concentrated in Fe2SiO4 CaFeSi2O6 and (Fe,Mn)2SiO4 as silicate phase. The melting point of slag increases gradually with the addition of SiO2; whereas viscosity decreases with an addition of 15~19% SiO2 and increases with an addition of 19~27% SiO2.IntroductionVanadium is an important element which is used almost exclusively in ferrous and non-ferrous alloys. The major vanadium products include FeV, V2O5, V2O3, VN and Al-V-Ti alloy. Furthermore, vanadium slags are mostly produced by oxidizing the elements in V-containing hot metal during a duplex refining process. Therefore, the process of removing vanadium from hot metal has its significance on the subsequent process[1].The extraction of vanadium is greatly affected by the mineralogical composition of vanadium slag[2], the distribution of the elements between the spinel and silicate phases and its physic-chemical properties. These characteristics of vanadium slag have been studied in some details. It has been reported that Si mainly exists mainly in the form of silicate which wraps the spinel crystals while small amount of Si stands as phosphorus quartz or diopside[2]. Chen et al.[3, 4] points out, when SiO2 content in vanadium slag increased every 1%, V2O5 decreased 1.48%. Moreover, silicate phases would embarrass the oxidation of V-containing spinels through decreasing the exposing probability[5]. Meanwhile, melting point and viscosity of vanadium slag has been greatly influenced by the SiO2 content. Therefore, this work attempts to analyze the above-mentioned questions systematically."

Jan 1, 2012

By B. S. Covino

The Bureau of Mines has conducted a laboratory and field corrosion test¬ing program to determine materials of construction for the leaching and gas-sparging crystallization environments of the clay-HC1 process in order to more fully utilize the alumina from domestically available kaolinitic clays. Laboratory tests were used to determine the corrosion rates of 22 metals and alloys by weight-loss measurements in these two environments of the process. The results of this laboratory study were used both to suggest metals and alloys for field testing and to determine the effect of the individual solution components on the corrosion behavior of the metals and alloys. Results from the field tests were used to recommend Ta, Ta-2.5W, and Ta-10W for con¬struction of the agitators for the leaching process. The metals and alloys recommended for construction of the gas-sparging crystallizer heat exchangers were Ta, Ta-2.5W, Ta-10W, Nb, Nb-1Zr, Nb-3Zr, Nb-28Ta-10W-1Zr, Nb-10Hf-1Ti, and Zr for the first stage and Ta, Ta-2.5W, Ta-10W, Nb-28Ta-10W-1Zr, Nb, Nb-10Hf-1Ti, and Zr for the second stage.

Jan 1, 1981

Discussion of the previous paper E. N. H. MOLLOY The first 22-foot-diameter Aerofall mill was installed at Mangula in 1957. This was fitted with cast-iron trunnion'! located to the mill shell with 2-inch-diameter mild-steel bolts. O.F .S. Branch Minutes of the General Meeting held at the Welkom Club on Wednesday, 2nd June, 1976, at 4.00 p.m. Mr G. J. C. Young (Chairman of the O.F.S. Branch) was in the Chair. Also present were:

Jan 9, 1976

By A. G. Guy

IN the course of a research on steady-state diffusion it became necessary to make diffusion calculations for a finite solid. This problem was found to be sufficiently different from the corresponding problem for the semi-infinite solid for an entirely new approach to be necessary in obtaining a useful solution. The assumption of an exponential variation of the diffusion coefficient with concentration' was no longer a practical necessity, so that the new solution offered the possibility of handling diffusion in semi-infinite solids for arbitrary variations of the diffusion coefficient with concentration. In discussing the principle on which this method of calculation is based, it is convenient to consider the relatively simple problem of one dimensional diffusion into a matrix that initially contains none of the diffusing substance. The solution of the set- ond Fick Law,?C/?t=D0?2C/?x2, for diffusion into a semi-infinite solid is3 C/C=1-F(x/2vD0t [1] where C is the concentration of the diffusing substance at a depth x cm below the surface after dif- A. G. GUY, Member AIME, and M. GOLOMB are Professor of Metollurgicol Engineering and Professor of Mathematics, respectively, Purdue University, Lafayette, Ind., A. S. YUE, formerly with Purdue University, is now with the Research Laboratory, Dow Chemical Co., Midland, Mich. TP 4505E. Manuscript, July 18,1956. fusion has occurred for t seconds; C, is the concentration of the diffusing substance at the surface of the matrix; Do is the diffusion constant, expressed in sq cm per sec; and + represents the Gauss error function. The corresponding solution for diffusion into a finite solid of thickness, 1, is conveniently written for the change in concentration, C+, at a point midway through the matrix and for times, t, great enough for the following equation to be used4 c1/2/C1=(1/2-2/?e-?2D0t/l2) [2] In Eqs. 1 and 2 the diffusion coefficient is represented by the symbol Do (rather than by D) to emphasize that these equations are valid only for constant values of D. To understand how these equations can be modified to take account of actual variations of D, such as that shown in Fig. 1, first consider the fact that for a given time of diffusion theconcentration at a given point is determined, not by the D value alone, but by the ratio x/vD0 in Eq. 1 and by a similar ratio, l2/D0 in Eq. 2. Even though in fact D varies, it is possible to keep this ratio constant by using a special coordinate system, x,, that varies with D in the appropriate manner. The necessary character of this special coordinate system can be easily visualized by imagining that

Jan 1, 1958

By Matthew A. Perras

With growing populations, infrastructure projects are utilizing underground space to expand transportation networks, water supply and sewer disposal systems and hydropower facilities. These new projects require large diameter tunnels to meet the growing demands. As the tunnel diameter increases, not all rock mass properties are scalable and precedent experience becomes less reliable. One such non-scaleable property is lamination thickness. Numerical modelling was conducted to determine the influence of lamination thicknesses on a 16 m diameter tunnel. Five different areas of excavation response were found to exist for laminations ranging between 0.16 to 16 metres in thickness. For this tunnel diameter, critical lamination thicknesses of 6 metre and 1 metre were found to exist. Above 6 metres the excavation response was similar to isotropic models. Below 6 metres the stresses and yield are channeled by the lamination boundaries, increasing plastic deformation. Below 1m multiple lamination units become unstable and the displacements increase significantly and the shape and extent of the yield zone size changes dramatically. The yield zone is controlled by bed deflections and bed parallel shear. As the lamination thickness decreases tensile failure first begins in the haunch area and progressively extends above the crown until a self-limiting plastic yield zone shape is reach at lamination thicknesses below 0.4 metres. Conclusions drawn from observations at the Niagara Tunnel Project are those of the authors.

May 1, 2009

By J. T. Ryan

IN making a comparison of mine inspection methods in Europe and the United States, it is necessary to have some basis to start from, which makes this subject rather difficult, as such methods are governed largely by the authority given the inspector by the mining laws. In the United States there are 31 coal producing states and territories and 32 different mining laws under which inspectors operate, as one state-Pennsylvania-has both a bituminous and an anthracite code. Some of these codes are distinctly coal mining codes; others are essentially coal mining but apply also to other mines; several codes are sub-divided referring partly to coal mines and partly to other mines, and a few codes are mainly metal mining but apply in part to coal mining. Having all these different codes in the United States and the departments organized in a variety of different ways, there is of necessity a great difference in inspection methods in this country.

Jan 1, 1926

Water retention, water loss and delay in tailings storage rehabilitation are major challenges for many Coal Mines. Work by Stewart, Backer and Busch in the early 1980s suggested that there were improvements to be made in tailings dewatering and density by the addition of flocculant. This prompted ACARP, in cooperation with Bulga Coal Management (Xstrata), to initiate a research project investigating the impact of flocculant addition on tailings deposition density, water retention and the tendency for tailings to form surface crusts suitable for subsequent rehabilitation. A polyacrylamide-based flocculant (200 - 250 g/tds) was injected into the tailings line immediately prior to disposal into the impoundment area. The flocculated slurry rapidly released clear water and created a beach due to the immediate increase in deposition density. The deposition density increased from 35 per cent w/w to 61 per cent w/w solids within 24 hours and continued to increase to 75 per cent, seven days after treatment. The water capture at the tailings storage facility improved by more than 90 per cent; water which would otherwise be lost from the circuit through retention and evaporation. The impoundment capacity had nearly tripled due to the improvement in initial deposition density from 420 kg/m3 up to 1163 kg/m3. Four weeks after disposal surface crusts were forming on the storage facility, suggesting that there would be less delay between cessation and tailings storage rehabilitation.

Jan 1, 2008

By François Robichaud

"The Laronde mill has been in operation since 1988. Actual milling rate ranges from 7,000 to 8,500 mtpd. Laronde uses SAG/ball mill grinding followed by copper and zinc flotation circuits. A cyanidation/Merrill-Crowe process recovers the remaining gold and silver in the flotation tails.In 1999, the carbon in pulp circuit was replaced by a Merrill-Crowe circuit in order to cope with a much higher ratio of silver/gold associated with the discovery of the Penna shaft. Marine type diatomaceous earth was used as filter aid in both clarifier pressure leaf filters and recessed pressure filter presses from 1999 to 2005. In 2005, this filter aid was gradually replaced by alpha-cellulose after several laboratory and plant filtration trials. The selected cellulose is considered to be much less sensitive to parameters such as pH and reagent concentration and have increased clarifier and filter press filtration performance. Also, since cellulose is exothermic, replacing diatomaceous earth with cellulose as filter aid in the filter presses has increased calcining and oxidation rates in the calcining ovens since cellulose is exothermic. Finally, better calcining conditions have resulted in energy and reagent savings at the arc furnaces.This paper describes how the filter aid replacement has contributed to increasing productivity and Net Smelter Return of the refinery while reducing worker’s hazards and operating cost.INTRODUCTIONAll Merrill-Crowe circuits in the world are operated with filter aids. For years, the market for precoat filter aid has been dominated by mineral filter aids such as diatomite and perlite. Flowsheet and equipment selection at the Laronde refinery were performed in the late nineties. At that time, some key parameters of the design criteria had clearly identified marine type diatomaceous earth (DE) as the most successful filter aid. Parameters such as reagent cost and availability, clarity of the filtrate solution and good historical filtration performance in other concentrators had designated DE as the best suited filter aid. Pregnant solution processed in the refinery from its start-up through 2001 was fairly stable in flow rate and reasonable in terms of impurity content (cationic and anionic compounds)."

Jan 1, 2007

By Tim McMahon

"A slurry is any combination of liquids and solids where solids make up more than 10 percent of the mixture. Mining operations create various types of slurries from processes such as dewatering, bitumen extraction in oil sands, concentrator plants, milling operations, tailings, lime addition and so on. The mines then transport these slurries through pipelines (Fig. 1).Slurry valves are used when the mine needs to transport ore a long distance and there are no other viable transportation methods, such as roads or railroads.Severe service valves must be used in slurry applications and they must be tested to ensure reliability. This article describes how Emerson designs and tests its Fisher valves for use in mining slurry applications.Slurry pipeline valvesWithin a slurry pipeline system, valves are required as part of the pumping stations, choking stations and isolation stations. There may be multiple pumping stations depending on the length of the pipeline or the terrain it crosses. Choking stations are used to reduce the velocity and the pressure in the pipeline, either before a pumping station or at the end of the pipeline, and to ensure the pipeline does not slack (remains full and pressurized). Isolation stations exist so that a pig (a device sent through a pipeline to clean or inspect the pipe) can be inserted or removed from the pipeline.Typical valves used in a slurry pipeline are severe service ball valves. The valves use floating balls that are held between the seats and are not pinned or permanently attached to the shaft that rotates the ball. The inside diameter of the ball typically matches the pipeline inside diameter, enabling the pipeline to be cleaned or inspected with a pig.They can be built to accommodate the high pressures required for the typical slurry pipeline. These pressures can require up to ASME Class 2500 valves and flanges. The valves can get qlarge, up to NPS 36 inches.Specialized segmented ball valves and slurry knife gate valves are also used in some slurry applications when pressures are lower, in the ASME Class 150-300 range."

Sep 1, 2019

The American Society of Mechanical Engineers extends an invitation to members of the Institute to participate in an exceedingly interesting excursion on Saturday, November 11. Permission has been secured for a visit to the plant of the Electric Boat Co. at New London, Conn. There will be run a special-test on a high-power 8-cylinder, 4-cycle Diesel engine. A large number of submarine and other engines in various stages of construction will be seen, also the boring of torpedo tubes, cylinders and other equipment for submarines. The drafting rooms and foundry mill also be open for inspection. The party will have an opportunity to see at close range the submerging of several submarines, and an attack on a vessel on the surface, an exhibit which is being arranged by courtesy of Rear Admiral A. W. Grant, who is in command of the submarine forces of the United States. The Boston members will leave South Station on train No. 7 at 8.30 A. M. Those from Providence will board this train at 9.36 A. M. The Worcester members will leave on train No. 745 at 8.36 A. M. The New York contingent will leave the Grand Central Terminal at 8.31 A. M. on train No. 8. This train will leave New Haven at 10.30 A. M. Upon arrival at New London, each group will go directly to the Mohican Hotel, where a "get-acquainted" luncheon will be served

Jan 10, 1916

By A. Buncombe

In March 1984, two years' work by senior metallurgical personnel from the six major mining groups culminated in the formation of the Mine Metallurgical Managers' Association of South Africa. This Association has joined a group of specialist Associations operating within the South African mining industry whose aims are to uphold the standards and promote the interests of their various professions.

Jan 1, 1987