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Slurry technology developed for the marine transport of mineral commodities has been increasingly applied to on-shore slurry transport systems. Reclaim of mineral concentrates, sand tailings for mine backfill and various industrial minerals from storage tanks or ponds normally require a slurry of high density at constant flow rates to improve process performance and to reduce handling costs. An efficient system must accomplish this at minimum capital costs with maximum reliability. Continuing improvements in equipment design to improve repulping efficiency and their application are discussed.

Jan 1, 1986

From depths of 400 - 600 m, coal is transported by a conveyor in a drift or a bulk winder in a shaft, whilst men and/or materials are transported by a slope hauler or a cage winder. Assessment of the effect of alternative combinations on the key cost factors - output, capital, labour cost and construction time - allows the optimum choice for particular circumstances, there being no uniform solution.

Jan 1, 1976

By M. Pantazidou

The wide use of chemical grouts, in combination with increasing environmental awareness, necessitates the evaluation of possible adverse effects if grout constituents may leak in groundwater. Acrylamide-based grouts are of particular interest, since the engineer has to balance the superior properties of these grouts and the known human health impacts of acrylamide. This paper identifies the properties of acrylamide that are required for the evaluation of its fate and transport in the subsurface and presents results of numerical simulations of acrylamide transport for a hypothetical tunneling application.

Jan 1, 2006

By Kirk Carlton

The Athabasca tar sands of Alberta are an increasingly important source of crude oil for the North American continent. Published figures indicate estimates of recoverable resources in the tar sands at some 300 billion barrels of synthetic crude of which some 86 billion barrels can be recovered by surface mining techniques. At the present time, two commercial plants are in operation, Great Canadian Oil Sands Limited and Syncrude Canada Ltd. Their present combined capacity is approximately 150,000 barrels per day. Some of the factors which will make this oil expensive will be noted here. The location of the present producing plants is 500 kilometres north of Edmonton at an elevation of approximately 320 metres. Recorded temperatures range from +38 to -55 degrees Celsius. Wind velocities are not high but the chill factor with even a slight breeze and minus 40 degrees is very uncomfortable.

Jan 1, 1979

By M. Westerstrand

It is known that the water chemistry of the process water during ore refinement can affect product quality, such as iron pellet strength. The main objective of this study was to quantify the amounts of major elements, such as Ca, Mg, Na, S and Cl carried by process water and by magnetite grain surfaces to the end product, iron ore pellets made from magnetite ore from the Kiirunavaara Mine in northern Sweden. In addition, the amount of colloids (0.22µm ? 1kD) in the process water was examined by ultrafiltration. The amounts of various elements sorbed to the magnetite surfaces were estimated by leaching with Milli-Q water, MgCl2, NH4-acetate and Na-acetate. Total dissolved solids were between 1,446 and 1,775 mg/l, dominated by Ca, S, Na and Cl (89%). The colloidal fraction was less than 3% for major ions. For Ca and Mg, sorption to magnetite surfaces was a much more important transport mechanism for the pelletizing process than evaporated process water, but for Na, Cl and S process water was an important carrier.

Jan 1, 2010

By B. van der Moolen, P. J. M. Groot

The introduction of liberalisation in Dutch mineral provision has created a lot of uncertainty on how and where to supply for the need of construction raw materials. Some possible effects of this policy shift are: 1. the extraction of materials from small pits with truck transport, 2. an increasing dependence on foreign suppliers, 3. the usage of marine dredged materials, 4. more input of secondary substitutes. The outcome of this policy and the resulting marketbehaviour have consequences for transport and infrastructure and hence for sustainability issues. Mineral provision, on the other hand, is also influenced by the availability of infrastructure. Insufficient transport capacity could hamper the development of mineral projects that render benefits to society. (Even) in a liberalising market for mineral provision, the central and local governments have an important role to play with regard to infrastructure and the effects of transport. Various trends point towards an increasing internationalisation in mineral provision. What will increasing trade and increasing influence of the market mean for transport infrastructure? How should increasing transport be judged with respect to sustainability? In the sustainability discussion these questions will have to be answered on a national as well as on a European scale.

Jan 1, 2005

By W. S. Fyfe, R. J. Puddephatt, S. Zhou

Gold is easily mobilized at temperatures within range 600-11OO°C by gases such as Cl2, CO, H2S, in gas mixtures, at low pressures. Such gases are relevant to conditions of granulite facies metaomorphism in environments of magma underplating. These observations suggest an efficient mechanism for moving gold to the upper crust during major thermal events. The efficiency of precipitation of gold at lower temperatures is related to available mineral surfaces and pyrite appears to be an excellent substrate for gold precipitation.

Jan 1, 1989

By N. Saldía, C. Riveros, R. Hills, S. Barrera

The transport of tailings composites provided by different sources is a field of study where a limited amount of research has been conducted. Nevertheless, such systems are important sources of operational difficulties, especially in the case of high clay content tailings. The case presented in the present paper consists of a free surface flow pipeline transporting a composite of two different tailings with high clay content. It has presented operational difficulties such as partial blockages and upstream box and air intake overtopping events. In the present paper, the causes of these difficulties are identified. These include lack of complete mixing of the different tailings, multi-layered flow with low velocity and high yield values with high frictional losses. The pipeline characteristics and performance are analysed in three stages: design, initial operation and enhanced operation, the latter accomplished by means of increasing turbulence in the box located upstream from the pipeline. The last section of the pipeline and another distribution pipeline system located downstream from the pipeline have performed well. The cause of different behaviour of both systems is also assessed.

Jan 1, 2007

By Slavoljub D. Maksimovic, Steve J. Page

The Bureau of Mines measured respirable dust emission rates from overburden drilling at a surface coal mine and the transport of this dust to downwind locations. The emission rates were estimated by using multiple gravimetric dust samplers mounted on a cross-shaped tripod located immediately downwind of the drill. The transport of this dust was measured at more distant downwind locations by a combination of respirable gravimetric sampling and integrated bag sampling of sulfur hexafluoride (SF6), which was used as a tracer gas. Two modes of sampling were used: (1) At five sampling locations arranged in a semicircle around the drill. The radius of this arc ranged from 15.85 m (52 ft) to 71.32 m (234 ft). (2) In-line sampling at downwind locations with samplers located at intervals of either 10.67 m (35 ft) or 15.24 m (50 ft) for a total distance of 76.20 m (250 ft). Samples were taken 1 .22 m to 1.52 m (4 to 5 ft) above ground level. Test results for the semicircular test arrangements showed that at any downwind location, the maximum contribution of respirable dust due specifically to the drilling operation was 42%; the average for eight tests was 13.6%. In general, there was no correlation between the downwind distance of this maximum contribution and the maximum contribution itself because of changing wind direction. Test results for the in-line arrangements indicated that the transport of the dust from the drilling operation usually decreases rapidly with distance and that, even though the drill dust may produce significant health hazards for the drill operator and drill helper (or other personnel in the immediate vicinity), the exposure of downwind personnel to drill-generated dust may not be a significant problem.

Jan 1, 1987

By Jing G. Yen

When a solid-liquid mixture is conveyed through a pipe,' four hydrodynamic conditions may develop depending upon the properties of the transporting medium, the properties of the transported material, the properties of the pipeline and the flow characteristics. They are classified as homogeneous flow, heterogeneous flow, intermediate flow and saltation. Heterogeneous flow, which is the subject of the present analysis, occurs when solid particles are coarse, of high density, and the mean velocity of the flow is relatively low, such that the combination allows the establishment of a pronounced concentration gradient in the cross-section of the pipe. In this type of system the suspended matter does not change the rheological properties of the conveying fluid, and solid and fluid phases behave somewhat separately. In recent years much work has been directed toward gaining more insight into the hydrodynamics of heterogeneous flow (1,2,3,4,5,) However, almost all knowledge obtained is empirical in nature and limited in scope. Much effort has been extended to collect experimental information on the energy losses associated with systems of slurry flow (6-13) The work of Durand and Condolios(14,15) represents one of the most extensive experimentations in this field. Through systematic test runs, the effects of the major flow-parameters were studied one at a time. From the results, they concluded empirically that:

Jan 1, 1969

By Lifeng Zhang

The transport of fluid, heat and particles (bubbles and solid inclusions) in flowing molten steel is investigated in steel refining ladles, the continuous casting tundish, continuous casting mold and strand, and steel ingot casting processes. Inclusion removal from the molten steel by flow transport and bubble flotation, and inclusion growth by collision and diffusion are discussed. Removal of impurity elements such as [C] and [O] during steel refining are reported.

Jan 1, 2006

By Julian Szekely

Transport phenomena, that is heat transfer, mass transfer and fluid flow, play a critical part in the operation of metallurgical reactors. In this paper, we shall present a review of our current state of ability to model these systems mathematically, with emphasis on the use of computational codes that are generally accessible to the public and on the comparison of the theoretical predictions with measurements.

Jan 1, 1993

By David Forrest

In 1981, K. E. Drexler proposed using massively parallel nanomechanical systems to manufacture large atomically exact structures. As in macroscopic mechanical systems, they would contain components that serve traditional functions such as trusses for support, gears to transmit power, bearings for low-friction support of rotating surfaces, motors to supply torque, pipes and conveyor belts for material transport, and channels for coolant. Many of these components would only contain a few thousand atoms. Specific designs for these devices became available in the early 1990s, and a few working devices appeared in laboratories by the early 2000s. As advances continue, a thorough understanding of the operative transport phenomena will guide the intelligent design and construction of nanomechanical structures, devices, and systems. The familiar equations of continuum mechanics are generally inadequate to describe the flow of heat and mass in the proposed nanosystems. Boundary conditions often need to be described in terms of potential surfaces. Surfaces are not geometrically smooth, but periodic according to the locations of atomic nuclei. Friction occurs not due to the plastic deformation of asperities on mating surfaces, but to phenomena such as thermoelastic damping and phonon viscosity when atoms slide past each other. Electrostatic forces dominate over gravitational forces by orders of magnitude; there is no role here for natural convection. Structural components, no matter how stiff and strong, are in constant motion due to the thermal noise in the system. The fluids are described in terms of individual molecules in constant motion.

Jan 1, 2006

By Yogeshwar Sahai

Submerged gas injection into melts contained in furnaces, ladles, or similar transfer vessels is commonly used in industrial practice. In this review paper, conditions leading to gas bubble formation at the nozzle are first summarized. The increasing gas injection rates and other conditions, such as nozzle size, lead to regimes which are commonly known as "bubbling" and "jetting". These are explained. The gas/melt interactions result in energy transfer to the melt. In recent years, a large number of researchers have investigated the relationships between the energy density and the mixing times. Their work is reviewed, and the mixing mechanisms is described. Finally, computational approaches of modeling submerged gas injection are briefly presented.

Jan 1, 1993

By P. K. Songfack

The transport of slurry within the ball mill depends on the peripheral velocity and porosity of the ball charge. Residence time distribution and mill hold up are of-ten used as indicators of the mode of transport. In this work, the transport problem is tackled via direct simulation of the three dimensional motion of the ball charge. In doing so, the following quantities are calculated: (i) ball size distribution as a function of the distance from the feed end of the mill (ii) mean peripheral and longitudinal velocity and longitudinal velocity of balls of different sizes, and (iii) the spatial distribution of porosity within the ball charge. Hence, the problem of transport is handled as a motion of part of the slurry with the ball charge and part as hydrodynamic flow through the porous structure.

Jan 1, 1993

By John C. Draper

The principal object of an underground coal mine transportation sys tem is to move coal from the face where it is produced to the outside of the mine where it is prepared for market. In addition to the movement of coal, a transportation system must also move supply materials to the inside; it must move men in and out of the mine ; and it must move rock and other debris out of the mine for disposal. Usually, mine haulage is divided into three categories named for the various areas of the mine served: 1) Face Haulage. This is used at face from the mining machine to the intermediate transport system. 2) Intermediate or Secondary Haulage. Generally this is used between face haulage and main haulage. Sometimes this is merely an extension of the main haulage. 3) Main Haulage. This extends from the secondary haulage to the outside and is usually either a track or conveyor system, sometimes a combination of both. Transportation modes of coal in the various areas pose different problems, but the whole system must be synchronized. For instance, at the face the coal should be removed quickly from the various places to facilitate the movement of machines, whereas the intermediate system just passes the same coal on to the main transportation system. Selection of the transportation system must be based on the seam height, mining methods used to extract the coal, capacity required, ease of coal handling, and haulage efficiency. When driving rooms, mine cars can be used. They often simplify supply haulage and rock handling because they can also handle these items. Conveyors could be used and would have a greater haulage capacity but they cannot handle supplies easily or segregate the rock. When using a different mining method, such as longwall, mine cars cannot be used because there is not sufficient space to move the cars at the face nor can the cars haul the coal without delays which would cause excessive losses in production. As for ease of handling

Jan 1, 1973

By Duluth Engineers' Club, Engineers' Club of Northern Minnesota

"Duluth & Iron Range Railroad. The Duluth & Iron Range Railroad was built from Two Harbors to the Vermilion range at Tower, a distance of 67.6 miles, in 1884, and extended to Ely, twenty-one miles east of Tower, in 1888. It was built into Duluth in 1886, and branches were extended from its main line to the Mesabi mines in 1892 and 1893. The original grades on this road are very steep, going north, and in the thirteen miles from Two Harbors to Highland there is a rise of 1,150 feet. A new line between these points has been built with an increase of three miles in distance and with maximum grades of 1 per cent. Duluth, Missabe & Northern Railway. The Duluth, Mis¬sabe & Northern Railway was constructed from Stony Brook to Mountain Iron, a distance of 48.62 miles, in 1892. The Biwabik branch from Iron Junction to Biwabik, a distance of 15.54 miles, was constructed in 1892. The Superior branch from Wolf to Hibbing, a distance of 16.06 miles, was co11structed in 1893. The Alborn branch from Coleraine Junction to Coleraine, a distance of 53 miles, was constructed in 1906. The total main line mileage is 242 miles, of which 82 miles from Duluth to Hibbing is double tracked"

Jan 1, 1920

By John C. Draper

The principal object of an underground coal mine transportation system is to move coal from the face where it is produced to the outside of the mine where it is prepared for market. In addition to the movement of coal, a transportation system must also move supply materials to the inside ; it must move men in and out of the mine ; and it must move rock and other debris out of the mine for disposal. Usually, mine haulage is divided into three categories named for the various areas of the mine served : 1) Pace Haulage. This is used at face from the mining machine to the intermediate transport system. 2) Intermediate or Secondary Haulage. Generally this is used between face haulage and main haulage. Sometimes this is merely an extension of the main haulage. 3) Main Haulage. This extends from the secondary haulage to the outside and is usually either a track or conveyor system, sometimes a combination of both. Transportation modes of coal in the various areas pose different problems, but the whole system must be synchronized. For instance, at the face the coal should be removed quickly from the various places to facilitate the movement of machines, whereas the intermediate system just passes the same coal on to the main transportation system. Selection of the transportation system must be based on the seam height, mining methods used to extract the coal, capacity required, ease of coal handling, and haulage efficiency. When driving rooms, mine cars can be used. They often simplify supply haulage and rock handling because they can also handle these items. Conveyors could be used and would have a greater haulage capacity but they cannot handle supplies easily or segregate the rock. When using a different mining method, such as longwall, mine cars cannot be used because there is not sufficient space to move the cars at the face nor can the cars haul the coal without delays which would cause excessive losses in production. As for ease of handling

Jan 1, 1981

By John C. Draper

The principal object of an underground coal mine transportation sys- tem is to move coal from the face where it is produced to the outside of the mine where it is prepared for market. In addition to the movement of coal, a transportation system must also move supply materials to the inside; it must move men in and out of the mine; and it must move rock and other debris out of the mine for disposal. Usually, mine haulage is divided into three categories named for the various areas of the mine served : 1) Pace Haulage. This is used at face from the mining machine to the intermediate transport system. 2) Intermediate or Secondary Haulage. Generally this is used between face haulage and main haulage. Sometimes this is merely an extension of the main haulage. 3) Main Haulage. This extends from the secondary haulage to the outside and is usually either a track or conveyor system, sometimes a combination of both. Transportation modes of coal in the various areas pose different problems, but the whole system must be synchronized. For instance, at the face the coal should be removed quickly from the various places to facilitate the movement of machines, whereas the intermediate system just passes the same coal on to the main transportation system. Selection of the transportation system must be based on the seam height, mining methods used to extract the coal, capacity required, ease of coal handling, and haulage efficiency. When driving rooms, mine cars can be used. They often simplify supply haulage and rock handling because they can also handle these items. Conveyors could be used and would have a greater haulage capacity but they cannot handle supplies easily or segregate the rock. When using a different mining method, such as longwall, mine cars cannot be used because there is not sufficient space to move the cars at the face nor can the cars haul the coal without delays which would cause excessive losses in production. As for ease of handling at a longwall face, conveyors are convenient because of their low height, ruggedness, and ability to operate while being advanced. Similarly, in low seam heights, conveyor systems are easier and more economic to operate than the regular track haulage because roof has to be taken down for handling mine cars of adequate size.

Jan 1, 1981

By John C. Draper

The principal object of an underground coal mine transportation system is to move coal from the face where it is produced to the outside of the mine where it is prepared for market. In addition to the movement of coal, a transportation system must also move supply materials to the inside; it must move men in and out of the mine; and it must move rock and other debris out of the mine for disposal. Usually, mine haulage is divided into three categories named for the various areas of the mine served : 1) Face Haulage. This is used at face from the mining machine to the intermediate transport system. 2) Intermediate or Secondary Haulage. Generally this is used between face haulage and main haulage. Sometimes this is merely an extension of the main haulage. 3) Main Haulage. This extends from the secondary haulage to the outside and is usually either a track or conveyor system, sometimes a combination of both. Transportation modes of coal in the various areas pose different problems, but the whole system must be synchronized. For instance, at the face the coal should be removed quickly from the various places to facilitate the movement of machines, whereas the intermediate system just passes the same coal on to the main transportation system. Selection of the transportation system must be based on the seam height, mining methods used to extract the coal, capacity required, ease of coal handling, and haulage efficiency. When driving rooms, mine cars can be used. They often simplify supply haulage and rock handling because they can also handle these items. Conveyors could be used and would have a greater haulage capacity but they cannot handle supplies easily or segregate the rock. When using a different mining method, such as longwall, mine cars cannot be used because there is not sufficient space to move the cars at the face nor can the cars haul the coal without delays which would cause excessive losses in production. As for ease of handling

Jan 1, 1981