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By Ashirbad Satapathy, Sanket Rawat, Ramanand Shukla, Ravi Kant Mittal

Bearing capacity factor (Nq) and Adhesion factor (α) are the key parameters for analyzing the load carrying capacity of pile foundations embedded in cohesionless and cohesive soils respectively. Numerous models are available in the form of charts or equations for the computation of these parameters and hence, have been adopted by most of the International and National standards. Indian Standard for the Design and Construction of Concrete Pile Foundations, IS 2911–Part 1 (2010), also makes use of charts detailed in its Annexure B. However, the sources of these charts have not been specified clearly, making it difficult to back-refer to the actual models to assess their basis for resolving any critical scenarios encountered during design. The present study aims at acquiring a distinct understanding of the development of these charts in order to bring more clarity to the design process of pile foundations. The given charts have been compared with various models specified in existing literature and international standards for the calculation of Nq and α for both driven and bored piles and hence, the basis of Indian Standard charts has been identified. Moreover, it is evident that the use of these charts complicates the process of automation of analysis and design of pile foundations as well as the associated optimization studies. Additionally, the manual entry of data especially, from the logarithmic graph of Nq, escalates the chances of error thus, making it a critical concern for design offices. Therefore, this paper also presents a non-linear regression model for Nq and α, developed using NCSS software for both driven and bored piles. Through multiple iterations, the value of coefficient of determination for Nq and α has been found to reach greater than 0.995. The developed equations can be simplistically used for both manual and automated analysis of pile foundations.

Nov 1, 2022

By W. G. Pariseau

A two-dimensional finite element program has been modified and extended to account for some of the rock mechanics complexities associated with single entry development of longwall coal mine panels. Program capability includes arbitrary assignment of element properties without regard to element ordering, anisotropic elastic, plastic and brittle rock properties that may be time dependent (aging), arbitrary mining sequences and provision for the effects of artificial support on the adjacent strata. Failure is according to an extended von Mises criterion that may be linear or quadratic in form; flow rules are obtained from the yield function taken as the plastic potential, but brittle behavior is treated as a discontinuous process of material properties change with deformation. In either case the extent of failure is calculated from the external boundary conditions. Application of the program to essentially two-dimensional problems resulted in lose agreement between calculated displacements and field measurements in the double entry system. Bleeder entries were stable in one locality and not in another. Artificial support had little influence on stability.

Jan 1, 1978

By Christopher Jon Preston

This paper describes a type of ammonium nitrate (AN) produced in a patented experimental atomization/aerodynamic process. This AN exhibits outstanding properties for use as a main ingredient to a new family of AN-based commercial explosives. Micro-particle ammonium nitrate (MP-AN) is produced by atomizing either an 83% or 85% AN solution which has been doped with a two component surfactant NSol 1000 (NSol). NSol imparts some water-resistance as well as provides a means of increasing density and bulk strength. Increased detonation velocities, well in the range of emulsion explosives, can be achieved. The maximum manufacturing temperature is less than 100°C. The methodology has the potential of being environmentally friendly since any effluent can be recycled back into a make-up tank to be re-used by the closed loop method. The process has a small footprint.

Jan 1, 2015

By Jeremy Bosman, Johan de Korte

Traditionally the feed to coal preparation plants was de-slimed at 0,5 mm. The +0,5 mm size fraction was processed via dense-medium cyclones and the -0,5 mm size fraction was beneficiated with froth flotation, water-only cyclones or spirals. With the introduction of large diameter cyclones, the aperture sizes of de-sliming screens have progressively increased to about 3 mm in the belief that the larger cyclones are not able to effectively beneficiate coal which has a particle size below the ?breakaway? size. The efficiency of separation in the large dense-medium cyclones is improved by presenting a coarser feed to the units. At the same time, the capacity of the de-sliming screens is increased due to the larger screen apertures and in effect, the throughput capacity of the dense-medium section is increased. The 3 x 0,5 mm size fraction, which was previously processed in the dense-medium cyclones, is now added to the fine coal size fraction and processed by water-only methods such as Teetered Bed Separators (TBS) and spirals. Whether this practice is the most economical way to process the 3 x 0,5 mm size fraction requires further thought since the best processing route for the 3 x 0,5 mm size fraction will depend on a number of factors, amongst which are: o The washability of the coal and the amount of near-density material o Processing efficiency o Specification of the required product o The price paid by the customer for the product o The cost of processing the coal Breakaway size The ?breakaway? size is defined as the particle size below which the Epm of the smaller particles starts to decrease significantly. Bosman1 provides an approximate breakaway size versus cyclone diameter (Figure 1). It should be kept in mind though that the Epm of the small particles is a function not only of the cyclone diameter but also of feed pressure, medium density, medium viscosity, particle shape and density, top-size of particles in the feed, etc.

Jan 1, 2006

By H. R. Bullis

"Abstract- This paper discusses what appears to be a flaw in the current belief, widely held within the gold mining industry and investment community, that the creation of ever-larger gold mining companies is desirable for mining companies and investors alike. The basis of the flaw is in the underlying assumption that very large gold producers can discover or acquire new gold deposits of the size necessary to replace extracted reserves on a year-on-year basis over the intermediate to long term (i.e., five to ten years and longer). As it will be noted in this paper, deposits of the size required to replace annual production of very large gold producers (VLGPs) are relatively few in number. Although discoveries of new gold deposits continue to be made, they are predominantly in the 0.5 to 2.0 million ounce range. Data represented here suggest that, although gold production from individual VLGPs continues to increase, the change is due to merging or acquiring other companies or projects with similar reserve life profiles. Therefore, the reserve life profiles of VLGPs have remained flat or have decreased.The paper will note recent changes in the industry and the remarkable increase in gold production reported by individual mining companies over the past several years. It will provide an overview of the geographical and geological distribution of known gold deposits and the range of deposit sizes. Finally, the paper will discuss the challenges that face large gold producers in replenishing their reserves that are being depleted at an ever-increasing rate. Unless otherwise stated, all production and reserve data have been taken from company documents in the public domain or publicly available information."

Jan 1, 2001

By Andrew A. A, Hamilton P. J

Constraints on pore water evolution in the aquifers of a sedimentary basin may be realised through stable isotope analyses of present day waters, and their comparison with water compositions calculated to have been in isotope equilibrium with the products of diagenesis during burial. Integrated with detailed petrographic observations, and thermal, structural and stratigraphic analyses, fluid migration patterns at various stages in a basin's history can be identified. This has important implications for modelling basin hydrology, hydrocarbon distribution, and reservoir quality in the Latrobe Group, Gippsland Basin, and oil-prone successions Elsewhere.

Jan 1, 1992

By B. Gigas, M. Preston, M. Giralico

Optimized mixer settler designs will now handle total flows of over 6,000 m3/hr.Computational Fluid Dynamics (CFD) is a timely and predictable tool for design development. Lightnin has the capability of using numerical analysis methodology to evaluate flow patterns and phase separation. CFD can show performance differences between changes, in mix tanks, in settler geometry, and in liquid depth, against variable flow rates. Understanding the differences allows the development of optimized designs. This paper focuses on the major design components of the mixer settler and how technological advances will lead to further improvements, when designing for today’s largest flow plants.

Jan 1, 2004

By K. Hoover, G. Labarre, S. Rantanen

"As part of the Namew Lake project a mill was constructed to treat 1900 tpd of ore grading approximately 0.90% CU and 2.45% Ni to produce copper and nickel concentrates.Nickel occurs mainly as pentlandite and violarite while copper occurs as chalcopyrite. Two main ore types are present1 lower grade disseminated sulphides in a talcose ultramafic gangue and a higher grade solid sulfide with a granitic breccia matrix.Primary crushed ore from underground is treated on surface in a conventional closed circuit crushing plant using 2-stage cone crushing. Crushed ore is conveyed to storage and then fed at a controlled rate to a grinding circuit employing a rod and ball mill with hydrocyclone classification. Rougher flotation separates and cleans nickel and copper sulfides from waste materials followed by a high lime separation circuit to separate the minerals into final concentrates. Dewatering is achieved through use of high capacity thickeners and pressure filters prior to delivery to a loadout area. The crushing and milling control is highly automated.Plant design was based on metallurgical samples obtained from drill cores. After the first year of operations, plant results compared favourably with design projections.INTRODUCTIONThe Namew Lake Project is a joint venture partnership between Outokumpu Mines Ltd. (Canada) and Hudson Bay Mining and Smelting Company Ltd. (60%). The project included construction of a mine and milling complex to treat approximately 500,000 tonnes per year of copper-nickel ore grading o.91% and 2.44% Ni. Known reserves are estimated at 2. 65 million tonnes. The deposit is located approximately 65 km south of Flin Flon (120 km by road) and about 5 km east of the Manitoba-Saskatchewan border. The decision to construct a concentrating facility was made June 15, 1987 and construction started a week later. The facility, designed for 1900 tonne per day throughput, was ready for commissioning in September 1988. Outokumpu Engineering of Finland was chosen to prepare metallurgical flowsheets, select and develop plant layouts, and provide construction management. Kilborn (Toronto) contributed detailed engineering for civil, structural, mechanical and electrical components and outokumpu Equipment of Canada, the design, the supply, and commissioning of the instrumentation package. Hudson Bay undertook the initial metallurgical test work and preliminary design work."

Jan 1, 1990

By M. Shapiro, L. A. le Grange, B. Henning

Effective pyrometallurgical process vessel design requires accurate assessment of the heat fluxes through the walls of the furnace. This is particularly important for freeze lining operation which is designed to protect refractory materials exposed to chemically corrosive molten contents, or facilitate high temperature operation when the refractory materials are used at conditions close to their service limits. Numerical modelling of fluid flow and heat transfer in process vessels is often used to aid in the design of process vessels. Sophisticated models are used to analyse the three dimensional flow and heat transfer predicting the effects of electrical heating, magnetic stirring, buoyancy, shear forces, various cooling effects and ultimately heat fluxes at the walls of the furnace and refractory. Traditionally these models are applied to the separate single fluid systems in a vessel such as the freeboard region including the arc, the slag region and the metal bath. Boundary conditions such as shear forces and heat fluxes between connecting regions such as the slag and metal bath are either estimated or carried over from separate solutions. Shortcomings in these traditional approaches include the estimation of sometimes critical boundary conditions leading to unreliable heat flux calculations. Also when boundary conditions are carried over between solutions, the process is difficult to set up, time-consuming and finally not fully coupled. In this paper the definition and results of a fully integrated numerical model of a complete arc furnace are presented. The most important mechanisms acting in an arc furnace were considered, including the fields of electrical potential, current, magnetism, momentum, heat transfer and radiation. Temperature dependant properties included electrical conductivity, density, viscosity, and thermal conductivity. The geometry consists of the freeboard, the arc, slag, metal baths and different refractory regions. Although the combined model of air, slag and metal would be defined as a multi-phase problem it is not solved as such. Instead the different fluids are separated by sets of special solid baffles. These baffles allow the implicit transfer of current, magnetism, heat transfer and shear forces between the different fluids and disallow mixing of the separate fluids. The strengths of the integrated model are threefold: Firstly, it provides robustness in defining the geometry and boundary conditions for the overall model. Secondly, it provides the capability to switch on and off individual mechanisms such as buoyancy, magnetic stirring and shear forces in order to observe their individual importance. Finally, it provides a useful tool in the design process through its ability to obtain results of parameter changes in short time scales.

Jan 1, 2004

By P. Hickey, J. Spenceley, T. J. DeMull

Development of the Batu Hijau Project was successfully completed in the fourth quarter of 1999 with the final handover and start-up of ore processing facilities. The development project had started more than three years earlier, in August 1996, when the Owner, PT. Newmont Nusa Tenggara (PTNNT), awarded an EPC contract to Fluor Daniel (FD) for design and construction of the project including: copper concentrator, port, power plant, town site, and infrastructure. PTNNT managed the development of the mine and procurement of mine equipment with its own forces. Bringing the Batu Hijau copper deposit into production was the largest mining project ever undertaken. Development of Batu Hijau was a complex project involving the work of tens of thousands of people in all parts of the world to complete engineering, manufacture and deliver equipment, supply materials, and build the plant. The ore deposit is located on the tropical island of Sumbawa in a remote and undeveloped section of Indonesia. The location and environment presented challenges for all phases and aspects of the project. To meet the challenges, the project team combined good planning and teamwork to best utilize the resources available. This approach assured continuity of personnel through construction to operations and minimized cost, resulting in completion of the project ahead of schedule and under budget.

Jan 1, 2001

By H. L. Anthony, A. C. Richardson, G. D. Coe

"INTRODUCTION The Warrior View mine of the Seaboard Coal Corporation is located in Tuscaloosa County on the Warrior River about 14 miles northeast of Tuscaloosa, Ala. The Brookwood bed at this point yields a coal with fair coking qualities, and the product from neighboring mines on this bed has been used for the manufacture of blast furnace coke. The output of the Warrior View mine, however, is used exclusively for domestic and steam-raising purposes.This paper continues the series° of reports on the washability of Alabama coals which are based upon the study of coal preparation in Alabama now being conducted by the U. S. Bureau of Mines and the University of Alabama with the cooperation of the different coal mining companies. This paper contains screen-sizing and float-and-sink tests of a representative sample of run-of-mine coal, and flakiness and crushing tests on certain sizes.Published information on the Brookwood bed is very meager. Fieldner6 gives the proximate and ultimate analyses for a number of seam samples taken from representative mines working this bed. Gandrud and Britton7 show sections of this bed taken at Searles, Ala. They also give the specific gravities of the coal, the bone, and the shale partings.Table 1 give the proximate and ultimate analyses for the 3/4 to 3/16 inch size of raw coal. Table 2 gives the sulphur content and the ash fusibility temperatures of the float-and-sink fractions for this same size. The character of the coal is very uniform throughout the range of sizes produced and, as it was not convenient to have these analyses on all sizes, this size was chosen as being representative of the coal. From the information available it is evident that the coal preparation problem is restricted to one of ash reduction.SAMPLING AT THE MINEAt the Warrior View mine the run-of-mine coal is dumped from the mine cars upon a 3-inch grizzly. The oversize is crushed in rolls set at 24 inches and joins the undersize before being elevated to the raw-coal bin ahead of the jig. The sample was caught at the point where elevates discharges into the raw-coal bin, by taking a proportional amount of the coal at 10-minute intervals over the period of a day's run, The total sample amounting to 2.7 tons was shipped to the laboratory at Tuscaloosa for the washability studies."

May 1, 1932

By K. Oraee

Proven and probable coal reserves in Iran are estimated to be in excess of 5 Billion tons while the annual coal production is a mere 2 Million tons. Underdevelopment of the industry has proved higher production levels to be impossible, despite growing demand for energy supplies. The existences of numerous legislation are thought to have a detrimental effect on coal mining activities to the extent that some business entities have become uneconomical in many areas. This paper provides an analysis of the prevailing mining laws, policy making, legal frameworks and obstacles. It also outlines some other obstacles enshrined in the law and also highlights areas where foreign direct investment should be encouraged. The costs of lost opportunities are then estimated. The paper concludes by demonstrating that deregulations, amendments and in some cases complete abolishment of the incumbent legislations governing the coal mining industry will greatly enhance development of the industry. The analysis provided in this paper together with the results obtained, can prove useful to macro-economic policy makers both at local and national levels.

Feb 27, 2013

By G. Price

The Building Research Establishment installed a base load cell in a driven cast-in-place pile prior to it being tested under vertical load. The monitored base loads were found to be significantly less than could have been predicted by current design methods. The less than expected capacity was attributed to the drilling out procedure. An electro-level system installed in a second similarly formed pile, provided detailed information on the performance of the pile under lateral load. The information obtained was used to check several current design methods for laterally loaded piles. The findings show the potential dangers of attempting to improve design parameters from only limited performance data.

Jan 1, 2010

By J G. Brady

This paper discusses the ceramic products used in the construction industry in Canada, as well as the main raw materials used in their manufacture. The products include the! following: (1) clay prorlucts -such as facing brick (glazed and unglazed), common brick, facing tile (glazed and un-glazed), terra cotta, load-bearing tile, non-load-bearing tile, structural clay floor tile, quarry tile, drain tile, sew-er pipe, conduits .and flue liners -which are made mainly from domes-tic common clays and shales and from domestic or imported stoneware clays and low-grade fire clays; (2) floor and wall tiles of the whiteware type, which are produced from ingredients such as kaolin, ball clay, feldspar, nepheline syenite, talc, pvro-phyllite and wollastonite; (3) glass products -the major ones being sheet glass, plate glass and mineral wool (glass wool, and rock or slag wool) -which are made from such materials as silica sand, soda ash, salt cake, feldsspar, nepheline syenite, dolomitic limestone, high-calcium limestone. borax and (for rock and slag wool) various rocks or slags;

Jan 1, 1963

By Tim O’Neil

The search for precious metals opened up the American West. And Nevada was right in the heart of this development. In the mid-19th century, prospectors seeking gold roamed the hills of Nevada and discovered the ComstockLode. The development of this huge silver and gold deposit began in1859 and was responsible for Nevada’s early entry to statehood. Mining was Nevada’s first industry. In more recent years, the Nevada mining industry has led the nation in gold, silver and barite production. Nevada also produces many other minerals. These include aggregates, clays, copper, diatomite, dolomite, gypsum, lime and limestone, lithium and magnesium compounds, perlite, salt and silica. Even today, Nevada’s mining industry continues to be a major economic force in the state. The mining industry has made more than $10 billion in capital investments in Nevada since 1985. And the value of Nevada’s mineral production last year was about $2.7 billion.

Jan 1, 2000

By M Stevens, M P. Simpson, J L. Mauk

The Karangahake deposit was the second largest producer of gold-silver bullion in the Hauraki Goldfield, New Zealand. New mapping of a 2 + 3 km (6 km2) area demonstrates that hydrothermal alteration surrounds productive veins. Wallrocks proximal to veins are intensely altered and alteration decreases toward the margin of the system.   At Karangahake, distinct zonation of adularia, calcite, epidote, illite and illite-smectite surrounds gold-bearing lodes with unaltered rocks containing magnetite and plagioclase occurring on the margins. Adularia, illite, illite-smectite, and calcite zonation defines hydrothermal alteration extending 2 km to the east of productive lodes. Epidote and adularia zonation occurs proximal to veins. The adularia zone compares well to potassium/thorium studies conducted in the area. Illite zonation is well developed to the east of the veins grading into interstratified illite-smectite containing 5 to 40 per cent smectite 1.5 km from the Maria Lode. Calcite is restricted to the east of the study area occurring in 18 per cent off surface samples. Less altered rocks containing plagioclase and magnetite occur distal to veins. The magnetite occurrence compares well to aeromagnetic studies conducted in the area.   Adularia and coexisting adularia and albite indicate the host rocks were highly permeable. Epidote, illite, illite-smectite and previous fluid inclusion evidence implies temperatures graded from >240¦C in the core of the system to approximately 150¦C on the periphery. The alteration association of quartz, adularia, calcite, pyrite, chlorite, illite and illite-smectite reflects a near-neutral to weakly alkaline water. Calcite occurrence and the absence of zeolite imply the fluid contained significant dissolved CO2.

Jan 1, 2005

By Shaoyang Yan, Xinming Chen, Huazhe Jiao, Huaibao Chu, Chang Wang

In terms of the technical problems of rib spalling in large mining height coal face, a long-distance advanced pre-grouting layer flexible reinforcement technology is proposed in this paper. Based on the mechanism and failure mode of rib spalling in the coal face, the mechanical properties of the aluminum plastic composite pipe were analyzed by using the tensile and compression experiment. The deformation and strength characteristics of “flexible pipe + grouting” specimens were studied by uniaxial compression test, splitting test, and shear test. The UDEC numerical simulation software was used to simulate the reinforcement effect of “flexible pipe + grouting” at different positions. Combined with the field application, the feasibility of long-distance advanced pre-grouting layer flexible reinforcement technology was verified. The test results show the following: The coal face has the characteristics of brittle and large deformation. The aluminum plastic composite pipe has the characteristics of good elongation and tensile strength, which can endure the large deformation of the coal face. The “flexible pipe + grouting” can improve the tensile and shear strength of coal. The UDEC numerical simulation analysis indicated that the grouting hole layout of “flexible pipe + grouting” has a significant difference in the reinforcement effect of the coal face. Compared with single row grouting reinforcement, the reinforcement effect of double row grouting holes 1.5 m and 3.0 m away from the roof is better. According to the field application, it is feasible to use aluminum plastic composite pipe as a flexible grouting pipe to reinforce coal seam with 80–100 m long-distance pre-grouting. Long-distance advanced pre-grouting layer flexible reinforcement technology can improve the daily production of coal and reduce the support cost of the coal face. As a new method of reinforcement, long-distance layered flexible reinforcement has a significant effect on the prevention and treatment of rib spalling in large mining height coal face.

Sep 27, 2022

By Robert W. Bartlett

"Economic and other factors, mostly outside of metallurgy, that strongly influence applied research, development and especially successful commercial adoption of new processes for producing primary metals and other commodity materials are reviewed. These factors, which can be both positive and negative in their influence, are often too lightly regarded in the research planning stage. They include continuing imperatives that have long influenced new process development as well as more recent trends. Both are discussed. Nearly all new materials eventually become commodities--products made to standard specifications with no producer control over price. Success requires being a low cost producer on a world wide basis. Composites and other complex material assemblages are unlikely to escape this fate as they mature.INTRODUCTIONThe adoption of new processes, beginning with research and development, for primary metals and other commodity materials is particularly difficult because each new process must supplant an existing process that is already being used commercially. There are many requirements besides technical innovation and cost superiority that must be met by the new process. Consequently, few innovations make it all the way from the research laboratory to commercial success.This paper discusses some of the factors that influence success in developing new processes for primary metals and commodity materials, based on the authors experience as a research metallurgist and industrial research manager. It begins with some of the factors that are always present and constrain successful process research and development, and proceeds to current trends that are expected to continue long enough to influence processes in the year 2000. Many of these trends are contradictory in their effect on new process development, and the future remains uncertain.The prevailing importance of these trends will vary with the material, process concept and other factors intrinsic to each case. Nevertheless, an awareness of these influences can help to avoid some of the R&D pitfalls and dead ends. Such awareness is deemed to be a necessary condition to avoid failure when commercial adoption of a new process is the goal."

Jan 1, 1988

By A. Noël, R. Lapierre, M. Provencher

"Modem aluminum smelters are facing significant operating cost pressure. Key methods used by smelters to manage this pressure are automation and production-information systems to optimize processes, manage quality, anticipate problems and reduce operating costs. In 2002, Aluminerie Alouette Inc. began its Phase II Expansion project, and retained the joint venture of SNC-Lavalin and Hatch (SLH) as its engineering, procurement and construction management (EPCM) team. Alouette had the distinction of being one of the most efficient aluminum smelters in the world. Alouette already understood the importance of systems integration in project delivery. For Phase II, key objectives were identified to ensure ""a state of the art"" integrated architecture that would support Alouette's production goals to integrate the existing facilities with the expansion, to form a single efficient facility and meet project schedule and budget targets. Achieving those objectives within the context of a large project often creates major challenges due to the nature of the traditional EPCM delivery model, which relies on several vendors and third-party-systems integrators. In this case, an integrated Alouette-SLH team was made responsible for all aspects of the systems integration, taking over the task from most suppliers. The integrated team was responsible for delivering an automation system and plant-wide-production IT system for the new facilities while accommodating migration for the existing systems. Through the use of rigorous methodology and advanced state of the art technology, the IT and automation strategy led to significant value creation and is recognized today as one of the key factors of the project's success. The primary results were: fast and efficient start-up of facilities, due to quality programming and implementation; a plant able to operate as a single entity; automation and IT systems delivered before time and under budget; standard programming methods implemented throughout the plant; and reduced and simplified maintenance."

Jan 1, 2006

By Kirstin Girdner, Tom BoBo, Brian Norton, John Kemeny

Split Engineering is a truly customer oriented company dedicated to providing quantified fragmentation information of the highest integrity to enable process management and control. Technical decisions, blasting costs, operational efficiency and productivity and equipment performance can all be related to optimum fragmentation. In the past, the lack of an easy, non-disruptive, economical measuring technique has meant that, in most cases, rock fragmentation has not been defined in quantitative terms. Now, the Split-Desktop@ software provides an economical alternative to manual sampling and screening and an objective measure rather than subjective qualitative estimates. This workshop will present the latest features of the Split-Desktop@ software and show users how to quickly get quantifiable results from their blast fragmentation. A step-by-step demonstration will display the software’s flexibility, user-friendly options, and ease of use. Outlining where other mines have benefited from using the Split-Desktop@ software will provide insight to a wide range of software uses and potential applications like creating a database of geologic zone specific post-blast fragmentation information, underground draw point monitoring, stockpile, leach pile, and waste dump size measurement and monitoring, as well as many other applications.

Jan 1, 2000