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By David S. Yang

The Cement Deep Soil Mixing (CDSM) method introduces and mixes cementitious materials with in situ soils using hollow-stem rotating shafts equipped with a cutting tool at the tip and mixing paddles above the tip. CDSM generally produces a soil-cement panel consisting of three overlapping soil-cement columns. The soil-cement panel is then extended to form walls, which are effective for excavation support and groundwater control due to the continuity and low permeability of soil-cement walls. Two design approaches could be taken in the application of CDSM for excavation support: 1) single wall design and 2) gravity wall design. The former one is treated as a wall technology and the latter one is treated as a soil stabilization method. This paper will review the CDSM equipment and installation procedures for the construction of these two types of soil-cement walls. Four case examples are used to illustrate the design and application of these two types of soil-cement walls.

Jan 1, 2003

This paper discusses the history and development of the system and the benefits that are being gained for Yabulu from Solar Drying. Following the end of mining of the local Greenvale and Brolga nickel deposits, QNI Yabulu Refinery is dependent upon imported ore from over 15 different mines in New Caledonia, Indonesia and the Philippines.

Jan 1, 2003

By Daniel J. Rider

In 1980 the Niagara Frontier Transportation Authority contracted for three miles of cut and cover box structure and station construction in Main Street, Buffalo, New York. Project depths ranged from 30 feet to 60 feet below street grade. Soils, Figure No. 1, consisted of loose to very compact sands and gravels. Ground water level was generally 20 feet below grade. Specifications required a soldier pile and timber lagging support system with external dewatering. Soldier piles were to be installed in prebored holes with bentonite slurry and lean concrete backfill. Conventional pile driving was not allowed due to concerns over excessive noise and vibrations and its effect on nearby historic structures and the surrounding population

Jan 1, 1987

One of the engineering proposals in the last Congress which was of interest to engineers was the soldiers' land settlement plan proposed by Secretary Lane, under which returned soldiers, sailors and marines would be employed on construction work in the reclamation of swamp and arid lands and would thereafter be given preference in the selection and settlement of those lands. This bill failed in the fillibuster at the end of the session. It is likely that some sort of a plan for soldiers' settlement will come before the next Congress. A new bill has been written up for introduction at the next session which proposes an "infiltration method" of buying improved farms in established communities for' the soldiers' settlement purpose, under the authority and direction of the Farm Loan Board. The contrast of this bill to the one recommended by Secretary Lane is of vital importance to engineers at this time; first, because of the broad engineering improvement program that the latter bill proposes as against no engineering improvement under the infiltration plan; secondly, the community settlement plan of Secretary Lane means improvement of waste lands requiring much engineering work.

Jan 7, 1919

By A. Krishnan

Keywords: Tantalum extraction, SOM Technology, inert anode, membrane stability The Solid Oxide Oxygen Ion conducting Membrane (SOM) technology offers great potential for environment friendly and energy efficient extraction of high-energy content metals. This work was performed to demonstrate the technical and commercial viability of the technology to produce tantalum metal directly from tantalum oxide and ore concentrates using a solid-oxide, oxygen-ion-conducting membrane (SOM). The process can be used to efficiently produce tantalum metal without expensive pre-processing of raw materials and without harmful by products. The work reported in this paper is: the proof that high purity tantalum metal can be produced, study of the electrochemical behavior of the cell and the method to increase membrane stability.

Jan 1, 2005

By M. Sibanda

The diffusion of carbon in Co-5% Fe alloy was studied in a belt-type pressure system at temperatures of up to 1330°C and press loads or nominal pressures of 7 020 tons or 42±3 kbar. Under these conditions, this alloy is in the solid state. Discs of graphite and prealloyed Co-5%Fe were used to make up the diffusion couple. The diffusion coefficient increased with increasing press load due to the tendency of the low density graphite to dissolve in the metallic phase reducing the overall volume and increasing the density of the system. Furthermore, inhomogeneous plastic deformation may have promoted diffusion by creating defects in the alloy. Diffusion couples treated at atmospheric pressure exhibited graphite particles in the metal, while those treated at high pressures exhibited carbide in the form of Widmanstatten laths. Carbon analyses indicated increased carbon solubility with increasing pressure. This was confirmed from calculated high-pressure phase diagrams.

Jan 1, 2005

By T. Watanabe, S. Hayashi, M. Hayashi, K. Nagata, H. Fukuyama

Chemical states of fluorine in CaO-SiO2-CaF2glasses in a composition range of CaO/SiO2=0.5?1.3 and 5?25 mol%CaF2have been investigated by 19F solid-state NMR with and without MAS. The isotropic chemical shifts of the glasses are close to those of cuspidine crystal (59.4 and64.3 ppm with respect to C6F6) and CaF2crystal (58.6 ppm). The fluoride ions are coordinated with four or less than four calcium ions in this composition range. The chemical shifts move to the lower frequency with an increase in the CaF2content, whereas those are not affected by theCaO/SiO2ratio. The ionic distance between calcium and fluoride ions increases with an increase in the CaF2content. The chemical state of fluorine is not disturbed by the degree of polymerization of the silicate network. Comparing the MAS and static NMR spectra, the second moment attributed to 19F-19F dipole-dipole interaction has been estimated. The values of the glasses range over 3.1?7.3107Hz2andthose are larger than the calculated value of cuspidine crystal. This indicates that fluoride ions form Ca-F clusters in the glasses and that the size of clusters increases with increasing the CaF2content. Keywords: chemical state of fluoride ion, CaO-SiO2-CaF2glass, solid state 19F NMR spectroscopy

Jan 1, 2004

By Moyle F. J

This paper describes an apparatus which was developed to study solid-vapour equilibria and presents results which were obtained during a study of the FeCI3-AlCI3-CI2 system. Analysis of the results showsthat fractional desublimation might offer a means of achieving a useful separation of the iron and aluminium chlorides produced by the chlorination of bauxite. The results, presented in the form of isothermal vapour pressure curves covering the range of temperature 160-200°C, support the earlier findings of Semenenko et al (Dokl Akad Nauk SSSR, 154: 42-43 (1964)) that the solid phase contains two terminal solid solutions.The equilibrium constant for the formation of the mixed dimer, FeAICI6, was approximately 4. The latent heat of sublimation of aluminium chloride varied from 18 to 26 kcal/mole AI2CI6 for solid compositionsfrom 0.9 to 0·5 mole fraction FeCls3.

Jan 1, 1979

By S. L. George

The semi-solid metal casting process results in a unique solidification path. The microstructural features that were identified during the characterization of the as-cast microstructure, were used as evidence of the process history in order to determine the solidification path followed during the evolution of the microstructure. The morphology of the grains was characterized using SEM and the extent and distribution of the elemental segregation within the grain structure was analysed using EDS. Keywords Semi-solid casting, solidification path, segregation.

Jan 1, 2011

By Charles H. Jacoby

The solution mining of evaporites has a history of approximately 5,000 years. The insitu leaching of metalliferous ore will have many of the same characteristic problems which have confronted industry for years in the production of evaporite minerals. Basically we will be converting the less soluble forms of valuable metals into their more soluble salts and producing these in much the same manner as, for example, sodium chloride. There are a number of problems which we are faced with that are more complex and complicated and, therefore, will require a higher degree of sophistication than previously employed. One of our most important undertakings will be the clearcut definition of the problems involved. While a great deal of expertise can be drawn from the solution mining of evaporites and the oil industry, problems peculiar to the hydrometallurgical field will need to be solved. One of these is the introduction of permeability into an impermeable rock so as to expose the sought after values of metals which by volume are infinitesimal when compared with sodium chloride, potash or other type water soluble mineralization. After establishing this permeability which will be miniscule when compared to a solution cavity, there will be the maintenance of this permeability. In general, salt deposits are of a somewhat uniform chemical composition and thus their chemistry was relatively simple. Each metalliferous ore body is somewhat unique in its chemistry and will need to be treated accordingly.

Jan 1, 1974

By Charlie Yates, Max Ramey, Kurt Nielsen, Michael Hardy

The Yankee Gulch sodium minerals project (YGP) is a solution mining project operated by American Soda. The mine operates on a federal lease administered by the U.S. Bureau of Land Management (BLM). Commercial operations began in November2000. In 1964, Irv Nielsen discovered nahcolite mineralization where the YGP pilot plant is now located near the Piceance Creek in Rio Blanco County, Colorado (Nielsen, 1969).Development of the project accelerated after Williams Corp., of Tulsa, OK, joined with American Alkali in1996 to form American Soda. Pilot testing by American Soda led to commercial permitting, plant design, construction and startup. Figure 1 shows the location of the Yankee Gulch leases and the location of the upper and lower plant sites.

Jan 1, 2003

By Javier Támara

Para aumentar la productividad de la empresa minera es necesario conocer el sistema de aire -en tanto se prioriza los intereses de los clientes, y así se puede suplir todos los componentes necesarios para garantizar una máxima eficiencia y confiabilidad del sistema completo de aire comprimido que va desde el filtro de admisión hasta el punto de uso. En ese sentido, el presente texto describe las estrategias para realizar Solucionazing en ahorro energético y así aumentar la produtividad de los sistemas de aire.

Aug 25, 2002

By O. Bernal, G. Velarde

Sociedad Minera Cerro Verde, majority owned by Phelps Dodge produces 200M lbs per year of LME Grade A copper from low cost leaching of secondary sulfides and SXEW processing. Central to the success of Cerro Verde has been the continuous improvement of leaching practices which currently yield over 80% recovery of the contained copper in the ore. This recovery has been achieved by careful attention to operational practices and leaching process fundamentals. This paper details the development of the concept of “Lixiviant Request Rate” where by solution is applied at an optimal rate for the grade, mineralogy, and the point in the leach cycle. Also paramount to the success of Request Rate technology has been the development of irrigation practices such as drip irrigation and irrigation grid design. These developments have ultimately resulted in improved copper production, decreased sulfuric acid and water consumption, decreased pumping cost, and more consistent PLS grades.

Jan 1, 2004

By R. Abela

In over ninety per cent of mineral sand plants, the most commonly used equipment is the spiral concentrator. The tonnage treated over typical spiral plants can range from as low as 200 ton per hour up to 6 000 tons per hour. Due to the limited capacity of each spiral, plants consist of multiple spirals assembled into banks. The mixture of minerals present in the sand feed requires several spiral stages to achieve the desired mineral recovery. Due to the complexity of the spiral circuits, there are always some design and operating problems that present themselves in plants. These range from slurry distribution, spirals operating at incorrect design parameters and feed variations. The material being treated is difficult to maintain in suspension due to its high density, resulting in segregation and preferential flow in pipelines, distributors and sumps. The objective of this paper is to highlight common problems associated with spiral installations to designers and operators of plants. Practical solutions are recommended in order to prevent and minimize these mistakes in the design. These solutions may be used to improve performance on operating plants.

Jan 1, 2003

By Brian P. Stapleton, Bill M. Stewart, Joel R. Warneke, Curtis C. Clark

Of the 28 accident/injury classifications listed by the Mine Safety and Health Administration, handling materials is second only to roof falls in terms of generating the highest number of reportable accidents in active underground coal mines. Two materials-handling activities that cause numerous injuries each year are the categories of “handling supplies or material, load and unload” and “moving power cables.” Mechanization and mine worker activity training are two methods that can aid in preventing these injuries. This paper describes three mechanical methods—the mobile manipulator, the in-mine hoist, and a cable-handling system—being developed and tested at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health. Two of the devices are specifically designed for loading, unloading, and moving supplies and materials, and the third device is for handling trailing cables in the confined spaces of coal mines. Also described are safety solutions developed for underground coal mines geared to showing miners safe and unsafe ways of performing various materials-handling tasks.

By W. Rogers

Blast-induced rock mass displacement can have a significant impact on ore loss & dilution. The mischaracterisation of the grade boundaries both prior to, as well as a result of blasting can lead to significant financial losses on account of ore loss and dilution. Ore dilution occurs when waste material is miscategorised as ore and sent for processing or stockpiling, diluting the run of mine head grade and recovery. Ore loss takes place when valuable mineral is miscategorised as waste and sent to the waste dumps, thus never being processed and recovered. Extensive research has been conducted at the University of Queensland over the last fifteen years to understand the impact of blast movement on ore loss and dilution. Recent outcomes of this research have developed innovative tools and techniques to measure and model blast movement. These techniques have been implemented at Ahafo gold mine in Ghana to understand blast movement dynamics and to implement solutions to reduce blast-induced ore loss and dilution. These solutions are validated through controlled trials and have been incorporated into site standard operating procedures to sustain the benefits.

Jan 1, 2012

Three types of communication systems have become popular in solving communication requirements underground: Loud-speaking pager phones, carrier current phones, and magneto ringing phones. Basically, all three are simply single-channel party line systems. Although these systems are quite reliable, the single channel creates a variety of problems. For example- 1. Since no call is confidential, messages are sometimes purposely made vague, especially if accidents or safety topics are being discussed. 2. A potential user must literally "wait in line" until the channel becomes clear for his use; thus, when foremen have to wait to call in reports or supply requests, this single chan-nel creates a serious productivity bottleneck. 3. In many large mines, there are independent branch lines that must be tied together by a dispatcher, adding further delays to the system. To solve these problems, some mines have installed other phone systems-mostly commercial dial phones in industrial enclosures that offer extra channel capacity and private line features. Others have installed a system that combines both dial- and page-phone features in a single unit. Although these do represent improvements, they do not truly solve the overall problems that face modern mines. Besides extra channels, a communication system should have the following features to enhance productivity and safety: 1. A means of paging a roving miner to alert him that he is wanted on the phone. 2. Wireless-to-wired system interconnects by which a miner can talk on the wired phone system by using a remote portable radio. 3. Remote monitors that alert personnel when there is a toxic or explosive gas buildup. 4. Control interfaces that allow remote control of fans, pumps, or other devices. 5. Transmitters and receivers that can serve as emergency links. 6. Loopback that allows an alternate path of communications if the main path is cut. This chapter focuses on equipment and methods to meet the special communication needs of individuals in various places of the underground mine. The communication requirements can be broken down into four categories: 1. The mine entrance (shaft communication). 2. Permanent and semipermanent locations (shop areas, lunchroom, crusher stations, etc.). 3. Mining areas (the room-and-pillar sections, longwall faces, block caving areas, etc.). 4. Haulageways (tracked trolley haulage, diesel, belt haulage). Methods of implementing systems to meet the communication needs of these areas are described in sections 3.2 through 3.5. Section 3.6 discusses methods of satisfying special communication requirements that exist. Major topics in this category include communications with roving personnel, the isolated miner, and motorman-to-snapper communications. Emergency communication systems are described in section 3.7.Detecting and

Jan 1, 1984

By S. A. Sass

The design and construction of Solvay Minerals (formerly Tenneco Minerals) Soda Ash Expansion Project, which is the world's most modern natural soda ash facility, is detailed. Along with a discussion of design considerations, the international joint venture ownership and teaming arrangement for design and construction companies is examined.

Jan 1, 1994

By D. Mohapatra

The possibility of using 2,2,4-trimethyl-1,3-pentanediol dissolved in tetrachloromethane as extractant for boron recovery is discussed. The parameters optimized for this purpose are contact time, boron concentration in the aqueous phase, extractant concentration, equilibrium pH and phase ratio. NaOH is used as stripping agent for boron recovery from the loaded organic phase. Boron extraction is found to be a slow process (equilibrium time 20 minutes) compared to boron stripping, which is reasonably fast (equilibrium time 5 min). Maximum boron extraction is possible at a broad pH range from 1.0 to 6.0. Using 1.0M extractant concentration, a 1:1 phase ratio (organic: aqueous) and two stages, ~99% boron extraction is achieved. More than 97% boron stripping is possible using 0.5M NaOH at a 1:1 (organic: aqueous) phase ratio in two stages. Overall, a 95.6% boron recovery was achieved. Loss of solvent into the aqueous phase and co-extraction of Ca, Na and K into the organic phase at higher equilibrium pH are two major concerns in his process.

Jan 1, 2008

By G. Bacon

The past decade has witnessed unprecedented growth in the development and implementation of solvent extraction technology in the extractive metallurgy of nickel and cobalt. Solvent extraction is proving to be a powerful tool, opening new opportunities for simpler, more cost efficient and environmentally sound metal refining processes. These advances, however, could not have been possible without the cooperative efforts between the nickel industry and the people and organizations involved with reagents, materials and equipment development and supply as well as solvent extraction research, aided by the accumulated knowledge and practical experience from the copper and uranium solvent extraction operations. This paper provides an overview of these developments and some of the challenges ahead.

Jan 1, 2002