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By Gennaro Gerald Marino

Vast improvement in methods of design and analysis of the long- term stability of overburden above room and pillar mines is needed. Improved methods are vital for planning and land development and for prediction above existing, presently stable, room and pillar mines. As shown on the flow chart in [Figure 1], the assessment of the long-term stability is an integral part of the site investigation process regarding mitigation of surface damage effects. In Illinois, flat farmlands with subjacent coal reserves cover vast areas. In some of these areas high extraction of the underlying coal layer(s) may not be possible since the resulting surf ace subsidence combined with a pre-existing shallow water table would make the land too wet. Thus recovery of this coal might only be accomplished by room and pillar mining where the ground surface does not subside and the hydraulics of the overburden are not significantly affected.

Jan 1, 1986

By S. Budavari, F. M. C. C. Vieira

For several decades, the deep, gold-bearing reefs of the Witwatersrand basin have been mined predominantly according to layouts characterised by longwalls with strike pillars to provide regional support. During the past few years, a new generation of mining layouts has been introduced. These layouts are based on the concept of grid-type, scattered mining with dip pillars for regional support. As the extraction of the gold reefs extends to depths below 3500 m, the hazards associated with mining at these ultra-depths are expected to increase to unacceptable levels. Therefore, the question arises as to, which of the currently applied mining layouts is most acceptable for the economic and safe extraction of an ultra-deep orebody. The purpose of this paper is to describe a research investigation carried out to evaluate the degree of acceptability, from the rock engineering view point, of four currently used mining layouts for application at a depth-range of between 3500 and 5000 m. Pendant plusieurs décades, les filons d’or profonds du bassin du Witwatersrand ont été exploités d’une manière prédominante selon des dispositions caractérisées par des longues tailles avec des piliers directionnels pour donner un support local. Les dernières années ont vu la naissance d’une nouvelle génération de dispositions de mine. Ces dispositions sont basées sur le concept d’extraction type grille, éparpillée, avec des piliers au pendage pour le support local. Comme l’extraction des filons d’or va à des profondeurs en dessous de 3500m, il faut s’attendre à ce que les risques associés à l’exploitation à ces profondeurs extrêmes atteignent des niveaux inacceptables. Par conséquent, la question se pose de savoir laquelle des dispositions de mine couramment utilisées est la plus acceptable pour l’extraction rentable et sans danger d’un gisement ultra profond. Le but de l’étude présente est de décrire les recherches exécutées pour évaluer le degré d’acceptabilité, du point de vue d’ingénierie de roche, de quatre dispositions de mine couramment utilisées pour application à un rayon de profondeur entre 3500 et 5000m. Die tiefen, goldträchtigen Riffs des Witwatersrandbeckens wurden über einige Jahrzehnte hindurch vorwiegend nach jenen Layouts abgebaut, die von Langfrontstreben mit Schlagpfeilern charakterisiert waren, um regionale Unterstützung zu gewährleisten. Während der letzten Jahre wurde eine neue Generation von Grubenlayouts eingeführt. Diese Layouts basieren auf dem Konzept der Rasterfeld-Art, gestreuter Bergbau mit Neigungspfeilern für regionale Unterstützung. Es kann erwartet werden, daß auf Grund der Tatsache, daß sich die Extraktion der Goldriffs auf Tiefen unterhalb 3500 m verlagert, die Gefahren, die mit dem Bergbau an diesen Ultratiefen verbunden sind, sich auf ein nicht annehmbares Niveau erhöhen. Folglich erhebt sich die Frage, welche der gegenwärtig angewendete Abbaulayouts für die ökonomische und sichere Extraktion eines ultra-tiefen Erzkörpers am annehmbarsten ist. Zweck dieser Arbeit ist es, eine durchgeführte Untersuchung zu beschreiben, die vom Gesichtspunkt der Gesteinstechnik gesehen, vier gegenwärtig angewandte Abbaulayouts für den Einsatz in einem Tiefenbereich zwischen 3.500 und 5.000 m evaluiert.

Jan 1, 2003

By Charles L. Morgan

In June 1996, the United Nations International Seabed Authority opened shop in Kingston, Jamaica as an autonomous international organization charged with the administration of seabed mineral developments in all areas beyond national jurisdictions. The Authority is a consequence of the 16 November, 1994 entry into force of the 1982 United Nations Convention on the Law of the Sea (UNCLOS) and the 1994 Agreement relating to the Implementation of Part XI of UNCLOS. The total seabed area included within the Authority?s purview has yet to be assessed accurately, but clearly constitutes the largest single jurisdiction on the planet. The Authority is governed by legislative bodies called the Assembly and the Council and an administration called the Secretariat. The Assembly includes representatives of the 132 member states which are currently parties both to UNCLOS and to the 1994 Agreement. These member states directly fund the operations of the Secretariat. They include most of the world?s developed nations, island nations, and others among the 188 independent countries which are members of the United Nations. Notably absent are the United States and Canada, which are the only developed coastal states not represented. The Council is a 36-member subset of the Assembly representatives selected through a somewhat involved process designed to achieve a balanced representation of the specific interests of the members. Ultimate responsibility for the Authority?s actions resides in the Assembly, but most initiatives originate in the Council. Also included in the Authority are two subsidiary advisory bodies, the Finance Committee, which reviews the Secretariat?s budget, and the Legal and Technical Commission, which evaluates claims and drafts technical regulations. The Secretariat itself includes a staff of about 30, including 15 highly qualified and competent attorneys, accountants, engineers, and scientists. Details describing the composition and activities of these bodies can be found at the Authority?s website (http://www.isa.org.jm).

Jan 1, 2000

By GEORGE T. Harley, Walter R. Storms

This paper, which describes mining mothods at International Minerals & Chemical Corp, 'e. potash mine. in. Eddy. County, N. Mex., is one of a sories being prepared by the Mining Branch of the Bureau of Minos. on mining method a and practicos in, various mining districts of the United States. The mine shafts and. surface plant or International Minerals & Chemical Corp. are situated. in. sec.. 12, T. 22 S., R. 29 E., N. M. P. M., about 26-1/2 miles by paved highway east of the city of Carlsbad (figs. 1, 2, and 3). A spur line of the Atchison, Topeka & Santa Fe Railroad connects the mine with the Clovia-Pecos branch of the same road near Loving, a few miles south of Carlsbad. This spur also serves the refinery of United Staics Potash Co. This report gives. the history and describes the geology of the district. Methods of prospecting, exploration, sampling, and estimation of tonnage and values are explained; development and mining methods are discussed in con- siderable detail; transportation, ventilation and drainage are outlined; safety measures are noted; and the wage scale and organization are mentioned.

Jun 1, 1949

Air tabling of zircon-rich non-conductor products containing quartz enables most of the fine quartz present to be rejected without a markedloss of zircon. The coarser quartz in the air table feed can be separated from the zircon by screening one or more air table products, the oversize products containing most of the quartz and little of the zircon. Air tabling, with or without screening, is more efficient than wet tabling alone for the removal of fine quartz, but not for the removal of coarse quartz. Practically all of the quartz can be separated from the zircon by using wet tabling in conjunction with hydraulic classification, or by using air tabling in conjunction with dry launder treatment, in which a degree of sizing takes place that is advantageous for subsequent air tabling.INTRODUCTIONBack-dune and inland beach sand deposits usually contain fine wind-blown quartz, and neither spiral nor wet table concentration, alone or in conjunction, makes a clean separation of heavy minerals from quartz. Many rutile plants recover rutile and zircon from a low-quartz, wet-table concentrates by means of magnetic and electrostatic separation; some rutile and zircon are lost in the table tailings. Other rutile plants, and two of the ilmenite plants in Western Australia, recover rutile or ilmenite respectively, from a spiral concentrate containing several per cent of quartz, and then subject the non-conductor product to an additionalgravity concentration process to separate the zircon from the quartz. Some zircon is lost in the additional gravity process, but all of the rutile or ilmenite in the spiral concentrate is, or should be, recovered as high-grade concentrate. The higher recovery of rutile or ilmenite by this treatment method is offset by the expense of drying part of the feed twice, as a wet process is usually used to separate the quartz...

Jan 1, 1962

By J. Riss, S. Gentier, A. Marache

The study of the hydromechanical behaviour of fractured rock masses requires a detailed knowledge of the isolated fractures. The aim of the paper is the simulation of the evolution of the void space, located between both walls of a fracture, during a shear test under constant normal stress. Results of the mechanical simulation model are first validated then analyzed in detail. We observe that, during the shear process, there is an opening of the fracture with the creation of preferential channels. These channels are determined at the early phase of the shear process (pre-peak phase), and we observe during the post-peak phase that void areas increase in size rather than the creation of new apertures. Die Untersuchung des hydromechanischen Verhaltens eines zerlegten Felsmassivs erfordert genaue Kenntnisse der einzelnen Spalten. Ziel dieses Artikels ist die Simulation der Evolution des Hohlraumes zwischen den beiden Wänden eines Spaltes während eines Abscherungsexperimentes unter konstantem senkrechtem Druck. Die Ergebnisse der Modellierung werden zunächst mit dem Abscherungsexperiment verglichen und dann im Einzelnen ausführlich analysiert. Während des Abscherungsprozesses tritt eine Öffnung des Spaltes auf, die die Bildung von bevorzugten Fliesswegen fördert. Diese Kanäle werden bereits in einer frühen Phase des Abscherungsprozesses (pre-peak Phase) festgelegt. In der post-peak Phase tritt dann eher eine Vergrößerung dieser Kanäle, als die Bildung neuer Hohlräume auf. L’étude du comportement hydromécanique d’un massif rocheux fracturé ne peut se faire sans une connaissance approfondie des fractures le constituant. L’étude présentée dans cet article concerne la simulation de l’évolution de l’espace des vides présent entre les deux épontes d’une fracture au cours d’un essai de cisaillement à contrainte normale constante. Les résultats du modèle sont tout d’abord validés puis analysés en détail. On constate que, au cours du cisaillement, il apparaît une ouverture de la fracture permettant la création de chenaux préférentiels. Ces derniers sont déterminés très tôt dans le cisaillement (phase pré-pic), et on observe dans la phase post-pic davantage un accroissement de la taille des chenaux plutôt que la formation de nouvelles zones de vides.

Jan 1, 2003

IN concentrating mills, where several millerals are recovered for realisation in more than one product, various systems are used to express the relative economic value of the work done, and, in the hope that it may prove of use to other operators, the writer will describe a system which, in his opinion, is more complete than any other that he has seen published.The controlling factor in all mill work must be based on the economic result represented by the greatest margin possible between the realizable value of the products and the cost of obtaining same.From a mill-man's point of view these are affected by the following factors:1. Metal contents of ore.2. Grade of products.3. Recoveries.4. Working costs.The grade of ore milled is usually outside the mill-man's control, but this may exercise a considerable influence on the grade of his products, metal recoveries, and revenue per ton of ore. Higher grades or recoveries may be obtained by using a more expensive process, or by additional grinding or reagents, and the economic comparison can only be arrived at by obtaining an analysis showing the monetary value of each variation within the possible limits.In the system to be described, the value of unit variations of metal contents of the ore, grade of products and recoveries are calculated in terms of a monetary unit per ton of ore with the returning charges ruling, and any suitable metal prices. To do this it is necessary to assume what, for convenience, is termed a "standard" set of results from the mill, preferably representing about average conditions, and having calculated the effect of unit...

Jan 1, 1931

By Jan E. Nesset, Antonio DiFeo, James A. Finch, Jose Hernandez-Aguilar, Cesar O. Gomez

"The gas dispersion measurement sensors and methodology developed by the mineral processing group at McGill University have to-date been employed at a number of plants in Canada, Australia, the U.S., South Africa and South America. In some cases the measurements have been directly linked with metallurgical performance while in others the gas dispersion surveys on their own have proved very useful in understanding the behaviour of the flotation cells. In addition to reviewing the current state of the gas dispersion measurement technology, the paper will present a series of case studies from the various plants and will show how this technology brings a remarkable new level of understanding to flotation behaviour. The influence of the bubble size distribution on recovery and grade are emphasized in the paper.INTRODUCTIONBackgroundThe advent of new sensors to characterize gas dispersion parameters in flotation cells is a development that is long overdue. While the chemistry of flotation has been studied since the early 1900’s, it is only now that the significance of bubble size distribution, gas rate and gas holdup can be meaningfully measured in-plant with robust and precise sensors. Early researchers, like T.A. Rickard (1916) recognized the importance of understanding the role of air and bubbles in flotation when he wrote in 1916 “we know that the key to the flotation process is to be found not in the oil, the acid, or the apparatus, but in the bubbles. The man who understands the mystery of a soap bubble has mastered the chief mystery of flotation”. In his 1999 review paper on The Froth Flotation Century D.W. Fuerstenau laments the fact that due to their “inert nature”, bubbles have never received their due attention from researchers who tended to focus on the chemical, physical, surface and colloidal aspects, rather than the physics of the process. It is perhaps fitting that now, 100 years after the inception of industrial flotation practice at Broken Hill, Australia, researchers and industry have turned their attention toward the importance of truly understanding the role of bubbles in flotation."

Jan 1, 2005

By Prosser A. P

The conditions under which vanadium is rendered insoluble by silica in the alkali-roast process have been investigated starting with both slag and reagent-grade materials. The inert phase is a glass formed slowlyfrom soluble NaV03 produced at lower temperatures. It contains approximately 30 per cent V in a partly reduced state; iron is not a principal component. Some of the vanadium in the inert phase is slowly returned to a soluble form by heating in an oxidizing atmosphere below the temperature at which the glass is formed (750°C). As the reaction leading to the required, soluble form of vanadium is also slow between 600 and 750° optimization and control of the temperature profile and atmosphere in the furnace, and the residence time of the solids, are necessary to ensure high vanadium extraction during subsequent leaching.

Jan 1, 1976

By Susanne Hahn

The Siemens VAI software model DynaPhase calculates thermodynamic properties depending on the chemical analysis of steel. It can be used online together with Siemens VAI’s secondary cooling model SIMETAL Dynacs 3D which is a unique feature. Offline it can be used to investigate the thermodynamic properties of steel grades and therefore supports the development of new grades. The core of DynaPhase is a substitutional solution model for the Gibbs free energy to calculate multi-component phase diagrams. The parameters of this model are determined by employing the CALPHAD approach. This model is combined with a microsegregation model to account for the interdendritic solidification process. New DSC (differential scanning calometry) measurements of the department of metallurgy of the Mining University of Leoben have been used to improve the DynaPhase database for high Al or Si concentrations. By comparing this experimental data to calculations it has been found that some of the widely used commercial software tools do not describe the ternary system FeAlC for high aluminum concentration correctly. In this paper we will show how thermal properties of high Al grades change with the optimized database and what impact this has on the secondary cooling of continuous casting, e.g. how the solidus point shifts on the strand. Moreover we will show that the online use of DynaPhase has many advantages for the production. Since DynaPhase uses the actual chemical analysis of the steel grade and not just concentration ranges or averaged concentrations it is possible to optimize the cooling strategy during casting for the actual chemical analysis of the actual heat.

Jul 30, 2018

By E. C. Grunsky, B. W. Smee

"The development of low-cost, rapid multielement analytical techniques has generated large geochemical databases in many exploration programs. When a sampling program consists of several thousand samples, the resulting data matrix is enormous and effective interpretation using all of the elements individually becomes burdensome. However, the application of multivariate statistical techniques can extract geochemical patterns related to the underlying geology, weathering, alteration and mineralization. Imaging the results over topography enhances the interpretation of these patterns. Examples of this approach are shown from mineral exploration programs in Canada and Mexico. IntroductionThere has been a dramatic change in the effectiveness of using geochemical survey data in the past ten years. This is mostly due to:• lower cost of geochemical analysis;• lower detection limits;• new methods of multi-element analysis;• a marked decrease in the turnaround time;and• the intelligent use of computers in presenting geochemical data.Geochemical surveys commonly have two objectives: locating abnormal concentrations of ore-forming or pathfinder elements and characterizing the underlying host lithologies. Geochemical surveys often employ a wide range of sample media that may typically include whole rock lithogeochemistry, various soil horizons, till and basal till sampling, stream sediments, lake sediments, and various forms of weathered regolith. Each of these sample media will exhibit a unique element distribution that must be factored in the interpretation phase of a geochemical survey study. This can become a cumbersome process if univariate data handling methods are employed."

Jan 1, 2003

By W. H. Schiffbauer

The protection of miners, equipment, and infrastructure is discussed. While the primary focus of the described technology is to prevent miners from being injured, struck-by, or crushed by heavy equipment; another major benefit realized is also the protection of equipment and infrastructure. An attempt is made to define and classify the systems used to provide proximity detection and warnings as well as collision detection and avoidance. Information about the speed of vehicles and human operator response time can be a factor in the choice of what type of system and what features are needed to properly address the needs. How the technology adjusts to compensate for various vehicle speeds, while maintaining the same level of protection is noted. The statistics which justify the need of miner protection are provided. The primary system components required, what attributes they feature, and how they respond in the environment, is briefly highlighted. The physics behind the danger zone marker technology and what makes it so robust and reliable is established. Examples of a few mining applications and specific operational modes are provided for both surface and underground.

Jan 1, 2011

THE object of the present paper is to give a brief description of the metallurgical process followed by the Grand Junction Co, and the results obtained therefrom. All figures quoted are from the actual working of the plant over a period of six months from January to June, 1910. The short ton of 2000 lb. is used by the company. Its gold is valued at 84s. per oz. fine, silver at 2s. per oz. fine. The ore consists essentially of a gangue of quartz and calcite, with 8 to 10%sulphide-pyrite, sphalerite, galena, chalcopyrite, and traces of arsenic and antimony. The colmtry-rock is a highlyaltered dacite. Small stringers of highly-mineralized ore penetrate the footwall of some of the lodes, forming a valuable stockwerk up to 3 ft. in thickness. In stoping, this is mined with the well defined lode, thus bringing into the mill at times a considerable quantity of hard country-rock. The gold exists in an exceedingly fine state of division, consequently rendering it necessary to grind very fine to obtain a satisfactory extraction.

Jan 1, 1912

By W. Pariseau, S. Puri, S. Schmelter

Introduction Joints often have profound effects on elastic properties and strength of rock masses and therefore on rock slope stability. In surface mine slopes, joints are usually too numerous to be taken into account individually, so an equivalent properties approach is necessary. Previous work that treats a jointed rock mass as an equivalent composite material of joints and intact rock between resulted in excellent agreement between estimated and true rock mass elastic moduli in case of fully persistent joints (e.g., Pariseau, 1999) Rock mass failure mechanisms on joints and through intact rock were retained obviating the need for an equivalent rock mass strength. Impersistent joints, which are not continuous on a joint plane, can be accommodated (Pariseau, 2003). However, slope stability analysis of a large, deep copper mine indicated a need for computational efficiency even in two-dimensional analysis of vertical sections through pit walls (Puri, 2006). The analyses by the popular finite element method used small elements of bench size near the pit slopes and much larger elements away from the pit walls. The reasons for the graded meshes were numerical quality (small elements) and computational economy (large elements). Small elements contained only a few joints, while the larger elements contained hundreds of joints and led to impractical computation run times (days!). A new modeling procedure that recognizes sufficiently large elements as representative volume elements (REV’s) overcomes this obstacle. A companion improvement recognizes the concept of a representative area element (RAE) in association with joint impersistence and the probability that joint material occupies a considered site. Both are steps towards greater model realism and a practical slope stability analysis procedure. Consider the open pit mine photo shown in Figure 1(a), a companion plan view in Figure 1(b), and the problem of slope stability where high slope angles favor economics but low slope angles favor safety. These competing factors in surface mining generally result in some sections of the mine that have unstable slopes that require monitoring and perhaps mitigating action to improve stability. Although stability of a given section may not be easy to quantify with a single number, useful design guidance can be obtained from a finite element analysis of a proposed mining sequence leading to future pit slopes and profiles. The presence of water from rain and snow melt indicates a need for a coupled analysis that links water pressure, effective stress and total stress (Schmelter, 2001).

Jan 1, 2007

By D Crequer

Land rehabilitation at Golden Cross is reviewed, 8 years after mine closure in 1997/98, from the perspectives of a Peer Reviewer (land rehabilitation) and a Regional Council Officer (Resource Consents compliance). Land rehabilitation items we discuss include: management of restored pastures, native plantings (on-site riparian and block plantings and off-site environmental riparian enhancement plantings), wetlands (on-site tailings lake and sediment ponds littoral zone plantings, and basement of the open pit; and off-site wetlands enhancement plantings), pine plantations on-site and on surrounding land, stabilization of the Tailings Lake Embankment (landslide) and Open Pit capping, capping of acid-mine-rock, stability of discharge channels, buildings and amenities, public access for recreation, educational uses, and future management of the site. Pest control has helped to conserve the rare and endangered HochstetterÆs (Leiopelma hochstetteri) and ArcheyÆs (L. archeyi) frogs, and a regionally significant stand of rare swamp maire (Syzygium maire) has been conserved and fenced.

Jan 1, 2006

By Claudio Asioli

"The project’s goal was to construct the Al Ghazala Intercontinental, a multi-use development in the bay area of Tripoli overlooking the Mediterranean Sea. The site of the project is located approximately 500 ft (150 m) from the Mediterranean coast, near the Al Ghazala roundabout in the town center of Tripoli, Libya. The investor of the project was Magna Properties Group, Ltd. – Libya, the main contractor was Man Enterprise S.A.L., and the design and construction management was performed by Dar Al-Handasah Engineering. Trevi S.p.A. was contracted to perform the design and construction of the anchored diaphragm walls and dewatering systems for the excavation of a two-level basement car park, which extends across the full footprint of the site.The site was approximately 640 ft by 230 ft (195 m by 70 m) in plan and nearly flat. The groundwater level typically varies from about 11 ft to 23 ft (3.4 m to 7.0 m) above mean sea level. To construct the required raft foundation, it was necessary to excavate the area down to El. -15.7 ft to -26.3 ft (-4.8 m to -8.0 m), which resulted in an excavation depth ranging from about 27 ft to 39 ft (8.3 m to 12.0 m) below the existing ground surface.Subsurface ConditionsThe subsurface site investigation was performed in three phases by Al-Tamier Engineering Consulting Bureau. During Phase 1, a preliminary investigation was undertaken during the early stages of the project to obtain information about the general stratigraphy and groundwater level at the site. Phase 2 was performed to obtain subsurface information and design parameters, and Phase 3 was performed as a supplementary ground investigation to investigate unexpected ground conditions identified during Phase 2. In total, 14 boreholes were drilled to depths ranging from about 80 ft to 180 ft (24 to 55 m). The generalized subsurface profile is quite heterogeneous, and is predominantly composed of sand with silt and gravel that is underlain by limestone, calcarenite and claystone"

Jan 1, 2017

By Claudio Asioli

"The project’s goal was to construct the Al Ghazala Intercontinental, a multi-use development in the bay area of Tripoli overlooking the Mediterranean Sea. The site of the project is located approximately 500 ft (150 m) from the Mediterranean coast, near the Al Ghazala roundabout in the town center of Tripoli, Libya. The investor of the project was Magna Properties Group, Ltd. – Libya, the main contractor was Man Enterprise S.A.L., and the design and construction management was performed by Dar Al-Handasah Engineering. Trevi S.p.A. was contracted to perform the design and construction of the anchored diaphragm walls and dewatering systems for the excavation of a two-level basement car park, which extends across the full footprint of the site.The site was approximately 640 ft by 230 ft (195 m by 70 m) in plan and nearly flat. The groundwater level typically varies from about 11 ft to 23 ft (3.4 m to 7.0 m) above mean sea level. To construct the required raft foundation, it was necessary to excavate the area down to El. -15.7 ft to -26.3 ft (-4.8 m to -8.0 m), which resulted in an excavation depth ranging from about 27 ft to 39 ft (8.3 m to 12.0 m) below the existing ground surface. Subsurface ConditionsThe subsurface site investigation was performed in three phases by Al-Tamier Engineering Consulting Bureau. During Phase 1, a preliminary investigation was undertaken during the early stages of the project to obtain information about the general stratigraphy and groundwater level at the site. Phase 2 was performed to obtain subsurface information and design parameters, and Phase 3 was performed as a supplementary ground investigation to investigate unexpected ground conditions identified during Phase 2. In total, 14 boreholes were drilled to depths ranging from about 80 ft to 180 ft (24 to 55 m). The generalized subsurface profile is quite heterogeneous, and is predominantly composed of sand with silt and gravel that is underlain by limestone, calcarenite and claystone."

Jan 1, 2017

By C. A. Lavery

A DISCUSSION is presented of natural gas production and field processing equipment as now utilized in the gas producing areas of the United States, with reference to use of such equipment in Canadian gas areas. The scope of the paper is confined to a general description of various types and methods of using surface production equipment. The discussion is divided under two general groups: well-head production equipment, and field processing. The first will be concerned primarily with indirect heaters, separators, knockouts, and special versions of this equipment. The second major group includes the field processing equipment for handling natural gas. A delineation should be made here as to the meaning of field processing as used in this discussion. We will limit our term to mean such processing equipment as may be used in producing fields to process gas or its by products in a manner that does not require conventional plant practices either in operation or supervision. This covers such equipment as is necessary to complete preparation of gas for sale to pipeline and/ or is necessary to recover valuable components. Under this heading we will discuss glycol dehydration, solid desiccant dehydration, low-temperature separation, mechanical refrigeration, and desorbtion-stabilization. These are all processes involved in preparing gas for final sale or disposal. They do not include the more conventional and large-scale plant process systems.

Jan 1, 1956

Underground Mine Drainage may be conveniently divided into two operations:(a) Collecting and transporting drainage water to the pump eastern.(b) Elevating water to the surfacc by pumping.This short paper describes a system which automatically performs operation "a" and which has been developed on the South mine at Broken Hill, under the supervision of the mine foreman, Mr. F. McDonell. Operation "a" does not come under the heading of "subsidiary mine" drainage.SUMMARY(1) All drainage waters are collected by gravity flow into sumps.(2) Automatic control boxes operate syphons which transfer water from level to level to pump cisterns or to feed water service.EQUIPMENTSyphon Control Boar - Constructed of 10 ft. x 2 ft. oregon timber, suitably bolted together and equipped with a Bailey's cistern valve, with copper ball float control, and 12 in. pipcs and fittings forming a syphon (Fig. 1). One of these boxes is placed on each level at the shaft.The valve and float are so arranged that when the float is up (ie, box full) the valve will be fully open, and when the float is down (ie, box empty) the valve is closed. The vertical range between the cxtreme positions can be altercd by lengthening orshortening the adjustable arm of the float. The ideal valve is one...

Jan 1, 1927

By Bruce Richardson

A contractor-manufactured 4.75m (15'-7") diameter EPB shield excavated a 115m (375 ft) long tunnel under the San Antonio River as part of the Salado Creek to Dos Rios Pipeline Interconnect Project in San Antonio, Texas. Lignite, limestone concretions, and sandstone in the face of the tunnel required the use of disc cutters. Less than 7.6m (25 ft) of sand and gravel hydraulically connected the top of the tunnel to the channel of the river. Fully lagged steel ribs with filter fabric were used for initial ground support and water control. This and other contractor manufactured TBMs in the 1.2 to 4.75m (4 to 16 ft) range are presented with descriptions of the jobsites, equipment, performances, and problems.

Jan 1, 2008