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By Mario Terceros H, Bengt H. Fellenius

"ABSTRACTThe city of Santa Cruz, Bolivia, is historically dominated by houses and three to five storey buildings.The geology in and around the city is such that even very light buildings need to be supported onpiles. The recent increase of the Bolivian economy, notably that of Santa Cruz, has created a demandfor new residential as well as office and industrial buildings, which mostly consist of multi-storey orhigh-rise buildings with significantly larger foundation loads. Foundation piles have become largerand longer, and the load on individual piles is increased. The development has resulted in an increasein the demand for more sophisticated design and construction methods and stricter approach toverifying the quality of the construction processes and results.This paper describes to geology of the Santa Cruz region and how the geotechnical conditions areconsidered in the design and construction of piled foundations. The improvement of past constructionand design techniques, based mostly on bored piles constructed with bentonite slurry, is beingreplaced with new methods of constructing bored piles, e.g. the Full Displacement Pile (FDP) andincorporation of techniques such as enlarging the pile toe, e.g., with the Expander Body. This paperpresents the results of several full-scale tests and discusses the incorporation of the test results indesign and construction.1 GEOLOGY OF THE REGIONSanta Cruz de la Sierra is located in the eastern lowlands and sub-Andean zone of Bolivia, SouthAmerica. The area lies at an elevation of about +400 m and the geology is a Paleozoic (250 millionyears old) sedimentary basin. The soils of interest to civil engineering construction are quaternarywith the dominant minerals being calcite, silica and feldspar. The main agent is the Piray River and itstributaries. Their past meandering over the area has resulted in a sedimentation-erosionsedimentationprocess and a profile dominated by fine to medium sands with intermittent layers ofclay or clayey sand. With increasing distance from the river, the clay-containing layers are thicker.Fig.1.- View of Bolivia with location of Santa Cruz and map of Santa CruzThe upper about 15 to 18 m thick part of the profile consists of normally consolidated layers of clays,silts, sands, in various combination and thickness. Below, the soil is more homogeneous and consistsmostly of sand and gravel. The groundwater table lies typically at a depth of about 6 m in the highestpart of the city and at about 1 to 3 m depth in the lowest part of the city."

Jan 1, 2014

By Timothy A. Clancy

To help reduce the Nation's dependence on imported chromite, the Bureau of Mines is conducting research on the use of dolomites as an alternate material. Dolomite is a plentiful domestic resource and offers certain advantages as a refractory raw material. A review of the literature has indicated that there are many sources of high-purity dolomite in this country and that European nations use a greater proportion of dolomite refractories, primarily in steelmaking, than the United States, The Bureau of Mines characterized 14 domestic dolomites as to chemistry, density, mineralogy, microstructure, and thermal behavior, to develop baseline data on their suitability as refractory raw materials.

Jan 1, 1983

By Robert C. Speck

The U.S. coal industry has long utilized the pillar-extraction mining technique as a method for maximizing coal recovery. Like longwall mining, it causes large-scale movements that progressively propagate from mine-level to the ground surface and may affect the groundwater regime, surface drainage and surface structures. The U.S. Department of Energy, in an effort to foster in- creased use of total extraction mining techniques, has recognized the need for a better understanding of these movements that will lead to a greater compatibility between coal mining and present and future land use. As part of that goal, GAI Consultants, Inc. is currently in- stalling instrumentation to monitor the ground movements associated with pillar extraction mining at Kitt Energy Corporation's No. 1 mine in northern West Virginia.

Jan 1, 1982

By J. P. Josien, J. F. Noirel, F. Lahaie, P. Bigarre, M. Al Heib

ABSTRACT: In June 2001, a fatal rockburst affected a longwall face in the Houillères du Bassin de Lorraine (HBL), France. Subsequently, a large operation of in situ stress measurements by overcoring was carried out with two main objectives: providing input data for the back analysis of the dynamic event and characterising the stress field in the next panels to be mined for identifying other potential high-risk zones. This paper makes a synthesis of the results of the overcoring tests performed and discusses those results in connection with the mining context, numerical model predictions, laboratory rock test results and microseismic activity. KEY WORDS: Mine, rockburst, stress, overcoring, measurement. ZUSAMMENFASSUNG: Im Juni 2001 hat ein Bergschlag eine Kohlengrube des Houillères du Bassin de Lorraine (HBL, Lothringen, Frankreich) schwer beschädigt. Nach diesem Unfall sind Spannungsmessugen durch Überborung durchegeführt worden, mit zwei Hauptziele : 1/ Daten zu liefern für die Retro-analyse des dynamischen Gebirgsschlag und 2/ die Spannungen in den zukünftigen Ausbauen so gut wie möglich zu charakterisieren, um eventuele andere Risikozonen festzustellen. Dieser Artikel stellt eine Synthese der erzielten Ergebnisse vor. Er diskutiert diese Ergebnisse in Verbindung mit dem gesamten Kohlengruben Zusammenhang, mit den Ergebnissen von numerischen Modellierungen, mit der Labor-Charakterisierung und mit der microsismische Überwachung. SCHLÜSSEL-WÖRTER: Kohlengruben, Bergschlag, Spannung, Überborung, Messung. RESUME: En Juin 2001, un coup de terrain a gravement affecté une longue taille aux Houillères du Bassin de Lorraine (HBL) en France. A la suite de cet accident, une importante campagne de mesures de contraintes par surcarottage a été réalisée, avec deux objectifs majeurs : fournir des données d’entrée permettant la rétroanalyse du phénomène dynamique et caractériser au mieux le champ de contraintes dans les futurs panneaux exploités afin de détecter d’éventuelles autres zones à risque. Cet article présente une synthèse des résultats obtenus, et discute ces résultats en liaison avec le contexte d’exploitation, les résultats de modélisation numérique, de caractérisation en laboratoire et de surveillance microsismique. MOTS CLES: Mine, coup de terrain, contrainte, surcarottage, mesure.

Jan 1, 2003

By Valentine A. Chanturiya

The aim of this paper is basically to show progress in the study of nanosecond processes involved in the disintegration and breaking-up of mineral complexes with fine noble metals. We studied the influence of nanosecond High-Power Electromagnetic Pulses (HPEMP) on the physical and technological properties of refractory gold-containing ores and beneficiation products. Experimental data are presented to confirm the formation of breakdown channels and selective disintegration of mineral complexes as a result of pulse irradiation, which makes for efficient access of lixiviant solutions to precious metal grains and enhanced precious metal recovery into lixivia during leaching. Preliminary processing of gravity concentrate with a HPEMP resulted in significant increase of gold and silver extraction into lixivia during the cyanidation stage, with gold recovery increased by ~31% (from 51.2% in a blank test to 82.3% after irradiation). Gold recovery from stale gold-containing dressing tailings products increased after pulses-irradiation from 8-12% to 80-90%.

Jan 1, 2006

By W. Stumpf

Mean flow stress analyses from plant mill logs for the conventionally produced hot rolled low carbon steel from the Ispat Iscor Vanderbijlpark strip producing plant, indicated a higher temperature sensitivity than that found for the equivalent SAE 1006strip steel produced in the compact strip plant of Saldanha Steel. This was confirmed quantitatively through detailed hot deformation studies on an as-cast structure as well as on a finer grained condition on the same steel. In the conventionally produced steel, activation energies for hot deformation of 309 kJ.mol-1and 388kJ.mol-1for the two respective starting structures were found, both values extending over the entire normal hot deformation temperature range of 1140 to 900°C. These and other experimentally determined constitutive hot deformation constants were applied to the hot rolling austenite grain size development model used earlier. From this, it is predicted that dynamic recrystallization occurs only in the first two break-down passes at the Vanderbijlpark plant and thereafter static recrystallization occurs after exiting from all of the remaining ten or eleven roughing and finishing passes. This is significantly different from what was predicted earlier for the Saldanha Steel plant with its lesser number of passes where static recrystallization is predicted to occur only in the last three passes. The effects of this process difference and other observed product differences between the two types of product are discussed. Keywords: Low carbon steel, hot rolling of strip steel, rolling mill log analyses, austenite grain size, grain size modelling.

Jan 1, 2004

Develop tools that mine personnel can use to comply with 30 CFR,Part 47. Background The new MSHA rule, 30 CFR, Part 47 (also known as the HazCom rule), requires all mines to develop a written program to track hazardous chemicals at their sites. More specifically, the rule requires that mines list all chemicals and determine which are hazardous; develop a written Hazard Communication Program; label all containers used to store hazardous chemicals; obtain or develop Material Safety Data Sheets (MSDS) for all chemicals stored or produced; provide miners with training in working around hazardous chemicals; and make information about hazardous chemicals available to all workers. All mines with six or more employees must have complied with the new rule by September 23, 2002, and mines with five or fewer employees will have to be in compliance by March 21, 2003.

Mar 1, 2003

By C. W. Davis

This paper is the second of a series of progress reports on a study, of the hydrometallurgy of manganese which is being conducted in an endeavor to make possible utilization of the large deposits of low-grade domestic manganese ores that occur in several States. There are at least four processes in which a knowledge of the action of SO2 gas on manganese oxides at elevated temperatures may prove of value. One ,of these involves dissolution of manganese from ores. The Bureau of Mines has investigated the hydrometallurgy of manganese by a process in which SO2 gas, a waste product at many smelters, is passed into water to form a solvent for manganese. Although Several manganese minerals acre readily dissolved, rhodochrosite (MnCO3) was attacked but superficially.§. Recent experiments have shown that a roast at 650 to 900°C converts the manganese of rhodochrosite to a form that is quickly dissolved by a weak SO2 solution. Introduction of smelter gases containing as much as 5 per cent SO2 during such a roast would not add much to the cost of the operation and might result in the formation of considerable water-soluble manganese sulphate.

Jan 1, 1930

By C. W. Davis

This paper is the second of a series of progress reports on a study of the hydrometallurgy of manganese which is being, conducted in an endeavor to make possible utilization-of the large deposits of low-grade domestic manganese ores that occur in several States. There are at least four processes in which a knowledge of the action of S02 gas on manganese oxides at elevated temperatures may prove of value.

Jan 1, 1930

By Bruno Deves Flores

O presente trabalho tem como objetivo investigar a influência da adição de carvão vegetal e do seu tamanho de partícula na reatividade do coque. Para isso, um carvão vegetal de eucalipto foi adicionado a um carvão médio volátil americano em três teores (3%, 5% e 8%) e em duas faixas granulométricas distintas (abaixo de 1 mm e entre 3 mm e 4 mm). O carvão individual e as misturas de carvão/carvão vegetal foram carbonizados em um forno de escala laboratorial (1 kg). A reatividade dos coques produzidos e do coque de referência foi avaliada e comparada usando análise termogravimétrica. Também foram realizadas análises morfológicas através de microscópio óptico e eletrônico, usando amostras antes e após os ensaios termogravimétricos. Baseado nos resultados, a influência da introdução de carvão vegetal na reatividade do coque foi analisada e discutida neste trabalho.

Aug 1, 2018

By C. D. Thompson

Pile load test programs were carried out in 1984 and 1985 at Stelco's and Dofasco's Steel Making Plants in the Hamilton Bayfront area. 323.9 mm outside diameter by 9.5 mm wall thickness Grade 3 steel closed-end pipe piles were driven to practical refusal at depths of 21 to 30 m in very dense silt till with Delmag D30 open-end diesel hammers. Ultimate bearing capacities of up to 5330 kN were proved by dynamic monitoring and static load tests. Allowable bearing capacities of 1780 kN were achievable on production piles without undue difficulty. It was found that the impact stress at the top of the pile was controlled by the yield strength of the steel rather than a useable upper limit based on the modulus of elasticity. A bearing to impact stress ratio of 1.2 at practical refusal was observed to be reasonable but conservative at this site, and is felt to be generally applicable for piles driven to practical refusal elsewhere. Dynamic monitoring during production pile driving was able to show that apparent relaxation was caused by pre-ignition of the hammer when visual observations indicated that pile driving was proceeding satisfactorily.

Jan 1, 1987

By William Seymour, L. D. Schmidt, J. W. Myers, W. T. Reid

"This investigation was conducted by the Bureau of Mines as part of a program of the Solid Fuels Administration to encourage the utilization of anthracite fines, the objective being to determine the practicability of using anthracite fines in the manufacture of packagedThe experimental loss of packaged fuel covered by this report were made at a commercial plant using the Glenn Smith process and ordinarily making packaged fuel from Pocahontas screenings. These lots included several made from straight antimacite mines and others made from various blends of anthracite fines with four different bituminous coals. In all cases an asphalt binder was used. Determinations of the physical properties and the cobustion characteristics o the various samples of packaged fuel were made by the. Bureau of Mines at the Central Experiment Station.The physical tests indicated that a packaged fuel of sufficient strength for ordinary handling can be made from straight anthracite coal or from a wide variety of blends of anthracite fixes with bitunimous coal, using asphaltic binder. However the combustion tests indicated that packaged fuel made from anthracite alone tended to crumble excessively during burning and that as much as 30 to 50 percent of a caking coal may be required In the mixture to produce a block having satisfactory combustion characteristics.The authors wish to acknowledge the. splendid cooperation of Messrs. H. W. Kelly, J. L. Mooney and C. H. Stoss of Columbus, Ohio, who were chiefly responsible for obtaining the materials and making all the arrangements necessary for the production of the packaged fuel for testing.Thanks are due to the officials of Carnegie Institute of Technology for the use of their Olsen. Testing Machine and to H. M. Cooper and W. A. Selvig of the Bureau of Mines for analyses and tests."

May 1, 1946

By E. D. Calvert

Molybdenum has been successfully cast into static and rotating molds in conventional equipment used for casting titanium and zirconium. Melting was accomplished by using an arc potential of 36 to 40 volts with a current of 10,000 amperes. Pouring efficiency, after a skull had been formed in the crucible, averaged 70 percent. Techniques are described by which four successful castings were made. Tensile properties on specimens cut from one centrifugally cast tube averaged: Tensile strength, 39,800 p.s.i.; yield strength (0.1 pct. offset), 35,300 p.s.i.; elongation, nil; reduction in area, nil; impact strength, 2 ft.-lb.; hardness DPH (diamond pyramid hardness) 180. Mold reaction was not evident in shapes cast in machined graphite. This was not true, however, for rammed graphitic-base molds.

Jan 1, 1960

By R. M. Owens, J. F. Lupo

The Shirley Basin Uranium mine, located in southeastern Wyoming, USA, was an open pit mining operation consisting of a series of several open pit mines excavated into poorly consolidated sandstones, siltstones, and claystones. Since the initial open pits were developed in 1969, slope failures have plagued the mine and mining operations. These slope failures have persisted into the current mine reclamation period. When the mine was first developed, the open pit slopes were designed to range between 45 to 55 degrees. Numerous slope failures during mine development required the pit slopes to be redesigned with slopes as shallow as 26 degrees. At present, movements are occurring within the open pits on reclaimed slopes that are shallow as 12 degrees. Several detailed slope studies were conducted at the mine in the early 1970s. These studies, combined with more recent geotechnical investigations, provide a unique detailed history of pit slope failures on shallow slopes. This paper presents an evaluation of the slope failures at the Shirley Basin mine, highlighting important mechanisms causing slope failures on very shallow slopes. The evaluation demonstrates important key parameters for shallow slope design.

Jan 1, 2001

By D. C. Bailey, D. I. Hodson

Paper presented at the annual joint meeting of the IMM and IMinE held in Harrogate, 31 January 1991. The Neves-Corvo copper-tin mine is the highest-grade large-tonnage copper operation in the world and is now arguably the most significant producing base-metal mine in Europe, rating in the top ten world producers of both copper and tin. A description is given of the initial exploration work and the development of the project from the orebody discovery in the Iberian Pyrite Belt of southern Portugal in 1977 to full operating capacity in 1990. The chronological account includes discussion of the main organisational, financial, technical and environmental decisions and of the various difficulties encountered, and the challenges of the future are identified. The project was brought in on schedule and within budget

Jan 1, 1991

By Alcides Meléndez González

La formación profesional del personal minero es importante en tanto mejora su desempeño y responsabilidades con la empresa y actividad minero. En ese sentido, el presente trabajo describe los programas de educación profesional desarrollados por el Estado u organizaciones privadas a través de tres etapas: formación profesional elemental, formación profesional especializada y la formación profesional universitaria. Los principales objetivos son: adquirir los fundamentos técnicos, científicos y tecnológicos de la actividad minera y establecer mejores métodos de trabajo como nuevos procesos tecnológicos.

Nov 1, 1972

By H. R. Thorpe

A floating gold dredge operating in coarse alluvial gravels of the Grey River on the west coast of the South Island, New Zealand, generated high concentrations of clay and colloidal particles in the dredge pond, which entered the groundwater system. Sampling was carried out at depths down to 20 m and it was found that variation of the length of the flow path occurred because of the movement of the dredge towards the piezometers. The alluvial gravels, the suspended sediments, the groundwater system and the water chemistry were all studied. Sediment concentrations were found to be highly variable with depth, but the relative concentrations in the depth profile were generally consistent as the flow distance shortened. The sediments were extremely fine and travelled further through the gravels than predicted. Comparison of field results with the available theory of deep filtration in clean beds of porous media gives some basis for estimating the behaviour of fine sediments in other alluvial systems

Jun 19, 1905

By Judy B. Jones, Bradley A. Crenshaw, Theodore DePooter

This paper reviews groundwater issues leading to a secondary grouting program at the Chattahoochee Tunnel that was implemented subsequent to the contact grouting program. The secondary grouting program was developed based on infiltration data, geology, and testing programs. This paper includes a brief description of the geological features encountered, as well as describing the grouting program. The success of this grouting operation has been quantified by several methods, and is presented to help others project the costs and benefits of this type of program. Review of initial results and refinements of techniques are also discussed.

Jan 1, 2005

The Wongawilli system of mining has been in use for over 30 years and has enabled high production rates and acceptable extraction ratios to be achieved in seams less than 4 m in thickness. A modification of the Wongawilli system has been developed to permit the use of a continuous miner and mobile equipment to extract a coal seam 6 m thick. Following physical and mathematical model studies the new mining method is now undergoing field trials at Collinsville, Queensland. Progress of the field trials to date has achieved 99 per cent extraction of the upper slice by remote control operation of the continuous miner and established the feasibility of installing resin grouted wooden dowels in the coal floor to reinforce the coal septum. The method is explained in the text. Monitoring of the goaf gases as an early indication of spontaneous combustion has been incorporated in the mining cycle by placement of tubes in the goaf as the face retreats and continuous analysis of the goaf gases made at the surface by the National Coal Board tube bundle monitoring system.

Jan 1, 1980

By Vince Luongo

PROJECT DESCRIPTION The York Durham Sanitary System (YDSS) Interceptor in the Town of Richmond Hill located just north of Toronto, Ontario, Canada will see the construction of a tunnel extending along 19th Avenue for a length of approximately 3.8 Km from Yonge Street, east to Leslie Street and will have a minimum internal diameter of 2.1 m. t to Leslie Street and will have a minimum internal diameter of 2.1 m. The tunnel will connect into four shafts, for which two of the shafts will be constructed using the slurry wall construction method given the high water table and difficult ground conditions encountered at these locations. The two shafts noted as Access Shaft No. 2 and No. 3 were designed and constructed to meet regulatory conditions, which required a sealed shaft construction method. GEOGRAPHICAL PROFILE The ground conditions in the Toronto region consist predominately of glacial till, glaciolacustrine and glaciofluvial sand, silt and clay deposits, and beach sands and gravels. The shallow geological formation found in the project area consists of four types of deposits: Oak Ridge Morain deposits, Halton Till, Glacial lake deposits and Organic soils. The Oak Ridge Morain is the dominant deposit encountered along the tunnel alignment. This formation consists of three deposits: The Upper Till, Middle Sand and the Lower Till. Standard penetration tests (SPT) carried out in these deposits measured N-values ranging from 2 to more than 100 blows/300mm which indicate very loose to very dense soil conditions. The Middle Sand deposit will be the dominant feature within the slurry wall construction at access shafts 2 and 3. Access Shaft 3 The base of the slurry wall will be 20.5 M below the ground surface. Slurry wall excavation will be within peat and organic soils found at the upper 3 M, followed by 5 M of the Upper Till. The remainder of the excavation will be within the Middle Sand. The piezometric head elevation is found at the ground surface. Access Shaft 2 The base of the slurry wall will be 22.5 M below the ground surface. Slurry wall excavation will be entirely within the Middle Sand 2.The piezometric head elevation is found at 7 M below the ground surface.

Jan 1, 2007