Search Documents

By J. M. Weehuizen

Complete details are given of the drilling method by which two shafts were sunk at the new Beatm'x mine of Staatsmijnen in the Netherlands. The nature of the rock strata in the Dutch mining district determined choice of the drilling rather than the freezing method. Data for each step and details of the equipment used are given in the illustrations. Staatsmijnen was founded in 1902 with government financial backing, but it is run as a private enterprise, on a commercial basis, with the normal fiscal obligations. The company now has four mines in operation with annual outputs amounting to 7 1/2 million tons of coal. In 1952 it was determined that a new mine—the Beatrix—would be opened. Details of the shaft-sinking operation are described in this paper. SHAFT LOCATION The coal-bearing carboniferous rock in the Dutch mining district is overlain almost completely by soft water-bearing strata, which at the site of the new shafts are about 1600 ft thick. The sinking of the new shafts through this soft water-bearing overburden (Fig. 1) is a costly and time-consuming affair. From the two availaible sinking methods: 1) Poetsch's well known freezing method or 2) the drilling method of Honigmann-de Vooys, the latter was preferred, not only because of its relative cheapness, under the prevailing conditions, but primarily because by using the drilling process, a special type of shaft lining of steel, concrete, and bitumen could be used. The new shafts, located 330 ft apart, have an inner diameter of 18 ft, 4 1/2 in. The boreholes, which have a diameter of 25 ft and which were drilled through nearly 1600 ft of overburden and some 100 ft of carboniferous, each contain more than 29,000 cu yd—by far the largest in the world. DRILLING METHOD The drilling method is based on the use of mud-flush—a thin mixture of clay and water—to keep the borehole filled during the entire drilling period and during insertion of the lining (Fig. 2). The pressure of the mudflush against the borehole wall is greater than that of the water in the surrounding

Jan 1, 1961

By M. Reuter, C. Schuffeneger, T. Seppälä, L. Holappa

Reaction kinetics of solid-state reduction of chromite pellets (laboratory made and industrial) and lumpy ore was investigated by the thermogravimetric analysis (TGA) technique. Carbon monoxide was used as the reducing agent, with the presence of graphite in proximity to chromite. The experiments were carried out at both rising temperature and constant temperature in the range of 1450 - 1550°C. Scanning electron microscopy was employed to observe and analyse the structure and composition changes of the chromite samples. For the lab-made chromite pellets, the effects of particle size and bentonite addition on the reduction behaviour were studied. The pellet with smaller particle size gave a higher reduction rate. Bentonite addition had slightly negative effect on the reduction rate. When reducing industrial pellets, temperature and CO flow rate had positive influence on the reduction rate. Reduction of lumpy ore took place slower than reduction of a pellet. In all samples, chromite reduction proceeded longer in the outer part of the sample than in the centre part. The porosity of the chromite samples was determined before and after the experiments. The porosity of lumpy chromite increased significantly during the reduction. However, the porosity of lab-made chromite pellet decreases due to sintering effect. The reaction mechanism is discussed on the basis of experimental results and earlier investigations.

Jan 1, 2004

Triboelectric Separation - Beneficiation of Coal The performance of triboelectric separators is highly sensitive to the selectivity of the particle charging process. This paper presents a quantitative study on triboelectric coal beneficiation. The performance of different charging media was studied. Stainless steel was identified as having a work function between that of coal and silicate gangue and found to be the optimum charging medium for coal beneficiation. Recent results from separation tests were performed where silicate gangue was separated from crude coal using a parallel plate free-fall separator are illustrated.

Sep 13, 2010

A rough simulated borehole has been developed for the installation and dynamic testing of rock bolts a the WASM Dynamic Test Facility. The rough simulated borehole is used for rock bolts that are sensitive to equipment installation technique or borehole geometry (particularly friction rock stabilisers and resin encapsulated bolts). An extensive axial test program has quantified a difference between the static and dynamic capacity (kN/m of embedment) for friction rock stabilisers once sliding starts. The 47mm split tube bolt has a 50% reduction in embedment capacity (but with significant variation) dissipating 2.7kJ/100mm of sliding per meter of embedment, and the Omega (inflatable) bolt had a 70% reduction in embedment capacity dissipating 6.2kJ/100mm of sliding per meter of embedment. The Omega bolt dynamic capacity remainder at least equivalent to the split tube bolt static capacity.

May 1, 2009

By George Bell

THE mine and milling plant of Demonstration Gold Mines, Ltd., is near the city limits of Baguio, Mt. Province, P. I. The mine road connects with the main highway to Manila. The nearest railway point is near sea level, approximately 40 miles distant. The Baguio district is very mountainous and has one of the heaviest rainfalls in the world. It is therefore difficult to maintain roads or to impound tailings and mine dumps. All supplies are trucked into the district direct from Manila or the nearest railway point, which means uncertain deliveries and high freight rates. Installation of equipment is difficult and costly. The average elevation at the mine is 4000 ft. and the climatic condi-tions.are ideal except for a three months rainy season. The company generates its own power for mining and milling opera-tions with three 400-hp. Ruston Diesel engines direct connected to 250-kw. General Electric alternating current generators. Labor conditions have been excellent, although at present social security laws are causing some unrest. Labor receives a higher average wage rate in this district than other labor in the Islands. The com-pany also furnishes free living quarters, hospitalization and work-men's compensation. Taxation has been reasonable up to the present time, but some of the new mining legislation may make it difficult to operate and pay dividends. The future depends largely upon the continuation of $35 gold and the political outcome in the Islands.

Jan 1, 1939

By C Fischer

The introduction of digital communications technologies into the underground mining industry, in both coal and hard rock mining, has enabled high bandwidth applications to be applied in the mining industry. Digital networks based on 802.11 b/g/n open Wi-Fi standards have allowed numerous applications to be run over a single communication backbone. One of the many important applications is the tracking of personnel and equipment via RFID Tags. This tracking application has formed the basis of a Proximity Detection System or Collision Avoidance System (Schiffbauer and Mowrey, 2001; Kent, Fischer and Schiffbauer, 2011) thereby improving safety and increasing control in the mining environment. This paper discusses the growth of digital technology as the backbone for communications in underground mining applications. This growth has allowed the ‘convergence of technologies’ (occurring in the general business world) to be available to mine operators in general and underground mine operators in particular. Mine Site Technologies’ involvement with major mining companies and mining equipment manufacturers (OEMs) in developing and supplying their communication systems is also discussed.The latest technical requirements and specifications for communication systems for underground and open cut mines will be reviewed.

Nov 22, 2011

By Leslie Burnside

Homestake Mining Co. set out to complete final reclamation at a former open-pit gold mine in west central Nevada. The goal was to exceed regulatory standards by satisfying the company's own high corporate standards for successful reclamation. Homestake's completion requirements challenged available technology due to the unsuitability of heap material as a growth medium, the harsh environmental conditions of the site and the region's lack of native growth medium. Accomplishing these goals required enlisting a multidisciplinary project team to develop, test and implement appropriate and cost-effective revegetation alternatives.

Jan 1, 1999

By D. Brandt

The Dos Pobres Mine is a copper oxide heap-leach mine located near Safford, Arizona. Mine production is 180,000 tons (163,293 tonnes) per day with a stripping ratio of 2:1. During the startup phase of the mine, the required fragmentation size was easy to achieve as the ore was highly weathered and fractured near the surface. As the mine depth increased, the proper fragmentation size became harder to achieve due to less weathering and different rock types. Because copper recovery increases as crusher product size decreases, achieving the appropriate product size at the crusher is the operating priority. The Engineering Department started a project to improve fragmentation through blasting and thus increase throughput in the crushing system. It soon became clear that input from other departments was going to be required to make this a safe and economical project. Therefore the Crush and Convey and Ore Control departments worked together to evaluate all available data on blast patterns and explosive loads and tracked performance and results. Using image analysis, Drill Energy Index and databases, we have been able to improve fragmentation size and verify the results while controlling costs.

Jan 1, 2011

By Sam S. Taylor

Subsurface disposal of oil-field brines was practiced in Oklahoma on a limited scale as early as 1925. The technique of subsurface injection has been improved immensely and has been applied with varying success in many oil-producing areas in Oklahoma, and elsewhere. This method of disposal, however, is only one of several methods available to operators of oil-producing properties, but, in contrast with usual methods of handling brines on the surface it eliminates the damaging effect of mineralized water on fresh-water supplies, vegetation, and aquatic and other animal life. Other methods of brine disposal approved by regulatory agencies in some States include (1) impounding in impervious ponds and solar evaporation, (2) controlled diversion into surface waters, and (3) recovery of the mineral salts of the brine. In most, States where oil is produced regulatory bodies authorize the use of one or more of these methods of brine disposal. In Oklahoma, for example, the Oklahoma Planning and Resources Board of the Conservation Commission has been authorized to adopt whatever methods or means may be necessary to prevent contamination by mineralization of all potable waters within the State.

Jan 1, 1942

Formation of either sodium jarosite or lead jarosite from concentrated chloride solutions containing small concentrations of sulphate has been demonstrated. Sodium jarosite is precipitated at 95-100°C from FeC13-FeCI2-NaCI-PbCI2 solutions to which was added Na2SO4 or Li2SO4 in amounts greater than 0.05 M. In the absence of alkali metal ions capable of forming jarosites, lead jarosite was precipitated from either FeCI3-PbCI2 or FeCI3-FeCI2-LiCI-PbCI2 solutions to which had been added small amounts of sulphate. Many of the factors affecting jarosite precipitation from chloride solution have been elucidated, and the most critical were sulphate concentration and initial pH. Concentrations of HCI in excess of O. I M essentially suppressed the production of jarosite in chloride media. Alkali jarosite, precipitated in the presence of dissolved lead, incorporates a small amount of this metal into the alkali jarosite lattice. Small but significant amounts of copper can also be incorporated into alkali jarosite and the amount is further increased in the presence of lead. Other divalent base metals such as Zn, Cd or Ni are not significantly precipitated. Sulphate control in either FeCI3 or FeCl3-NaCI leaching systems could likely be maintained by jarosite precipitation provided that the acid concentration of the solution was low.

Jan 1, 1981

By W. Dziurzynski

Transient states of the air parameters in mine workings occur as the effects of natural and technological disturbances, and in particular as a result of changes in ventilation conditions, caused by alteration of the mine workings geometry, state of fans performance or emission of gases. Particularly significant are those transient states caused by disturbances resulted from catastrophes, since they are frequently associated with violent phenomena that may be a danger for life and health of the staff working underground. The paper presents a number of examples of transient states of the air parameters in mine workings after a catastrophe, like the bump in the ZABRZE-BIELSZOWICE coal mine. Registration of air disturbances by the monitoring systems of ventilation in mine workings in the area of disaster both at the moment of a catastrophe occurrence and later during the rescue operation, enabled to track out the incident and identify the circumstances and reasons of those tragic events which caused death of 18 miners during last two years. Furthermore, computer simulations of processes occurring in mine ventilation network make effective research tools to be applied in practice, among others for the study of accidents and disasters.

Jan 1, 2003

By J. Kempken, T. A. Schreiter, R. Degel, H. Schmieden

Keywords: Pyrometallurgy, SMS Demag, Germany, submerged arc furnace, ferro alloys, non-ferrous, FeCr, FeNi, FeMn, copper, cobalt, slag cleaning, PGM, rectangular furnace After a short summary of the SMS Metallurgy part of the SMS group, the paper will focus on Submerged Arc furnace technology. After general aspects of furnace design, the focus will shift to different applications and their specific furnace requirements. Finally, a state-of-the-art design tool as well as a new invention to improve slag-cleaning technology will be featured.

Jan 1, 2006

By Bruce Vandenberg, R F. Chiappetta

"The High Speed 2D Analysis program allows the user to bring in data from several different sources. Of course, keyboard entry is included as a source. Other data is inputted through the serial port (X-2321 of the PC. Two types of data are transferred via the serial port. The first is the tablet digitizer data. The three types supported presently are the GTCO, tablet digitizers. and the Calcomp 2500 and 9100 series To transfer digitized data turn on the selected digitizer and place the cursor on the tablet. Enter the High Speed pmg.ram and select from the Input Program menu the Digitize Inputs(20) option and follow the instructions. TO exit the session, either a keyboard entry or a cursor button is pressed. The second type of serial port input Is from the collectors of the listed survey systems. Typically a file transfer program will be used to send the data from the collector to the PC. This topic will not be addressed at this time."

Jan 1, 1989

By Raúl Prebisch

Continuando con el análisis de la realidad latinoamericana, el presente texto señala los factores estructurales internos de la insuficiencia dinámica de desarrollo latinoamericano como la absorción productiva de mano de obra, el aumento de productividad y necesidad de nuevas inversiones, los motivos principales de la insuficiencia dinámica, acumulación de capital, el obstáculo de la tierra, el funcionamiento de la estructura social, la inflación y la estructura social, los tipos de capital extranjero y la planificación y funcionamiento del sistema económico.

May 1, 1964

By Y. El-Mossallamy

The piled raft foundation was extensive applied in the last two decades in different soil conditions e.g. in soft to stiff clay as well as in medium to dense sand and even in highly weathered rock. The piled raft is now applied not only to control the foundation settlement but also to minimize the required raft thickness to reach the most economic foundation design. An innovative application of the piled raft is its special adjustment to cases of foundations with large load eccentricities or very different loaded parts of buildings to avoid the need of settlement joints, which are especially complex below ground water table. Recently, the piled raft is applied for foundations of highway and railway bridges with special serviceability requirements regarding the allowable total and differential settlement as well as tilting. Actually numerical analyses are the mostly used design methods for piled rafts. For all day design practice a simple and modest design method is highly needed -at least in the first design stage- to check the feasibility of the piled raft on the specific project conditions. In this paper, a general overview on the recent innovative applications of piled rafts in Germany will be presented in a short overview. The results of the simple design method will be discussed and compared with the results of more enhanced numerical methods.

Jan 1, 2006

By R. J. Durrheim

The seismicity of the Witwatersrand Basin and Bushveld Complex has been analysed, revealing significant differences in source and damage mechanisms. A comparison of mining taking place at similar depths and extraction ratios indicates that the seismic energy release rate is considerably lower in the Bushveld Complex. Technologies introduced in the past decade to manage the risk of rockbursting are reviewed and assessed. These include geophysical methods to detect hazardous structures ahead of mining, new mining layouts and support systems, and the mechanization of in-stope processes. Despite important differences in geology, in situ stress, mining layouts and methods, there are many opportunities for the reciprocal transfer of knowledge, experience and technology between the gold and platinum mining sectors to improve the management of the rockburst risk.

Jan 1, 2005

By M. H. Stanczyk, I. L. Feld

Dewatering of typical Florida phosphate rock slime by electro - osmotic techniques was investigated to determine if a compacted , plastic solid product could be obtained with simultaneous recovery of the water for re - use . Tests with porous cathodes and rod - type anodes imbedded in dilute slime charges of up to 4 tons in weight showed that the slime could be dewatered to about 35 percent solids . The dewatered products had the consistency of modeling clay . In the large - scale tests using 2.5 - foot electrode spacings , about 21 kilowatthours of power were consumed per ton of water removed in thickening the slime from 17 to 25 percent solids , but the rate of water removal was so slow that the process was not considered commercially feasible . Other tests made with electrode spacings of from 2.5 to 8 feet showed that more rapid dewatering could be obtained but that the power required was excessive . However , for special uses such as stabilizing slime pond dikes where the cost of dewatering might not be a prime requisite , high voltages could be used to rapidly remove the water . Tests of 400 - pound slime charges using a combination of electroosmosis and vacuum filtration showed that the rate of dewatering could be expedited . The average power required to thicken a ton of slime from 15 to 35 percent solids was 5 and 50 kilowatt - hours when operating the electroosmotic filtration cell at potentials of 20 and 100 volts , respectively . calculated filtration area of about 10 square feet per ton of slime treated per day was required to thicken the slime from 15 to 35 percent solids .

Jan 1, 1964

By J. M. Cardoso, E. F. Quadros, A. Chiarini, F. Fernandes, G. Vilela, J. Ireno, L. C. Agostini

Based on the geological-geometric characterization of the basaltic rock at the site of a factory for chemical products situated in the Southern region of Brasil, and on results of a significant number of packer tests, the principal directions of flow were estimated, taking into consideration the intersection and the orientation of the joints and the amount of contaminant flow measured in each interval. The tests were performed using the multi-packer hydraulic multitest probe of IPT (HMTP) instrumented with an electric conductivity meter. A method of analysis for three-dimensional evaluation of the amount of contaminant flow in the area was proposed for future mitigation of the problem. Basé sur une caractérization géologique-géotechnique de la roche basaltique existant sur un site dune fabrique de produits chimiques située au sud du Brésil et sur les resultants dún nombre significantif déssais du type packer, les directions principales d´écoulement ont été estimées en considerant l´intersection et orientation des joints et la quantité de contaminant mesurée sur chaque intervale d´essais. Ceux-ci ont été realizes en utilisant une sonde multipacker developée au IPT – São Paulo (HMTP) instrumentée avec un mesureur de condictivité électrique. Une méthode d´analyse 3-D pour l´évaluation du transport du contaminant sur ce site a été proposée pour une future mitigation du problème. Auf Grund der geologischen Struktur des Basalts auf dem Gelände einer chemischen Fabrik in Südbrasilien und der Ergebnisse einer ansehnlichen Zahl von Pumpversuchen wurden die Hauptfließrichtungen bestimmt unter Berücksichtigung des Kluftgefüges und der in jedem Intervall gemessenen Menge kontaminierten Wassers. Die Versuche erfolgten mit dem im IPT entwickelten Verfahren (HMTP) mit Mehrfachpackern und elektrischen Leitfähigkeitsgebern. Ein analytisches Verfahren zur dreidimensionalen Ermittlung der Mengen kontaminierten Wassers wurde für die künftige Befassung mit dem Problem entwickelt.

Jan 1, 2003

By W. C. Blanchard

Time Domain Reflectometry (TDR) is a remote sensing technique using active backscatter. This technique is applicable to the testing for faults and multiple partial faults on cable. The battery operated hardware developed on this con¬tract has tailored this technique for testing of mining equipment trailing electrical cables. The processing of-t-he back-scatter is accomplished using a microprocessor. The visual output from the hardware to the operator is; the type, magnitude and distance to the cable fault in a numerical format. This greatly simplifys the use of this techniques for the operator.

Jan 1, 1980

By Sam S. Taylor

Disposal of brines produced with crude petroleum and natural gas is a continually increasing problem. The necessity for studying this problem has been realized more generally in recent years, and in August 1934 an agreement was made between the Kansas State Board of Health and the United States Bureau of Mines to conduct a cooperative technical study of methods of brine disposal. To date one paper in the technical press4/ and three reports5/6/ have been published in which are given results of studies carried on under this cooperative agreement. In the Mid-Continent fields, the methods used most generally for handling oil-field brines are: (1) Impounding in evaporation ponds; (2) controlled diversion into surface streams; and (3) injection into subsurface formations through wells assigned for this purpose. Various States recognize one or more of the methods as legally authorized procedure. Impounding brine in ponds and solar evaporation have proved inadequate as a general rule, owing, usually, to the porous nature of the soil, the low rate of evaporation, or both. Diversion, of

Jan 1, 1937