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By C. Larsen, E. Gratch, B. Flintoff, R. Bradburn

"In 1973 Brenda Mines Limited first investigated the potential use of a process computer to aid in the development of a control system for the concentrator grinding circuit. This initial study and its results are reviewed (1) in a previous paper.Since that time the computer system and its applications have been expanded. After the initial success of grinding circuit control, a second process computer was purchased to function as a back-up device. The two processors are currently operated in a foreground-background mode which allows extensive use of the computing facility for engineering and development work as well as operator training.Because of the relative ease of expansion, the computer has been incorporated into a flotation control system as well as an electrical peak power savings program.It is the purpose of this paper to review the successful application:; of the process computer and to indicate applications which are envisaged for the future."

Jan 1, 1978

The need for the hydraulic transportation of coal in the New South Wales coal industry, both from the coal face to the surface and from the coal mine to the consumer or the port for export, is explained. Details of research projects currently in progress and involving the hydraulic transportation of New South Wales coals are given together with information on the hydraulic transportation of coal in the United States of America. The potential of hydraulic transportation as a viable alternative to the proposed expansion and upgrading of the New South Wales railway system to meet the projected New South Wales coal production to the year 2000 is described.

Jan 1, 1980

By Marlos Henrique Alves Gomes

Aços resistentes ao desgaste são amplamente aplicados em partes estruturais que exigem propriedades como resistência mecânica, tenacidade e resistência ao desgaste abrasivo. O presente trabalho foi realizado devido à necessidade de desenvolvimento de materiais necessários para minimizar os efeitos causados pelo desgaste abrasivo. Os objetivos são: obter microestrutura multiconstituída (ferrita, bainita, martensita e austenita retida) por meio de tratamentos térmicos; e compará-la a microestrutura martensítica revenida. O aço estudado possui a seguinte composição química 0,26%C-1,13%Mn-0,92%Si-0,72%Cr- 0,29%Mo-0,18%Ni-0,17%Cu. Conduziu-se os tratamentos térmicos na sequência apresentada: recozimento subcrítico a 700°C, têmpera em óleo (temperatura de austenitização 940°C) e tratamento isotérmico de transformação bainítica (temperatura de austenitização de 820, 860, 900 e 940°C) ou recozimento subcrítico a 700°C seguido de têmpera/revenimento (940°C e resfriamento em água/250°C por 2 horas). Microscopia Eletrônica de Varredura (MEV) foi empregada para se avaliar a microestrutura do aço. Dureza Rockwell C foi utilizada com intuito de comparar a dureza das diversas microestruturas obtidas. Constatou-se que com a diminuição da temperatura de austenitização houve decréscimo do valor de dureza; e as amostras temperadas e revenidas demonstraram dureza média maior que as amostras que passaram por tratamento isotérmico de bainitização. A microestrutura multiconstituída foi obtida.

Aug 17, 2017

By Remo Grandori, Manfred Jaeger, Fabrizio Antonini, Luis Vigl

The EVINOS-MORNOS tunnel project with its 30 km of length is one of the longest hydraulic tunnel in the world realised with TBM method. The adverse geological conditions, the high cover and the short construction schedule were a great challenge for the successful construction of this tunnel. The paper will describe: the criteria adopted for the tunnel design, the selection of the construction methods and equipment, the productions of the 4 TBMs adopted and the comparison of the behaviour of the different type of TBMs in the various rock conditions, including special conditions, the characteristics of the adopted in situ and precast linings, a comparison between the foreseen and actual construction schedules, the contractual implications of realising a tunnel in such a severe and complex conditions.

Jan 1, 1995

The VoD of non-ideal explosives depends on the charge diameter and the thickness, strength and sound velocity of the confiner. VoD measurements are made to evaluate explosives for development, quality control and prediction of field performance. In testing, the container is part of the explosive system and affects the measured VoD. Pipe testing in cardboard tubes delivers the best guide to unconfined critical diameter and minimum VoD range, but the thickness of the pipes affects the result close to critical diameter, even in emulsions. PVC pipes are not good for unconfined test work because they provide relatively strong confinement. Care must be taken to select pipes with constant relative pipe area across the range of diameters. Where pipes are used to evaluate the effect of confinement, the ratio of the wall thickness relative to the thickness of the detonation driving zone in the explosive needs to exceed 0.5 to create full confinement and the ratio of the detonation velocity to the confiner wave speed must be considered. Estimates for critical thicknesses are provided from Non-Ideal detonation models. The relationship between confinement modulus and VoD is discussed and indexes are suggested for quantifying the explosive performance.

Jan 1, 2007

By J. Osterberg

A new device has been developed for load testing driven piles and drilled shafts which consists of an hydraulic jack or bellows which has a telltale rod fastended to the bottom. The rod extends upward to the surface through a pressure pipe. When pressure is applied, the jack or bellows expands, applying an equal upward and downward load at the bottom. The downward movement at the bottom is indicated by the rod and the upward movement is indicated by the movement at the top. Thus, upward and downward load-deflection curves can be drawn. As load increases, failure will occur either in end bearing or friction. Results of field installations are described. Total loads of up to 1,100 tons metric have been used. The method obviates the need for the reaction load required for the conventional pile loading test and separates friction and end bearing. It is especially advantageous for use over water, in crowded spaces and for inclined piles.

Jan 1, 1989

By R. H. Oitto

To determine whether reflectors could substitute for the trip lights referred to in the Federal Mine Safety Code, the Bureau of Mines studied trip safety devices under simulated haulageway conditions. The noticeability of reflectors compared with trip lights and fluorescent panels was evaluated from distances of up to 850 feet with light source intensities of up to 1-6 foot-candles (ft c). Reflectors tested consisted of a reflective lens in a holder secured to a frame that can be attached to a trip. Reflectors were found to be suitable for use as a trip safety device. In fact, for the conditions in many underground haulageways some reflectors would be more effective than a permissible trip light.

Jan 1, 1968

By Ji-He Wei

Keywords: stainless steel, AOD refining, side and top combined blowing, mixing characteristics, water modeling The fluid mixing characteristics in the bath during the side and top combined blowing AOD (argon-oxygen decarburization) refining process of stainless steel have preliminarily been investigated on a water model unit of a 120 t AOD converter. The geometric similarity ratio between the model and its prototype (including the side tuyeres and the top lances) was 1:4. On the basis of the theoretical calculations for the parameters of the gas streams in the side tuyeres and the top lances, the gas blowing rates used for the model have more reasonably been determined. The influence of the tuyere number and position arrangement, and the gas flow rates for side and top blowing on the characteristics has been examined. The results demonstrated that the liquid in the bath underwent vigorous circulatory motion during gas blowing, without obvious dead zone in the bath, resulting in a well mixing effectiveness. The gas flow rate of the main tuyere had a governing role on the characteristics, a suitable increase in the gas flow rate of the subtuyere could improve mixing efficiency, and the gas jet from top lance could make the mixing time prolong. Corresponding to the oxygen top blowing rate specified by the technology, a roughly equivalent and good mixing effectiveness could be reached by using six side tuyeres with an angle of 27 degrees between each tuyere, and five side tuyeres with an angular separation of 22.5 or 27 degrees between each tuyere. The relationships of the mixing time with the gas blowing rates of main-tuyeres and sub-tuyeres and top lance, the angle between each tuyere, and the tuyere number have been obtained.

Jan 1, 2005

By D Brett

"Mine waste storages including tailings dams and waste rock dumps represent arguably the biggest risk on a mine site from both physical and geochemical viewpoints, related firstly to structural stability and the consequences of failure and secondly from potential on-going seepage or run-off of acid and metalliferous drainage (AMD). The risks are most likely to increase during operations and continue through the closure and post-closure phases, with the waste storages likely to be the most difficult features to resolve in the mine closure process. Contaminated water quality from tailings dams and waste rock dumps can require treatment "in perpetuity" at a cost of hundreds of millions of dollars. The problem is increasing with ever larger mine operations and waste generation volumes. This paper identifies leading practice methodologies in planning and operating mines and process plants to minimise the risks from tailings storages and how this might also affect waste rock management and even the design of mine excavations. These methodologies require a "big-picture" approach to develop an understanding of the overall issues and identify synergies between the different operational areas on a mine site that can reduce overall risk. With a conservative approach and realistic allowance for future costs it is possible to facilitate decisions at the mine planning stage that can reduce risk and save cost over the long term. This is in contrast to the common approach where each operational area is looking to minimise its own costs with a short-term view. Incorrect mine methodologies can be developed by allowing net present value (NPV) accounting methods to trivialise future closure issues.Methodologies discussed include: Integrated Waste Management - Significant structural improvements to tailings dams can be achieved if the structures can be incorporated into the waste rock dumps. Risk of AMD can also be reduced by utilising the tailings and waste rock effectively. This could go even further to consider the placement of wastes to limit mine void environmental issues; Process Optimisation - Water quality and the nature of potential tailings dam structures can be highly influenced by the geo-chemistry of the tailings. This can be modified by processing, where simple changes such as maintaining separate streams of geo-chemically different tailings rather than recombining them or by initiating further processing to remove problematic minerals such as sulphides; Enhancing Geophysical Properties - The geochemical performance of waste repositories can be greatly influenced by the geophysical properties of the stored materials, particularly the air-water characteristics, which are influenced by particle size, density and permeability. The geotechnical properties can be enhanced by strategic paddock dumping, blending and compaction.These methodologies are demonstrated by case histories.CITATION:Brett, D, 2013. Mine waste risk minimisation by integrated waste management and process optimisation, in Proceedings MetPlant 2013, pp 247-258 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 15, 2013

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

By Tianfei Liao

Extensive site investigations revealed that abandoned shallow mine workings exist under a site planned for construction of a major new facility. Since the mine voids were susceptible to collapse, they were stabilized by grouting. After completion of the mine remediation, three types of deep foundations (micro-piles, auger-cast piles, and drilled piers) were considered for this site. Micro-piles spread the load via the bond between the pile and the bedrock. Without significant length socketed in rock, the axial load of auger-cast piles and drilled piers has to be concentrated on end bearing. Although spreading the load is preferable in this environment, economic consideration dictated the choice of drilled piers for construction.

Jan 1, 2009

By Liu Run, Jia Zhao-lin, Yan Shu-wang

"Piles with diameter larger than 2m in engineering can be defined as large diameter pile, and piles used for oil platform foundation in Bohai Gulf, are usually over 100m long and 2m in diameter. Such long piles have to be manufactured by segments before installation, because of transformation and hoisting difficulties. The segments of the pile are assembled by welding during installation one to another. Normally, assembling two pile segments takes one day or even a longer time, which mainly depends on construction conditions. After pile segment assembling, it proves to be difficult to restart the successive penetration. The mechanism of pile refusal is discussed and the process of driving a segmented pile is simulated with a finite element program. The calculating results show that, when the stick-up stability was satisfied, increasing the length of the last segment of the pile and assembling the pile segments when the pile tip penetrates into a clay layer could greatly ease the difficulty of driving the pile. Furthermore, cutting down the pile extension time is also one of the most effective measures to minimize the refusal risk.1. InstructionIn recent years, more and more oil platforms with six or eight legs have been adopted in Bohai Gulf, China. The leg piles with diameters of 2m or more have to be driven to about 100m below the sea bed. Such long piles have to be manufactured by segments before installation, because of transportation and hoisting difficulties. The segments of the pile will be assembled during installation, in which a successive segment will be attached to a formerly penetrated one by welding (Fig.1). The assembling work often takes one day or even a longer time."

Jan 1, 2014

By Arndt C. R

The Ispat Mexicana SA de CV (IMEXSA) pelletising plant is located at Lazaro Cardenas on the west coast of Mexico. It is the primary source of feed stock for the adjacent direct reduction (DR) plants and steelmaking facilities. The initial design of the pellet plant began in 1981 for 3 Mtpa of DR grade pellets using local concentrate received by pipeline.' Several construction delays, an ownership change, and a decision to use imported concentrates delivered in 60 000 to 90 000 tonnes ship cargoes required flowsheet modifications and additions. The design concepts are described for the plant which includes concentrate regrind to final pelletising particle size.

Jan 1, 1999

By Haigh J. E

An accurate measure of the earth's magnetic field can be made in a few seconds with the portable proton precession magnetometer. Such an instrument increases the applicability of the long successful method of magnetic prospecting for minerals. As an example of the usefulness of the proton magnetometer, a survey over volcanic rocks near Apsley (Tas.) was made.INTRODUCTIONA completely portable magnetometer whose operation is based on the free precession of polarized protons in the earth's magnetic field, is now available on the market at a price competitive with magnetometers based on the classical physical principles. The ease, accuracy, rapidity, and reliability with which measurements of the earth's total magnetic field can be made with the proton precession magnetometer, led to the try-out of the instrument in an actual field problem so as to evaluate fully the capabilities of the instrument. Such evaluation is important, because the history of magnetic prospecting has shown that whenever significantly improved instrumentation has been introduced, prospecting costs have been substantially cut and many areas in which the prospecting costs were formerly considered excessive in relation to probable returns, have become economic mineral prospects. The proton precession magnetometer offers the possibility of opening up new areas for successful magnetic prospecting.AN OUTLINE OF THE HISTORY OF MAGNETIC PROSPECTINGWhile an outline of the history of magnetic prospecting is not directly connected with the evaluation of a proton pre...

Jan 1, 1963

By P. K. Das, S. K. Singh, C. C. Chang, E. C. Wang, R. B. Roberts

As part of the New York City’s redevelopment of the far west side of mid-town Manhattan, this project will add 1.5 miles of twin bored tunnel to No. 7 Subway Line. The proposed alignment extending from the Times Square Station west beneath 41stStreet turning south under Eleventh Avenue and terminating at 25th Street will include two new stations. The tunnels and station caverns will be primarily constructed in the Manhattan Schist, and will pass in close proximity to several major overly ingstructures. This paper discusses the lithology and structural discontinuities of rockmass along the project alignment, tunnel and cavern rock loading, groundwater hydrology, groundwater quality, groundwater treatment and sustainable design.

Jan 1, 2005

By R A. Lynch, D A. Malovichko

The implementation of routine real-time micro-seismic monitoring of open pit mine slopes has been discussed. Some examples of seismic arrays have been given, and a recommendation of suitable seismic sensors made. Unfortunately near-surface sensors are required for good location accuracy, and the effects of reflection, mode conversion and surface waves must be accepted and compensated for during processing of the seismograms. It makes sense that mining at the base of a slope and levels of seismic activity within the slope should be related, and this is confirmed using both 2002-2003 and 2005 seismic data recorded at Navachab mine. An example of how seismic data can be used to gain information about seismically active geological structures has been described. The removal of broken rock, and not blasting nor the breaking of supporting rock, has been found to cause slope micro-seismicity. While the standard Brune source model is suitable for some 20% of the seismic events, unreasonable results are obtained for the rest. A moment tensor inversion has been performed after S-wave splitting and surface effects have been filtered out. This approach confirms a predominantly shear mechanism for a typical high frequency source.

Jan 1, 2006

By S C. Dominy

This contribution examines the effect of feedstock sampling before the sorting stage of polyethylene terephtalate (PET) bottle recycling. Batches of waste PET bottles may contain non-PET bottles which need to be removed by sorting. Any residual presence of PVC is detrimental for the quality of products manufactured from recycled PET. The maximum tolerated concentration of PVC in cleaned PET is extremely low, which places high demands on the recovery of PVC achieved by sorting. To be confident of attaining the desired PET quality after sorting, acceptance sampling of truckloads of PET bottles may take place prior to sorting. It is shown that accounting for sampling uncertainty requires that the sorting process achieves a consistently high recovery of PVC bottles.CITATION:Glass, H J and Dominy, S C, 2017. Plastics recycling and sampling, in Proceedings Eighth World Conference on Sampling and Blending , pp 129–134 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By B. C. Lewis

Have technological advancements in underground coal mining driven people's skills to new highs or have the expanded skills of mining people driven the industry's technological advancements. Who knows? What we do know is that both our technology and our people have made meaningful and significant advancements. Overall, longwall systems continue to increase productivity and retreat faster. Globally, gate road development is the primary bottleneck in a longwall mine. The primary bottleneck in gate road development is roofbolting. Generally, roofbolting is the bottleneck in room and pillar operations as well. This paper will present an integrated manufacturer's (Joy Mining Machinery) vision of the future in comparison to current equipment performance. Particular emphasis will be placed on roofbolter technologies.

Jan 1, 1999

By Magnus Ruin

The dry deep mixing method for stabilization of soft soil has been used in the Scandinavian countries for 25 years. The typical application has been stabilization of soft inorganic clay. Today the method is used more frequently in organic soil with good results. The Limix System, introduced in the USA by Hercules Grundläggning AB and TREVIICOS Corporation, is a cost-effective dry deep mixing method used to stabilize most types of soft soil. This paper presents the general principles of stabilizing organic soil with the dry mix method and two case histories of soil stabilization projects in organic soil. Between October 2000 and June 2001 the Limix System was used in England to stabilize soft organic alluvium at the Channel Tunnel Rail Link, Contract 440. During year 2000 the Limix System was used in soft organic soil in Holland near the Groene Hart Tunnel entrance to support trench excavations for slurry walls and concrete barrettes.

Jan 1, 2001

By Jack F. Harang, P. B. Leavenworth

Development during the year 1941 on the Texas Gulf Coast resulted in the dis covery of 27 new fields as compared to 26 fields for the year 1940. Drilling.—During the year, 1405 wells were drilled. Of this number, 1031 were completed as oil wells with 375,000 bbl. daily of new production; 50 were com pleted as gas wells and 324 were failures. The most active area was Jackson County, where 375 wells were drilled and 336 of them accounting for 190,000 bbl. daily of new production. Types of Fields.—Of the 2 7 new fields, 14 are considered to be oil fields, 8 are listed as gas-distillate fields and 5 as gas fields. This may be compared to 26 fields found in 1940, of which 14 were oil fields and 12 gas-distillate fields. Producing Sections.—Frio discoveries retained their predominant position by having 10 Frio fields discovered in comparison to 6 fields in the Wilcox, 4 in the Yegua, 5 in the Miocene and 2 in the Jackson. In the previous year 15 Frio fields were found, 4 in the Wilcox, 2 each in the Yegua, Cook Mountain and Miocene, and I in the Jackson. Production.—Production increased over 1940 approximately 10 per cent, being 113,726,893 bbl. for the year 1941 and 104,127,247 bbl. for 1940. The statistics in Tables I and 2 include distillate and condensate as oil production because no separate reports have been compiled. It is hoped that this separation may be possible some day, but as a great many fields produce both oil and distillate and these arc commingled in pipe lines, separation of statistics will be more difficult than for other areas. New Fields Big Hill, Jefferson County.—Stanolind Oil and Gas Company's No. I George D. Anderson was completed as a gas well from a Frio sand at 8705 to 8720 ft., on Dec. 24, 1941, after having been drilled to a depth of 9500 ft. Additional development is being carried on but it is not possible to evaluate this discovery at this time. Brushy Creek Field, Lavaca County.— Shell Oil Corporation's No. I D. G. McManus was completed as the discovery well in the Brushy Creek field on Oct. 29, 1941, from a Wilcox sand through perforations at 7225 to 7230 ft., making gas and 180 bbl. of 59° gravity distillate. This well was bottomed at 10,998 ft. in the Wilcox. No statement can be made at this time as to the importance of this discovery. Chenango Field, Brazoria County.—J. N. Rayzor et al. completed their No. I Sarah J. Christian through perforations at 8564 to 8572 ft. in a Frio sand, for 453 bbl. of 37.7° gravity oil, on Feb. 6, 1941, after having drilled to 9564 ft. Several wells were drilled in this area during the year but failed to establish important production. This is considered a minor discovery. Clodine Field, Fort Bend County.—Providence Oil Company's No. I Hatfield was the discovery well of the Clodine field, being completed through perforations at 7499 to 7502 ft. for 108 bbl. of 51.2° gravity distillate, on June 19, 1941. The well was bottomed at 8090 ft. Several wells

Jan 1, 1942