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This paper describes new research and development currently being undertaken by the CSIRO Mining Technology Group to advance the automation capability of continuous mining equipment in underground coal mining operations. The effort aims at increasing the overall rate of roadway development as well as providing a safer working environment for underground mine personnel. The activity is funded by the Australian Coal Association Research Program (ACARP) and forms part of a larger underground development initiative, known as the CM2010 project. The CM2010 is managed via a consortium of leading mining industry representatives through the Roadway Development Task Group (RDTG). The Task Group has identified three research areas requiring new development in order to realise the CM2010 project objectives: self-guiding (autonomous) continuous miner capability, an enhanced drilling and bolting process and improved mesh deployment. CSIRO's primary role in the CM2010 project is in the development of the autonomous continuous miner guidance capability.This paper reports on outcomes achieved at the half-way mark of a three year research and development project. It details the technical developments undertaken towards demonstration of a 'self-steering' capability to enable a continuous miner to automatically maintain a given mining heading and mining horizon under production conditions. A primary technical requirement of this automated functionality is the means to accurately determine both the location and orientation of the continuous miner in real-time. Testing and validation of the guidance system solution has been implemented using a combination of an instrumentation-grade inertial navigation unit and radar technology. Comprehensive performance evaluations have been conducted using a scale skid-steer mobility platform known as the Phoenix. Results achieved to the present stage of the project are highly promising and suggest that an automated self-steering functionality is achievable under production conditions. This new outcome represents an important move towards implementing a step change improvement for future underground roadway development.

Dec 6, 2010

By Patrick R. Stephenson

The current version of the JORC Code was issued in 2004 and since that date the Australian Securities Exchange, in collaboration with JORC, has issued a number of companies? updates to provide guidance on various reporting issues. An interim review will be undertaken during 2010 to meld these updates with the current 2004 Code. This will be followed by a full review during 2010/11 covering all aspects of the Code and focusing particular attention on: ? clauses / guidelines relating to Exploration Results1, exploration targets and the reporting of historical estimates; ? issues relating to the Public Report2, including definition, the requirements for Competent Person sign-off, level of disclosure and mandatory requirements; ? guidance on techniques to quantify resource / reserve estimation uncertainty; ? the level of study required to convert Mineral Resources to Ore Reserves, and disclosure of prices and economic factors; ? expansion of the requirements for reporting of marketable material for bulk commodities; ? the use of language and tone that anticipates new and emerging technologies and techniques for the qualitative and quantitative measurements of data; and ? linkages to valuation and the valuation code (The VALMIN Code). Although the Canadian and Australian reporting regimes for public statements on Exploration Results, Mineral Resources and Mineral (Ore) Reserves are similar in intent and coverage, they differ in detail, sometimes substantially. Canadian requirements are generally more wide-ranging and prescriptive than Australian requirements, including in the need in many situations to publicly lodge a Technical Report, a requirement that does not exist in Australia. Australian-listed companies seeking to list in Canada, and Competent Persons seeking to act as Qualified Persons in Canada, need to ensure that they are fully conversant with Canadian regulations and how they differ from those in Australia.

May 1, 2010

By A. O. Drysdale

In Canada, the market for cement is not a national one but rather a collection of local or regional markets. Excess capacity on a national basis does not necessarily preclude a shortage on a regional basis. with portland cement selling for less than a cent a pound, the low price-to-weight factor makes transportation to the market a major cost item and thus a small plant can be justified to serve a limited regional market. The Brookfield plant of the Canada Cement Co. is designed to supply the Province of Nova Scotia, a regional market that shows promise of growing to a point where it will support a one-kiln plant. The market is presently being served by boat shipments from the Canada Cement Co. plant at Montreal East, Quebec, and from the North Star Cement Ltd. plant at Corner Brook, Newfoundland, and by rail and road shipments from the Canada Cement Co. plant at Havelock, N. B.

Jan 4, 1965

By Gabriel Pessoa Vilas Boas

O presente artigo apresenta um estudo sobre a mistura do nióbio em chapas de alumínio pelo processo Friction Stir Welding (FSW), levando em consideração o efeito de forjamento envolvido na soldagem. O processo FSW, consiste em utilizar uma ferramenta rotativa que em contato com o material a ser soldado gera atrito, provocando aumento de temperatura e deformação plástica. O aquecimento gerado é abaixo do ponto de fusão dos materiais envolvidos, por isso é considerado como solda em estado sólido. Para alcançar os objetivos desta pesquisa, conta-se com a colaboração da Companhia Brasileira de Metalurgia e Mineração (CBMM), que forneceu amostras de Nióbio Metálico em cavaco para proceder aos experimentos deste artigo. A amostra adquirida foi triturada manualmente, em seguida, cominuido em moinho de bola para obtê-lo em forma de pó, viabilizando, assim, a inserção na junta a ser soldada. O nióbio foi colocado entre dois metais de base de Al-Mg 5052F que foi soldado pelo processo FSW, em uma máquina adaptada para esse processo. Após a soldagem foi feito a metalografia na seção transversal onde observou-se uma boa mistura do nióbio no metal soldado. Além disso, foi analisado a microestrutura formada e a composição química através do microscópio eletrônico de varredura (MEV).

Oct 30, 2017

By Christopher M. Kenney

Augered-cast-in-place (ACIP) piles have been utilized on commercial projects throughout many parts of the country for years, but are only beginning to be scrutinized for use on major infrastructure projects and other critical structures in some regions. Numerous engineers are aware that ACIP piles are an economical foundation alternative, and many technical papers have been presented that provide reliable methods of estimating ACIP pile load capacity. However, designers may not yet appreciate that the load-settlement behavior of ACIP piles is very similar to that of drilled shafts. This paper analyzes ACIP pile case histories from throughout the country and demonstrates that ACIP pile settlement under applied load is consistent, predictable, and very similar to the documented behavior of drilled shafts. This paper also presents a simple but accurate method of estimating ACIP pile settlement at the design load, and illustrates the need to estimate the equivalent diameter of the as-built ACIP pile when estimating pile behavior. Finally, this paper presents back-calculated values of the drained elastic modulus from the ACIP pile case histories that may be useful to those using more sophisticated methods of estimating ACIP pile settlement.

Jan 1, 2001

By J. D. Dixon

This Bureau of Mines report describes a technique for determining the confining pressures that must be provided for stabilizing underground openings in incompetent rock. The technique is adapted for use with a nonlinear finite-element computer code, NONSAP, to obtain stabilization pressures for linear or nonlinear stress distributions in the rock media around the excavation. This analysis permits a point-wise calculation of active rock pressures that depend on the values of shear stress and strength along the excavation surface. The approach is applied to the solution of several sample problems. The results show that both the magnitude and the distribution of stabilizing confining pressures are significantly influenced by rock and joint strengths, joint orientation, and biaxial nature of the load field.

Jan 1, 1976

By R. John Caulfield

The primary water supply system for the City of San Francisco and adjacent peninsula areas consists of aging and deteriorated pipelines crossing under the San Francisco Bay (the Bay). This system is highly vulnerable to seismic damage from the nearby San Andreas and Hayward fault zones. The Bay Tunnel Project will replace the existing system with a 8-km-long (5-mi-long) tunnel underneath the Bay. The tunnel will be constructed using earth pressure balance methods and will have a two-pass lining system of precast concrete bolted, gasketed segments for initial support, and a welded steel pipe final lining. The project challenges include tunneling through both soft ground and rock conditions without any intermediate shaft access over the entire alignment. Seismic performance criteria include maintaining service flows after a large earthquake.

By Joseph W. Horne

This report presents the results of an investigation by the U. S. Bureau of Mines in cooperation with the State of Colorado, on the yields and properties of oils produced from oil shale, lignite and subbituminous coal using the standard assay method developed by the Bureau for oil-shale testing,. The purpose of this work, which is part of the general study of oil shales being conducted by the Bureau of Mines and cooperating agencies, was to obtain information on the amount and character of the yield of crude oil or tar from different typical oil shales, the yield of light oil or naptha that might be suitable for use in motor fuels, and other products of shale oil. As the west has large resources both of oil shale and low-grade non-coking coals, it is of interest to know the relative yields of tars, light oils, and combustible gases that can be produced from these coals when retorted under conditions similar to those suited for oil-shale retorting. Source of Samples The coal samples were obtained from deposits on or adjacent to the public lands in the States of the Rocky Mountain region. Many of the mines sampled are operating under Government leases or permits. The number of coal samples secured from the various states are: Colorado, 6; Montana, 9; north Dakota, 6; New Mexico. 1; South Dakota, 1; Wyoming, 9. Of these samples, 14 were lignite coal, 16 subbituminous coal, and a bituminous coal. The standard channel method of the Bureau of Mines was used for sampling. Coal samples received at the Boulder Office weighed about twelve pounds each, and duplicate samples were sent to the Pittsburgh Station for proximate and ultimate analyses. The origin of the samples and description of the deposits are given in Table 1.

Jan 1, 1927

By José Antonio Enríquez

El presente texto describe las características estructurales y estratigráficas de los yacimientos epitermales de baja sulfuración en el corredor estructural de San Pablo en Porculla, Cajamarca. En este sentido, el corredor se relaciona a un sistema de fallas regional que tiene rumbo general NW-SW y está segmentado por fallas transformantes de dirección NE-SW, que limitan bloques estructurales. Asimismo, sobre este corredor estructural se ubican en forma alineada una serie de yacimientos epitermales del tipo baja sulfuración. Los yacimientos están controlados por fallas de dirección NW-SE y contienen mineralización en vetas y mantos con relleno de cuarzos, calcita y baritina con importantes valores de oro y oro-plata y las estructuras menores relacionadas a las fallas transformantes. Finalmente, estos yacimientos pueden constituir un nuevo e importante objetivo de exploración por minerales de oro – plata del tipo bonanza.

Sep 12, 2005

In a gravity separation device, particle shape, size and density all play a role. The combination of these determines where each individual particle reports to in the viscous fluid, where particle crowding (solids to water ratio) also plays a role. To understand the performance of gravity separation devices in the heavy mineral industry, these particle characteristics need to be measured. There are various challenges in analysing particle density and particle size simultaneously for the purpose of quantifying gravity separator performance, not to mention particle shape. These analytical challenges include the high cost of high-density sink-float fractionation, toxicity of high-density sink-float media, inability of sink-float media to fractionate at densities greater than 4.0 g/cm3, and the time-intensive nature of these fractionations. The use of the detailed particle-by-particle output from Qemscan® particle mineral analyses (PMA) as a fast and cost-effective alternative is evaluated. The size and density outputs from the Qemscan® were employed to characterize the performance of a heavy mineral spiral concentrator as an example. Critical analytical requirements are to be addressed before the Qemscan® output data can be utilized. Keywords Gravity separator, performance, heavy minerals, Qemscan® particle mineral analysis

Jan 1, 2011

By J. D. Clendenin

Systematic practices for protecting crops from frost damage began in the United Metes more then 40 years ago when the Weather Bureau Fruit-Frost Warning Service was organized; however, various practices employed in frost protection are centuries old. Although there are areas where little doubt exists as to whether protection is needed, there are also circumstances where there is some doubt as to the need for frost protection. Many factors influence this, including not only critical temperatures but also the maturity dates of the crops relative to marketing. Critical temperatures for frost damage to trees, plants, blossoms, and fruits very with weather, plant variety and nutrition, and stage of growth. In the case of truck crops, a single night of protection from frost injury might yield big dividends with a variety of sweet corn or tomato that matures early while price is high yet be worth very little with a midseason or late-maturing variety. Consequently, it is the individual grower who must decide whether to use frost-protective measures on the basis of his returns, the quantity and quality of his crop, the marketing situation, the sensitivity of his crops to frost damage, and the frequency of damaging frost in his area.

Jan 1, 1955

By M. B. Balachandra

A three-dimensional finite element analysis was performed of an instrumented section of a double-entry coal mine in order to provide a comparison between field measurements and existing analytic techniques. The BMINES computer code was used to perform the analysis. The sequence of excavation of the entries was considered, as well as the installation of rock bolts and cribbing during the mining cycle. The materials In the region under investigation were idealized into four rock types and coal. The rocks were assumed to be isotropically elastic, perfectly plastic. Coal was represented by an elastically anisotropic (transverse isotropy) and plastically isotropic model. A fracture yield criterion of the Coulomb form was used for all materials. The strength and stiffness of all materials were substantially reduced from available laboratory data to account for in-situ properties. Qualitative trends and stress distributions obtained from the calculation were found to be reasonable. However, computed displacements and closures were greatly exaggerated and an excessive degree of inelastic deformation was indicated in the coal, especially adjacent to the excavated faces. It was established that both these effects were the result of an excessive reduction in the strength and stiffness of the materials. The analysis underscores the need for three-dimensional calculations by identifying a number of important structural response parameters that would be either outside the scope of, or misrepresented by, two-dimensional analyses. The analysis also emphasizes the need for comprehensive and accurate measurement of material properties in order fully to exploit the power of the analytical techniques to generate reliable predictions.

Jan 1, 1976

By Bruno Gemmi

A new warehouse built with prefabricated components over an area underlined by soft marine soil deposits started showing differential settlements well before its completion. Its 103 spread footings carrying up to 4,000kN (450t) axial loads had been cast on jet-grouted columns extending and penetrating a layer of sand at a depth of 10m (33ft). Investigations performed to assess the wholeness and consistency of the jet-grouted columns revealed a state of loose jet-grouted masses and uncontrolled, off target migrations of the jet-grouting. Most of the jet-grouting itself was settling. The following remedial solutions were suggested: 1. Construction of new and better controlled jet-grouted columns. 2. Cement-based soil grouting. 3. Expanding resin injections. 4. Minipiles drilled-through the existing footings and reaching into a denser layer of sand existing at 23m below grade. Remedial solution 1. was immediately discarded due to cost and the possibility of a repeating failure in this non-granular and highly compressible soil. Tests of remedial solutions 2. and 3. were carried out. The outcome of the grouting was monitored by Electro Resistivity Tomography (ERT) (Bares et al., 2003), an innovative 3D electro tomography procedure showing where grout had been actually placed and its migrations off target. A successful 4,000kN (450t) load tests confirmed the validity of the solution. Finally, upon the completion of a successful load test, solution 4. was chosen. It supplied the highest degree of reliability thanks to the ease of controlling the final and actual location of the minipiles and to the higher safety factor provided. All remedial work to install the minipiles was eventually performed inside the building. Additional load tests and settlement measurements confirmed the adequacy and success of the chosen solution.

Jan 1, 2011

By W. H. Schiffbauer

NIOSH has developed an active proximity warning system called HASARD (Hazardous Area Signaling and Ranging Device) for warning workers as they approach known dangerous areas around heavy mining equipment and other dangerous work zones. HASARD is composed of a transmitter and a receiver. The transmitter generates a 60-kHz magnetic field using one or more wire loop antennas. Each antenna is adjusted to establish a magnetic field pattern for each hazardous area. The receiver, worn by the worker, is a magnetic field strength meter. The received signal is compared against preset levels which are calibrated to identify levels of danger. The receiver outputs can include visual, audible, and vibratory indicators and it can also be made to disable machine functions. HASARD was field tested on a Joy 12 continuous miner, a Komatsu 210 M Haulpak, and on a highwall launch vehicle. Slight modifications were made for each application. HASARD provided warnings as designed and proved to be rugged enough to withstand the harshest of production environments.

Jan 1, 2001

By S. K. Kawatra

Outokumpu Electronics has designed a new on-line coal slurry ash analyzer, based on an instrument developed at Michigan Technological University. The primary goal was to build an accurate instrument at the lowest possible cost. The instrument determines ash content from measurements of x-ray backscatter, iron Ka fluorescence, and low-energy y-ray absorption. It is capable of measuring the ash content with a standard error of 1.1% ash over an analysis range of 9-21% ash and 7-22% solids. The analyzer was tested on coals from United States, Poland, Great Britain and the USSR.

Jan 1, 1992

By R. K. Agarwal

In this paper, a new technique developed to analyze two-dimensional nonhomogeneous models is described. A simple three-layered medium with a circular hole centrally located in the intermediate layer is considered. The layered sheet is loaded uniaxially perpendicular to the stratification. The Young's modulus of the intermediate layer is lower than that of the outer layers. The stress distribution around the circular hole in a stratified medium is significantly different when compared to the case of a continuous homogeneous medium. The distribution depends upon the ratio of the height of the intermediate layer and the hole diameter. A comparison of stress distribution and procedures for preparation and testing of the model are given. The potential of the technique is outlined. In the process of applying the techniques of stress analysis to problems of rock mechanics, the recent discernible trend has been to postulate highly idealized models of physical situations. As new techniques have been developed, more complicated models have been conceived to simulate mote accurately the physical environment to which the analysis results are eventually applied. In this investigation, a new technique is developed to analyze two-dimensional nonhomogeneous models. The technique is used to determine the stress concentration around a circular hole in a soft material overlain and underlain by a hard material. In mining practice, such situations arise commonly in coal deposits and frequently in bedded or vein-type metallic mineral deposits. DEFINITION OF THE PROBLEM A plate, consisting of three layers with a circular hole in the intermediate layer, is loaded uniaxially, Fig. 1. The variable in the experimental investigation is the height of the intermediate layer, H. The diameter of the hole, D, is kept constant. The stress concentration factors around the periphery of the hole, for various values of H/D, are evaluated using the technique of photoelasticity, Table I. TECHNIQUE OF EXPLORATION Photoelastic analyses of composite models have hitherto been limited to the study of lap and butt joints between glued metals and dissimilar materials.1-3 In mining, Haber and Oudenhoven used composite models to study the stress distribution around a circular hole in two-layered media and the behavior of elastic liners in shallow underground openings.4-5 They used the stress freezing technique devised by Dally et a1.6 The procedure used in this investigation is outlined below: Casting of Layer A: Flat sheets of plastic were cast in a silicon-coated mold using Araldite 502 with hardener 951 in the ratio of 100:8 by weight. After

Jan 1, 1969

By G. M. Steed, A. O. Oyinloye

The deposit lies in amphibolite-facies biotite granite-gneisses of Proterozoic age, 4 km east of a major crustal break known as the Ifewara-Zungeru fault. Gold mineralisation is contained in a zone of quartz-carbonate (mainly calcite) veins and hydrothermally altered gneisses with associated small-scale intrusions along a steeply dipping second-order fault zone that roughly parallels the main fault. Gold is present mainly at grain boundaries between quartz and carbonate as discrete particles up to 100 micrometres in size, in general association with sparse, scattered pyrite, pyrrhotite and some base metal sulphides. Adjacent to the gold-bearing zone the granite-gneisses have been hydrothermally altered with minor volume increase, most notable enrichment being in K2O, S, Pb and Cu (and Au). High concentrations of Th, Y, Ce and Zr in the granite-gneisses imply derivation from S-type granites. It is likely that their high heat production capacity maintained the high temperatures needed to transport gold in the hydrothermal systems. It is most probable that the mineralisation dates from the Pan-African orogeny (650-450 Ma)

Apr 1, 1996

By Benjamin Cebrian

Traditional dilution control systems range from computer modeling, use of physical markers on the field as polypipes to a technology that marks some control points where displacement is measured. The latter includes walking over a muckpile which is prohibited by some mining companies as a safety measure. The new technology presented in this paper is a patented system that is installed on board excavators (backhoe or front shovel types). Several control points are set along ore/waste contacts and their position is uploaded on the corresponding shovel. The operator proceeds on mucking until he is alerted when reaching any of the several control points previously located in the blast patterns and that have moved with the muckpile. A case study is presented at a high grade copper mine, were unique 3D shapes are showing as a result of using an on-board excavator dilution control system. Both ore-loss or dilution cost of opportunities are analyzed.

By A. Sandberg, M. Nzotta, Du Sichen, N. N. Tripathi, K. Beskow

The present study was carried out to investigate the impact of slag refractory lining reactions on the formation of inclusions during ladle treatment of steel. The experiments were conducted on an industrial scale in the ladle at Uddeholm Tooling AB in Hagfors, Sweden. The inclusion chemistry and population during ladle treatment were studied along with the composition of the ladle glaze, taken from the ladle lining. The inclusions in the steel were classified into four groups according to the Swedish standard SS 111116. SEM/EDS analyses were carried out to identify the phases present in both the inclusions and the ladle glaze. The number of inclusions in the steel before deoxidation was found to increase with the ladle age, i.e. the number of times the ladle had been in use. A similar increase was also found after vacuum degassing and before casting. A great portion of inclusions before casting was found to be supplied by ladle glaze. This observation was further confirmed and explained by thermodynamic analysis. The present results show that ladle glaze is a major source of inclusions in the ladle at Uddeholm Tooling. Keywords: Slag/ refractory/ lining?reactions, ladle glaze, inclusions, inclusion chemistry, ladle treatment

Jan 1, 2004

By G. D. Schena, C Chiaruttini

The feasibility is demonstrated of reconstructing the volumetric distribution of liberated particles and middlings by use of a damped, weighted least-square regularisation method. This allows a precise mass balance to be obtained around a separation/concentration unit, permitting evaluation of the partition curve (Tromp curve) of the separator. Areal grade measurements are made on polished sections of feed, concentrate and tailings and a kernel-based inversion technique is then used to obtain the volumetric grade distribution of the three assemblages. A plain kernel (number of occurrences) and a weighted kernel (each occurrence counted with its area) are used for the solution. Testing of the method on computer-generated synthetic areal grade measurements indicates that it offers a valid alternative to the tedious conventional procedure of conducting experiments with heavy liquids

Jun 21, 1905