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By Heidi Beers

Teijin Limited ? Global technology-driven group operating in six main fields Advanced fibers and composites business group Healthcare business group Trading and retail business group IT business group New business development group Electronic materials and performance polymer products business group ? Listed on Tokyo and Osaka stock exchanges ? 150 companies and around 17,000 employees worldwide ? Consolidated sales of USD 9.1 billion*

Aug 1, 2013

By Konstantinos Modis

According to recently established theoretical analysis and under certain conditions, a critical sampling density can be determined for an earth-related space-distributed natural variable. Sampling above this critical limit adds little to the mapping results. The objective of this paper is the application of the above theory to the Sesklo clay quarry in Greece, where Heracles General Cement Company had conducted a sampling campaign to estimate its reserves. The structural analysis of Al2O3 values generated a variogram model, from which the critical sampling density was identified. This critical number was by far lower than the existing sampling density. Clay reserves were then estimated using geostatistics and inverse distance squares in different data schemes with variable densities. The results of the comparisons between the various models revealed that, when the sampling density was greater than its critical value, geostatistics and deterministic interpolation gave similar estimations, which is also in agreement to the theory. The optimal sampling grid finally proposed here, will result to significant cost savings in the next drilling program which is now in plan by the company.

Oct 1, 2009

By L. Yuan, A. Smith

In order to provide insights for the optimization of ventilation systems for U. S. underground coal mines facing both methane control and spontaneous combustion issues, a computational fluid dynamics (CFD) study was conducted to model the potential for spontaneous heating in longwall gob areas. A two longwall panel district using a bleeder ventilation system was simulated. The permeability and porosity profiles for the longwall gob were generated from a geotechnical model and were used as inputs for the CFD modeling. In this study the effect of methane emissions from the mined coal seam, including the longwall face and overlying rider seam reservoirs on the gob gas distribution was considered. The spontaneous heating is modeled as the low-temperature oxidation of coal in the gob using kinetic data obtained from previous laboratory-scale spontaneous combustion studies. Unsteady state simulations were conducted and the effects of the coal’s apparent activation energy and reaction surface area on the spontaneous heating process were also examined. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.

Jan 1, 2007

Rio Tinto has embarked on a journey to use automation to improve the performance of its surface mines. The driver for automation is to improve the accuracy and consistency of mining processes and less to do with cost savings through labour reduction. A key task in most surface mines is blasthole drilling. The degree to how well this is done cascades through the downstream mining process. It impacts scheduling, excavation, slope stability, material handling, beneficiation and final product blending. Improved blasthole drilling was identified as an objective that has a significant business case in most of Rio Tinto's surface mines. This paper describes Rio Tinto's drill enhancement project that has developed a robust system for automating most of the functions on a Terex SKSS16 drill rig. Automated drilling is currently being used in production at the West Angelas iron ore mine in the Pilbara region of Western Australia. A description of the essential elements of the drill automation system is given together with an overview of how automated drilling is performed remotely from the mine office. A review of some of the benefits of the enhanced drill system is given together with the future plans to extend the functionality of the automated drill and the expected benefits.

May 1, 2010

By H. Meseck

The new building of the Central Bank of Iraq in Baghdad was footed in difficult underground conditions on more than 600 reinforced concrete driven piles, with cross-sectional diameters of 45 x 45 cm and pile lengths of 12.0 to 18.0 m. The necessary embedded depth and the bearing capacity thus reached were established on all 600 drives piles by means of dynamic pile tests. For the calibration of the dynamic pile tests, 6 static pile load tests were carried out. The execution of the construction and the results of the extensive tests on the building site are shown.

Jan 1, 1989

By A. T. Iannacchione

Recent fatal injuries occurring during pillar retreat coal mining call for better identification of the hazards and recognition of risks. Ground control hazards associated with room-and-pillar retreat mining tend to intensify with depth, requiring extra precautions in the form of additional controls. In many locations these activities are further complicated by local complexities often associated with unique or novel circumstances, such as over-mining or under-mining. One technique recently studied by NIOSH, Major Hazard Risk Assessment (MHRA), may help mine operators to mitigate the risks associated with pillar recovery operations. The approach was trialed at two underground coal mines in southern West Virginia that are currently practicing pillar recovery. The first step in the MHRA process involved reviewing the segments or parts of the pillar extraction mining system and identifying associated hazards and threats to the operation. Some of the high risk hazards at these two sites included: ? Rock fall during pillar extraction covers equipment and injury ? occurs during recovery operations, Rock fall above the roof bolt horizon, potentially injuring ? workers and/or requiring recovery action,Rib fall under deep cover, potentially injuring workers, and; ? Strata instabilities associated with subsidence of the ? interburden due to simultaneously mining two seams in close vertical proximity to one another. The mines? risk assessment teams then considered each threat individually in order to systematically identify potential unwanted events. The top unwanted events were examined individually using structured risk analysis tools. The output from the process includes a list of priority existing controls for monitoring and auditing, and a second list of potential new controls. These controls consisted of: ? Examples of best practices, ? Enhanced communication, ? Implementing standard operating procedures (SOP), ? Protocols for emergency response actions, ? Effective layouts, ? Efficient monitoring, and; ? Successful audits. This paper documents the process as it unfolded at the two mines, and analyzes the strengths and weaknesses of the MHRA technique as it applies to pillar recovery operations. This work was part of a larger NIOSH research project. NIOSH was responsible for: 1) facilitating the risk assessment process known as Major Hazard Risk Assessment (MHRA), 2) documenting the risk assessment process, and 3) providing mine management with a written draft summary of the risk assessment process. The results of the risk assessment represent the thoughts and opinions of the individual risk assessment teams and should in no way be construed as an endorsement of the risk assessment output by NIOSH or the University of Pittsburgh.

Jan 1, 2009

By Tom Ireland, Tony Rock

The proposed 1.83km long twin bore A3 Hindhead road tunnel planned for contruction in 2008 is being delivered under a Highways Agency Early Contractor Involvement (ECI) contract. The proposed construction methodology is progressive mechanical excavation of a horseshoe shaped tunnel with shotcrete installed close behind the face using robotic spraying equipment. The tunneling medium is a ‘soft rock’ sandstone for which there was little previous tunneling experience, requiring extensive geotechnical investigations and an innovative approach to lining design. A 240m long portal section though sandy material utilising a steel pipe umbrella is also required. This paper describes the development of the tunnel planning and design including the most recent developments in UK road tunnels, and the innovation included in the ‘permanent’ primary lining design.

Jan 1, 2007

By D Crequer

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

Jan 1, 2006

By M. Hopf, E. Rossouw

Keywords: Pyrometallurgy, furnace, copper coolers, freeze lining, monitoring, Saveway The use of water-cooled copper components as sidewall elements of submerged arc furnaces and other pyrometallurgical applications has become increasingly common. The high cooling efficiency of copper has made it possible to increase the service life of furnace refractories when compared to conventional refractory linings. However even the self-healing effect of ?freezing? worn areas of the lining does not necessarily protect the copper coolers against wear or corrosion completely. In order to avoid furnace explosions, various methods have been used to monitor the wear of coolers. Unfortunately, these have not been able to consistently identify localized wear. Thos Begbie (South African) and SAVEWAY (German) jointly developed technology to embed a line sensor into the copper cooler during the casting process. This system allows an exhaustive monitoring of the copper cooler. A SAVELINE sensor is placed inside the copper-cooling panel between the water-cooling passage and the hot face of the panel. The sensor follows the meandering shape of the cooling water channels. In the first instance, the sensor provides analogue information as the thickness of the copper reduces. Secondly, this wear signal will be confirmed by a signal of interruption if the sensor is washed away. Because of the structure of the sensor, a self-diagnosis is possible and indications can be confirmed (double proofed). Subsequent to the manufacture of some test pieces, coolers for a large submerged arc furnace were manufactured. The sensorized coolers have been installed at the intermittent surface (slag line) where the largest amount of corrosion has been encountered. The system has been operating since December 2005 in what is considered one of the largest submerged arc furnaces in South Africa.

Jan 1, 2006

By Sanjeeva Latchireddi, Travis Orser

"Today’s high capacity semiautogenous grinding (SAG) mills expend vast amounts of energy and in doing so consume tons of shell liners and steel balls, while processing ore. The energy efficiency of these high throughput grinding mills can be attributed to the field of breakage and slurry discharge system. The charge motion and breakage of particles inside the mill depends on the shell lifters design, while the discharge of ground particles is controlled by the grate and pulp lifters. The limitations imposed by poor grate and pulp lifter design become increasingly apparent with increasing size of ag/sag mills and their operation in closed circuit. The design of these mill components has been largely based on trial and error and hence varies considerably between manufacturers. This paper discusses the use of two state of the art design tools - Millsoft™ and FlowMod™. Millsoft™ is an effective tool to design the shell lifters and optimize charge motion, whereas FlowMod™ simulates the slurry discharge system to design grate and pulp lifters. The application of these simulators will be discussed using case studies of full scale mills.INTRODUCTIONMany large mining operations around the world have one or more semi-autogenous (SAG) mills doing bulk of the work in their size reduction operation. The SAG mill is usually followed by a ball mill to finish the size reduction prior to the concentration step. In the past when primary, secondary and tertiary crushers fed material directly to large ball mills, the energy efficiency of the concentrator was determined for the most part by the ball mill operation, whereas now the energy efficiency of a plant often rests largely on the SAG mill operation. As a result mines have shifted their emphasis in optimization from ball mills to SAG mill"

Jan 1, 2005

By J. A. Caceres

Mining planning and mineral processing are almost two unconnected areas. The mining area builds its economical models considering the plant like a constant parameter: a constant throughput, an average recovery and a unitary cost. On the other hand, the mineral processing area assumes a mine plan with grades, ore type, work index, estimating the performances in an independent way. Previous researches have evaluated the advantage for increasing throughput by increasing the liberation size, thus sacrificing recovery. These valuables approaches have left behind the work index factor, critical variable for Recovery-Throughput capacity estimation. This study describes a method combining mineral processing and mining planning. This method incorporates the grinding and flotation performances into the mining economic models optimizing simultaneously the Throughput- Wi(Work index)- Recovery relations with mining sequence, cut-off strategies, and reserve schedules. This method has been used at Andina Mine Chile, showing 18% net present value increasing with minimum investment associated.

May 1, 2003

By J. Brian Anderson

Jointed micropiles were investigated to support bridge foundations where shallow rock was present. In this application, micropiles would have some amount of unsupported length, and would be subject to nominal lateral loads. Five lateral load tests were conducted on micropiles to demonstrate the impact of casing joints and rock socket embedment on lateral behavior. Load tests were simulated with FB-Multipier, a hybrid-finite element program for analysis of deep foundations, for proper design of the loading apparatus and instrumentation. The micropile sections were 2 m (6.56 ft) long, 273 mm (10.75 in) in diameter, 13 mm (0.5 in) thick walled, with a 50-mm (2-in) long threaded joint. Micropiles were made of one to three casing sections and were embedded 0.3, 0.6, 1.5, or 3.0 m (1, 2, 5, or 10 ft) into rock. In each test, two identical micropiles were pulled together using a simple frame until the weaker pile failed. All micropiles were instrumented with inclinometer casings while two contained strain gages at 0.76 m (2.5 ft) intervals. Load and displacement were measured at the pile heads. Tests showed the embedment of 0.6 m, 1.5 m, and 3.0 m (2 ft, 5 ft and 10 ft) sufficiently carried lateral loads over 180 kN (20 tons). The piles embedded 0.3 m (1 ft) were not able to maintain lateral load. In general, all micropiles tested to failure exhibited a brittle failure mode where there is small lateral deflection followed by a sudden failure at the casing joint. This was demonstrated in three of the load tests. In most cases, the micropiles were stiffer and stronger in the load tests than originally predicted numerically. The final test, where piles were not loaded to failure, verified that embedding vibrating wire rebar strain meters in the grout captured the bending moment profile of the micropile. The results showed the maximum moment in this case being carried directly across the threaded joint as predicted by the preliminary models. The results of these tests were used to calibrate the FB-Multipier numerical model. Using a load test that included bending strain measurements for a match, the soil properties were adjusted to produce reasonable matches for all of the load tests.

Jan 1, 2011

Judicious placement of a range of geotechnical instruments was employed at the Tasmania gold mine, Beaconsfield, Tasmania, as a key strategy in the monitoring of rock mass conditions over the past four years. The range of instruments employed included vibrating wire stress-meters and hollow inclusion cells to monitor changing stress conditions, resistance wire and multipoint borehole extensometers to monitor the impact of stress changes on the integrity of the rock mass, and instrumented cable bolts and threadbar bolts to monitor the static and dynamic impact of rock mass changes on the installed ground control system. Initially the monitoring was of a qualitative nature, monitoring change from the time of installation. The value of the output was considerable when considered in relation to the ongoing seismic record which was also being monitored. It was clear from the seismic record and the monitoring results that stope blasting was the primary trigger for changing rock mass conditions. However, it was unclear how well observed behaviour was reflecting conditions anticipated by elastic numerical modelling. The latter had predicted significant stress increase in the near field of man-access footwall development. Qualitative monitoring and visual inspection did not support the modelling prediction, and this led to a program of quantitative measurement being undertaken. Measurement of the absolute stress condition in the backs of footwall development immediately adjacent to monitoring hollow inclusion cells provided the benchmark for tracking quantitative stress change. The program provided insight into the evolution of principal stress field magnitude and orientation in relation to rock mass change observed with extensometers and instrumented ground control elements, as well as providing a degree of calibration between the elastic numerical modelling and the virgin stress field. Calibrated monitoring data has also provided a useful benchmark for finite element modelling which is to be used for future mine-wide design.

Nov 25, 2010

By N Clarke, G R. Ballantyne, M S. Powell, P Elms, A Anyimadu

AngloGold Ashanti Ltd nominated Sunrise Dam Gold Mine as a case study via their involvement with the long-running Australian Mineral Industry Research Association (AMIRA) International P9P research program (AMIRA, 2015) . A group of researchers from the Global Comminution Collaborative (GCC) conducted a comminution circuit survey and review together with a large group of graduate metallurgists, senior metallurgists and operators. Fundamental and applied research understanding was used to identify productivity and efficiency improvements around the crushing and grinding circuits. The limitations of current scientific knowledge were identified through this process and this will allow future research to be more focussed on what is required by industry.The comminution circuit at Sunrise Dam comprises three stages of crushing followed by two stages of ball milling. The secondary crusher and primary ball mill classification were identified as the primary limitations of the circuit. The secondary crusher was found to be underperforming through overall equipment efficiency (OEE) analysis and an improved chamber design was identified by Chalmers University. This improved design will promote higher power utilisation, choke feeding and a finer crushed product for the milling circuit. The primary ball mill product is classified by a combination of a trommel, 3 sieve bends and a hydrocyclone. The combination of poor classification and coarse, competent feed led to a situation where the primary mill was overfilled with rocks, reducing grinding rate due to cushioning of impact. Size specific energy (SSE) benchmarking methodology was used to identify that a 10% increase in throughput could be achieved with improved primary classification.CITATION:Ballantyne, G R, Clarke, N, Elms, P, Anyimadu, A and Powell, M S, 2015. Application of research principles to identify process improvement at Sunrise Dam Gold Mine, in Proceedings MetPlant 2015, pp 221–229 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By F. N. Voskoboyev

The suggested new method for control of geomechanical state of undermined rock mass ensures, as a safety measure for the earth surface protection, the decrease of deformations by 2,5 - 10 times in mining the single seam, and by 1,5 - 5 times - in mining bed series, i. e. approximately within the seam ranges as in the application of full packing with various compressive properties or partial extraction of resources over the area with different coefficients of extraction. It should be noted that this new method has the following advantages o\w rhr. conventional methods: a) the decrease of the packing area and packing works volume by 2 - 4 fold including the operating and productive expenses; b) the elimination of mineral losses due to the increase of extraction coefficient up to 100 5%; c) rock utilization from workings drivage by its placing in the mined - out space. Perspective field of application of this method: disconservation of mineral resources in the left protective pillars of various designation.

Jan 1, 1996

By Tristan Worsey, Nathan Rouse, Kyle Hall

Drilling accuracy is the foundation to any successful blast operation. Even the best blasting practices cannot overcome poor drilling and still obtain desired results. Inaccuracies in boreholes can result in flyrock, increased vibration, uneven floor, and other undesired effects. As depth increases, variation in actual burden and spacing is expected even if collars are located precisely. Problems arise when this deviation reaches a point where it adversely affects the function of the blast design. Not only can unsafe conditions such as insufficient burden at the face develop, but poor fragmentation can compound adverse effects. As with any troubleshooting, problems cannot truly be fixed if they cannot be measured. As a result, significant work has been done in the past on this subject. Currently, there are both cheap and expensive methods used to quantify deviation for a given borehole. However, implementation of these techniques is limited. In general production blasts, little is known about the variance in designed versus true borehole geometry. This is especially true if the blaster does not see telltale signs of drilling deviation. However, losses in blast performance may exist and provide an opportunity to obtain better fragmentation and reduce fines. As drill and blast operations strive for better optimization, greater focus is being placed on drilling accuracy and solutions to this problem. The following paper details the use of several current methods for deviation measurement in order to help prevent compromises of safety and improve overall blast performance.

Jan 1, 2018

By Alfred W. G. Wilson

THE ultimate purpose of the Chemical Manufacturer is to produce consumer products which can be sold to customers. Such production and sales can be continued only if the operations yield a profit to the manufacturer and if the products meet the requirements o the consumer--bath parties to the transaction must be satisfied. There are vast numbers of consumer products, made by chemical pro-cesses. The production of some of these ultimate products may involve the use of several intermediate chemicals, applications of few or many different processes, and the utilization, somewhere in the series of operations, of a variety of raw materials. On the other hand, some ultimate products have a very simple chemical history between raw materials and end products. There are no chemical products in use which are completely independent of the mineral industry. For many, the association is direct and obvious; for others, it may be indirect and even obscure. Analyses of the process and raw-material ancestry of a very large number of consumer products would suggest that many products are derived from Industrial Mineral products directly, that there are many in which the connection is indirect, and that there are only a few products with which industrial minerals are not in some way or other associated. The vast majority of the more important chemical products, and especially the basic chemicals from which other products are made, are directly dependent for their production upon Industrial Minerals or their derivatives. In the preceding part of this paper, for each raw material mentioned some references have been made to the leading chemical products based on this material. This, however, is only part of the story, because in most cases the consumer product can be made from any special raw material mentioned only by the use of other materials or chemicals made from them. The production of consumer chemicals is really possible only through an intricate interlocking of processes, materials, and apparatus.

Jan 1, 1940

By Chris Breeds, Larry Leone, Jerry Wallace

Project Owners typically require General and Detailed Blast Plans when blasting close to important structures and specify the maximum allowable peak particle velocity for each potentially affected structure. Low, residential level PPV limits may be specified which significantly restricts the potential for blasting to be effectively used. Contractor’s responding to these contract conditions typically cite historic case studies which may, or may not, apply to the specific situation and/or types of structures for which limits have been set. A long submittal cycle typically follows.

Jan 1, 2010

By G Anderson, M Mativenga, C Stanton, M Larson

Arrium’s magnetite concentrator has recently completed a modification program to improve the process that has been in operation in Whyalla, South Australia for the previous seven years. The magnetite concentrate is pumped via pipeline to the coast and serves as pellet plant feed, eventually being turned into steel in the Whyalla blast furnace. With the addition of a new 3MW IsaMill at the concentrator, the plant has seen increased production from a reduced feed grade, enabling Arrium to treat ores previously stockpiled as waste. This paper will focus on the design work and commissioning of the fine grinding circuit along with the year of optimisation that followed, taking the IsaMill up to 350+ tph of throughput.CITATION:Larson, M, Anderson, G, Mativenga, M and Stanton, C, 2015. The Arrium IsaMill from design through commissioning and optimisation, in Proceedings MetPlant 2015, pp 110–119 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By Dwight L. Sawyer

To provide technology that can help decrease the dependence of the U.S. aluminum industry on imported bauxite, the main ore of aluminum, the Bureau of Mines is investigating the extraction of aluminum from abundant domestic reserves of kaolinitic clay. Miniplant studies of the continuous leaching of calcined kaolin with boiling 25-pct HC1 acid resulted in a 93- to 99-pct extraction of the acid-soluble alumina in the calcined kaolin feed. Data are presented for an acid leaching study carried out in three or four continuously stirred tank reactors (CSTR) in series, feed rates of 100 to 250 lb/hr of calcined kaolin, and total nominal residence times of 0.7 to 2.3 hr. A material balance for a 176-lb/hr calcined kaolin feed rate in a circuit consisting of three reactors, four classifiers, and five thickeners is given. Data provide detailed compositional and physical information for calcined kaolin, process liquors, and acid-leached residue solids.

Jan 1, 1983