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By Daniel W. Kappes

Testing ores for heap leach operations traditionally follows a progression of bottle roll tests, bucket and column leach tests, and very expensive large field leach tests. Enough data is now available to streamline the procedures. Data from five different operations shows that recoveries from large field leach tests can be predicted from the bucket tests. Initial recovery times in large field leaches are longer than in bucket tests- a typical response is eight days versus twenty days to the same recovery percentage; but the ultimate percent recoveries (after 60 days) are normally very close. Methods of mining and stacking can radically affect recoveries from clay-rich ores. Leaching of uncrushed ores provides special testing problems, since accurate samples smaller than several tons cannot be taken.

Jan 1, 1981

By H. Zhu, Y. Sato, O. Takeda, K. Nakano

Recycling of rare earth magnet wastes is essential to insure the stable supply of rare earth resources. For the development of a novel recycling process, the removal of rare earth oxide from an off-spec alloy magnet was investigated by melting the alloy magnet at 1503 K together with fluoride flux, LiF-50 mol% NdF3 and LiF-?25 mol% NdF3-25 mol% DyF3. After melting, the separation of magnet alloy from the fluoride flux was achieved, and neither suspension of alloy in the flux nor suspension of flux in the alloy was observed. Oxygen concentration in the alloy decreased from 5000 mass-ppm to 160 mass-ppm by utilizing 1.5 times of equivalent amount of flux needed to completely dissolve the oxide. The investigated process is suitable for mildly contaminated waste such as a used (end-of-life) magnet because of its simplicity, low energy consumption and small limitation on location for operation.

Jan 1, 2014

By D. R. Wilburn

The worldwide budget for nonferrous, nonfuel mineral exploration was expected to increase by 58 percent in 2004 from the 2003 budget, according to Metals Economics Group (MEG) of Halifax, Nova Scotia. The increase comes two years after a five-year period of declining spending for mineral exploration (1998 to2002). Figures suggest a subsequent 27 percent increase in budgeted expenditures from 2002 to 2003. For the second consecutive year, all regional exploration budget estimates were anticipated to increase. The worldwide budget for gold exploration achieved about 50 percent of the total amount budgeted in 2004.This was 68 percent, or US$715 million, higher than the reported 2003 budget. The 2004 worldwide exploration budget estimates for copper increased by 70 percent, orUS$237 million, to US$577 million from the 2003 budget. The budget for nickel exploration increased 52 percent, or US$89 million more than in 2003. The 2004 exploration budget for other mineral targets (primarily cobalt, heavy minerals, industrial minerals and silver) increased114 percent, or US$118 million.

Jan 1, 2005

By A Brzovic, E Córdova

In an underground mine, different mining activities such as undercutting and cave progression generate redistribution in the present in situ stress field, and these changes are represented in the rock mass through induced seismicity.In order to study and analyse the induced seismicity generated in El Teniente, a block model was developed to account for the dissipated seismic energy through different areas of the mine from 1992 to 2015. More than 2.1 million seismic events were unified and classified in 3D in order to be used for the interpolations. The resultant model variables account for the accumulated energy releases in a monthly time resolution, and provide the ability to intersect different 3D entities with the stored information in the blocks, and estimate the energy evolution inside these entities.The generated model was used to analyse the geotechnical variables that determine the seismic response for the rock mass in the mine, such as geometry and direction of advance of the undercut fronts, lithological domains, and to study the ‘work’ the rock mass needed to go through in order to generate caving in areas with different stress settings.A specific area of the mine under high-stress conditions was analysed by studying the seismic energy associated with two subsidence caves interacting around the project, the modelled lithology. Using the same approach two adjacent projects are analysed to understand the released energy from the rock mass based on different stress and geotechnical settings for each project.CITATION:Córdova, E, Brzovic, A and González, R, 2016. Analysis of progressive seismicity and its correlation with geotechnical variables at the El Teniente Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 835–844 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By D Wyatt, J Domenico, W Kow

Over the past few years developments in heavy minerals processing have concentrated on the mineral separation portion of the business. The best example of this would include new developments in rare-earth magnetic separators and associated flowsheet modifications. Except for some minor modifications in spirals, the æwetÆ side of the separation business has lagged behind the ædryÆ side. Basic concentrator design has not changed in 20 years. Recent pilot trials by Outokumpu Technology have shown the benefits of a new gravity flowsheet that combines density separation and spiral concentration on a variety of heavy mineral deposits. This concept is already well utilised within the iron ore industry. The synergistic combination of these two technologies allows smaller, simpler, and controllable gravity concentrators to be built while providing equivalent or better grade and recoveries of valuable heavy mineral. This is contrasted to the all spiral flowsheet characterised by the diminishing returns of multiple stages of spirals and associated recirculating loads. Examples of the flowsheets and associated benefits will be presented from a variety of cases.

Jan 1, 2001

By F. Dahl, P. Raleigh, J. Holzhauser, B. Nilsen

Tunnel excavation using tunnel boring machines (TBMs), has become increasingly common in recent years, despite the fact that precise evaluation of certain risks have not kept pace with the use of these machines. One of the risks easily overlooked by Engineer and Contractor alike are the effects of abrasive ground on the costs and schedule of a given project. The impacts of worn and damaged TBM cutter heads have been observed on hundreds of tunnel projects around the world. It would appear that a reliable prognosis of the abrasiveness of soils on a project would be of great importance for designers, clients and contractors alike. Several well acknowledged test and prognosis methods already exist for rock, however there is only very limited knowledge available to describe the abrasiveness of soil and its impact on soft ground TBMs. This paper will examine approaches to this problem and suggest a new approach based on a current project undergoing design.

Jan 1, 2007

Developments in the technology of explosive production and deliveryallow a greater amount of flexibility in rock fragmentation by blasting. The rock fragmentation efficiency of an explosive is currently given by a rating which is determined by the explosive manufacturers using proprietary formulae and methodology. Hence, comparison of explosives from different manufacturers may be misleading. Modeling of explosive energy, using a thermochemical code such as CHEETAH provides an objective standard by which the likely performance of different explosive formulations can be determined. Such modeling can be used for optimisation of explosive composition to match specific rockfragmentation objectives.

Jan 1, 2001

By Maya Kamenetsky, Khoi Nguyen, Natalee Bonnici, Steve Walters, Claire McMahon, Julie Hunt, Ron Berry

"The analysis of meso- and micro-scale textural attributes has been undertaken on ore samples from the Ernest Henry iron oxide-copper-gold (IOCG) deposit in NW QLD. Quantified textural data including grain size, shape and mineral association have been extracted from classified images of core with the aim to better predict potential mineral processing behaviours such as comminution, liberation and flotation. Data have been extracted from images of intact core at meso- and micro-scales using high resolution continuous images collected using automated core-logger technology, SEM-based and optical microscopy platforms.The results of this study will show examples of quantified size, shape and mineral association data from meso- and micro-scale classified images. Analysis of the data shows that there are domains of variable grain size and mineral association that can potentially be related to crushing and liberation behaviour. The trends that are observed at the drill-core (meso-) scale are consistent with those at the micro-scale. The results from the micro-scale analysis show that the domains defined at the core-scale have clearly different chalcopyrite sizes and shapes as well as variable bulk mineralogy.INTRODUCTIONInnovations in technology have allowed automated extraction of information about mineral shape, grain size and mineral association, i.e., texture, from meso- and micro-scale images of intact rocks. The overall aim of this research is to investigate trends in quantified textural data that can potentially give an early view of processing parameters such as predicted grind size and liberation behaviour."

Jan 1, 2009

By Scott Rosenthal, Logan Connolly

Butte, Montana holds a prestigious place in the history of mining, deemed “The Richest Hill on Earth,” containing a plethora of underground mines. The Orphan Boy/Orphan Girl underground mines, on the western side of Butte, operated from 1895-1956 producing zinc, lead, silver, and manganese. Today, the Orphan Boy mine is part of Montana Tech’s Underground Mine Education Center (UMEC) and the Orphan Girl mine houses the World Museum of Mining. Underground development in the Orphan Boy mine continues to progress as students from Montana Tech receive hands-on underground training; in addition, the UMEC is a multi-disciplinary research facility. Repeated underground blasting occurs in close proximity to old mine workings (wood supports installed circa 1950 or earlier). Research began to determine the impact of underground blasts on nearby pre-existing structures. Using the ISEE Field Practice Guidelines for Blasting Seismographs, one seismograph monitors the predominately-wooden structures to measure their response during each underground blast and one seismograph positioned on the surface to monitor surface structure response to the blast. This paper presents the findings of the research conducted to date for the project. The paper includes analysis of the research data, and conclusions determined from the research. Recommendations for the future work are included as well.

Jan 1, 2018

By Jason Ryan, Stephen Harria

Q.E.D. (QED) is a blast design and evaluation model that allows full three-dimensional design specification including the development of unique “live” terrains and an unlimited variety of complex charge configurations. QED’s analysis package allows the examination of likely outcomes resulting from changing various design variables in terms of vibration, fragmentation, rock-mass damage and muck-pile profile. Especially applicable to use cautious blasting applications, QED’s damage model uses vibration to estimate rock damage beyond excavation boundaries. This relates directly to operations such as Yucca Mountain Nuclear Waste Repository in Nevada, where damage beyond the excavation perimeter must be tightly controlled. The U.S. Department of Energy (DOE) h as b een studying a site at Yucca Mountain, NV to determine its suitability for long term storage of nuclear waste. The main mechanism of waste isolation will be the natural barrier of the host rock Total Systems Performance Assessment (ISPA) is used to model the excavation design and its behavior over time. Of importance to TSPA is quantifying the condition of the rock-mass before and after excavation. Ideally, there should be no excavation-induced changes to the rock-mass’ structure (removing the requirement to model the effects). At the least it may be possible to keep excavation-induced damage far enough away from waste packages so that modeling of these effects will not be required. QED can calculate a prediction of the extents of blast induced damage to the rock-mass. By using this metric as a design parameter, it may be possible to complete excavation of the repository more rapidly and inexpensively than previously thought, without jeopardizing the structural integrity of the waste containment areas or requiring blast damage to be modeled by the TSPA. This paper will explain the structure of the QED blast modeling system and show the analysis of historical data from Yucca Mountain. Processing of the historical data and the subsequent results will demonstrate how blast modeling can be used on an ongoing basis to assist the excavation process at Yucca Mountain.

Jan 1, 2000

By R B. Stewart

Where pasture production is the intended land use of the areas to be reclaimed, the creation of a suitable growing +medium is a major objective. To achieve this land reclaimers require a sound understanding of the proposed mining plan and a knowledge of the physical, biological and chemical properties of materials intended for resurfacing disturbed areas. Where the original soil is not being replaced in its natural state, research is usually required to determine an alternative growing medium. Results from field research conducted on waste material from the Waihi Gold mine are reported with emphasis on the significance of soil depth in relation to pasture production in this environment.  Problems in extrapolating field research to large scale operations are also considered.   Essentially the requirements for successful pasture production, on surrogate growing medium, are akin to conventional approaches used in New Zealand in the development of unimproved agricultural land. High inputs of fertiliser are initially needed, especially where volcanic soil is used, and careful management of pastures and soils is required to minimise soil erosion and create a sustainable system. In the first three to five years of pasture production, grazing use of the land requires to be dictated by pasture availability and soil conditions and not by animal feed requirements. The use of light stock (young dairy or sheep) is recommended.   Successful land restoration requires a team approach by a range of cooperative specialists including engineers, soil scientists, farm managers, agricultural contractors, landscape architects and environmental officers.

Jan 1, 1991

By C. Slotta, F. Charlier, P. Blomen

"Within the energy concept of the German government, the operating time of nuclear power plants was initially extended from about 8 to 14 years. It is planned, however, that every power plant will gradually be decommissioned until 2025 and that simultaneously the amount of renewable energies will successively be expanded. According to the political state, nuclear energy is a discontinued model. Looking at the global energy market, though, an obviously opposed development can be observed. At the moment, 443 nuclear power plants are running worldwide and further 62 facilities are being built. These about 500 nuclear power stations have to be supplied with nuclear fuel right now and in the future. The present paper will describe the worldwide use of nuclear energy, the extraction of the nuclear fuel uranium and in detail the available and predicted resources of uranium. The conclusion of the paper is the statement that uranium as nuclear fuel is no scarce resource but sufficiently available."

Jan 1, 2011

On June 4, Kennecott Utah Copper (KUC)marked the centennial of the founding of the original company. Bill Champion is president and chief executive officer of KUC. He said, “What has happened during the past 100 years far surpassed even the most optimistic visions of men like Daniel C. Jackling and Robert Gemmell when they promoted the concept of mass production techniques for a low-grade deposit of copper ore. At that time, it was a totally new way of doing things and the mining leaders of that day scoffed at the idea. They said it would never work,” Champion said. The company will celebrate this once-in-a-lifetime occasion with a few special projects, mainly for the benefit of our employees, said Louie Cononelos, director of government and public affairs for KUC. The company has designed and minted a commemorative copper coin that reflects early steam shovel and locomotive operations on one side, and today’s modern electric shovels and huge haulage trucks on the other side. “The history of the company stems from the ores of the Bingham Canyon Mine. That coin has been encased as part of a10-panel brochure that captures the company’s 100 year history,” he said. KUC also developed special centennial banners and comparable framed posters that were displayed throughout its operations and at selected community locations that have enjoyed a long-time partnership and special relationship with the company. Some of the plants also designed their own centennial hardhat decals.

Jan 1, 2003

By P. K. Narasimharaghavan

The major threat to the sustainability of Aluminium Industry is its significant contribution to global warming by way of generation of non eco-friendly gases during its production cycle from Bauxite to the finished product. Though reduction measures are taken in control and effective recovery of values from pot room gases, efforts in use of environment friendly additives in the final products production line is warranted. In this line, the present paper describes our efforts in the use of a new generation refining flux which apart from helping in effective removal of alkali metals, reduction in inclusions and ensure a better metal cleanliness shall also aide in reduction of obnoxious gases generated during the metal refining process prior to casting. The aim of the current work was to reconcile the practical results with the old generation fluxes used. Further improvements to bring in a better metal cleanliness will also be discussed.

Jan 1, 2010

By Juan M. Antorena

A dynamic testing program was performed to evaluate installation procedures, assess capacity of 610-mm (24-inch) diameter open ended steel pipe to evaluate set-up and provide minimum pile tip elevation based on the dynamic testing results. The program was performed for a marine terminal project consisting of a 570-meter (1900-foot) long, overwater railroad trestle. The project location is Santa Marta, Colombia, South America. The subsurface profile generally consisted of 4m (12 ft.) of water and soft to hard silty clays. The piles were installed to an approximate tip elevation of -22 meters (MSL). Three piles were initially dynamically monitored during installation and then later monitored during restrike driving to evaluate pile drivability and bearing capacity including time related capacity increases due to soil "set-up". Knowledge of change in pile capacity with time after end of initial driving is important for design of pile foundations.

Jan 1, 1995

"The first SkimAir flash flotation cell was installed in Outokumpu’s Hammaslahti Copper Concentrator in 1982 to prevent overgrinding of soft sulphides in the milling circuit. Since this first installation the popularity of the flash flotation has fluctuated depending on metal market conditions and regional preferences. Units have been installed in many commodities including copper, lead, gold, PGMs, silver and nickel. Though it has been successfully employed in many operations around the world, flash flotation technology is still not well understood by many in the mining industry. This paper will discuss aspects of flash flotation flowsheet development along with some of the metallurgical and engineering considerations required to successfully incorporate flash flotation into new or existing milling circuits. This paper will also try and debunk some of the myths that exist around flash flotation cells and their operation. Case studies of flash flotation implementation will be discussed.IntroductionModern flash flotation technology was developed several decades ago by Outokumpu, with the first commercial installation of this technology being at the Hammaslahti concentrator in Finland in 1982 (Kallioinen & Niitti, 1985). This was a relatively modestly sized SK80 cell producing final grade copper concentrate directly from the flash flotation cell operating in the grinding circuit. Since that time the size and number of flash flotation cells installed globally has grown considerably to the point where today, it is a widely known application of flotation technology for amenable ores. Owing to their long history in developing the technology, Outotec are the market leader with their SkimAir range of flash flotation cells. Though there is a general awareness of flash flotation process in the mineral processing industry, there is a lack of detailed understanding of the process and the benefits it can provide to new and existing operations."

Jan 1, 2017

Variations in delay timing can have a marked influence on blasting effectiveness and, hence, on total production costs. In single-row bench blasts, delay firing is invariably more effective than simultaneous initiation. In single-row delayed blasts, there is an optimum inter-hole delay above and below which inferior blasting results are obtained. This optimum delay is equal to the time required for each charge to just effectively detach its quota of the burden. The inter-hole delay should seldom be less than 4 ms.m-l of burden.In multi-row blasts in which holes in a given effective row are fired on the same delay, the entire burden on any effective row should be detached from the rock mass just before charges in the next effeotive row detonate. Delays shorter than this give inferior blasting results and an increased likelihood of environmental and slope stability problems. If the inter-row delay is too long, cut-offs can occur, especially where the delay unit is located outside the blasthole. For a surface delay system, the optimum inter-row delay usually varies between 4 ms.m-l and 8 ms.m-l of effective burden. The number of rows that can be fired effectively with surface delay systems (in a single blast) is limited by the threat of cut-offs. Greater interrow delays and a larger number of rows per blast can be fired to advantage with down-the-hole delay systems.There are practical limits to the timing accuracy of all available delay systems. The existence of delay time variability should be recognized and duly considered in the design of blasts.The relationship between delay timing and blasting vibrations is not discussed.

Jan 1, 1977

By Linda L. Chasko, Charles P. Lazzara, Gary Braselton, Ronald S. Conti

Preparedness is an important element of any underground mine's strategic plan in dealing with an unexpected event, such as a fire. A fully implemented fire preparedness and response plan is essential in reducing the probability and seriousness of a mine fire. This report describes the development of an underground coal mine fire preparedness and response checklist (MFPRC). The checklist is a data collection instrument for profiling both the fire prevention and response capabilities of a mine site and usually requires 3 to 4 days to complete. The checklist encompasses conditions, procedures, and equipment that have frequently been identified as the primary or contributing causes of underground coal mine fires. At least 1 day is needed underground to evaluate the water system. This entails measurements of water flows and pressures at fire hydrants, and water throw distances of fire hose and nozzles at several locations (mains and branch lines). A few of the other topics that are discussed with mine personnel include detection and suppression systems, combustible materials, mine rescue and fire brigades, and firefighting equipment. The MFPRC was developed by the National Institute for Occupational Safety and Health (NIOSH),Pittsburgh Research Laboratory. Under a Cooperative Research and Development Agreement (CRADA) with Cyprus Amax, Twenty mile Coal Co. (Oak Creek, CO), the checklist was field tested and further refined. Additional field tests were conducted at several other operating coal mines.

Jan 1, 2000

By Kim M. Cornelius

Musculoskeletal injury is a term used to describe a wide range of soft tissue disorders which affect the nerves, tendons, and muscles. Common examples include lower back pain, tendonitis, and carpal tunnel syndrome. The majority of these injuries are not the result of sudden mishaps, but usually develop gradually from repeated wear and tear. Symptoms may first appear after weeks, months, or even years. Symptoms may result from many types of activities, performed at work or at home, and it is often difficult to attribute a single event. In fact, it is more common to identify the factors which may have contributed to the development of the condition. The terms repetitive strain injuries or cumulative trauma disorders (CTDs) have been commonly used to refer to disorders that have occurred due to work related activities (Putz-Anderson, 1988; Fraser, 1989). Three main risk factors contribute to CTDs: force, repetition, and awkward postures. Any one or combination of these may contribute to the development of CTDs. Therefore, the design of equipment in conjunction with the required tasks should attempt to reduce these risk factors. Examining the layout of the work area to help identify tasks which may contribute to cumulative trauma is necessary. The following list(Putz-Anderson, 1988), describes ergonomic concerns that, overall, should be minimized at the work area:

Jan 1, 1997

By Gerald V. Gibbs

Quadratic functions, Q(hkl), are given to six places in increments of 0.01° for 2? from 0° to 90° for CuKa and from 25° to 180° for CuKa1. The wavelengths used for Cu in the computation are those agreed upon by the Editorial Commission of the International Tables for X-ray Crystallography (1950): CuKal 1.54051 A.; CuKa2 1.54433 A. INTRODUCTION At the Federal Bureau of Mines laboratory, Norris, Tenn., X-ray diffraction crystallography using tubes with copper targets revealed a need for a handy reference for the quadratic functions of copper radiation. The tables presented here were prepared to satisfy that need. The quadratic form Q(hkl) may be expressed in terms of the Bragg diffraction angle 2? and of the wavelength ? as

Jan 1, 1961