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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 MINER Act of 2006 mandated that all underground coal mines must install and maintain refuge chambers. Refuge chambers serve as a temporary shelter in case of emergency. Several factors affect the performance of a refuge chamber: heat production inside the chamber and introduction of CO when chamber doors are opened are two major factors. This study examines the CO purging process and to determine total air quantity and time necessary to lower the CO con-centration to safe levels for different inlet/outlet configurations using three-dimensional simulation technique. The study uses Reynolds Averaged Navier Stokes and continuity equations along with the spe-cies transport model assuming uniform air mixing. The heat transfer of any kind is neglected and the purging process is assumed to take place isothermally. The standard k-e model is utilized for simulating turbulence in the flow field. This research provides useful guidelines in developing an efficient strategy for purging refuge chamber. Keywords: Airlock chamber, Purging, Carbon monoxide, Turbulence

Feb 27, 2013

By M. Gouet-Kaplan, J. A. Finch, S. Gélinas

Methylisobutyl carbinol (MIBC) and methoxy polypropylene glycol (Dowfroth 250) bubble thin films were characterized by composition and thickness determinations, using FT-IR spectroscopy and UV-Visible spectrophotometry, respectively. The infrared investigation indicates that the role of frother molecules in creating bubble thin films is based on their effectiveness in inducing H-bonding reorganization of the surrounding free water molecules into a coherent network. From UV-Visible interference patterns, it is found that MIBC forms films with a measured critical end thickness of less than 160 nm, compared to 612 ± 30 nm for Dowfroth 250. The observed values of the free water layer thickness are comparable at 5.65 ± 0.28 µm for MIBC and 6.75 ± 0.34 µm for Dowfroth 250. A higher stability of an MIBC bubble over a Dowfroth 250 bubble is related to the different polarization and orientation of the molecules sustaining the boundary surface water network. The findings are used to explain the different action and associated froth characteristics of the two common industrial frothing agents.

Jan 1, 2006

By M. J. Ramos

Without an exclusive definition of administration in business, we could propose to define it as performance by management to adopt or implement established business formulas. Administration could also be defined as a universal process that organizes people, and achieves, through efficiency, common objectives and goals. Humanity developed some form of this process from the beginning of civilization. To imply that something is new in administration might be considered specious or naïve. Moreover, what is new in management? Administration of business is not new to the world. To prove this statement, we need only ask this question: Does the architecture and monumental workmanship of the past civilizations of ancient Egypt, Rome, and the Incas demonstrate management without administration and without definition of objectives? The answer must be a resounding ?NO!? In spite of this acknowledgment and for the purposes of this presentation, I will use the word ?new? in business and hope that the reader will follow my reasoning. The mining industry has unique characteristics in respect to other industries. It is multi-disciplinary, has a single purpose (majority for one metal), has two players (man and nature), and it involves high risks for generating environmental imbalance. Mining exploits non-renewable and finite resources, creates an unstable job market (work hard to have no work) and a speculative economic market with unpredictable prices ? a one-time payment for a finite resource with multiple recycling. On top of all that, the industry still operates within obsolete petroleum-based technology, utilizing practices that were designed two centuries ago. Today, we confront the challenges of the millennium with outmoded practices and management. Ordinarily, several styles of administration are standardized into a FRAGMENTED vertical system of organization. Mining has rigid objectives in production, with profitability as the focus from the beginning to the end. Citing the concept of safety, as an important facet of production is bombastic since, in truth, mining is an experimental industry that consistently reports high numbers of fatal accidents. In mining, we designed a process to work according to our objectives, demanding attention and supervision of all levels of management with a halo of parameters that are not assimilated into the design. We continue to perform a rigid style of management in an industry that is still not responsive to variations of the market ? losses in particular. The existing design process generates loss without capitalization and without response to said loss. This perception is reflected in a mindset that is only too ready to ignore mining liabilities. The reality of the enterprise has created an immense pressure from top to bottom in the hierarchy to do more with less. It is for all of these reasons that I propose to set forth a new essence for administration that encompasses an alternative vision and style in mining: Management by Loss. MANAGEMENT BY LOSS Management by Loss (MBL) is a systematic, integral process organized to quality control operation and the human profitability within the industry. It permits focus on achievable goals by utilizing the best practices (Mining Open-closing). Identification and characterization of loss in the process determine how objectives are defined, controlling the time limits to execute based on constant balance of mass, energy, water, and ?wastes? in each stage of the industry, in order to reach final objectives. The concept of loss can be defined by various criteria. Generally, it is the mass that could not make or arrive at its destination from a designed process or simply, it could not maintain balance. Otherwise, the design of the process describes the final point of the resource. However, those resources could not make their destination because of failure to use the best design, resources and TIME. The loss has typical characteristics such as Identifiable, classifiable, measurable, manageable, controllable, valuables, negotiable, avoidable, reportable, and monitoring. In the traditional scheme, these losses are not registered; they are made exclusions. We are trapped within a system, which was designed to obtain objectives of the industry in a specific timeframe. In the present style of administration, the focus is total - our emphasis in this treatise is in the loss. The current traditional report form contains only the most positive achievement of objectives, only the best of the exercise, humanizing numbers, without touching what we left behind or what we were waiting for to assimilate as a ?surprise account?(new account of liabilities). Management by loss is a method that redefines the concept of waste (waste zero) for controlling the mine operation under the equilibrium of the ecosystems. This method confronts the problems that impact our industry in this millennium. Understanding and quantifying losses (reserves, resources, time, energy, water, soil, materials, equipment, tasks, labor, ecosystems, etc) is a priority mandate for the industry and demands the application of a ?new ? style of administration by seeking to maintain balance instead of the disequilibrium that mining now creates in nature. It is necessary to answer questions such as: How can we minimize loss? How can the loss be assimilated during the life of the mine? What is the vision of mining in respect to the generation of waste? How can we convert liabilities into assets? In addition, the control of loss is determined in the achievement of the plan. Loss occurs because of a failure of the process in the original plan. Still we do not plan to fail but we fail to plan appropriately. It is a remarkable thing to accomplish and compel those objectives described in the original plan when that plan is designed with a determined budget. If not, we lose time and, of course, capital. Moreover, in Management by Loss (MBL), we can find answers to the following questions: What is the multiplier of productivity in mining? What are the influences of identification and characterization of loss and what is the level of efficiency of energy in order to achieve waste zero (effective cut off grade)? The challenges of mining in this millennium validate this new style of administration. Finally, it is important to point out that mining is entering into an era that has different rules, but the industry is still run by companies functioning with objectives from two centuries ago. They are trying to confront issues with concepts that are not designed for new tasks. Therefore, I ask you to consider this new style of administration of business under a vision of how the industry should be organized and managed, with an attitude of balance toward nature and social responsibility.

Jan 1, 2009

By K. Burke, G. Zhan, A. Mayer

A cover with capillary barrier effects (CCBE) is being constructed on the AA Leach Pad at the Barrick Goldstrike Mine site near Carlin, Nevada. The purpose of the cover is to eliminate/minimize infiltration of meteoric waters into the leach pad. Laboratory and numerical analyses indicate that Carlin Formation siltstone (TCS), a locally available material, has the necessary hydrologic characteristics when placed on the leach pad to act as a CCBE. A pilot study has been conducted on a small-scale test cover placed on the AA Leach Pad to examine the cover performance under irrigated conditions. The preliminary test results demonstrate that the designed cover is capable of preventing meteoric water infiltration.

Jan 1, 2001

By Morris T. Worley

Editor’s note: Mining companies doing business in Central Asia, and parts of the developing world, should look for ways to promote community development through the introduction of appropriate technology. This article should be of interest to SME members. It shows sustainable development type projects need not be massive or expensive. Smaller, utilitarian projects are equally valuable to developing communities as they seek to develop their own economic and social infrastructures. Joint Development Associates International (JDA) began humanitarian relief and community development in Central Asia in 1992, following the collapse of the former Soviet Union. Appropriate technology has played an important role in the company’s efforts to assist those segments of society that are most vulnerable to poverty and disease.

Jan 1, 2005

By R. Fedors, T. Ghezzehei, D. Or

The phenomena of dripping into cavities (e.g. tunnels and drifts) within an unsaturated fractured porous medium under ventilated conditions is studied to improve estimates of dripping rates, drop sizes, and chemical composition of droplets that could affect the integrity of high-level nuclear waste packages placed in drifts. The sensitivity of dripping rates and water chemistry to ventilation is analyzed at various flow rates using analytical expressions linking flow on fracture surfaces to drop formation and evaporation. The model was tested using laboratory experiments involving machined aluminum slabs designed to represent a simplified morphology of a fracture face intersecting a cavity and using natural fracture surfaces from a welded tuff. Comparison with ten years of data on dripping in natural caves showed good agreement with model predictions. In particular, for low dripping rates, evaporation due to ventilation leads to larger drop sizes and alters drop chemistry by increasing the concentration of solutes in the drop relative to that in the water flowing on the fracture face.

Jan 1, 2000

By R. Fuenzalida

Since 2007, a number of Multivariable Predictive Control (MPC) Applications have been implemented on SAG mills, among others, within the Kairos Mining Concentrator Automation Program using ?Profit Controller?? and other tools comprising the ?Profit Suite??. Along this journey, several interesting and challenging issues related to SAG mill operation and control have been faced, which are relevant to be shared with the Mineral Processing community. These advanced control applications have an operational objective whose goal is to increase marginal profit on the concentrator, together with increasing mill stability. In regard to this objective, the issues to be presented and described are in direct relationship with ?Profit Controller? features and the SAG role; they are also stated and linked to get the most of the mill. Some conclusions and findings are also presented, leading to recommended practices on how to use the controller. These findings have also lead us to decide further actions to be taken on new applications to deploy and also on devising and implementing some complementary components to increase robustness of the overall automation solution, as well as reducing the need for operator intervention.

Jan 1, 2012

By T. McKeon, G. Luttrell

Spiral separators are commonly used to upgrade sand-sized particles in both the coal and mineral processing industries. Many plants utilize multiple stages of cleaning and/or scavenging spirals to improve recovery and/or final product grade. Field studies suggest, however, that the layout of industrial spiral circuits is often less than optimal. This oversight can usually be attributed to a failure by plant designers to consider fundamental process engineering rules that govern the layout of complex separation circuits. This article reviews some of these important rules as specifically applied to multistage spiral circuit design. Two industrial case studies, one involving the upgrading of heavy mineral sands and a second involving the cleaning of fine coal, are presented to illustrate the impact of good design protocols on spiral circuit performance.

Jan 1, 2007

By M. Baumann

Introduction Gold Quarry is one of the largest gold deposits in Nevada, located along the Carlin Trend, approximately seven miles north of Carlin, NV. Owned and operated by Newmont Mining Corporation, as of December 31, 2005, Gold Quarry had produced over 13 million ounces of gold. Multiple simulations were constructed for gold and metallurgical variables using the Stepwise Conditional Transformation method. Analyses of these simulations have been used for a variety of purposes, including an assessment of uncertainty with various ore types. This assessment provides insight for improved modeling and reconciliation. Geological Framework Gold Quarry is a large, low-grade disseminated gold deposit hosted in Silurian-Devonian aged sediments at the Chukar/Alunite-Good Hope fault intersection. Gold bearing hydrothermal fluids appear to have migrated upwards along the Chukar/Alunite and Deep Sulfide Feeder faults and then moved outward along favorable stratigraphic horizons and structural intersections.

Jan 1, 2007

By Brian Fulcher, Michael Bell, Shimi Tzobery, Werner Burger, John Bednarski

The Arrowhead Tunnels Project represents the final portion of a 70 km (44-mile) long water conveyance facility that will bring up to 28 m3/sec (1,000 ft3/sec) of water into Southern California. The 13 km (8-mile) tunneling project is well underway and consists of two, 5.8 m (19-foot) diameter TBM bores through extremely variable geological conditions. The tunnels lie near the base of the San Bernardino Mountains and several significant faults including the San Andreas Fault run within one kilometer (0.6 miles) of the tunnel alignment. Numerous other significant faults cross the tunnel alignment and water pressures in the tunnel have been recorded as high as 20 bar (300 psi). This paper describes some of the problems and challenges encountered and the solutions implemented to advance the two hybrid TBMs under conditions that ranged from hard rock with no water inflows to full-face granular material under 10-bar pressure and in excess of 32 l/sec (500 gpm) inflows. Due to the range and severity of ground and water conditions actually encountered, the Owner-Contractor-Designer team eventually found that adjusting the means and methods to be more responsive—virtually on a day-by-day basis—was needed to suit the conditions

Jan 1, 2007

By Luminita Calin

King County (Seattle, WA) is on a monumental task of building the new Brightwater System complete with a new treatment plant, three main conveyance tunnels, a new outfall into Puget Sound and other ancillary works. This paper will describe the first conveyance tunnel, Brightwater East currently under construction by the Joint Venture of Kenny (Sponsor) / Shea / Traylor that is scheduled for completion in early 2010. The project located in Bothell, WA (north of Seattle) is in both King and Snohomish Counties. It was the first of the major tunnel projects that was scheduled by King County for the Brightwater System. The East Contract consists of the following major elements: 14,000 ft of 19'-2' EPBTBM mined tunnel using 16'-8' ID bolted, gasketed precast concrete segments for a primary liner; installing and encasing 14,200 ft each of 48', 66', 27', 84' in diameter steel pipes inside the tunnel along with three runs of fiberoptic cable; 2,430 ft of 72' in diameter microtunnel including three caisson shafts and associated structures; one Intercepting Structure (IS) shell to mine from that is 74 ft deep and 74 ft finished in diameter with 130 ft deep slurry diaphragm walls, tremie slab and final concrete wall lining; one Influent Pump Station shell (IPS) 83 ft deep, twin 77 ft inside diameter cells, with 160 ft deep slurry diaphragm walls, tremie slab, and final lining; two short 12 ft in diameter inter-shaft connector tunnels; one extraction shaft 40 ft deep by 40 ft wide and 140 ft long for connection to the new treatment plant piping.

By Steven I. Majtenyi

There is a growing interest among transportation planners to make more use of the subsurface to preserve the landscape and make transportation more efficient and economical. At the present time, utilization of the underground for transportation facilities is severely restrained by the adverse environmental impact and high construction costs. However, recent studies performed by the United States Department of Transportation indicate that, in spite of such problems, the volume of underground construction has significantly increased during recent years and projections point to continuation of these trends(1). It is estimated that the total volume of transportation tunnel construction will exceed $4 billion in this decade. This level of Investment justifies a significant research program. Due to the common interest in transportation tunnels and to the similarities of problems encountered during their construction, the tunneling research activities of the Federal Highway Administration (FHWA) are closely coordinated with the programs other agencies of the U. S. Department of Transportation DOT); specifically, the Federal Railroad Administration (PRA) and the Urban mass Transportation Administration (UMTA). The FHWA is responsive to the particular needs of these agencies but will benefit from the research results obtained also. In 1971, the Office of Secretary, DOT, initiated plans for an overall coordination of the DOT, FICA, UMTA, and FHWA tunneling research activities. The objectives of this effort have been to reduce tunneling costs by 30% and to increase the rate of excavation by 200% within 10 years. This coordinated program was developed and promoted during 1972 and 1973 by Dr. Eugene L. Foster, at that

Jan 1, 1974

By R. Heersink, C. H. Wells

Innovations in communications and real-time information systems are providing industry opportunities to improve profitability. Real-time operating data is collected from equipment across a site or even several sites into a central server for secure PC and PDA-based Internet access. This paper includes discussion of how operating staff can use wireless devices to see equipment and processing data from anywhere throughout the mines and concentrators, and how management can view results from multiple mines, all in real time. Additional opportunities enabled through the remote access by equipment vendors or mining consultants is also presented, as well as an overview of typical benefits and current installations.

Jan 1, 2002

By S. C. Brown

A number of studies have suggested that microscale asperities enhance bubble-particle attachment efficiency; however, in practice the roughening of particulate surfaces can also lead to a decrease in flotation. In the present investigation, it is proposed that nanoscale asperities may be partially responsible for this phenomenon. It is suggested that as inter-asperity separation distances are reduced capillary effects are enhanced leading to the formation of stable liquid domains, which adversely impact bubble-particle adhesion. In addition, obstruction of surfactant self-assembly may occur, further limiting flotation.

Jan 1, 2003

By VIVEK KASHYAP, PATRICK TAYLOR

The presence of iron in sphalerite induces the formation of zinc ferrite (ZF) during roasting. Zinc refinery residues (ZRR) and electric arc furnace dust (EAFD) contain a significant amount of zinc ferrite and are difficult to treat. According to the literature, up to 71% ZF has been found to be present in ZRR. The dissolution of zinc ferrite is inefficient even in aqua regia. The Waelz process is an existing process to recover zinc from electric arc furnace dust by reduction using carbon monoxide followed by the volatilization of zinc. In this study, zinc was selectively extracted from zinc ferrite by partial reduction of zinc ferrite at relatively low temperature followed by leaching in dilute sulfuric acid (20 g/L). Pure zinc ferrite samples were partially reduced to zinc oxide and magnetite by using H2 gas as a reductant. The presence of magnetite and zinc oxide was confirmed by X-ray diffraction (XRD) technique. A maximum of 95%zinc extraction was achieved after leaching with sulfuric acid on the reacted samples. The paper also discusses the effect of time, temperature, and concentration of H2 in the reducing gas on the extraction of zinc and iron from ZF.

Sep 16, 2020

By I. D. Lindley

The Wild Dog vein gold deposit in East New Britain Province, Papua New Guinea, forms part of a recently discovered 26 km zone of auriferous quartz vein mineralisation. The deposit, which was discovered in July 1983, has no silt anomaly, and a panned concentrate anomaly and float train restricted to within 500 m and 800 m respectively, of the discovery outcrop. Discovery of the Wild Dog deposit was a result of the methodical followup of regional panning which, as followup progressed, was replaced in importance by float sampling. Of the sampling methods used during the exploration leading to discovery, panning and float followup provided immediate indications of the presence of mineralisation. This high degree of spontaneity of followup is not provided by geochemical techniques, and has obvious advantages in high cost exploration for precious metal deposits in remote locations.

Jan 1, 1988

By S. D. Bearden

Color enhances expression and communication in all physical objects experienced in life. Pigments provide color and in some applications have a specific additional function. Natural iron oxides are widely distributed throughout the world but only a few deposits are sufficiently pure and possess acceptable color and brightness properties to merit their processing into pigment form. Ochre, the common name for goethite ore, is the best and most under used material in the buff colored pigment market. The geological occurrence of ochre in the basal Shady Formation of the Cartersville Mining District (Georgia) is described. Exploration, processing, and product applications of New Riverside Ochre Company, Inc. are discussed. An overview of the worldwide pigment market is presented with emphasis placed upon the North American activity in iron oxide production and application. The purpose of this paper is to increase the awareness of ochre and its potential market in the colored iron oxide pigment industry, encourage research on the origin of ochre deposits, and stimulate interest in new applications of this unique substance.

Feb 27, 2013

By Roy A. Grancher

Construction materials indeed face a dilemma...as does the building industry as a whole. A stop & go economy; a severe drop; in housing starts; lingering indecision over just what corrective steps are to be taken or to their degree of commitment; no less basic disagreement in regard to which of the, Nation's problems is really the most pressing -- inflation or recession? Optimism has become a rare quality these days. At moat the cautious view is that this new year will see a long, hard struggle back, with hopes that 1976 at least can truly mark a dual anniversary celebration for the United States and its economic health. Yet the paradox is that once recovery does return, those very construction minerals and materials --which in recent years have experienced the ups and downs of overcapacity, shortage, and now declining demand again-- will once more face the spectre of mass inability to service revived and growing needs for its product. Mounting costs, present marginal expansion investment, and substantial lead times required for new facilities to come into production, could well form a bottleneck to economic upswing. The result again can be another cycle of shortage-induced inflation, and with it continued gyrations within the demand supply relationships of the country's building industries.

Jan 1, 1975

By Michelle L. Ramos

INTRODUCTION The Ballard Siphon was built in 1935 and consists of two 91.4 cm (36-inch) diameter wood-stave pipes. These pipes convey sewer flowsunder the Ship Canal from northwest Seattle and the Ballard Regulator to the North Interceptor and the West Point Treatment plant. The siphons were constructed using open cut construction, are now buried in the sediment on the floor of the canal, and have severely limited ability to be dewatered, inspected, or cleaned. The existing siphon is 394.7 m (1,295 feet) long from the junction structure on the southern shoreline to the regulator structure on the north. The location of the Ballard Siphon is shown in Figures 1 and 2. The area around the Ballard Siphon has become more populated and developed since the siphon was built. Additionally, the Ballard Siphon is subject to high flows that are greater than the capacity of the pipelines. This has resulted in predict-able Combined Sewer Overflows(CSO?s) whenever a large, long duration rain event occurs. The aged pipeline of uncertain viability has become a critical piece of the sewer system infrastructure. Because of the age of the pipelines and their importance, a sonar survey was completed on both barrels of the Ballard Siphon in December of 2005. The sonar images appeared to indicate crown intrusion of the wood-stave pipes, which suggested that the pipes were in imminent danger of collapse. As a result, an Emergency Declaration was executed by King County and the Ballard Siphon Replacement Project was initiated. Staheli Trenchless Consultants was retained to perform feasibility studies to deter-mine the viability of using microtunneling and horizontal directional drilling (HDD) for replacement of the Ballard Siphon. For the evaluations, the preferred site location was determined to be at or near the site of the existing Ballard Siphon in order to minimize the ancillary sewer work which would accompany moving to a new site. To meet flow demands and hydraulic requirements, the replacement siphon needed a mini-mum equivalent diameter of 182.9 cm (72 inches). This could be accomplished with a number of different siphon diameters and configurations including, but not limited to, three 106.7 cm (42-inch) diameter pipelines, two 152.4 cm (60-inch) pipelines, or two 91.44 cm (36-inch) pipelines and a 121.9 cm (48-inch) pipeline.