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By Mina M. Shinouda

Brightwater West (BT4) represents the state of the art in utility tunneling, namely a long relatively small diameter, soft ground tunnel, with no intermediate shafts, under significant groundwater pressures, requiring very precise survey control in order to hit a small exit window. The tunnel is over 6.4 km (4 miles) in length, is expected to encounter active earth pressures of over 5 bars in glacial geology, and a planned hole through into a shaft eye constructed at 45.7 meter (150 feet) below the water table. Despite the fact that all of these challenges have been previously overcome in larger diameter tunnels, the technical solutions are much more challenging in a smaller diameter due to the lack of space available for implementing the equipment and techniques required. In addition to the technical challenges, the project is faced with many of the constraints designed to minimize the impact of these types of projects on the neighboring community and environment. The work shaft for BT4 is within 15.2 m (50 feet) of Puget Sound and is on a site that was previously occupied by petroleum storage tanks, and all of the tunnel muck has to be removed from the site by barge as trucking is not allowed by contract. The paper addresses the work performed during the preparation for tunneling stage of this project both in assembling the TBM and in preparing the site for its arrival.

By Russel Delmar, Rick Everdell, Harry Charalambu, John Tait

Award of the Design/Build Agreement for construction of Ontario Power Generation’s (OPG’s) Niagara Tunnel Project was made after an intensive 8-month international procurement process. The 14.4-m diameter × 10.4-km long rock tunnel will divert 500 m3/s of water from the Niagara River to the Sir Adam Beck hydroelectric generating complex. The procurement process and Design/Build Agreement included features to address the owner’s requirements regarding risk allocation and cost and schedule certainty, while encouraging innovative ideas from the industry, both technically and commercially. The process included an international expression of interest and prequalification, followed by an invitation for design/build proposals to qualified proponents, and comprehensive proposal evaluations and negotiations with several respondent proponents. An honorarium was provided to the unsuccessful participants in the proposal stage. The resultant negotiated Design/Build Agreement includes Owner’s Mandatory Requirements, negotiated contract terms and conditions, performanceincentive bonuses and liquidated damages for schedule and water delivery performance, a multistaged Geotechnical Baseline Report, joint risk management, references to preexisting community impact agreements and measures to reduce impact on tourism. It also addresses regulatory approvals and permits, an owner controlled insurance policy that required reference to the International Tunneling Insurance Group (ITIG) Code of Practice for Risk Management as a condition of coverage, site specific safety, security and environmental plans, formal team building, a dispute review board, and escrow documentation.

Jan 1, 2007

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

M.S. Azun I have many objections to the content of the author's paper. Before discussing it, however, I would like to repeat the property of semivariogram function. Second order stationary properties of regionalized variables (ReV's) such as semivariogram function y(h) are perfectly known in geostatistics. Also, the kriging equations in the language of mathematical statistics using second order stationary properties are well understood. However, the way to use the sample (estimated) semivariogram function in any one of the kriging procedures is vague. The sample semivariogram function is given as follows: [ ] where N is the total number of samples, Xi is the sample value at the i - th location, Xi+h is the sample value at the i + h - th location, and h is the distance among the samples. An estimation variance of sample semivariogram function of first lag is smaller than that of higher order lag. The theoretical semivariogram function reaches the variance of samples asymptotically. But this is not easily observable because of the larger variation involved in the estimate of semivariogram function. In general, an estimation procedure is done for h = 0, 1, 2, up to the greatest integer less than N/2, even though sample semivariogram function can be computable through N-1. After estimating semivariogram function, the critical question of how to model sample semivariogram function arises. As seen in the above equation, sample semivariogram function is discrete and can be smoothed by the model being selected. Therefore, modeling of sample semivariogram function is the most important step in geostatistics. It not only smoothes a discrete function but also affects the results of the kriging procedure. When the only aim is to model the semivariogram function, which is the basic point of the author's paper, one can employ any fitting techniques, such as curve fitting, or any arbitrary functions, which are called submodels in the paper. The term "arbitrary function" is used rather than "submodel" because there is no basic understanding of developing them. The author suggests that the sum of those submodels can also be used for the modeling of sample semivariogram function. The combination of any arbitrary functions brings many problems instead of giving an insight of the domain structure considered. The author used two arbitrary functions and the nugget effect in response to sample semivariogram function (Fig. 10). For the same example, he stated that the parameters involved in the mixed arbitrary function model can be accepted when the discrepancy between sample semivariogram function and the model is small visually. For verifying the fitting behavior of any selected model, one should not be contented with the visual satisfactory. Some statistical measure such as goodness of fit has to be used. The author's practice is no more than an exercise in curve fitting without any fundamental understanding or conceptualization of the underlying physical mechanism. Furthermore, the selection of any model is not an easy task if the purpose is the search for the "best" response to the observed second order properties of ReV's. I suggest that the Markovian model (Azun, 1983), on the basis of a theoretical understanding of underlying mechanism, which gives more information about the occurrence of regionalized variables, is used to respond all properties of ReV's. There are a lot of problems for modeling of one-dimensional sample semivariogram function. Thus, it is not appropriate to go to higher order dimensional sample semivariogram function modeling. In the meantime, I would recommend that one can connect the values of standardized sample semivariogram function rather than simple values of semivariogram function in the two-dimensional estimation. The standardized values can be computed in dividing the semivariogram function value by the number of sample pairs involved in each lag regardless of the directions. In conclusion, geostatistics is an interdisciplinary area in mining that uses the principles of mathematical statistics. Thus, it should not violate any probabilistic and statistical rules. When Matheron was developing the theory of geostatistical study in the early years of geostatistics, many mining people had a reservation accepting the geostatistical tools. However, this does not mean that we, the geostatisticians, might try to convince those people using some "strange" tools or rules as some authors implied (Baafi and Kim, 1984). Instead, we have to develop and explain the geostatistical tools staying only in the framework of statistical concepts and properties. References Azun, M.S., 1983, "Stochastic Process Modeling of Spatially Distributed Geostatistical Data," Columbia University, Ph.D. Thesis. Baafi, E.Y., and Kim, Y.C., 1984, "Discussion - Comparison of Different Ore Reserve Estimation Methods Using Conditional Simulation," Mining Engineering, Vol. 36, No. 3, p. 280. Reply by J.M. Rendu The interactive method proposed by Rendu allows practitioners to develop semivariogram models that take into account not only the numerical information obtained by sampling, but also highly significant additional information that often cannot be quantified. The geology of the deposit - including hypotheses concerning its genesis, sampling methods, assaying methods, and mathematical methods used to calculate the semivariograms - all have an influence on the numerical results obtained and on how these results should be interpreted. If all the information concerning the spatial distribution of values in a mineral deposit was contained in the sample values, it could be argued that statistical techniques alone would produce optimum models. However, this is rarely, if ever, the case. Methods that allow the user to take into account his experience and his geologic understanding of the deposit should not be rejected for the sake of theoretical statistical purity.

Jan 11, 1985

By T. Mills, M. Evatz

Newmont’s Lone Tree Mine, located in northern Nevada, is an open pit gold operation supported by a standard truck and shovel mine production fleet (Caterpillar 785Bs and Hitachi EXs). Newmont continues to search for ways to decrease capital expenditure and lower operating cost, hence the implementation of the Ultra Light Body (ULW) concept. The fundamental idea associated with the ULWs is the increased payload potential. Economic justification comes from successful achievement of additional payload, within the truck’s rated GVW, without changing its loading and hauling characteristics. The increase in payload capacity allows equivalent tonnage movement using fewer trucks.

Jan 1, 2001

By I. A. Costa, Y. Fouquet, F. Barriga

"Lucky Strike and Menez Gwen are two hydrothermally active sites located along the border of the Azorean plateau, southwest of the Azores islands where the alteration processes affecting basaltic rocks are prominent (Costa et al., 2003). Here we report on a slabby brecciated rock, abundant at both Lucky Strike and Menez Gwen, composed mainly of basaltic fragments cemented by hydrothermal precipitates from warm fluid circulation system. Research reveals that hydrothermal alteration takes place mainly by replacement processes, in which silicification is dominant (Costa et al., 1997 and Costa, 2014).Petrographic observations, including scanning electron microscopy (SEM), microprobe analysis, and mass balance studies made on basaltic fragments within the breccia show that silicification is one of the main processes resulting from hydrothermal fluid circulation. This alteration process leads to complete replacement by silica, in extreme cases, forming an impermeable cap that may contribute to the formation of sub-seafloor sulphide deposits, including examples in the geological past."

Sep 1, 2014

By S. Shi, J. Y. Hwang, B. Li

Silver, copper, and zinc are commonly known elements with antibacterial and antifungal capabilities. Attempts have been made to dope silver on minerals, glass, and ceramics and the resulting materials have been investigated for their antibacterial and antifungal properties. Since silver is expensive and very reactive, silver doped materials have been found inappropriate in some applications. Copper-vermiculite is investigated as an alternative. Vermiculite has high cation exchange capacity on the magnesium ion in the crystal structure. Copper ion may have a high tendency to replace magnesium because of similar charge interference and ionic radius. Copper-vermiculite is prepared by reacting vermiculite and copper chloride solution. By impregnating copper ions into the nanometer openings between the layers of vermiculite, it is possible to render the composite with antibacterial functions if the copper ions could be released gradually from the composite. The antibacterial efficiency of Cu-vermiculite against Escherichia coli was studied using the Halo method. The results show that Cu-vermiculite is effective for preventing the reproduction of the bacteria. Heat treatment of Cu-vermiculite at up to 400°C does not show significant changes in antibacterial activities.

Jan 1, 2002

By Gunter Swoboda, Harald Wagner

Until a few years ago tunnel construction was based exclusively on experience. In recent years, however, numerical models have increasingly become an integrated part of tunnel design [2]. These models permit good evaluation of the tunnel's support behavior even before it is designed. In particular, numerical methods are highly suited for the development of new construction methods. The prerequisite for this is the application of high-performance pre- and postprocessors, permitting the design engineer to come to a quick interpretation of the analysis results. In future, 3D analysis will take on increasing significance, for which reason this paper also deals with this type of models.

Jan 1, 1993

By Thomas P. Kwiatkowski, Joginder S. Bhore, Christopher D. Orlandi, Jose Velez

Three case histories of successful TBM tunneling for New York City Water Tunnel No. 3 are presented. The tunnels, costing about one billion dollars total, are the 5-milelong, 18'-11" OD Brooklyn Tunnel; the 5-mile long, 23'-2" OD Queens Tunnel, and the9-mile long, 12'-4" OD Manhattan Tunnel. The three tunnels are the first major tunnels constructed in New York City rock utilizing the TBM method of construction. This paper describes and compares the three tunnel projects in terms of geology, construction methods, TBM’s, rock and groundwater behavior, rates of advance and other performance data, and challenges and solutions encountered during the projects.

Jan 1, 2007

By R. J. Sweigard, C. T. Justice, T. Beckham, E. D. Thompson, T. C. Hopkins

Fine coal refuse is often pumped, as slurry, into surface impoundments as a means of permanent disposal. As the available volume is filled, the height of the embankments are frequently increased. Many times the additional embankment material is placed upon consolidated fine coal refuse. There has been some concern about the long-term effect of consolidation of this material at or above the liquid limit upon its shear strength. A laboratory investigation was performed using three different types of fine coal sluny taken from Central Appalachian coal preparation plants. The refuse was consolidated in 10-foot plexiglass columns under incremental amounts of surcharge loading. The incremental loads were designed to simulate the effect of increasing the height of a refuse embankment on top of the consolidating coal slurry. After the refuse in the columns had consolidated for several months, the columns were cut apart and triaxial tests were performed on both the consolidated material and unconsolidated material for comparison of their shear strength parameters.

Feb 24, 1997

By R. L. Virta

Twenty-three companies mined kaolin in nine States in 2004. Production was estimated to be 7.6 Mt (8.3 million st) valued at $912 million, based on preliminary data. This was a slight decrease from 7.68 Mt (8.46 million st) valued at $939 million in 2003.Georgia was the leading producer state with an estimated 6.5 Mt (7.1 million st) in production. It was followed, in decreasing order of tonnage, by South Carolina, Alabama, California, Texas, Arkansas, Nevada, Florida and North Carolina. Georgia accounted for nearly the entire domestic water-washed, delaminated, and pigment-grade calcined kaolin production. Consumption Sales to the paper industry accounted for 49 percent of domestic sales and 64 percent of total sales. Other major markets for domestic sales were refractory products (10 percent), paint (5 percent), fiberglass (4 percent), catalysts (3 percent) and rubber (2 percent).Paper coating and filler markets accounted for about 87percent of export sales of kaolin.

Jan 1, 2005

By W. H. Dickinson

The performance of seven antiscalants spanning a range of chemistries was evaluated for control of calcium carbonate (CaCO3) formation in gold processing applications. Three preferred chemistries were identified which provided up to 100 percent inhibition in static jar tests when applied at 30 ppm dosage. The three products were further evaluated using a model carbon extraction circuit developed for this application. The test circuit enabled direct measurement of calcium carbonate formed on the carbon from a supersaturated solution under dynamic conditions. The antiscalants lowered CaCO3 buildup on the columns by 15 - 26 percent compared to untreated controls. Impact of the antiscalants on the rate and extent of gold loading onto a carbon adsorbent was evaluated in laboratory carbon-in-pulp (CIP) studies. The antiscalants generated a 25 - 35% increase in gold loading at gold extraction efficiencies up to 65%. On-site testing at a gold processing facility demonstrated that 10 ppm of the preferred antiscalant was able to fully suppressCaCO3formation in thickener overflow water.

Feb 27, 2013

By L. B. Hales

Expert control of grinding and flotation plants has been successfully used in the minerals industry since the 1970?s. The earliest of these systems were written in a hard-coded fashion in FORTRAN, BASIC or Pascal. Second generation systems were built using the first experimental expert system shells that were being developed in the artificial intelligence community. Later systems were deployed in expert system shells designed for real-time processing plants that also included the ability to model the process with neural network models and optimize setpoint selection through the use of genetic algorithms. Significant performance increases have been achieved using these systems, but in general, they suffer from the static nature of their rules and to a degree the process models also. Typical improvements quoted in the literature suggest throughput rate increases of 4 to 8 percent and recovery increases of 1 to 4 percentage points. In over 30 years of designing and installing expert systems we have never seen performance numbers less that these but have often seen numbers in excess of the high values. However, once the system has been installed and tuned up the performance usually does not improve much thereafter. Granted, the initial increases in throughput rate and recovery are significant but a question always lingers, that is, can the expert strategies be modified further to squeeze a little more improvement out of the system. The answer to this question is a resounding yes, however a complete understanding of what we do well as designers and operators of expert control systems is required as well as how we can improve upon our best practices is required to move us from the performance plateau we have been on for a number of years to a new higher level of performance.

Jan 1, 2009

By D. R. Wilburn

This summary of international mineral exploration activities for 2006 draws upon avail-able information from literature, industry and U.S. Geological Survey (USGS) specialists. The summary provides data on exploration budgets by region and mineral commodity, identifies significant mineral discoveries and areas of mineral exploration, discusses government programs affecting the mineral exploration industry and presents analysis of the mineral industry based upon these data. Two types of information are reported and analyzed in this annual review. They include budgetary statistics provided by Metals Economics Group (MEG) of Halifax, Nova Scotia, and information on regional and site-specific exploration activities that took place in 2006 compiled by the USGS.

Jan 1, 2007

By William R. Yernberg

The combined 78th Annual Minnesota Section of SME Meeting and 66th Annual University of Minnesota Mining Symposium was held April 19 and 20, 2005, in Duluth, MN. More than 300 mining professionals, including engineers, executives, mining managers and suppliers, from throughout the United States and eastern Canada attended the meeting. This year’s theme was “Global Demand: A Window of Opportunity.” The meeting included a keynote address, technical presentations and a trade show. The atmosphere at this year’s meeting was upbeat. The iron ore mining industry in Minnesota is experiencing one of its biggest turnarounds in history. Because of greater demand, iron ore prices increased 20 percent during 2004 and 71.5 percent so far in 2005.

Jan 1, 2005

By W. X. Wang

In the mining and quarry industries, rock fragments are often transported by conveyor belt. To estimate the qualities of the rock fragments (i.e., size distribution and shape), an operator must take samples from the conveyor and manually perform a sieve analysis, which is time-consuming and tedious. Alternatively, an image-analysis system can be used to monitor the fragment quality on a fast moving conveyor belt. However, images of fragments on a fast moving belt vary to such a degree that the quality of any two successive images are not the same, and some of the images are of such poor quality that they are unrecognizable by human eyes. If poor-quality images are directly analyzed by a segmentation algorithm, the analysis will not be satisfactory. To resolve this problem, it is necessary to use an image-classification pro-gram for the automatic selection of fragment images with good quality. Because of this need, an image-classification program was developed and tested both in the laboratory and in the field. Testing of the system on different types of fragments showed that the system works reasonably well.

Jan 1, 1996

In this paper, uniaxial compression tests were conducted on intact rocks and broken rocks that were reinforced by grouting, and the effects of grouting on the strength of broken rocks were analyzed. The results show that after grouting reinforcement, the bearing capacity of broken rocks with different lithologies increased, and their uniaxial compressive strength recovered by approximately 6%–16%. The results indicated that the stronger the rock, the smaller the strength recovery of the consolidated body formed after grouting. At the same time, using borehole camera observation and deep overburden strata separations, the fracture development characteristics of surrounding rocks of the gob-side retained entry were analyzed and divided into different regions. On this basis, a guided grouting method was proposed; that is, shallow hole grouting was first used in the plastic zone of the broken surrounding rocks to form the isolation layer, and then deep grouting holes were arranged in the elastic-plastic zone of the transition zone to guide the slurry flow to the shallow unfilled zone. Therefore, the broken surrounding rocks were reinforced into an integrated body and selfbearing capacity improved.

Jul 28, 2020

By S. Chander, S. W. Musselman

The molecular structure of hydrophobic and hydrophilic groups in nonionic surfactants has been related to the wetting and dispersion of selected pigments. The nonionic surfactants included in this study are acetylenic diol based surfactants and ethoxylated alkyl phenols. The Langmuir model could be used to fit adsorption data. Further analysis of the data showed that the free energy of adsorption was a function of adsorption density of the surfactants at the interface. The change in free energy with adsorption density could be interpreted by considering a change in the orientation of the adsorbed molecules. Acetylenic diol based surfatants were found to have an area per molecule of 2-3 times that of similarly ethoxylated alkyl phenols. The wetting and dispersion properties of lamp black, a model hydrophobic surface, by these surfactants were investigated by contact angle measurements and particle size analysis. Acetylenic diol based surfactants with ethylene oxide contents between3.5 and 10 moles per molecule and alkyl phenol based surfactants with approximately 9 moles of ethylene oxide per molecule were found to provide superior wetting abilities. Longer ethylene oxide chains were required for superior dispersion capabilities within each family of surfactants. Complete wetting and dispersion was found to occur above the critical micelle concentration of the surfactants.

Jan 1, 2000

By H. R. Butler, J. F. Church, A. T. MacGibbon

Introduction Inco is the major North American nickel producer. Initially based in Sudbury, Ontario, its past exploration activity was directed toward finding new nickel deposits. New nickel sulfide discoveries outside Sudbury have included Thompson, Manitoba; Shebandowan, Ontario; and Widgiemooltha in Western Australia as well as a host of nickel laterite deposits. The company is currently diversifying into other commodities, including gold. Inco's exploration department participated in uranium discoveries in Saskatchewan and chromite discoveries at Tiebaghi in New Caledonia. In addition, it found new gold deposits at Lupin, Northwest Territories; Crixas, Brazil; Hoyle Township, Ontario; and Casa Berardi in Quebec. Crixas and Casa Berardi are currently being evaluated by underground exploration. Figure 1 shows some Canadian Shield gold locations where Inco is or was an active participant. Base metal developments Base metal exploration in shield areas has been greatly eased by applying scientific studies. Archean nickel sulfide deposits have been found using komatiitic-flow models (Fardon, 1971). Volcanogenic massive sulfide model has been applied to copper-zinc deposits (Sangster and Scott, 1976). Such deposits were subsequently seen developing on the sea floor through black smokers (Spiess, MacDonald, and Atwater, 1980). Sedimentary processes were recognized early as important in ore formation, particularly in the southern hemisphere (King, 1976). And many ore deposits are now regarded as a simple part of the geological column (Stanton, 1960 and 1972). Petrographic work on alteration patterns in and around ore bodies was used to develop standard porphyry copper models (Lowell and Guilbert, 1970). Epithermal models for precious metals followed. Stratigraphic zonation patterns have been formulated for base metal deposits, including keel facies, ore facies, and cap or distal facies. Gold developments The work on base metal deposits naturally spilled over into precious metal exploration when the gold price was allowed to float on world money markets. Early work on elements associated with gold deposits, especially arsenic, tellurium, selenium, and mercury, pioneered more detailed geochemical work (Bagby and Berger, 1985; and Groves, Ho, and Houstoun, 1984). Geochemical patterns have been recognized around microfine gold deposits. And the study of gold precipitation patterns in modern geothermal systems has helped understand gold deposition. In the late 1960s and early 1970s, it was noticed that numerous Archean banded iron formations contained anomalous gold values. From this and other observations, the syngenetic exhalite gold model has developed. Gold deposits also occur along shears in some plutons such as the Belmoral mine in Quebec. This indicates the importance of epigenetic processes in ore formation. Shield ore settings Initial studies recognized that the major gold camps in the Canadian Shield were mostly in greenstone belts and found along "breaks," especially zones of faulting and sedimentation. Gill (1948) wrote, "Only recently, as a result of detailed mapping, has the importance of major schist zones such as the Larder Lake, Cadillac, Porcupine Creek, and Destor Breaks been recognized. These zones of persistent adjustment mark broad belts favorable for ore occurrence." The importance of shearing in ore location and regional greenstone stratigraphic position close to late sedimentary packages was clearly understood. And structural models have been further developed for some Canadian ore deposits (Hubert, Trudel, and Gelinas, 1984). In the Beardmore-Geraldton camp of northwest Ontario, the importance was soon recognized of fold noses in banded iron formation, as localizers for gold ore. This importance had also been recognized in Western Australia,

Jan 2, 1987

By D. Rahal

All ores have an economic optimum particle size (Wills and Napier-Munn, 2006). This optimum value is often a compromise between the need to achieve adequate liberation for the efficient separation and recovery of valuable minerals and the energy consumed by the crushing and grinding process. It has been recognized for nearly three decades that grinding is the most expensive and least efficient stage in mineral processing (El-shall and Somasundaran, 1984). At that time it was estimated that grinding consumed between 25 and 70% of the total power required in mineral processing. This recognition drove the development of new stirred mill fine grinding technology in the 1990s (Jankovic et.al, 2003; Enderle et. al., 1997; Massey, 2008). These milling technologies have a reduced energy consumption compared to traditional fine grinding using ball mills. In the ?coarser? fine grinding applications this improvement is approximately 30%. The benefits increase to above 50% in ultrafine grinding applications (Lichter and Davey, 2006). Despite these gains, the US Department of Energy reported that an additional energy savings of up to 37% is possible in the minerals industry. They identified continuing research and development and implementing best practices in both grinding and materials handling as the primary avenues for the additional reduction (BCS, 2007).

Jan 1, 2011