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By D. N. Adams, M. M. Wong, M. J. Robison

Islais Creek Contract E, a transport/storage tunnel in San Francisco, was visited on a fieldtrip during construction by delegates to the 1995 RETC. This paper is a follow-up to that fieldtrip. The project’s two tunnels are 3.7 m and 3.2 m finished diameter, 155 m and 77 m long, respectively. The contractor used 1,000 overlapping jet grout columns to pre-treat the weak Bay Mud along the tunnel alignments, then mined them with an open faced tunnel shield, eliminating the need for compressed air tunneling. This paper documents the jet grouting program and the tunneling operation used on the project.

Jan 1, 1997

By S. T. Kok

This paper presents a case study in West Malaysia for passive piles failure in very soft marine clay in open excavation. In this particular case, the thickness of the very soft marine clay ranges from 5 m to 7 m (16 ft to 23 ft) from the ground surface. Preliminary site investigation reported SPT ?N? value of zero for the very soft marine clay. The design was based on a deep foundation utilizing driven piles to support the superstructure. During pile cap construction, the piles were subjected to uncontrolled open excavation, inducing bending moment in the piles, resulting in some cracked and broken piles. Analyses were carried out using an existing three-dimensional finite element code with a non-linear soil model to predict the response of these piles during excavation. Finally, the predictions of pile responses during excavation were compared satisfactorily with the observed results.

Jan 1, 2009

By Thompson D. R, Milton R, Perry K. M A

From the Department for Research in Industrial Medicine (Medical Research Council), The London Hospital; and the De Havilland Aircraft Company:M.R.C. INVESTIGATIONS IN 1936In 1936 the Industrial Pulmonary Disease Committee of the Medical Research Council investigated both clinically and radiologically a group of fifty workers who had been exposed for a number of years to the inhalation of alumina in the reduction factory of the British Aluminium Company. The results are shown in Table 1.They also considered the sickness records of all the workers (Hill, 1936), as compared with those in other parts of the factory (Table 2).

Jan 1, 1945

By John D. Godfrey

Geological mapping on the Canadian Shield in northeastern Alberta outlined severalgranitoid rock massespotentially suitable as building stone. A particularly attractive prospect, the Chipewyan Red Granite, was subjected to an aerial survey and ground check. The petrologic and fracture characteristics critical for quarrying and use as a building stone were assessed in the course of detailed mapping at two of the most favourable sites. The extension of good rock was tested to shallow depths at one site by shallow diamond-drill coring. , The Chipewyan Red Granite displays a warm red colour, medium grain size and fairly massive texture, and takes a good polish. Deleterious geologic features studied in outcrop and subjected to structural analysis included regular joint systems, quartz veins, pegmatite dykes, basic shear zones and fault zones. Many of these key geologic features are systematic and hence predictable for stone quarrying purposes; other features, such as irregular fracelM tures, are non-systematic and arefar less predictable. The megascopic structural features studied show similar preferred orientations which appear to be collectively related to the tectonic history.

Jan 1, 1979

This paper forms the second of a series, in which it is proposed to communicate the results of an extensive research into the influence of alloying elements on the physical properties of lead, now being carried out in the Metallurgy School of the University of Melbourne.Some general comments on this research were made by the present writer as an introduction to the first contribution by R. S. Russell*: It was there pointed out that it was the intention to prepare lead as pure as possible, to determine its properties and then to make alloys with the various elements added singly, and in various combinations, in order to determine the effect of each. This line of action is still being pursued.It occurred to the writer, however, that this fundamental attack might, with advantage, be accompanied by a parallel investigation in which lead of commercial purity would form the basis material. In this way, using a standard *Professor of Metallurgy, University of Melbourne.

Jan 1, 1934

By Lawrence M. Gochioco

The interpretation of coal seismic data requires a certain precision and accuracy to make the results more reliable. The signature of the seismic wavelet provides a host of valuable geologic information. Subtle features and anomalies, not easily observed in conventional black and white seismic sections, are enhanced through color attribute displays in terms of frequency, amplitude and phase. Coal seam anomalies like sandstone washouts produce a distinct pattern in frequency and amplitude displays due to the change in the net acoustic impedance contrast. Faults produce frequency and amplitude variations due to interference within the Fresnel zone that straddles the fault. The magnitude of displacement is estimated by studying the effects of faults on reflection amplitudes and frequency from computer-generated models.

Jan 1, 1989

By Bhaskar B. Thapa

The design of the Caldecott 4th Bore, located along State Route 24 in Oakland, California, is based on the principles of the New Austrian Tunneling Method (NATM). Typical NATM initial support design practices used in Europe were adapted for this project to account for U.S. conditions and requirements, such as degree of experience with NATM construction, the prevailing contractual environment, and preferences for contractual simplicity. Key design features are: (1) support selection criteria based on ground behaviors and ground conditions; (2) a prescriptive design with allowance for support adjustments based on observations during construction; and (3) organization of support requirements into only four major support categories, while permitting some adjustment for variations in ground behaviors and conditions using a few subtypes and additional support measures.

By John A. Herbst, Alexander Potapov, Xiangjun Qiu

"High Fidelity Simulation is a name applied to the use of first principles modeling tools including Discrete Element Modeling (DEM), Computational Fluid Dynamics (CFD) and Discrete Grain Breakage (DGB) to mathematically describe and study processing systems. Over the past few years, significant advances have been made in High Fidelity Simulation applications, particularly as many mineral processors have been drawn to the study and use of DEM of grinding mills for optimization purposes. This presentation provides an introduction to High Fidelity Simulation, with an emphasis on DEM. It will include insights into current applications of these tools including the optimal design (wear and throughput) of mill lining systems and media selection, the analysis and design (flow and efficiency) of the back-end of grate discharge mills. Advantages of full mill simulations versus individual sub-process simulations will be demonstrated for a SAG mill with different discharge system designs.INTRODUCTIONHigh Fidelity Simulation is providing mineral processors with the opportunity to analyze the behavior of mineral processing equipment from a fundamental or microscale point of view. In the past complex phenomena such as tumbling mill grinding had to be analyzed using black box tools such as residence time distributions for transport and classification functions for passage of particles through grates; while breakage had to be analyzed using PBM models who derived their form from theory but required direct measurement of kinetics. Today with the help of DEM, CFD and DGB these can be analyzed at a very fundamental level.The key element of DEM simulation is the application of Newton’s laws of motion to individual objects or discrete elements. Using this simulation method one can describe the position, velocity (both translational and rotational) of all objects and the transfer of momentum to other objects (Mishra and Rajamani, 1992; Cleary, 1998; Nordell et al, 2001)."

Jan 1, 2003

By P. Cole Gregory, Michael R. Yenchek, John C. Edwards

The U.S. Bureau of Mines investigated the performance of portable power cables under transient conditions. This research had a twofold purpose: (1) to define the thermal characteristics of electrically overloaded trailing cables, and (2) to conceptualize electrical protection for cables that allows maximum cable efficiency without diminishing electrical safety in underground mines. Several tasks were under- taken in support of these goals during the 3-year research effort. Overload tests ranging from 2 to 12 times rated ampacity were conducted in the Bureau's Mine Electrical Laboratory. Two thermal models of energized type G-GC trailing cables were constructed, one based on thermodynamic theory and the other using empirical data from previous Bureau load tests. The empirical model was then incorporated into an interactive computer program that can assist designers and approvers of mining machines in selecting the appropriate size trailing cable. This program can be the basis for a cable protection system that ensures that cables are not the source of fires, ignitions, burns, or explosions underground.

Jan 1, 1993

By O. Rabeau, M. Legault, A. Cheilletz, L. Z. Cheng, J. J. Royer, M. Jébrak

"By compiling geological, structural, geophysical, and geochemical information into a 3D geological model, we evaluated the orogenic gold potential in the vicinity of a hidden segment of an important Archean fault zone, the Cadillac-Larder Lake fault (CLLF) in the region of Rouyn-Noranda. The segment of CLLF in the present study is partly covered by Proterozoic sedimentary rocks. Because more than 2000 t Au have been extracted along the CLLF to date, our objective is to evaluate the gold potential at depth along a poorly known segment of this fault. A 3D geological model (50 km × 9 km × 1.5 km) including the covered segment was built through the compilation and homogenization of available geological data and the construction of 23 cross sections. The geology under the Proterozoic cover was evaluated using geophysical inversions, drill holes (42 in total), and surrounding geology. All available assays were filtered and upscaled to a 250 m × 250 m × 250 m regular cell grid to determine and quantify spatial relationships between geological features and mineralized occurrences using the weights of evidence method. Structural features, such as E-W-trending faults and fault intersections, and certain lithologies with a high primary porosity such as volcanoclastic rocks of the Blake River Group and Timiskaming sedimentary rocks, proved to be very prospective, yielding favourable factors with a weight of evidence index W+ > 0.24. These salient features were then assigned a combination index for ultimately evaluating the orogenic gold potential under the sedimentary cover. The zones resulting in an optimization of exploration targeting were attributed the highest probability, representing ~1% of the initial volume. La compilation des données géologiques, géophysiques, structurales, et géochimiques et leur intégration au sein d’un modèle géologique 3D a permis d’évaluer le potentiel aurifère dans les environs d’une importante zone de faille archéenne sous couverture protérozoïque. Cette méthodologie a été développée en utilisant le cas de la Faille Cadillac-Larder Lake (FCLL) dans la région de Rouyn-Noranda. Puisque plus de 2000 t d’Or ont été extrait à proximité de la FCLL, l’objectifs des travaux est l’évaluation du potentiel aurifère en profondeur de ce segment. Un modèle géologique 3D (50 km × 9 km × 1.5 km) incluant le segment sous couverture de la FCLL a été construit en utilisant l’ensemble des données géologiques disponibles et 23 coupes géologiques. La géologie du socle archéen sous la couverture protérozoïque a été interprétée avec des inversions géophysiques, des forages (42 au total) et les contacts géologiques exposés. Les teneurs aurifères dans le secteur ont été filtrées et ajusté à une grille régulière de 250 m × 250 m × 250 m afin d’évaluer et de quantifier les relations spatiales existantes entre certaines entités géologiques et les emplacements minéralisés en utilisant la méthode du poids de la preuve. Les failles de direction Est-Ouest, les intersections de failles ainsi que certaines lithologies possédant une porosité primaire importantes comme les certains tuf du Groupe de Blake River et les sédiments du Timiskaming se sont montrés très prospectifs avec des valeurs de W+ > 0.24. Ces entités géologiques ont ensuite été utilisées par le biais d’un indice de combinaison pour évaluer le potentiel en or de type orogénique sous le couvert sédimentaire. Cette méthodologie permet une optimisation des campagnes d’exploration puisque les zones pour lesquelles la probabilité de minéralisations a été évaluée à la plus haute valeur représentent 1% du volume initial."

Jan 1, 2009

By Natalia Konstantinova, Georgy Novikov, Pavel Rekant, Goergy Cherkashov, Olga Bogdanova

The economic interest of oceanic ferromanganese crusts and nodules is determined by high grades of major, rare and earth rare elements in these types of marine minerals [1]. Modern oceanic ferromanganese deposits have a global distribution with the largest fields in the Pacific Ocean. The Arctic Ocean still remains a poorly explored region. The first ferromanganese deposits from the deep part of the Arctic Ocean were recovered almost at the same time in 2012 both in US and Russian cruises to the Chukchi Borderland (1) and Mendeleev Ridge (2). Preliminary results of mineral deposits from the first area were reported at UMI-2012 by James Hein et al. [2]. We present here the data of ferromanganese deposits from the Mendeleev Ridge.

Sep 1, 2014

By David O. DeGagné

While mine backfill plants are becoming increasingly more automated and instrumented, especially with paste fill operations, underground backfill distribution systems have hardly changed over the years. While fill properties are appropriately measured in the preparation plants, as backfill enters the mine borehole, the technology for control, data gathering and reporting is somewhat lacking. Mines typically experience problems with borehole and pipeline plugging, pipeline bursting, bulkhead failure and exposed fill sloughing. With adequate instrumentation of the backfill system it is possible to obtain a complete, continuous and detailed picture of the entire filling operation from preparation to post-pour. Good data will, over time, provide the basis for needed improvements of backfill systems and will be essential to safer, more efficient and less costly fill practices. This paper will review the areas of the filling operations where monitoring would prove critical to eliminate failures such as pipelines, bulkheads, fill exposures, stope walls, etc. The types of monitoring systems currently available will be reviewed and potential areas for development will be highlighted.

May 1, 2001

Green policies have gained momentum since the 1972 Stockholm, Environment Conference. The environmental movement has influenced political initiatives both in New Zealand and abroad. Governments and international institutions have addressed local, regional and global environmental issues with varying degrees of success. New Zealand so far has not supported the United Nations' call for sustainable development in a consistent manner. New institutions and new rules for resource management mean there are opportunities to look after the land in different and more ecologically sensitive ways than has happened in the past. The increasing influence of regional councils in resource management planning will have important implications for mining and mineral exploration. These trends are discussed and possible future events outlined. Green policies have gained momentum since the 1972 Stockholm Environment Conference. Environmental issues are now global and the twentieth year Environment Conference planned for 1992 is likely to see new commitments made by world leaders and their national governments. Green politics may be the popular trend of the moment but green principles of managing the earth's resources are here to stay. There are many businessmen, many technologists, and many politicians who have hoped that the environmental movement was a passing fad and would fade into oblivion. The evidence is otherwise. Far from passing into oblivion, the environmental movement is growing rapidly. Each year brings further scientific data that indicates mankind is on a self destructive course unless we learn how to better manage the earth's natural resources. This information has contributed to a growing population of environmentally aware people. In the last 20 years there have been messages of concern about a population increase out of control and the energy crisis which focused on dwindling oil stocks. The issues are all interrelated including the present global issues of climate change and thinning ozone layers. The attention being given the messages by the United Nations and member states requires similar attention by industry. The problems have been identified; the challenge is to determine what should be done about them. Every challenge brings new opportunities and the future need not be doom and destruction. Mining is seen by some of the environmental action groups as unnecessarily destructive of the environment, but I do not see mining ceasing in the next few decades. Rather, the rules will be clearer with some areas excluded from mining, the methods of extraction will improve, the technology of processing will become more sophisticated and restoration of mining sites will be not only normal practice worldwide, but the end result may leave no hazards, may enhance the landscape and may result in acceptance of the industry by the general public. For that to happen, commitment and cooperation is required between the industry, the government, and society. As an Officer of Parliament my role is to review the system of agencies and processes established by Government for allocating, using and preserving natural resources and to report whether the system is maintaining and improving the quality of the environment. I also have a responsibility to see that the environmental planning and management carried out by public authorities is effective. That Ineans I have a keen interest in how the mining industry is administered by New Zealand public authorities, including Ministers of the Crown and district and regional councils. Today I intend to review the approach to resource management being taken by international agencies and by the New Zealand Government, and to comment on how environmental impact assessment for mineral exploration, as well as mining, may be administered in the future.

Jan 1, 1990

By J. C. Escobedo, J. M. Almanza, A. Flores, Cortés. D. A.

Secondary aluminum dross, which has been exposed for several years to atmospheric conditions, was characterized using chemical analysis, X-ray diffraction, optical and scanning electronic microscopy, and energy-dispersive spectroscopy. Based on the characterization, a method to purify the solids is presented. This method starts with the washing of the dross in boiling water to eliminate the soluble compounds like Na and K, followed by the physical separation of the metallic aluminum by milling and screening. Finally, an acid lixiviation process is applied using three different acid solutions, HCl, HNO3, and H2SO4. The best results were obtained using HCl. The main insoluble components of the dross after lixiviation were Al, SiO2, and Al2O3. MgAl2O4, AlN, Si, and Na2Al22O3·2H20 species were also found. Based on the alumina content, the solid product could be suitable as a raw material in the manufacture of castable refractories or metal matrix composites.

Jan 1, 2005

By A Raza, D P. Kohn, D A. Foster, A J. W Gleadow

A large and increasing data base of apatite fission track results from sedimentary and granitic rocks exposed within the south-eastern highlands and along the continental margin ofAustralia provides constraints for the tectonic development of the south-eastern passive margin. The fission track results suggest that many regions of the south-eastern margin of Australia experienced distinct episodes of relatively rapid cooling during the middle Cretaceous to early Tertiary that can be attributed to the effects of rifting. One cooling episode is middle Cretaceous in age and related to denudation of the south eastern highlands from Tasmania to northern New South Wales between ~90 - 100 Ma. Rocks exposed along the present coast line record a later episode of rapid cooling, which is diachronous and decreases in age northward from ~80 to 90 Ma in northern Tasmania to southern New South Wales, ~60 - 80 Ma in central and northern New South Wales, and to ~50 - 60 Ma in southern Queensland. The results are consistent with models suggesting that underplating occurred inward of the rift along the eastern margin of Australia as a result of the onset of continental extension in the Tasman Sea at ~96 Ma. This resulted in a significant change in base level and km-scale denudation of much of the southeastern highlands. Subsequently, as breakup commenced during the Late Cretaceous at ~80 Ma and continued into the Paleocene at ~60 Ma, the second stage of cooling was imprinted on the rocks along the margin. This cooling is probably due to the relaxation of elevated geothermal gradients associated with rifting as well as some denudation. Because rifting was oblique to the present-day coast, different regions record different ages of cooling associated with the rift. The southern regions of New South Wales and Victoria yield ages associated with earlier rifting while regions of northern New South Wales and southern Queensland give ages associated with later rifting.

Jan 1, 1995

The compliance sampling method for coal mine dust in the United States has not changed appreciably in the last 30 years. A call for more frequent sampling with immediately available results is leading to new instruments that may supplement or replace the existing sampler. This report discusses two such instruments that provide immediate results of dust levels. The first, called the Respirable Dust Dosimeter (RDD), is designed to supplement the existing U. S. cyclone compliance sampling method. It uses the pressure drop across a filter to provide an inexpensive screening type of measurement. The RDD has been tested in the laboratory and a limited number of coal mines. Side by side testing has compared the RDD performance with personal coal mine samplers in triplicate area sample measurements. Results show that the differential pressure of specific filtration media can be an effective surrogate for respirable mass. Data show that there is a dependence on coal type and an effect of relative humidity. There also appear to be two distinct responses related to coal type. For specific coals the coefficients of determination, R2, are better than 0.9. For general use the detector tube, using laboratory generated calibration curves, can be used to estimate respirable dust levels. However, a calibration to a specific coal type may substantially improve the accuracy. Another sampler in development is called the Personal Dust Monitor (PDM). Designed to give compliance quality accuracy, the PDM uses the frequency change of a vibrating element to measure dust and give immediate feedback of results. Results of laboratory comparison of the prototype PDM sampler to personal gravimetric samplers indicate R2 values of better than 0.99 for three different coal types. Work is in progress to package the components into a person-wearable unit combined with a cap lamp system with a total projected weight of less than 1.4 kg (3 lbs).

By A. M. Elmahdy

An amphoteric collector was tested for dolomite removal from phosphate ore. The effects of some operating parameters and their significance on the flotation of dolomite were studied using statistically designed experiments. The parameters studied were impeller speed, pH and collector dosage. Analysis of the results showed that pH is the most significant parameter. Moreover, a concentrate containing 0.53% MgO and ~31.1% P2O5 with a recovery of ~ 90% can be achieved at optimum values of studied parameters, i.e., a pH of 12, an impeller speed of 1,000 rpm and a collector dosage of 2.5 kg/t.

Jan 1, 2007

Factors of importance in the ntilization of coal fines are mentioned, and the results of flotation tests on coal fines from three important coal seams in New South Wales are presented.INTRODUCTIONEconomic utilization of fine coal is an important problem in the Australian coal industry, particularly as the proportion of fines mined is increasing with progressive mechanization.While the use of uncleaned coal fines may be economic, it may be preferable to beneficiate them, but the most economic process must be selected.For beneficiating coal finer than about 28 mesh, froth flotation can be applied, but mining engineers should avoid practices that may be detrimental to flotation. Such practices include the indiscriminate use of water, particularly that containing a wetting' agent, for dust suppression. In addition, clay stemming in wet conditions may produce slimes which could adsorb on coal surfaces, while the use of oils and greases as well as the application of stone dust and chlorides in roadway consolidation may influence adversely fine coal beneficiation.This paper deals with the application of flotation to samples of fine coal from the Bulli, Greta, and Victoria Tunnel seams. In addition a discussion is given of the mineralogical constitution, size analysis, and degree of liberation of ash constituents of the various samples.COAL SAMPLESRepresentative samples of coal from the Bulli, Greta, and Victoria Tunnel seams were obtained for testing.

Jan 1, 1961

By Tristan H. Jones

Beginning in 1987, miniature dataloggers approved by the Mine Safety and Health Administration (MSHA) were publicly available for sale. The principal among these was the model CR21XQM, manufactured by Campbell Scientific, Inc. These dataloggers had been tested and were deemed permissible by MSHA and thus could be installed in the return air of an underground coal mine. In 1996, production of all permissible Campbell Scientific dataloggers ceased due to lack of sales. Data collection with these dataloggers has been a staple of ground control research in the United States for decades, and, without them, or a replacement, the capability to monitor ground behavior is severely impacted. Since that time, any party requiring a permissible datalogger has needed to borrow one that was purchased during the production years. In order to fill this technology gap and ensure its own data-gathering capabilities, the National Institute for Occupational Safety and Health (NIOSH) has developed and refined its own miniature data acquisition system (MIDAS). On February 16, 2010, MSHA deemed the MIDAS to be permissible and approved it for use in the return air of an underground coal mine. The MIDAS is an intrinsically safe, 16- or 24-bit datalogger, compatible with a wide range of resistive, single-ended, and differential-type instrumentation. It contains enough data storage memory to operate for over a year with typical data rates and is efficient enough to do this on a single C-sized alkaline battery for that entire period. It is menu-driven and requires no programming knowledge to operate. It supports wireless or hardwired communication for datalogger setup and data download. This paper describes the design, field and laboratory testing, and capabilities of the MIDAS datalogger. While not as fully -functioned as the CR21XQM, it is the only new permissible datalogger available, and there is intent to make it available to the mining industry for purchase.

Jan 1, 2012

By Davies S. G, Mackey L. C

The oxidation of iron and nickel sulphide concentrates, and the dominant sulphide minerals which comprise them, has been studied under ignition conditions using thermogravimetry (fG). The concentrates were derived from various minesites and they showed differing tendencies to ignite. Ignition temperatures ranged from 416 to 488°C and the extents of reaction, measured at 500°C, varied from 64 to 88 percent. The reactivity of the least reactivematerial was improved significantly by grinding. Particles <63/lm showed 85 percent oxidation compared with 55 - 65 percent for particles >63/lm.Examination of the individual sulphide minerals revealed that these materials also have significantly different degrees ofreactivity and are subject to particle size effects. For particles <45/lm, the ignition temperatures were as follows:ò pyrite and violarite 380 - 385°C; pentlandite 425 - 430°C; and pyrrhotite 470 - 475°;ò for particles >90 /lm, the ignition values were: pyrite 395 - 400°C;ò violarite 430 - 435°C; pyrrhotite 540 - 545°C; and pentlandite 560 - 565°C.Using the data on the individual minerals it was possible to rationalise the differing degrees of reactivity of the concentrates. The role of the most reactive constituent in initiating the ignition reaction has also been discussed.Finally, the results of this work were found to compare. favourably with the behaviour ofthe concentrates in industrial and pilot-scale flash smelters.

Jan 1, 1989