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By SungJe Chi

Intrinsic remediation is the effect of natural attenuation mechanisms - dilution, dispersion, sorption/precipitation and biodegradation - reducing contaminant concentrations in ground water to specified levels at predetermined compliance points in the aquifer. Current monitoring and modeling for post closure was used to assess the current and long-term potential of intrinsic remediation of contaminated seepage originating from a large reactive (sulfidic) tailings impoundment near Questa, New Mexico. It is concluded that the natural attenuation mechanisms of precipitation within the tailings (as a result of buffering) and dilution/dispersion within the aquifer are currently active and likely sufficient to reduce contaminant concentrations to below state standards in the long-term. Other natural attenuation mechanisms such as sorption and biodegradation within the receiving aquife4s) were not assessed here, but are likely further reducing contaminant concentrations. Active interception and recovery of the seepage water is being maintained until monitoring demonstrates that intrinsic remediation has successfully achieved the level of water quality control required.

Jan 1, 2017

By J. Riss, S. Gentier, A. Marache

The study of the hydromechanical behaviour of fractured rock masses requires a detailed knowledge of the isolated fractures. The aim of the paper is the simulation of the evolution of the void space, located between both walls of a fracture, during a shear test under constant normal stress. Results of the mechanical simulation model are first validated then analyzed in detail. We observe that, during the shear process, there is an opening of the fracture with the creation of preferential channels. These channels are determined at the early phase of the shear process (pre-peak phase), and we observe during the post-peak phase that void areas increase in size rather than the creation of new apertures. Die Untersuchung des hydromechanischen Verhaltens eines zerlegten Felsmassivs erfordert genaue Kenntnisse der einzelnen Spalten. Ziel dieses Artikels ist die Simulation der Evolution des Hohlraumes zwischen den beiden Wänden eines Spaltes während eines Abscherungsexperimentes unter konstantem senkrechtem Druck. Die Ergebnisse der Modellierung werden zunächst mit dem Abscherungsexperiment verglichen und dann im Einzelnen ausführlich analysiert. Während des Abscherungsprozesses tritt eine Öffnung des Spaltes auf, die die Bildung von bevorzugten Fliesswegen fördert. Diese Kanäle werden bereits in einer frühen Phase des Abscherungsprozesses (pre-peak Phase) festgelegt. In der post-peak Phase tritt dann eher eine Vergrößerung dieser Kanäle, als die Bildung neuer Hohlräume auf. L’étude du comportement hydromécanique d’un massif rocheux fracturé ne peut se faire sans une connaissance approfondie des fractures le constituant. L’étude présentée dans cet article concerne la simulation de l’évolution de l’espace des vides présent entre les deux épontes d’une fracture au cours d’un essai de cisaillement à contrainte normale constante. Les résultats du modèle sont tout d’abord validés puis analysés en détail. On constate que, au cours du cisaillement, il apparaît une ouverture de la fracture permettant la création de chenaux préférentiels. Ces derniers sont déterminés très tôt dans le cisaillement (phase pré-pic), et on observe dans la phase post-pic davantage un accroissement de la taille des chenaux plutôt que la formation de nouvelles zones de vides.

Jan 1, 2003

By André C. Zingano

The coal pillars in room-and-pillar mining method are subjected to vertical stress due to overburden rock mass and horizontal stress relieve due to entries excavation around them. Some coal mining companies are applying rock bolts and steel straps to improve the pillar strength, consequently to reducing the pillar size and increasing coal recovery. This kind of approach deserves some discussion, whether it is pillar reinforcement or just rib support. The efficiency of pillar reinforcement (or rib support) is directly related to the initial load capacity of coal pillar, the type of excavation, and the width to high ratio of the pillar. The objective of this paper is to understand the mechanism of pillar reinforcement (or rib support) using rock bolts and steel straps on pillar ribs. Numerical simulation taking into account the relations listed above. The results showed that the increase of coal pillar strength is very short, and there is no influence on improvement of load capacity of pillar. However, the rib support avoids block falling, rib failure, and displacement, reducing the pillar failure propagation into the pillar center. Keywords: coal, pillar reinforcement, room and pillar.

Jan 1, 2006

By Lottrey A. L, Sowerby B. D, Cutmore N. G

On-line monitoring of low rank coal quality during input to a process has the potential to provide benefits through: ò anticipation of coal quality variations prior to utilisation; ò provision of a tool to help determine the influence of coal quality on process behaviour, and ò provide a direct measure of coal quality for pricing. Moisture and ash are the two most significant coal quality parameters for combustion. They determine the energy content which can be derived from the coal and the problems arising from the presence of ash in the process (eg ash fouling, corrosion, erosion, particulate emissions and ash disposal). Extensive pilot-scale testing and full-scale experience has shown that specific coal/ash constituents (eg Na2O/ash ratio, acid-soluble aluminium, silica, sulphur contents, etc) are also important for the behaviour of Latrobe Valley brown coal during combustion, ash formation, deposition and removal of ash in precipitators and furnace ash hoppers. This paper discusses the range of on-line analysis techniques which have been investigated and their application to low rank coal analysis. Preliminary results from a joint SECV/CSIRO project which aims to develop two separate advanced instrument systems are also presented. These systems are based on: ò microwave attenuation and phase shift - for direct determination of moisture content; and ò inelastic neutron scattering - to provide total hydrogen, carbon, chlorine and ash contents, with potential for calculation of moisture content, specific energy, sodium content and Na20/ash ratio using correlations.

Jan 1, 1992

By J. A. McCamley

Gypsum scrap generated from wallboard manufacturing, construction and deconstruction activities in North America, Europe and Japan is a recognized environmental problem. Landfill disposal of this gypsum scrap is problematic, with deposits often creating hydrogen sulphide emissions and metallic sulphide groundwater leachates. Of these regions, Europe is the most advanced in dealing with the issue having enacted legislation, which will come into effect in July 2005 that will strongly encourage gypsum recycling throughout the EU. An estimated 10% to 17% of all gypsum used in the wallboard industry becomes recyclable scrap, which represents approximately 1% of the total waste stream in North America. In the United States, 2.5 to 4.5 Mt of gypsum scrap is generated each year; the volume is similar in Europe (the percentage of total tonnage is less because of the higher use of brick and concrete). The Greater Vancouver region of British Columbia has banned gypsum from its landfills, and as a result, all gypsum scrap is now recycled. New West Gypsum Recycling, a Canadian firm, uses its proprietary technology to process large quantities of gypsum scrap that is reincorporated into new wallboard, at percentages ranging up to 25%. The operation of New West Gypsum Recycling Inc. of Langley, Vancouver is examined as a case study and recommendations are provided as to how other urban regions can implement similar gypsum scrap recycling programs.

Jan 1, 2004

For small particles of niekel flotation eoncentrate (av. size 50 pm) the predominant heat transfer mechanism under suspension smelting conditions, prior to ignition, is conduction from the gas and not radiation from nearby hot bodies. Results of laboratory tests using gas temperatures 380-700°C and furnace wall temperatures 380-1100°C were in accord with heat transfer theory. In practieal flash smelters earlier ignition, and hence better utilization of the space in the shaft, would result from introduetion at the top of the shaft of gases hotter than the ignition temperature of 500-600°C.

Jan 1, 1979

By Charles Stone, Madan Naik, Drupad Desai, Karel Rossler

Planning of New York’s new subway line dictated the location of shallow underground station caverns and track crossovers. Clear span openings ranging from70 feet to 100 feet and lengths in excess of 1000 feet, coupled with low rock cover ranging from 25 feet to 40 feet required judicious selection of construction methods, equipment, and proper sequencing of the excavation stages. Rock classifications alone could not predict the behavior of the rock mass during construction. A robust design procedure that considered most of the important aspects of rock behavior and elements of shallow tunnel design, minimized the negative impacts of variable geotechnical data. This paper describes the intricacies of the planning and design of the $16 billion Second Avenue Subway with insight into how to overcome the design complexities and construction challenges of the urban underground.

Jan 1, 2005

By Charles Taschereau

The statements made in this presentation contain certain forward-looking statements concerning potential developments affecting the business, prospects, financial condition and other aspects of Canada Lithium Corp. The actual results of the specific items described in this presentation, and the company?s operations generally, may differ materially from what is projected in such forward-looking statements. Although such statements are based upon the best judgments of Canada Lithium Corp. management as of the date of this presentation, significant deviations in magnitude, timing and other factors may result from business risks and uncertainties including, without limitation, the Company?s dependence on third parties, general market and economic conditions, technical factors, the availability of outside capital, receipt of revenues and other factors, many of which are beyond the control of the Company. Canada Lithium Corp. disclaims any obligation to update information contained in any forward-looking statement. Toronto Stock Exchange: CLQToronto CLQOTCQX: CLQMFOTCQX: CLQMF

May 1, 2011

By Lester G. Morrell

AGAIN in 1963, as in nearly every year since 1946, the Canadian mineral industry has established a new national record in value of mineral production. The 1963 estimated total value of $2,976 million is 5 percent higher than the 1962 value of $2,845 million.2 As in previous years, metals made up more than half the value of total production. For selected years since 1949 the category percentages and total value are as follows: [ ] Crude petroleum, Canada's most valuable mineral product, accounted for 21 percent of the total value of minerals in 1963. In descending order came nickel 12 percent, iron ore 10 percent, copper 10 percent, gold 5 percent, and uranium 5 percent. Asbestos accounted for 5 percent, sand and gravel 4 percent, and cement 4 percent. The complete list of Canada's mineral products includes more than 50 basic commodities.

Jan 1, 1964

By Tom Treleaven, Andrew Williams

The town of Greenwich, CT, an exclusive suburb of New York City awarded several contracts for the installation of sanitary sewer in the North Mianus section of town. The Valley Road section was the most challenging from a rock excavation standpoint. The cut was up to 14 ft (4.25m), with adjacent utilities [20 in. (500mm) water, 6 in. (150mm) water and 8 in. (200mm) gas] located to within 5 ft. (1.5m) of the proposed sewer trench. Rock types varied but were ultra metamorphic in nature, ranging from quartzites, granite gneiss and various types of migmatities.

Jan 1, 2004

By P Wopereis

The Nokomai valley is located within the pumpellyite/actinolite facies of the Otago Schist, a regional scale metamorphic belt in Southern New Zealand. The Otago Schist is dominated by psammitic and pelitic greyschist with more subordinate greenschist, quartzite, marble, and ultramafics. Mining in the Nokomai, began in the 1860s, with sluicing of terrace gravels in the lower valley. Good gold is reported to have been won from unconformities within very weathered gravels lower in the terrace sequences, and particularly from within channels which dissect these older deposits. Gold was recovered from these terraces in the main Nokomai Valley, and two major tributaries (Victoria Gully and Bullock Head Creek). In the period 1885 - 1887 further gold was discovered in basal gravels beneath the Nokomai flats when the Hunter brothers sank two shafts and excavated a connecting drive to discover a lead 1.2 - 1.5 m thick. The Golden Lion Sluicing Company began mining in 1896 using an hydraulic elevator on the very 'tight' 1.8 - 2.4 m of basal gravels. This operation was followed by the Nokomai Gold Sluicing Company whose average return grade was >485 mglm3 until mining ceased in 1943 (Wopereis; 1988, 1989). A quartz vein, Commissioners Reef, was worked for small production at some time during the 1920 - 1930 period, until fault termination of the vein ceased production.

Jan 1, 1996

By Mohammadreza Khanmohammadi, Kazem Fakharian

"AbstractIn driven piles, the gradual dissipation of excess pore water pressure and consequently the soil setup significantly contribute to increasing the pile capacity with time. The question is risen that how the scale differences affect the stress state variations around the pile shaft and at the pile tip? Would the CPT predictions better correlate with End-Of-Drive (EOD) or Beginning of Restrike (BOR) conditions? On the other hand, are the proposed a and ß parameters for clayey soils mostly predicting the EOD or BOR situation? The main objective of this paper is to back calculate the a and ß parameters from CPT profiles, pile Dynamic Load Tests (DLT) at the EOD and BOR as well as Static Load Tests (SLT) and evaluate how they compare with those suggested in literature. Four precast 400 mm square concrete piles driven in North Azadegan Oilfield in Khuzestan Province were selected for the comparisons. CPT test results were available from the extensive geotechnical investigation at the study site. DLT tests using PDA were carried out at EOD, 1 day and 14-day BOR on all the 4 piles. All the piles were SLT tested as well. The UniCone software was used to estimate the tip and shaft resistances using 4 methods including the Dutch, Eslami & Fellenius, LCPC and Schmertmann. The results indicate that the a-method based on the proposed values in literature has predicted a shaft capacity of 90% of the 14-day BOR. This is while the ß-method has predicted a shaft capacity equivalent to 1-day BOR results only. Therefore, both methods have under-predicted the shaft capacities compared to real capacities measured after the significant soil setup in the study area. Two of the CPT methods have underestimated, one has overestimated and one has matched the estimated 60-day capacity."

Jan 1, 2014

The excavation of ramps and tunnels often requires high-speed development with (or without) the use of high-energy mining equipment such as loaders, dump trucks, TBMs and roadheaders. This high-speed development creates a challenge in terms of providing a safe and productive working environment. For example, heat from continuously exposed surrounding rock, heat from broken rock, heat generated by mining equipment, potential in flows of hot ground water, pollution from associated diesel equipment and the distance of the advancing face from fresh through-ventilation all have to be taken into account when designing ventilation systems for high-speed ramp and tunnel developments. This paper discusses methods of achieving acceptable environments at the face and along the length of the tunnel. The methodology has been successfully implemented in the development of long (up to 20 km) TBM drives in the Lesotho Highlands Project and in mining projects in hot rock using drill and blast methods as well as mechanized methods using continuous miners and roadheaders. The determination of heat loads includes calculation of the heat flow within the surrounding rock, evaluation of the operating cycle of the equipment and the contribution to the overall heat load of the broken rock as it travels out of the tunnel. The determination of heat loads from surrounding rock in new tunnels required a modification of the algorithms generally used for established excavations. The paper also examines the use of, for example, mobile duct and fan systems to ensure that fresh air is delivered to the specific areas where workers are located.

Jan 1, 2000

By Iann Bouchard

Introduction à l?abrasion et l?érosion Avec le temps, tout solide va éroder et user les métaux les plus durs; de plus, la Corrosion va aussi laisser une couche mince et faible d?oxydation qui sera rayée du substrat. Solutions et guide de sélection Les polymères de Henkel Loctite® peuvent: ? Réduire l?abrasion par glissement ? Protège contre les agents corrosifs ? Prévenir la cavitation ? Augmenter l?efficacité ? Réduire la turbulence ? Résister aux hautes températures?

Feb 1, 2008

By J. Pei

The studies of dynamic measurements using stress wave theory has commenced in China. This paper introduces some practical experiences using "CASE method" in Shanghai showing applications of dynamic measurement to determine ultimate bearing capacity of pile, the change of capacity due to set up, determining the optimum bearing layer during pile driving, the efficiency of hammer system and integrity of pile and discussions of method concered.

Jan 1, 2010

By C. McCall, J. T. Knight, J. R. Ridley

Gold mineralisation in the gabbro sills is mainly stratabound to quartz- and Fe-rich, granophyric-textured units and is sited in undeformed, brittle quartz vein sets, which form pipe-like orebodies. Hydrothermal wallrock alteration consists of hornblende-plagioclase-calcite-quartz with minor biotite, garnet and chlorite and with arsenopyrite and pyrrhotite as the dominant sulphides. Geothermobarometric data suggest that gold was deposited at around 520 degrees C at 2.8-3.8 bar. Mineralisation is thought to have occurred during amphibolite-facies metamorphism. Fluid inclusion and isotope data indicate that gold mineralisation was the result of deposition from a low-salinity H2O-CO2-CH4 fluid of either metamorphic or magmatic origin. Although the Three Mile Hill deposit differs from others in the area in its wallrock-alteration assemblages, peak-metamorphic timing of gold deposition and distinct geochemical associations it forms a brittle stratabound ore body which suggests structural and gold-depositional mechanisms in common with those of the other gabbro-hosted gold deposits

Jun 18, 1905

By Phillip Cancilla, Daniel Roy, Frank Rosenblum

"The manual moisture determination methods employed today by mineral processing plants falls short in providing timely information required for automation control. The costs associated with transporting and handling concentrates still represent a major portion of the overall treatment price. When considering the cash flow of a mining operation, that is governed by both the smelter contract, with moisture penalties and the quantity and quality of the concentrates shipped, an efficient method of on-line moisture content would be a welcome tool.A novel on-line determination system for ore concentrate moisture content would replace the normally tedious classic manual procedure. Since the introduction of microelectronic-based control systems, operators have strived to reduce the treatment costs to the minimum therefore a representative and timely determination of on-line moisture content becomes vital for control set points and timely feedback. Reliable sensors have long been on the “wish list” of mineral processors since the problem has always been that you can only control what you can measure. Today, the task of moisture determination is still done in the classical technique of loss in weight by uncontrolled procedures. These same methods were introduced in the earliest base metal concentrators. Generally, it is acceptable to have ore concentrate moisture content vary within a range of 7 to 9%. Many times, delays in manually achieving reliable feedback on the moisture content results in the moisture varying from 5 to 12% before corrective actions can be made.This paper first reviews the traditional and widely available methods for determining moisture content in granular materials by applying physical principals and properties to measure moisture content. All methods are in some form affected when employed on mineral ore concentrates. This paper describes a unique and promising on-line moisture sensor in two mineral processing applications, which not only automates the tedious tasks but also results in reliable moisture feedback that can be used in the optimization of the de-watering process equipment such as pressure or vacuum filters and fuel-fired driers. Finally, two measurement applications will be presented to indicate the usefulness and to summarize the measurement requirements for the proposed method of employing drag force and mechanical properties of the material itself to determine the moisture content."

Jan 1, 2001

The pressure of low commodity prices forced the design process for the second lift of Northparkes E26 Mine to adopt a continuous improvement philosophy. The emphasis was to minimise capital expenditure while still maintaining the excellent low operating costs achieved on Lift 1. Although the first block cave lift at Northparkes is the most productive underground mine in the world and is held up as a benchmark for the use of technology in mining, areas for improvement were identified. Every area was critically assessed and investigated for the possible application of new techniques and technologies. Key learnings from the construction and production phases of Lift 1 were captured, documented and used as the starting point for the Lift 2 design. This paper shows how and why the design parameters initially used onLift 1 were changed to become the current E26 Lift 2 developmentproposal. The main differences between the two block caves arehighlighted. The alternative techniques and equipment that wereconsidered are also discussed. * Originally published in the Proceedings of MassMin 2000,published by The AusIMM.

Jan 1, 2001

A sinter plant baghouse dust has been treated as a hazardous solid waste, and disposed at a very high price. A series of leaching tests were conducted to examine the possibility to produce high grade potassium chloride from the solid waste. It is found that around 40% of the solid wastes can dissolve into water, and a deposit with more than 90% KCl can be produced after simply drying the solution.

Jan 1, 2009

Even though the economy of the United States remains in recession ? or not, depending on which economist you listen to ? muicipalities still need improved transportation, water and wastewater transit systems. And they are willing to spend the necessary funds on those systems, provided they are affordable, environ-mentally friendly and sustainable. From June 20-23, professionals in the tunneling and underground construction industry from around the world gathered in Portland, OR to learn new ways of providing those systems using the latest technology available. The North American Tunneling (NAT) conference attracted 803 attendees and 108 exhibiting suppliers of equipment and services.

Jan 1, 2010