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Wetting Characteristics of Mineral Surfaces - Contact Angle Measurements through Molecular Dynamics Simulations

Sep 13, 2010

By H. H. Fairfield

THE production and inspection of the materials of war involves thousands of observations. Logical action is generally based on the interpretation of many observations. The success of such action depends upon the accuracy of the observations and the soundness of the interpretation placed upon them. There are countless instances where the observer 'sees but perceives not'; that is, the significance of a group of observations is lost, due either to faulty interpretation or to no interpretation at all being placed on the results. This condition is being partly corrected in the United Kingdom and the United States (1) by the promotion of certain principles by Ordnance officials. The term Quality Control has been adopted to describe a system of studying and controlling industrial products by methods of handling observations. In these pages an attempt is made to outline in a non-technical manner some of the ideas used in the handling of observations. Of course the authenticity of the observations determines the worth of any decisions based on them. No matter how brilliant is the theory built on unreliable sampling, it is usually of little practical value. n some fields it is almost impossible to obtain observations free from bias. Let us suppose that observers of speed in miles per hour were available for judgment: (a) a bystander, (b) a motorcycle policeman, and (c) a motorist accused of speeding. The bystander might be unbiased but probably would be very inaccurate. The motorist is usually biased on the low side. The policeman is the only qualified observer and, if over-zealous, he might be biased on the high side. Conclusions drawn from large numbers of biased observations naturally would be of little value.

Jan 1, 1943

By Haijian Shi, Drew Pizzo

This article focuses on the appropriate application of subsurface investigation methods for transmission structures, which are typically designed to resist lateral rather than vertical loads. Currently, the three methods used most often for the subsurface investigation of transmission structures in the field are the Standard Penetration Test (SPT), the Cone Penetration Test (CPT), and the Flat Dilatometer Test (DMT). Each of these methods has advantages and disadvantages, and each is more applicable to some scenarios than to others. To gain a better understanding of these test methods and the implications of using them for various kinds of applications, a comparison study was conducted in the field in Maryland, for three boring locations. Each boring location was explored using each of the three tests as stated. The results of the tests and lessons learned are presented and compared, and these comparisons show that the three test methods agree on the majority of the findings. The results from each test method were also used to derive key parameters such as the soil friction angle for given foundation designs considered in order to establish a clear basis for comparison. Recommendations for performing transmission structure subsurface investigations are made in order to optimize the use of each method and thereby optimizing subsequent foundation designs. INTRODUCTION For overhead transmission structures, the most important structural requirement for determining the foundation design differs from the requirement for other structures such as buildings and bridges in accord with the conditions the transmission structures will need to withstand. In addition to the ability to bear a given vertical load consistent with its use, the foundation must bear lateral loads arising from wind and other weather conditions. The foundation types used most often for overhead transmission monopole structures include concrete drilled pier, vibratory caisson, and direct embedment. In order to determine an appropriate and even an optimum foundation design for any given set of conditions, an appropriate subsurface investigation method or approach is needed. Currently, the standard penetration test (SPT), the cone penetration test (CPT), and the flat dilatometer test (DMT) are the three most commonly used subsurface investigation methods.

Jan 1, 2018

By Jon C. Volkwein

The U.S. Bureau of Mines conducted a study to assess the impact of a directional water spray system on a unique single inlet dust scrubber on a low-profile mining machine. Tests were conducted in a full-scale model mine using a continuous mining machine. Tracer gas was introduced at the face and concentrations of the tracer gas were monitored at the face and in the return. Various parameters tested included mining position, depth of cut, brattice setback, and combinations of scrubber, and directional or symmetrical sprays. Results indicated that either water spray configuration improved the ventilation effectiveness of the scrubber by a factor of 2 to 3. Average face ventilation effectiveness (FVE) values for all testing of the scrubber and directional sprays were 0.95, versus 0.37 for a standard 20-ft blowing curtain without sprays. No FVE values were less than the standard 20-ft blowing results.

Jan 1, 1989

Large scale fluid extraction from the Latrobe Group in the Gippsland Basin is occurring as a result of offshore petroleum production and coal mine dewatering in the Latrobe Valley. Groundwater extraction in the Latrobe Valley exceeds recharge and is causing an expanding area of declining hydraulic head in the Latrobe Group, and regional land subsidence which is well documented. Recently the government water sector completed the installation of a network of Latrobe Group monitoring bores in the remainder of the onshore part of the Gippsland Basin. The bores situated along the coastal area show a steady decline in hydraulic head of about 1 m/year which can be attributed mainly to petroleum production.

Jan 1, 1992

Peñasquito is Mexico's largest gold producer, consisting of two open pits - Peñasco and Chile Colorado - containing gold, silver, lead and zinc. Over the next three years, mining activities in the pit are expected to be focused on lower grade ore in the upper parts of the Peñasco pit while stripping is emphasized to ensure an economically optimal pit shell design to maximize the net asset value of the operation. By 2019, Peñasquito’s gold production is expected to benefit from an improvement in mined grades as it recommences mining higher grades at the bottom of the Peñasco pit and significantly enhanced metallurgical recoveries with the planned completion of the Pyrite Leach Project ("PLP").

Jan 1, 2017

By H. W. Hunt

Accessories are increasingly used to protect and extend H, pipe, precast concrete, timber, and sheet piles for any soils conditions. With point protection, piles can be driven through boulders, layered rock, garbage dumps, and waterfront debris to provide dependable support for all types of structures. Splicers for pipe piles can be tapered for a water-tight drive-fit that does not require welding. The pipe splicer can be made applicable to precast concrete piles. Splicers for H make the long pile as strong as an unspliced length with only simple welding. Transition splicers quickly connect different types or sizes into efficient composite piles.

Jan 1, 2010

By T. Lenarcic, R. Svrkota, J. M. McNeal, E. Prohic, S. Pirc

Paper presented at the 28th International Geological Congress held in Washington DC, July 1989 (International geochemical mapping sessions). Surface drainage samples, the usual media employed in mapping national territories, cannot be used for the geochemical mapping of carbonate terrains because there is no regular surface-drainage pattern on karst. Suitable sampling media have been studied in Yugoslavia, one-third of which consists of karst terrain. Sampling designs for the work were based on analysis of variance techniques. During initial investigations of various sampling materials in NW Yugoslavia sediment and aquatic moss from karst springs, along with soil, were established as the most appropriate media. Modified sampling procedures were then carefully applied along the entire Yugoslav karst belt, which includes terrains of contrasting topography, climate, pedology and vegetation. The studies indicate that climate and relief do not systematically influence the geochemical composition of soil. Regional and local variability was assessed for 21 chemical elements and the feasibility of producing stable regional geochemical maps was determined for a number of elements on the basis of sampling aquatic moss and sediment from karst springs and soil

Jul 1, 1991

By R. Michael Digman

Few efforts have been undertaken to date to assess the quality of mandated coal mine health and safety training for new miners and for experienced miners. This study was concerned with the quality and effectiveness of existing classroom health and safety training programs. The study involved field data collection through pre- and posttesting of trainees, audio-taping class sessions, and administering short feedback forms with trainers and trainees at 14 sites in West Virginia, Maryland, Kentucky, and Pennsylvania. Results indicate that goals, methods, materials, and outcomes of existing training programs vary widely among trainers and sites. The report provides less by way of solution to problems, than it highlights the breadth of issues that relate to the question of training effectiveness and quality. The report concludes that additional work by industry, labor, government, and academia is necessary in order to improve health and safety training programs. Recommended steps are: (a) to develop performance standards and measurable criteria in each of the types of mandated training, (b) to develop better training of trainers, (c) to develop expanded training support services. and (d) to undertake further research and development in health and safety training in the mining industry

Jan 1, 1982

By K. Severin, B. Flanigan, P. Marion

“Plutonic-related” gold deposits in Interior and SW Alaska (Tintina Gold Belt) vary significantly in size, grade, vein/deposit morphology, depth of emplacement, distance from causative pluton and metal association. Metal associations such as Au-Bi and Au-As-(Sb-Hg) are a good empirical indicator of depth of emplacement and distance from causative pluton and have been used successfully in exploration. Results from a variety of analytical techniques also suggest a phenomenological cause for these metal associations, e.g. gold and bismuth have linked metallogenesis at high temperatures and thus are best correlated at deposits that are deep and/or close to causative intrusions.

Jan 1, 2000

By E. M. Shemang, C. E. Suh, L. Mbinkar, University of Yaounde

"Two iron deposits within the Precambrian mineral belt of Cameroon are described in detail for the first time: the Archean Metzimevin replacement iron deposit enclosed in Fe-enriched itabirite, and the Proterozoic granite-hosted, shear zone-related Mayo Binka magnetite deposit. In the Metzimevin de¬posit, quartz is corroded and microplaty hematite overprints martite-textured hematite. The Mayo Binka massive magnetite veins show evidence of deformation in magnetite (fracturing and microbrecciation) and in overgrowths of specular hematite (mechanical twinning and undulating extinction). The magnetite is partially replaced by hematite (martitization) and goethite. Ores from both deposits have >88% total Fe2O3 and low contents of contaminants such as SiO2, Al2O3, MgO, CaO, P2O5, and TiO2. They are also poor in Cu, Pb, Zn, V, Cr, and Ni. The Metzimevin massive hematite is characterized by an accentuated light rare earth element depletion relative to the Fe-enriched itabirite. It is suggested that the Metzimevin iron deposit is the result of hypogene leaching of gangue minerals from, and further hematitization of, an itabirite protore. Although the genesis of the Mayo Binka massive magnetite is unclear, it is spatially related to Neoproterozoic granitic rocks. The data allow some comparison of these little known, but pot¬entially economic iron deposits, with some of the world’s better investigated deposits, and are useful to the exploration efforts for iron ore currently underway in Cameroon and the Central African subregion.Deux gisements de fer de la ceinture minérale Précambrienne du Cameroun sont ici décrits en détail pour la première fois : le gisement de fer Archéen de Metzimevin formé par remplacement et encaissé par des itabirites enrichies en Fe, et le gisement de magnétite Protérozoïque de Mayo Binka as¬socié au cisaillement dans un granite. Au gisement de Metzimevin, le quartz est corrodé et de l’hématite en microplaquettes se développe au dépends de l’hématite a texture martitique. Les veines de magné¬tite massive de Mayo Binka présentent des évidences de déformation dans la magnétite (fracturation et microbréchification) et dans les surcroissances d’hématite spéculaire (Macles tectoniques et extinction ondulante). La magnétite est partiellement remplacée par l’hématite (martitisation) et par la goethite. Le minerai des deux gisements contient >88% de Fe2O3 total et un faible contenu en contaminants tels que SiO2, Al2O3, MgO, CaO, P2O5, et TiO2. Il est également pauvre en Cu, en Pb, en Zn, en V, en Cr et en Ni. L’hématite massive de Metzimevin est caractérisée par un appauvrissement relatif en terres rares légères relativement à l’itabirite enrichie en Fe. Il est suggéré que le gisement de fer de Metzimevin résulte du les¬sivage hypogène des minéraux de la gangue ainsi que de l’hématitisation poussée d’une préconcentration de fer dans l’itabirite. Bien que la genèse de la magnétite massive de Mayo Binka demeure obscure, elle est spatialement associée aux roches granitiques Néoprotérozoiques. Ces données permettent de comparer ces gisements de fer peu connus et potentiellement économiques avec certains des gisements mondiale¬ment mieux connus, aidant ainsi les efforts d’exploration présentement en cours en Afrique de l’ouest et au Cameroun."

Jan 1, 2008

A practical core-based method for estimating in situ stress was tested using 360° measurements of rock core diameter in a laboratory setting. In several mining districts across West Virginia, rock cores were recovered from exploration core holes and oriented using an acoustic televiewer (ATV) summary log. Measurements of diametral variation were performed at 0.1-foot depth intervals using a benchtop device comprised of a pair of diametrically opposed contact digital indicator gauges working in tandem. The diametral profiles were evaluated to determine strain direction and strain magnitude. Stress magnitudes were calculated when values for Young’s modulus, and Poisson’s ratio were available. Stress direction results are compared to other stress determination methods, including downhole overcores, drilling-induced fractures, and borehole breakouts. The testing and analytical methods used are similar to the diametrical core deformation analysis (DCDA) method (Ito, Funato, and Shono, 2012), but with a number of important improvements.

Jan 7, 2020

Two events during the past decade have combined to effectively alter the role of the geologist working in Papua New Guinea. The gold boom of the 1980s resulted in a substantial increase in the general awareness at village level of mining companies, gold and landowner issues, and as a consequence of the Bougainville tragedy, landowners are also very much aware of the potential problems of a mining operation in their area. Landowners know they have the power to remove a company from a project area, and government has shown itself to be virtually powerless and unable to help the company effectively. During a considerable proportion of a project's development time, the project geologist is viewed in the eyes of the local community as the 'company'. Good landowner relationships are nurtured over a reasonable time period and the input of the geologist is significant in determining the eventual fate of company-landowner relationships. The initial impressions of the company, gathered by the local community, will have a far reaching impact on the nature and direction of their future exchanges with the company.

Jan 1, 1991

By Taylor G. H

The Triassic Ipswich (SE. Queensland) coals are of bituminous rank. The more exact rank of individual samples was determined by measuring the reflectance of the vitrinite. While in general the rank of the coals increases with stratigraphic depth, minor reversals, probably related to igneous intrusions, occur.The Ipswich coals form a coherent group so far as petrographic type is concerned. All are comparatively rich in vitrite and clarite, cutinite being the common maceral of the exinite group. The mineral contents of all the coals are comparatively high, clay and quartz being most abundant. The coals appear to be of essentially autochthonous origin, and to have been formed under conditions of fairly rapid subsidence.While the use of the coals is at present restricted to combustion, most have pronounced coking properties, as would be predicted from their petrographic composition and reflectance. However, the high mineral content of the coals would be a limiting factor in their use for coke-making.INTRODUCTIONDuring the last ten years, the Division of Coal Research, Commonwealth Scientific and Industrial Research Organization has carried out an extensive investigation of Australian coals, providing a wide range of analyses of most of the important of them. Special attention has been given in recent years to Queensland coals.Most seams were sampled as a number of subsections, enabling the internal variations, as well as the overall properties, to be assessed. The lenticularity of many of the mineralrich layers may tend to limit the significance of the samples, particularly in respect of ash yield, but although the vertical distribution of mineral matter may vary considerably from one sampling position to another, the lateral variation of the total mineral matter in the whole seam may not be great.Apart from extensive chemical analyses and utilization...

Jan 1, 1963

By Fabrice Mathieu

The Cutter Soil Mixing (CSM) provides a cost effective solution for the rapid construction of retaining and cut-off walls using new equipment developed from diaphragm wall cutter technology. CSM consists of cutting and mixing drums mounted on compact hydraulic motors. Soletanche Bachy CSM has been designed to leave the space above the tool free, thereby mixing the soil efficiently during all the phases of the wall construction, with high penetration rates. The precise positioning and verticality of the wall is achieved using a kelly bar and full monitoring. Soletanche Bachy CSM is a versatile equipment which can be mounted on various carriers: pile rigs, hydraulic crane, carrier equipped with telescopic mast. The major phases of Soletanche Bachy CSM development are presented, including the results of an extensive trial carried out in Le Havre (France). The soil consists of hydraulic fill with soft soil lenses overlying sandy deposits. 20m deep panels were constructed to support a rectangular shaft. During the construction, and after its completion, the shaft was subjected to an extensive series of tests followed by a partial excavation. The paper discusses also the future development of the technique and its potential applications.

Jan 1, 2006

By S. A. Bortz

This report presents the results of an extensive laboratory testing program to determine the physical properties of shotcrete including the use of fast-set agents, controlled set cements, and both wet and dry shotcreting equipment. Shotcrete was placed under simulated field conditions using the dry and wet processes. Mechanical properties obtained for accelerated and nonaccelerated shotcretes include compressive, flexural, and shear strength, elastic modulus and Poisson's ratio, and shear and tensile properties of shotcrete bonded to coal, sandstone, and shale. Physical properties measured were unit weight and permeability to methane gas. The data show that rapid setting shotcrete has the potential for improved coal mine ground control. There is no clear evidence that either wet or dry process shotcrete is superior to the other; however, indications are that regulated set cement is preferred to cement containing fast-setting admixtures.

Jan 1, 1973

By Robert Torbin

The objectives of the Continuous Shaft Lining (CSL) System are to reduce the costs, safety hazards, and time currently required in lining mine shafts with concrete. The CSL will line machine bored shafts downward from the shaft collar on a continuous basis using an inverted, pressurized slipforming technique. The technique for slip-forming downwards has been demonstrated and refined under this program. The approach taken involved laboratory scale testing of key features of the CSL concept. These feature tests included concrete distribution, concrete sealing, concrete slipforming and development of a reliable concrete mix. Based on these results, a full scale above-ground test facility and CSL were designed and fabricated. The objectives of these tests were to demonstrate the viability of the basic concept; to establish operating limits; and to provide input data and information for the design of a second generation shaft lining system. The results of the program have led to a CSL design and operational philosophy which will need to be tested in an underground environment before industry will accept the technology. However, the next generation CSL promises to meet all the original program technical objectives.

Jan 1, 1983

By Stuart F. McTavish

Mechanically suitable grinding mills became available to the mining industry in 1908. Since then, mill operators have been searching for the best material and design with which to line the mills. These liner systems had to fulfill several criteria. Most important, they had to last long enough in an operating mill to protect its structure from the abrasive wear of the ore and the grinding media. In addition, they had to be capable of efficiently transferring the energy from the mill to the mill charge in order to facilitate the grinding process. And these liners had to be easy to install and remove. The first liners used were generally made of cast white iron, Hadfield manganese, unalloyed high-carbon steel and composites of steel and concrete or cemented in flint blocks or natural stone. In the early 1920s, pieces of solid rubber truck tires were used as emergency repairs for broken cast metal liners. Thus was rubber first introduced as a mill liner material. The first patent for rubber mill liners was awarded in 1921 to James Denny and Rolla Watson, both of the Coniagas Mine in Cobalt, Ontario, and to Dale Barnum of the Comstock Lode in Virginia City, NV. This original design was covered under US Patent No. 1470597. It had a fabric backed rubber that was bonded to the shell of the mill.

Jan 1, 1990

By B. E. Burakov, S. D. Lupal, O. A. R. Thalhammer, B. Saini-Eidukat

Electric-pulse disintegration is a mineral separation technique that liberates all mineral grains from any igneous or metamorphic rock irrespective of its lithology or grain-size distribution. The normal mechanical crushing of whole-rock samples is replaced by the rending effect of an explosion, produced by applying an electric current from a high-voltage power source. A voltage greater than the 100 kV necessary for the electrical breakdown of rock samples is achieved by using capacitors charged in parallel, but discharged in series. The sample sits in a water bath and the rapid distribution of electric pulses leads to an explosion which occurs preferentially along grain boundaries of the sample. Individual, undamaged mineral grains can be recovered in their original shape and form regardless of grain size. Examples are given of the liberation and concentration of important accessory minerals from different rock types. The examples show the recovery of diamond from two types of non-kimberlitic host rock in Popigai and Kumdykol in Kazakhstan and platinum group minerals associated with chromitites from the Konjdor intrusion and sulphides from intrusions in the Kola Peninsula in Russia

Apr 1, 1995

The recovery by flotation of some complex uranium minerals such as brannerite and davidite is described. Anionic reagents used for flotation of iron and titanium oxides' are suitable. If care is taken, to emulsify the reagents the slime fractions may be satisfactorilytreated.INTRODUCTIONUranium ores are usually treated by direct leaching with acid or alkali according to the nature of the gangue materials. Concentration of the uranium minerals prior to leaching is not commonly practised because of the earthy nature of most uranium minerals and the difficult mineral dressing problem they pose. Some of the harder complex oxides such as davidite and brannerite are amenable to flotation. This is fortunate since they usually require an expensive, strong acid treat~ent to dissolve the uranium. Flotation tests were commenced in 1949 by officers of the South Australian Department of Mines stationed at Adelaide, first in the School of Mines, then in the University of Adelaide and finally in Departmental mineral dressing laboratories at Thebarton. Separation of daviditefrom Radium Hill and Mount Victoria ores, brannerite from Crocker's Well ore, and secondary uranium minerals from Myponga ore was attempted.The development of the flotation reagents to separate the oxides from silica and the silicates is first described, then some of the results obtained are presented as tables.DEVELOPMENT OF FLOTATION REAGENTSThe davidite at Radium Hill is associated with iron and titanium oxides, qu;a,rtz and biotite as replacement deposits in shears. The davidite, rutile,' ilmenite and hematite usually occur in segregations from nut size to masses of several pounds. They are associated as a complexity of...

Jan 1, 1955