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By H. D. Mellom

The direction of the optic or "C" axis of a uniaxial metal crystal can be found with the metallurgical polarizing microscope by examining two planes of section on the crystal. Complete orientation of the crystal can be determined if a twin crystal is common to both surfaces of section. Examination of Uniaxial Metals in Polarized Light-Rotation of a uniaxial crystal surface, properly prepared,' shows four extinction positions 90 deg apart, provided that the surface is not close to a basal section. One of these two extinction directions corresponds with the projection of the optic axis on the surface of section. This direction can be found if the 'sign of the rotationr2 for the metal is known. To find the direction of the optic axis, the crystal is rotated on the stage 45 deg from an extinction position. With a crystal of negative sign, to produce extinction the analyser must be rotated towards the optic axial direction and vice versa. All sections, other than basal, of a uniaxial crystal have the same sign of rotation and, since there is no change in sign with wave length, white light can be used for these measurements. U the sign of the rotation is not known the presumed direction of the optic axis can be determined assuming a positive sign. A third section cut normal to the presumed optic axis will show basal extinction if the assumption is correct. It is convenient to use the edge between the two planes of section as a fiducial direction common to both surfaces. The optic axis can be related to this direction. If the above measurements are repeated on the other plane of section and the angle between the two section planes measured, stereographic projection can be used to determine the orientation of the crystal optic axis. Determination of Complete Orientation—The complete orientation of a uniaxial crystal can be determined provided that a twin crystal is common to both surfaces of section, and the twin law is known. The orientation of the twin crystal optic axis can be determined in the same way as for the main crystal

Jan 1, 1962

By Felicity Lloyd, Stuart Kearns, Roger McLimans

The metamorphic terrane of southwestern India is a geological environment containing ilmenite source-rocks, transport drainage systems, and resultant beach sand deposits that contain altered ilmenites greater than 60wt% TiO2. As such, this environment provides a geological laboratory, from source to deposit, for the investigation of ilmenite origin, alteration, and geochemical character. Ilmenite samples from potential source rocks, river sands, and beach sands all show degrees of alteration and a variety of alteration textures (iron leaching) producing leucoxene (here defined as >70 <90wt% TiO2) and progressing to rutile (here defined as >90wt% TiO2). Distinct alteration textures are specific to different source rocks and are used together with trace element geochemistry as provenance criteria. Ilmenites are classified on the basis of their trace element content. In India, the ilmenites are classified principally according to the Mg, Nb, and Mn content and this signature defines potential source rocks, even where the ilmenite is altered to a TiO2 content of 70wt%. The trace element data may fingerprint source rocks whose ilmenite is more prone to iron leaching and that criterion has application in exploration for higher-grade ilmenites.

Jan 1, 2005

By Douglas Bartley, Brian Wingfield, Robert McClure

Recent studies and limited tests indicate favorable results utilizing high accuracy electronic detonator technology over conventional non-electric pyrotechnic systems. This study discusses the application of this technology using the Daveytronic programmable system in an on-going production basis. The study quantifies the performance as it relates to fragmentation, excavation, vibration and productivity in an eastern U.S. aggregate mining operation. In order to insure accurate data, tight field controls were adhered to during the drilling and blasting process as they related to blast design, bench preparation, pattern layout, drilling and blasthole loading. Following the blast the excavation and crushing procedures were studied to quantify any down stream advantages due to improvements in fragmentation. This study will help provide the industry with information as to the advantages of high accuracy electronic blasting systems over conventional pyrotechnic systems and show the results of an operation utilizing electronic detonator technology through their production season.

Jan 1, 2000

By Joseph Daly

An investigation into inaccurate scatter of pyrotechnic detonators led to the innovation of utilising existing (every day) equipment in a manner to accurately determine the true scatter of detonators. This can then be utilised to determine the accuracy of a particular batch of detonators.

Jan 1, 2014

By S. E. Olsen, K. Tang

The complex heterogeneous equilibria associated with the production of manganese ferroalloys have been simulated by employing recently developed thermochemical databases. The non-ideal Mn-Fe-Si-C alloy and the MnO-SiO2-Al2O3-CaO-MgO-FeO slag system have been modelled separately by the compound energy and cellular model. A large number of experimental thermodynamic and phase-equilibrium data were used to evaluate the model parameters for the liquid and solid Mn-Fe-Si-C phases. In addition to the liquid metal phase, solid mixture phases occurring in the Mn-Fe-Si-C system have also been studied. Over 500 measured equilibrium data have been utilised to verify and calibrate the model calculations. The paper will present typical simulation results, from activities of components to multicomponent heterogeneous equilibria. Good agreements can be obtained for many important technological parameters such as carbon solubility, phase relations and equilibrium diagrams, element distribution as function of temperature and slag composition etc. Application of the present models to the silicomanganese production will be demonstrated in this paper.

Jan 1, 2004

By R. L. Amelunxen

"In January 1983, Gibraltar Mines Ltd. started an exploratory program on Column Flotation with hopes of improving performance of the Molybdenum Cleaning circuit. The encouraging results led to a column test trial in the Bulk Copper Cleaner circuit where the test unit has per¬formed well. A program was undertaken to understand the mechanics of column operation. A year and a half later, Gibraltar is considering the replacement of existing Bulk Copper and Moly Cleaning flotation cells with a fully computer con¬trolled Column Flotation circuit.BRIEF SUMMARY OF TESTWORKInitial testwork was done with a home made 20 inch diameter x 31 foot high column, equipped with a doppler flow-meter at the tail line and automatic level conrol. This loop maintained constant level in the column by throttling the tail valve. This column was placed in a variety of locations around the Moly circuit as shown on Figure 1 a, b. Test re¬sults indicated that the column could achieve much higher grades than the conventional cells, but recovery wise, the performance was low. Spillages from overloaded pump boxes were a common frustration during this time.Column control strategy was reviewed; and, in light of information received from McGill University, changed to conform with the methods that had been employed by D. Wheeler, of the Column Co. of Canada4 and Gaspe Copper Mines3.The column was tested replacing a portion of the bank, figure lc. The results obtained were more or less equal to the circuit. However, as we had Nitrogen gas connected to the column and not the regular cells, the column was kept in service. With the use of Nitrogen in the column, the usual copper depressant, Sodium Cyanide could be replaced with Sodium Hydrosulphide, hence lower operating cost.As time went on, a 10 inch diameter column was added in series to re-treat the concentrate of the 20 inch diameter column with hopes that the copper content would decrease from 0.6% down to 0.3% in order to save on subsequent leach¬ing costs. So far, results indicate there has been some im-provement, hut we are not achieving 0.3% copper. (See figure 1d)."

Jan 1, 1985

By R Zhou, B J. Monaghan, S J Chew, R J. Longbottom, D J. Pinson, H Li, P Zulli, G Zhang, L Lu

Steelmakers are increasingly motivated to use iron ore resources with a wider range of grades and mineral types that were previously considered unsuitable or uneconomical for sintering. In this respect, specific issues, which now require further investigation and understanding, include the sintering of ore types with:- overall higher gangue content- elements that cause problems in the steel manufacturing operations- distinctive sintering performance compared with traditional hematite-rich iron ores. Laboratory-based investigations of the sintering performance and the behaviour of gangue impurities during sintering is an important step towards the successful utilisation of these resources in steelmaking.In terms of laboratory-based sintering investigations, there are two generally accepted experimental scales utilised prior to undertaking industrial-scale trials, which include: bench-scale tablet (compact) testing and pilot-scale pot testing. The former has the advantages of flexibility and more precise control of sintering conditions; but it is difficult to simulate the heterogeneity of a sinter bed. The latter, which is carried out in pots with diameters between 150–500 mm, simulate the commercial sintering process and conditions quite well, but is time-consuming and labour-intensive due to operational complexity. It is therefore desirable to establish a smaller scale pot testing facility that avoids the disadvantages of the normal sintering pot but can provide comparable information.To explore the feasibility of small-scale pot testing, a ‘millipot’ facility was established to examine the sintering performance of iron ores and other non-traditional ferrous materials. The millipot has a diameter of 53 mm and height of 400 mm. The facility has the capability to monitor the sintering temperature at a number of locations (axial, radial) within the sinter bed and to adjust the suction (‘windbox’) pressure. This paper describes the development of the millipot facility and operational procedures, together with initial tests undertaken in order to match its performance with industrial sintering performance.CITATION:Li, H, Zhou, R, Pinson, D J, Zulli, P, Lu, L, Longbottom, R J, Chew, S J, Monaghan, B J and Zhang, G, 2017. A millipot set-up for sintering investigation of iron ores, in Proceedings Iron Ore 2017, pp 85–90 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Zoran M. Stevic, Mirjana M. Rajcic-Vujasinovic, Zvonimir D. Stankovic

"Huge electrochemical investigations have been performed on Technical faculty in Bor (Serbia) which main goal was the clarification of the copper sulfide minerals behaviour in hydrometallurgic and flotation processes. Modeling of these processes was a part of the effort for better understanding of the reaction mechanisms.The consideration of electrical analog circuit and mathematical model of processes at interfaces copper sulfide/electrolyte (CuS/(CuSO4+H2SO4), Cu2S/H2SO4 and CuFeS2/H2SO4), based on studies of the overvoltage – time transients, will be presented. The transients were obtained using single pulse galvanostatic method and electrochemical cell with standard three electrode assembly. In that goal it was developed an original system for computer measurements that enables the application of several methods for electrochemical investigations (galvanostatic, potentiostatic, cyclic voltammetry, electrochemical impedance spectrometry etc). The system was tested and adjusted using commercial electrochemical equipment made by AMEL, Milano.In the first stage of consideration the different equivalent electrical circuits have been tested by computer programme OrCAD 9.2 in order to identify the circuit with responses equivalent in shape to experimentally obtained ones. In that way it was established a configuration of an analog electrical circuit for investigated electrochemical system. That phase enabled only very rough determination of values of circuit components and their relative ratio.In the second stage the method for determination of all elements of electrical analog circuit is described. It is based on mathematical consideration of a given circuit on one hand, and valves of the overvoltages at selected times, obtained from charging and discharging parts of galvanostatic transients, on the other."

Jan 1, 2003

Willyamite from the type locality, Consols mine, Broken Hill, N.S.W., has been re-examined, and found to consist of zones with widely different Co:Ni ratios. The name willyamite is redefined to include the portion of the (Co, Ni)SbS series with cobalt in excess of nickel. Willyamite is pseudo-cubic, with the three axes equal to within 0&#183;001 A.

Jan 1, 1970

By G. Balletto, C. Furcas

"The mineral raw materials industry is a key-component of the Gross Domestic Product of industrialised economies, closely related to both the building and the industrial sectors. Despite this, at local level mining and quarrying are associated with both irreversible environmental damage and several visual alterations affecting the natural landscape. In this sense, SIA (Social Impact Assessment) has become a strategic tool that can not only improve the prediction but also the assessment of the social impact by involving the local communities in a participatory process. Taking into account the SIA experience, together with the examination of some relevant international case studies, it is possible to draw up a list of good practices for mining project management, from exploration through to closure and beyond, with quarry restoration. Such good practices will complement the existing studies, focusing on environmental issues, with the social issues arisen considered in SIA application."

Jan 1, 2011

By C. F. McCarroll

The effectiveness of an industry&apos;s safety activities can be gaged best by the accident records of that industry. In an effort to gage conditions in the petroleum industry, and with the objective of helping to reduce the number of accidents in it, the Bureau of Mines from time to time has tabulated, analyzed, and published pertinent statistical information.3/. These reports have dealt with distribution, causes, and costs and related phases of accidents for various and collective divisions of the petroleum industry in several sections of the country. This type of study aids the personnel of the Bureau in planning the course of its activities in accident-prevention work and gives useful data to persons engaged or interested in the promotion of safety in the petroleum industry, which will aid them in their efforts to reduce the number and severity of accidents. A majority of petroleum operators and "service? contractors have acknowledged their responsibility to provide their employees with safe working conditions and to their stockholders for greater economic value of invested capital by establishing safety divisions within their respective organizations. Such divisions have a primary duty, namely, to see that properly designed and guarded machinery and working equipment are furnished the employees and that they are trained in the safest practical methods of performing their work. Some companies and individual operators, however, have shown little or

Jan 1, 1939

By Minoru Kawamura, Shinya Tanaka

In Japan, a cartridged emulsion explosive is generally used for tunneling. The workers are compelled to approach the face on charging the explosives into the drill hole with the tamping rod. Therefore, the workers are exposed to the risk of the disaster with the cave-in and the falling rock. The mechanization of the tunnel work has been advancing gradually. Especially, the development of the mechanization for charging work is desired in order to avoid the risk of disaster on workers. Recently, some charging machines such as the bulk emulsion explosives have been evaluated. However, a universal method has not been established yet, because the evaluated machines were not adequately suited from the point of the regulations and the consumption style of explosives.

Jan 1, 2008

By R. Poulin, C. F. Gleeson

The Birimian rocks of the region are gold-bearing and show many similarities to those of Burkina Faso. All three greenstone belts (Goroual, Tera and Sirba) host gold-bearing quartz veins. It appears that, contrary to previous misconceptions, lateritic terrain is not an unfavourable environment for exploration geochemistry. This is demonstrated by the results for the Koma Bangou area, where soil and termite-mound geochemistry have been successfully used in the search for gold. Soil provides an effective sampling medium where it is shallower than about 2 m; there is evidence that some soil anomalies are enhanced by the presence of secondary (botryoidal) gold. In areas of thicker, allochthonous soil cover, termite-mound sampling is more effective. At Koma Bangou an identified resource of some 11 100 000 tonnes with an average gold grade of 2.44 g/t has been reported. The gold mineralisation occurs in quartz veins and stockworks aand in the wallrocks of shear and fault zones that trend N, NW and NE. The host rocks are a granodiorite-syenite porphyry and intermediate metavolcanic rocks and tuffs

Apr 1, 1996

By Roberto Chambi

"El presente trabajo señala la expansión de la producción de la mina Condestable a través de las innovaciones tecnológicas en clasificación de molienda como: la utilización de estas zarandas derrick de cinco pisos cada uno, donde se aumenta la capacidad de cada molino instalado en planta en un 17% en promedio, así como el grado concentrado supera el promedio de 26.35%."

Sep 9, 2007

By D. I. Smith

Constructing tunnels in congested urban areas requires tunnels to be placed closer together and with less cover than was previously necessary. Contract CQ031 of New York?s East Side Access project will construct four six-meter diameter bored tunnels in a three-up one-down ?T? configuration, with less than three meters of soil between the tunnels. Mixed-face rock and glacial till conditions with a high ground water table will be encountered under active railroad yards. The tunnels will also pass beneath the busiest railroad interlocking in North America with cover as shallow as three meters. This paper discusses the challenges of designing segmentally lined tunnels for these conditions.

Jan 1, 2008

By John A. Johnson

For the purpose of comparing the amounts of dust produced by various mining operations, samples of atmospheric dust were collected during a complete cycle of drilling, blasting and mucking at or near the face of the Bureau&apos;s Mount Weather testing adit while the efficiency of several types of stemming in metal-mine blasting was being investigated. ACKNOWLEDGMENTS All gas samples were analyzed in the laboratory of the Bureau of Mines Gas Section at Pittsburgh, Pa.

Jan 1, 1939

By Adnan A. Malik, Tadashi Maejima, Jiro Kuwano

"ABSTRACTTheoretical approach to estimate the ultimate pile capacity gives a rough idea at the initial stage of design that later on strengthen by the execution of static pile load test at site. The static pile load test is the only best option for the estimation of ultimate capacity of various types of piles. There are various methods based on strength, serviceability, net deflection for end bearing, shaft adhesion, graphical and extrapolation approaches for the interpretation of pile load test data to calculate the ultimate capacity. In this paper an attempt is made to evaluate the best-fit method for the estimation of ultimate capacity of single helix screw pile. The pile load tests on model scale were performed on screw piles of different helix diameter. The purpose of adopting model scale of testing was to achieve a state at which settlement increases without further increase in vertical load. The ground was compacted with dry sand at denser state. It was observed from the test results that extrapolation methods such as Chin- Kondner and Decourt predict the load settlement curve of screw piles very well, however ultimate pile capacity was on higher side which may not be suitable for the strength of helix plate. Decourt approach to plot the pile load data showed clear indication of the deformation of helix due to strong subsurface condition. A modified approach in Decourt method is proposed for estimating the ultimate capacity of screw pile having deformed helix whereas reduction factor is suggested for Chin-Kondner method for the estimation of ultimate capacity of intact screw pile.INTRODUCTIONDeep foundations are used to avoid the soft ground at shallow depth that is not suitable for carrying the structural load. Different types of piles have been used to transfer the load to deeper stratum. The screw pile is one of the new piling method and its use is considerably increasing. It consists of a cylindrical steel shaft with one or more helices at various length of the shaft. The diameter of helices (Dw) is usually 2 – 2.5 times the shaft diameter (Ds). The pile is installed to the required depth through torque and pressure. The advantage of screw pile over other piling system is its quick installation mechanism, high end-bearing and uplift resistance, noise reduction and minimum use of man power."

Jan 1, 2014

At Waiuta near Reefton there is a remarkable vein of quartz &lt;1 m thick which, apart from small offsets on late-stage faults, is a sheet like body essentially continuous down-dip and along-strike for&gt; 1 km. The vein strikes NNE and dips steeply west (032/78¦W). From 1906-1951 the Blackwater mine produced 740,404 ounces of gold from the vein, called the æBirthday ReefÆ, which was one third of the total production from Reefton Goldfield and the fourth largest gold mine in New Zealand. Within the mine the vein is disrupted into a series of northeast-plunging shoots by late-stage faults. Similar faults, but with larger displacements, were thought in the past to truncate the vein at the northern and southern ends of the mine. The implication of this fault dissection model is that offset remnants of the vein await discovery. This study investigated the geometry of the vein and its relationship to host-rock structures and late-stage faults. A new model considers folding and lithological variation in the host-rocks to be fundamental in controlling the scale and geometry of veining, but does not rule out the possibility of some late-stage fault dissection. The Birthday Reef truncates 200-400 m wavelength folds in Greenland Group host-rocks at c.10¦ angle, that results in variation in the structural properties of host-rocks along strike every ~1350-2500 m. The spacing of fold hinges in the wall-rock veins is equivalent to the strike length of historic mining, implying that the Birthday Reef is probably hosted in a single limb of a fold. Similar relationships between mineralisation and host-rock folds appear to be present elsewhere in the Reefton Goldfield (e.g. Capleston and Murray Creek group of mines). Exploration targets are located one fold wavelength (c.1350-2500 m) further along strike from the Blackwater mine and relatively barren rock is expected in between the mine and target areas. Refining the location of folds and different host rock lithologies, using geophysical data and quality geological mapping, is the key to reducing exploration risks and discovering further resources.

Jan 1, 2000

By Kiseong Hyeong, Young-Tak Ko, Gee Soo Kong

"The benthic environmental impact experiment addresses environmental impacts at a specific site related to deep-sea mineral resource development. For such a purpose, since 2010 we have carried out essential environmental research at both the BIS and a preservation site. We have acquired several tens multi- or box core samples at 32 sites within the BIS especially between 2011 and 2013, aiming to examine the basic properties of surficial deep-sea sediment as the potential source for deep-water plumes.In this study, we present physical the properties such as water content, shear strength and also geochemical properties such as major elements, rare earth elements (REEs), heavy metal contents at the BIS. Such proxies vary distinctly according to the Facies association. The lithology of all core sediments in the BIS corresponds to both Association Ib (Unit I/Unit II) and Association IIIb (Unit I/Unit III) on the basis of the KORDI classification (KORDI, 2004); Unit I is watery mud and dark grayish brown (10YR4/2) to dark brown (10YR4/3). Unit II is highly bioturbated mud and brownish yellow (10YR6/6). Unit III is very dark brown (10YR3/2) to black (10YR2/1) mud. Physical properties of these sediment types show that Association Ib is distinct from Association IIIb. The vertical profile of water content changed more sharply in Association IIIb probably due to compaction; water contents varied from 230 to 300% in Association Ib and changed from 200 to 250% in Association IIIb. The vertical profiles of shear strength are also quite different between Associations; the profile curve in Association IIb is much more gentle due to bioturbation."

Sep 1, 2014

ABSTRACTRock stresses can be modified by physicochemical processes.If rock pores allow the ingress of water and oxygen, but are not large enough to permit the exit of larger molecules of weathering products, anomalous rock pressures develop. Rock masses may also be subjected to osmotic pressures developed as water diffuses into pores and joints filled with saline water. Anomalous rock pressures may also develop as gels filling pores undergo syneresis and as salts crystallize from pore solutions.

Jan 1, 1968