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Laboratory testwork was carried out on an overall orebody composite, of 2.9 per cent Cu and 4.2 per cent Zn, prepared from drill core taken from the Currawong fine-grained, copper-zinc massive sulphide deposit near Benambra in Victoria. While 90 per cent of the copper was readily recovered in a concentrate of 20 per cent Cu, after grinding to 95 per cent passing 38 microns, zinc responded poorly to conventional flowsheet/reagent regimes. Experience elsewhere with the use of reverse cleaning, to separate pyrite from sphalerite, led to a series of tests in which better (but still modest)metallurgical results were obtained. The best result was a zinc recovery of 55 per cent in a concentrate of 50.5 per cent Zn. The major loss of zinc occurred in the reverse cleaning stage where the unit recovery of zinc was similar to pilot plant results achieved at Mount Isa Mines on similar feedstock. Diagnostic mineralogy suggested that an overall zinc recovery of 70 per cent was probably the practical upper limit, at a 50 per cent Zn grade.

Jan 1, 1999

By H Kundapen, J J, C Rumble, S Miller

This paper describes measures taken by Ok Tedi Mining Limited (OTML) to minimise the risk of acid rock drainage (ARD) resulting from mining operations at its Mt Fubilan porphyry copper-gold mine in the remote Star Mountains of Papua New Guinea. The risk of acid generation and metal leaching as a result of oxidation of these sulfidic deposits has long been recognised by OTML. In 1998, OTML instigated the ARD Management Program to fully evaluate these risks and to formulate, if necessary, trial and implement appropriate management strategies. In implementing the ARD Management Program, OTML has adopted a risk management approach consisting of five stages: risk identification, risk analysis, risk assessment, risk treatment, and review and monitor. Significant progress has been made in relation to risk identification, analysis and assessment. The work currently underway to put in place a comprehensive risk treatment and review process will ultimately determine the success or otherwise of this approach.

Jan 1, 2003

By George E. Williamson, Mikiya Higuchi, Michael T. Traylor

Extensive soil conditioning was required to allow Earth Pressure Balance(EPB) tunneling on the South Bay Ocean Outfall tunnel project in San Diego, California, near the Mexican border. This tunnel extends 19,000 feet out under the Pacific Ocean and was mined through soil formations including silts, sands, gravels, cobbles, and boulders. EPB pressures ranged from 3.0 to 7.0 bar, with the maximum pressures required when mining through the highly permeable granular formations.

Jan 1, 1999

By C. Poon

For slope stability, knowledge of major and minor discontinuity sets that form the rock mass fabric is paramount for pit slope designs. Due to the increased awareness of health and safety in mining projects, efforts have been made to limit structural mapping in order to minimize the risk to personnel associated with approaching potentially unstable areas. Recognizing the importance of such safety precautions, Golder Associates Ltd. is applying a combination of techniques including 3D photogrammetry, conventional mapping and drilling with core orientation to enhance structural data collection. Photogrammetry uses digital photographs to produce a virtual model of a rock mass surface. The application of these techniques will be exemplified through an expansion design of an existing open pit. A comparison of stereonets obtained using these techniques showed some agreements, but also highlighted limitations of each method. The application of photogrammetry was found to be very useful in complementing the other existing techniques.

May 1, 2009

By V. K. Paruchuri, J. D. Miller, J. Nalaskowski

The phenomenon of surfactant adsorption at mineral surfaces is of significant importance in many particulate processes ranging from mineral flotation and enhanced oil recovery to pharmaceutics, paint technology and the casting of high quality ceramics. Stability of the dispersions is related not only to the amount of adsorbed surfactant but also to the structure of the adsorbed surfactant molecules at the interface. This structure greatly depends on the type of surfactant and the hydrophobicity or hydrophilicity of the surface. On hydrophobic surfaces surfactants adsorb regardless of surface charge by van der Waals/hydrophobic inter-actions with hydrocarbon chains accommodated at the surface. On the other hand, on hydrophilic surfaces the surfactants adsorb through electrostatic interactions with their polar moiety fixed at the surface. In the latter case, the electric charge of the surface and surfactant plays a crucial role in the surfactant adsorption process. The recently developed soft-contact Atomic Force Microscopy technique has revealed images of adsorbed surfactant structures at various interfaces. The adsorbed structures of a cationic surfactant (CTAB) and an anionic surfactant (SDS) are presented in this work for different concentrations at hydrophobic graphite and hydrophilic mica surfaces. Different types of micellar arrangements have been observed at these surfaces for surfactant concentrations around the critical micelle concentration. The structures are more ordered and well defined at the graphite surface than at the mica surface. These results have been correlated with the hydrophobicity of the surfaces as revealed by contact angle measurements.

Jan 1, 2001

By Benjamin C. Allen

The surface tensions of liquid chromium and manganese were determined by a modification of the dynamic drop-weight method and found to be, respectively, 1700 * 50 and 1100 * 50 dynes per cm at their melting points. Molten drops were formed LITTLE is known about the surface tension of liquid chromium and manganese, even though they are technologically important metals and widely used in steelmaking. In the past, direct determinations have been hampered by their high reactivity on the lower end of a vertically held rod inductively heated under argon. The technique essentially reproduced surface tensions reported for liquid nickel and zirconium using static drop-shape methods. and vapor pressure. In this work, surface tensions were measured by the drop-weight method, using induction heating under argon. EXPERIMENTAL WORK Chemical analyses of rods used are given in Table I. Chromium rods were prepared from iodide-process crystals which had been are-melted, hot-extruded, warm-swaged, and centerless-ground.'

Jan 1, 1964

By I. Grigoryeva, G. Voiloshnikov, V. Dementyev, N. Moskaeva, N. Voiloshnikova

"Adsorption processes with use of anion exchange resins are widely applied in the gold mining industry of Russia and the former Soviet Union. Anion exchange resin AM-2B and its analogs (with mixed basicity) are used as adsorbents. This paper focuses on the study of weak base anion exchange resin and its comparison with AM-2B resin. Different nature of the ion exchange groups of the adsorbents mentioned above provides essential differences in their properties both during adsorption and elution of gold and silver. Multistage gold elution and resin regeneration procedure is used for AM-2B resin whereas alkaline cyanide solution is used for weak base resin and allows for the reduction Capex and Opex in comparison with AM-2B resin. Anion exchange resins AM-2B and PuroGold S-992 were tested. Weak base resin is sensitive to pH of adsorption medium. Optimal pH value is 10.1-10.3 (at ?? >10.5 gold loading onto resin decreases dramatically). Adsorption isotherms for gold, silver, nonferrous metals, cyanide and thiocyanate ions from synthetic individual metal cyanide solutions were defined. Adsorption of all components onto PuroGold resin was lower than for ??-2? resin. Adsorption of metals from the solution with equal molar metal concentration (0.1 mg-equivalent/L of each metal) was also studied. The affinity of resins to cyanide metals complexes was established. Weak base resin has higher selectivity to gold in comparison with ??-2B resin and is less sensitive to ion composition of cyanide solution or pulp treated. Weak base resin was tested for gold recovery from gold ores. On the base of test results it was recommended to introduce this resin at some new plants in Russia. Commissioning and operation performance of gold plants confirmed efficiency of weak base resin use."

Jan 1, 2014

Assuming that a gold ore has been effectively ground to ensure maximum economic liberation of gold, the circuits that will have the most effect on the successful operation of a gold plant will be that of the leaching and carbon-in-pulp circuit (CIP). The reagent and utilities operating costs associated with leaching, adsorption, elution and regeneration would typically make up some 15% of total operating cost, whilst the capital costs associated with these areas is about 16% of the total. Although not largest (capital and operating costs associated with comminution are generally dominant) these items represent a significant proportion of capital and operating cost. Much more importantly, these plant areas represent the primary gold recovery process and their technical and operational efficiencies will have a significant impact on overall plant efficiency. The objective during process design of these sections is thus to develop a design which provides maximum technical and economic efficiency and which is robust to potential changes in ore throughput, mineralogical characteristics and head-grade. Experience has shown that, particularly for longer life and higher-grade projects typical of the South African underground gold mining industry, small changes in recovery and efficiency have a significant value over the life of the project.

Jan 1, 1999

By M Scott, J J. McEwan

Silver and silver alloys tarnish readily by the formation of tarnish on the surface when exposed to a wide range of sulphur-containing atmospheres. This tarnish is unsightly and undesirable and can be removed either with a silver polish or a chemical dip. Polishes are, however, not suitable for irregular and embossed surfaces such as on coins, medallions and jewellery items, because of uneven removal of the tarnish layer and excessive wear. Successful tarnish protection can be achieved by either storing the items away from the aggressive atmosphere or by coating/treating the exposed surfaces with a protective layer. Storage is feasible for collections but is not suitable for items that are handled or worn regularly, such as jewellery. A number of commercial coatings and treatments have been developed, but to date there has not been a systematic evaluation of tarnish protection. This paper details the performance of a range of generic coatings in an accelerated tarnish test. The degree of tarnish was evaluated by means of loss in reflectivity and change in colour. Four coatings/treatments improved the tarnish resistance of silver by more than tenfold. These include an organic lacquer, rhodium electroplating and an organic self-assembled monolayer (SAM) conversion coating. Research is continuing to optimise these coatings. Keywords: silver alloys, tarnish resistant coatings, silver polishes.

Jan 1, 2006

By J. P. Piguet, Y. Wileveau

ABSTRACT : An experimental programme for damage assessment was performed in the vicinity of the main shaft of Andra’s Underground Research Laboratory, currently under construction in the East of France, when the shaft is crossing the Kimmeridgian marls between 80 and 100 m depth. The mechanical behaviour was analysed by mean of convergence and displacement measurements. The disturbance into the wall was assessed using numerous methods such as measurement of sonic velocities, permeability measurement and VSP measurement in radial boreholes. The intensity of the damaged zone is low, and its extension does not exceed 0.5 time the radius of the shaft. It does not seem to depend on blasting patterns. ZUSAMMENFASSUNG : Ein Forschungs- und Versuchsprogramm wurde aufgestellt, um die beschädigte Zone im Bereich der Kimmeridgemergel zwischen 80 und 100 Meter Tiefe beim Zugangsschacht des im Bau befindlichen Andralabors im Osten Frankreichs zu berechnen. Das mechanische Verhalten der Formationen wird auf der Grundlage von Konvergenz- und Verschiebungsmessungen ermittelt. Verschiedene Messmethoden, wie z.B. mikroseismische Geschwindigkeite Messungen, Permeabilitäs- und Beschleunigungsbestimmungen in strahlenförmigen Bohranordnungen, erlaubten die Ermittlung des Beschädigungscharakters der Schachtwand. Die Intensität der beschädigten Zone ist niedrig, ihre Ausdehnung übersteigt nicht die Hälfte des Radius des Zugangsstollens und scheint unabhängig vom Schema der Sprengstoffanordnungen zu sein. RESUME : Un programme expérimental visant à évaluer la zone endommagée autour du puits d’accès du Laboratoire de Recherche Souterrain de l’Andra actuellement en construction dans l’Est de la France a été mis en œuvre lors de la traversée des marnes du Kimméridgien entre 80 et 100 m de profondeur. Le comportement mécanique des formations est évalué à partir de mesures de convergence et de déplacements. La mise en œuvre de nombreuses méthodes, telles que des mesures microsismiques, des mesures de perméabilité et d’accélérométrie en forages radiaux, a permis de caractériser l’endommagement en paroi du puits. L’intensité de la zone endommagée est faible et son extension ne dépasse pas 0,5 fois le rayon du puits. L’endommagement semble indépendant des schémas de tirs testés.

Jan 1, 2003

By Trevor J. Smith, Kevork A. Chouzadjian, Rob S. Burns, Steve J. Roden, Michelle A. Spieth

Investigations were undertaken to improve the recovery of silver from CRA's Hidden Valley gold/silver deposit by the addition of calcium peroxide. The addition of 0.75 to 1.5 kg/mt of calcium peroxide improved silver extraction by 5 - 300 and reduced cyanide consumption by up to 30%. Gold extraction was also marginally improved in some of the tests. The results are of economic interest and plant trials will be initiated once operations are underway.

Jan 1, 1990

A number of mineral deposits occur in close proximity to the Pacific plate fronts. Among these deposits are gold-silver and the base metal sulphide deposits of copper, zinc and lead. Gold deposits that commonly occur in these areas are of hydrothermal origin. Of these the epithermal deposits have attracted the attention of the exploration geologists as well as the metallurgists. One vital aspect of the activity of the geologists is the development of models for epithermal gold mineralisation in the Pacific Rim. These models can also be used by metallurgists for predicting gold extraction processes. This paper reviews the mineralogy, fineness and the host minerals of gold and examines the data in the light of gold mineralisation in the southwest Pacific Rim. The gold mineralisation models proposed for the Pacific Rim have been used to predict gold extraction processes suitable for the various mineralisation types. Discussed also are the mineralisation and treatment processes of some selected epithermal gold deposits and gold-rich porphyry copper deposits in Indonesia, Papua New Guinea, Solomon Islands, Fiji and New Zealand.

Jan 1, 1999

By M. Kul

In this study, the effects of various extraction and stripping parameters, such as equilibrium pH (7.0, 8.5 and 10), extractant concentration (5, 10 and 20 volume %), organic-to-aqueous (O/A) ratio and stripping agent type and concentration were studied on chromium (VI) recovery from chromium electroplating rinse bath wastewater using Aliquat 336. Results showed that these parameters all had significant effects on chromium (VI) recovery. A pregnant strip solution from a chromium electroplating rinse bath wastewater with 33.4 g/L chromium content, suitable for sodium dichromate production, was generated by 20 vol. % Aliquat 336 in commercial kerosene. The O/A ratio was 1/4 and the equilibrium pH value was 0.87, the as-received pH value. The wastewater was treated with a two-stage countercurrent extraction process to produce a loaded organic phase, which was later stripped at the O/A ratio of two with a 4-M NaOH solution in a two-stage countercurrent stripping process using Taguchi?s optimization technique.

Jan 1, 2010

By D. Francois-Bongarcon

The ?Poisson effect? is defined and characterized. It takes place even when the material to sample is not liberated. Gy, Pitard, Ingamells, and others, including the author, recommend that a minimum average number of particles of mineral of interest characterize the recommended sample size. How many? Recommended numbers range from 6 to 40 particles depending on authors, corresponding to standard deviations of 41% to 16%. Some guidelines are proposed, and the often alleged ?double-Poisson? effect is examined.

Jan 1, 2009

By Mario L. Villa

During 1938, oil activities in the Argentine Republic showed a favorable balance due to the increase in crude-oil production, the incorpora- tion of new producing areas and the discovery of deeper productive horizons. Drilling was as follows:

Jan 1, 1939

By Mario L. Villa

During 1938, oil activities in the Argentine Republic showed a favorable balance due to the increase in crude-oil production, the incorpora- tion of new producing areas and the discovery of deeper productive horizons. Drilling was as follows:

Jan 1, 1939

By Dimitris Pachakis

In this paper, the authors give a brief overview of the current practice guidelines and tools for the seismic design of sheet pile quay walls, emphasizing how the design guidelines are lacking when the existing structure performance evaluation is required to meet performance-based criteria. Relying on recent experience they explain how the existing practices can be amended to focus more on performance evaluation as opposed to design. An example is given of an old sheet pile quay wall analyzed and evaluated for its performance according the recent performance criteria devised for Californian Marine Oil Terminals.

Jan 1, 2011

By G. R. St. Pierre, A. J. Wilhelem

In connection with the reduction of hematite or magnetite to metallic iron, it appeared desirable to study the rate of reduction of each oxide to the next lower oxide under conditions which excluded all other condensed phases. For this purpose, pellets of Fe,O,, Fe,O,, and oFeOo were prepared. A gas train for the preparation of Ar-Hz-H20 mixtures was employed to establish a continuous flow of a controlled atmosphere over a pellet suspended on a balance. In this manner the following individual reduction steps could be studied: For example, pellets of hematite were reduced solely to magnetite by adjusting the gas atmosphere such that it was oxidizing to wustite. In other words, the reaction was complete when the hematite pellet had been totally converted to magnetite. The pellets were prepared from Baker Chemical ferric oxide. The ferric oxide powder was moistened and handrolled. Air sintering at 950°C produced Fe,0, pellets with a density of 3.65 g per cm3. The pellets ranged in size from 0.6 to 1.2 cm diam. The magnetite and

Jan 1, 1962

INAP was formed in 1998 by a number of major mining companies, with a view to sharing acid rock drainage knowledge and experience, and to coordinate global research on the management of sulfidic mine wastes. INAP is now moving to further strengthen its global role by networking with regional organisations that are active in the area of ARD, including MEND 3/NEDEM 3 in Canada, the ADTI in the USA and ACMER in Australia. The INAP-Regional Organisation partnership will be formally launched at the 6th ICARD.

Jan 1, 2003

By R. L. Bowron

GROWING use of basic slag in the agricultural industry is of special interest and importance to the iron and steel industry of the Birmingham district, providing an increasing outlet for this by- product. Such use of basic slag was first developed in England about fifty years ago where it soon became wide- spread. About twenty years ago the Tennessee Coal, Iron & R. R. Co. began its production in the United States after exhaustive tests had demonstrated its high value here as in Eng- land. It is particularly valuable on heavy clay and acid soils, improving their physical condition, increasing their alkalinity where that is desirable, and providing soluble phosphate and small amounts of manganese to soils deficient in these respects. Its use in agriculture is growing as its advantages are becoming more widely known.

Jan 1, 1937