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By Robert K. Towner, Francis S. Kendorski

Shotcrete drift linings at the Climax Mine of the Climax Molybdenum Company have undergone four years of extensive evaluations as a replacement for thick poured-in-place concrete linings. Any drift lining at Climax must be able to withstand the rigors of undercut and secondary blasting, weight problems induced by panel caving, and the abrasion of slusher mining. Examined here are the conclusions reached so far on shotcrete drift linings which have not yet completed the approximately six-year cycle from development to ore exhaustion. Properly applied shotcrete is an adequate drift lining for all phases of the Climax panel caving system of mining. Undercut blasting will damage shotcrete unless blasts are correctly timed. Weight problems will destroy shotcrete drift linings as efficiently as it will destroy concrete or steel support systems. Abrasion and secondary blasting results are inconclusive as the shotcrete lined slusher drifts have not entered the ore production stage of the mining cycle. In addition to drift linings, Climax has found shotcrete to be invaluable for lining large underground shops, for temporary support systems, for permanent ventilation bulkheads and for the repair of abraded or weight damage concrete lined slusher and haulage drifts.

Jan 1, 1974

By Donald R. Williamson

Statistical studies at Cyprus Pima Mine indicate that samples from 22 blastholes are necessary for determining average copper grades, within a desired range of precision, for mine-model blocks by arithmetic averaging. The average number of holes in such blocks is 14. Many considerations show that more holes will not be drilled for sampling. A way to determine block grades more reliably than by" arithmetic averaging was sought. Thus far arithmetic averaging has proven to be the best procedure for the particular operation characteristics despite the small number of samples. It naturally follows that expenditure of great effort in sampling blasthole cuttings is unwise.

Jan 1, 1977

By J. E. Dodge

Tasu, currently an open-pit operation, services the primary crusher from two areas by ore-pass raises. The problems encountered and advantages gained are discussed. Mine equipment and operating practices are covered, together with blasting practices, line drilling and the pre-shearing necessary to stahilize the pit walls.

Jan 1, 1968

By F. M. Simonds, E. Z. Burns

The Rawley property is located in the Kerber Creek mining-district, Saguache county, Colorado, at an elevation of 10,600 ft. (See sketch-map, Fig. 1.) Ore was found in this vicinity as early as 1880, and claims covering a large area were located and in many instances patented. The ores, however, being of comparatively low grade, and the nearest railway station, Villa Grove, being some 20 miles away, it is extremely doubtful whether any considerable amount of ore was ever handled at a profit. It is safe to say that several hundred thousand dollars were spent (a large part in building mills) previous to 1902-03. About that time a very capable promoter gathered together a group of these claims and interested some New York people, who had had no previous mining experience, in the purchase of these claims. Following the organization of a company, this promoter became General Manager. As often happens under such conditions, the first step was to erect a mill to treat 100 tons per day. It may not be fair to this enterprise to say that the failure which followed might have been foretold, simply on general principles, but this much is certain—the water supply fluctuates in the course of a season through a wide range and for a considerable portion of the year was inadequate to run this mill at capacity. Further, it is currently reported that some of the mill foundations were placed on ice. However true this statement may be, it is a fact that, when first inspected by us, many of the belts in the mill were held on'their pulleys by means of idlers. A shut-down followed, with a material re-adjustment of interests, at which time we became consulting engineers for the company.

Jan 1, 1914

By K. L. Kasperski, M. T. Ityokumbul

The effect of reaction conditions on the desulfurization of oil-sand coke residues was studied. The variables investigated were temperature, reaction time, heat transfer resistance and mode of caustic soda addition. The results show that oil-sand coke desulfurization increases with temperature, reaction time and heat-transfer rate. In an oxidative environment, coke combustion during molten-caustic leaching (MCL) commences at temperatures above 500 °C. The mode of caustic addition has no effect on coke desulfurization.

Jan 1, 1996

By J. A. Baicker

A 2 1/2 inch diameter probe containing a high resolution gamma ray spectrometer was developed for downhole ore grade assays to depths of 6,000 feet. Tests have been conducted on the characteristics of this tool for in-situ determinations of uranium by means of natural gamma ray counting, and of copper, silver, gold, iron and coal quality by means of neutron-induced gamma rays. Application of the technique for improved carbon-oxygen logging in oil fields is promising. The probe contains a cryogenically cooled high purity germanium detector and a 4,000 channel spectrum analyzer. Gamma ray spectra are digitally transmitted up the cable to the truck-mounted data processing system. We found that uranium can be assayed directly in different types of formations independently of the degree of geochemical disequilibrium by counting the relatively weak 1.001 MeV gamma ray of protactinium-234m. Neutron activation work shows that in-situ determinations of copper, silver, iron and coal quality are technically feasible. In carbon-oxygen oil well logging the technique allows an accurate determination of carbon, oxygen, hydrogen, chlorine, silicon, calcium and iron, and shows promise of providing an improved oil/water differentiator.

Jan 1, 1982

Jan 1, 1946

By R. G. Davies

Isothermal annealing of quenched Fe3Al reveals that the superlattice forms by the nucleation and growth of ordered domains. The activation energy for isothermal ordering and initial domain growth is -29 keal per mole, which is thought to he the activation energy for vacancy migration. Domain growth, in the absence of excess vacancies, has an activation energy of -100 keal per mole. A maximum in the hardness is observed when the structure consists Of ordered domains, -35-4 in size, growing into a short-range ordered matrix and, also as a function of degree of order, S, with an infinite domain size at S = 0.4 to 0.5. It is proposed that both maxima are due to a transition from deformation by unit dislocations to deformation by superdislocntions. FE-AL alloys containing more than -23 at. pet Al, when quenched from above the critical temperature for the Fe3A1 type of order, always contain the maximum possible amount of FeAl (B2) type of order' (see Fig. 1). Thus when the Fe3A1 superlattice forms, in a 25 at, pet A1 alloy, it does so from an imperfect FeAl structure. The formation of the Fe3Al superlattice has been the subject of several recent X-ray,1, 2 electrical-resistivity,3"6 and dilatometric3 investigations. McQueen and Kuczynski3 concluded that the isotherma1 ordering of Fe3Al, after quenching from 800°C (T,, the critical temperature for order, is 55O°C), takes place by the nucleation and growth of ordered domains. However, Feder and Cahn4 found that the isothermal ordering was complex but more like a homogeneous nucleation process than a nucleation and growth process. Lawley and Cahn2 reported that the degree of order is a continuous function of temperature which is a characteristic of a homogeneous nucleation process. Thus, the evidence is conflicting as to the nature of the Fe3Al ordering reaction. Lipson7 was the first to suggest that ordered domains should exist in the Fe3A1 structure since, as

Jan 1, 1964

By E. J. Matson

From February until July 1943 the Bureau of Mines conducted an exploration project at the Majuba Hill mine to determine tonnage aria grade of the copper and tin ore and to search for extension of the mineralization. The work comprised sampling, long-hole drilling, underground excavation, and ore-dressing test.

Jan 1, 1948

By D. Cubicciotti

IT has long been known that some metals are capable of being dispersed or dissolved in certain of their fused salts.' Davy' and Bunsen³ were among the first to observe that in some fused salt electrolyses, a highly colored, strongly reducing salt phase appeared in the neighborhood of the cathode. Later workers found that the current efficiency of the electrolysis was markedly reduced when such a phase appeared. It was also found that the strongly reducing salt could be made by melting the metal and normal salt together. Chemical analysis showed that in such salts the metal ion to anion ratio was always larger than in the normal salt. From such observations arose two different explanations of the nature of metal in salt solutions. When a solution of this type is quenched, it is possible to find small globules of metal in the salt. From this and other observations, Lorenz' and co-workers assumed the metal in salt solution to be a colloidal dispersion of metal in the fused salt and called it "metallnebel" or metal fog formation. They made a number of experiments to substantiate this point of view. Another school felt that when the metal dissolved it reduced the salt partially to a mixture or solution of normal salt and subsalt. Both of these ideas could explain the strong reducing character of the salt formed and the low current efficiency of the electrolysis. If either a metal colloid or a subsalt were formed at the cathode and diffused to the anode, it would be oxidized to the normal salt. Thus a cyclic process of oxidation and reduction could be set up conducting the current without giving rise to a net change in the system. These facts led the author to investigate some of the properties of metal in salt solutions with the hope of elucidating their nature further. Among the metal-salt systems that form metal in salt solutions most markedly are the alkaline earth metal-halide systems and cerium, bismuth, and cadmium halides. Other systems of halides, oxides and sulphides form such solutions to a lesser degree. The first work undertaken was a study of the temperature-composition diagrams of some of the systems." From such diagrams it would be possible to distinguish between a subhalide formation or a colloid. A subhalide should give rise to characteristic changes in the phase diagram, while a colloidal dispersion of metal in salt would not alter the freezing point of the salt. The results obtained on a number of alkaline earth metal-halide systems were all quite similar. Fig. 1 shows the barium-barium chloride system. The other

Jan 1, 1954

A Helix Pressure Gauge to Indicate roof bolt loads was designed, fabricated and field tested. The gauge indicated loads between 3,000 and 15,000 pounds with a ± ten per cent error. The coat of fabrication of the gauge was estimated to be $3.39 including an assumed overhead and profit per indicator for a series production of 5,000 unite. The unit can be read on a bolt to within ± 1,000 pounds load from a distance of twenty feet.

Jan 1, 1974

High pressure grinding mills have been successfully introduced in the industry. They offer the possibilities for capacity increase of existing plants and reduction of operating costs. Further metallurgical advantages in gold and copper are possible. The plants in operation are running in different applications and modes of operation. They can be installed in a combination with SAG and ball mills or in a stand-alone mode. In combination with other grinding mills, it has to be investigated how the HPGR can be installed to reach the full efficiency. This paper describes the possibilities to implement high pressure grinding rolls and shows by case studies the potential of savings which could be reached

Jan 1, 1996

By Sebastian Fredes, Williams Calderon, Mauricio Toledo, Gonzalo Montes-Atenas

The influence of the temperature on leaching kinetics of copper-bearing minerals has been widely acknowledged: the leaching of copper oxide ores is generally described as exothermic reactions while copper sulfide ores are associated with endothermic reactions. Reports studying the influence of temperature on leaching kinetics at laboratory scale frequently involve the implementation of either fully flooded isothermal systems or jacketed column setups. Nevertheless, at industrial scale controlling or monitoring the temperature or temperature changes is almost impractical. In fact, leaching process is usually a large tonnage operation and changing the temperature of vast amounts of material would require an enormous amount of energy and highly specific heat transfer equipment. Preliminary computations on the amount of energy required to increase the temperature of a heap or dump in 1°C indicates that it would be impossible to find an energy source able to accomplish the task. In order to provide a solution to this matter it is suggested to create an energy managing protocol (EMP) that permits heat up or down the porous body locally taking advantage from the temperature gradients and from the reactivity of different regions within the material as a function of the leaching cycles. The aim of this study is to evaluate different heat transfer regimes in a 1 ton pilot column leach operation. It was found that best results of copper recovery are obtained when heating up the column in horizontal bands starting from the top of the column moving downwards as the leach cycle evolves. The system is expected to be suitable for industrial applications, but further development of the technique is required, particularly in the design of the heat transfer dispositive.

Jan 1, 2014

By Barry C. Roth

A Real Time Automated Remote Reading Electrolytic Tilt Monitoring System was effectively deployed for monitoring an existing five story brick building during underpinning, shoring and excavation operations for a directly adjacent thirty-foot deep excavation. The monitoring system was comprised of four sets of uniaxial electrolytic tilt meters connected to a Campbell datalogger with multiplexer, cellular modem and solar power. The excavation was for the foundation and underground parking as part of a new 55 story tower complex. Challenges to the contractors and to our monitoring personnel which were addressed included a tight urban site contemplating property line to property line new construction with directly adjacent old existing buildings, buried concrete foundations from former site use, cohesionless pervious sandy soils and high groundwater. Highly variable and diurnal ambient temperature regimes due to adjacent building shadows required careful corroboration and application of temperature corrections to the raw data. Earth tides were suspected on a very small scale and investigated by correlation between the data and the local sinusoidal tidal ephemera. Incidental inadvertent contractor interference with the instruments during underpinning due to site constraints was readily detected.

Jan 1, 2007

By R. I. Jaffee, R. M. Evans

IN recent years, the interest in liquid metals as heat-transfer media for power plants has been very great. The possibility of the development of nuclear power plants has increased this interest and served as the impetus behind much research on low melting metals and alloys for such purposes. The principal reasons for consideration of liquid metals as heat-transfer media lie in their high thermal conductivity and consequent high heat-transfer coefficients, stability at high temperatures, and the high ranges of temperature possible. The element gallium possesses some of the requisite properties for a heat-transfer liquid. It is a unique material, having a low melting point and a high boiling point. Pure gallium melts at 29.78oC, and suitable alloying will produce a metal which melts below room temperature. The boiling point is about 2000°C. As it is a liquid metal, the heat-transfer characteristics would be good. Gallium is not now readily available, due in part to a lack of uses for the metal. Nevertheless, it is not a rare element, and a sufficient supply of gallium exists to permit its consideration for this use. Since gallium has some promise as a heat-transfer liquid, owing to its unique properties, research on the subject was carried on at Battelle Memorial Institute at the request of the Bureau of Ships, U.S.N. The research had as its objectives the determination of the effect of alloying on the melting point of gallium, and the study of the corrosion of possible container materials. In this research, alloys were found which had significantly lower melting points than pure gallium, but none which simultaneously fulfilled other additional requirements, chiefly the corrosion problem. Neither was it found possible to reduce the melting point of certain otherwise suitable alloys appreciably by small additions of gallium or gallium alloys. The results gave little hope that gallium alloys can be developed which enhance the good properties and minimize the undesirable characteristics of elemental gallium. Thus, gallium now appears less promising than other metallic heat-transfer media. The experimental thermal-analysis techniques used in this work have been described.' Experimental Results As a first approximation, the development of low melting gallium alloys was based on alloying elements suitable for use in a nuclear power plant, which also lowered the melting point of gallium. Information from the literature, summarized in Table I, indicates that. tin, aluminum, and zinc are the only suitable elements which cause a lowering of the melting point of gallium. Indium and silver also lower the melting point of gallium, but are of little interest for use in nuclear power plants. Of the elements reported not to lower the melting point of gallium, there is some ambiguity on the behavior of copper. Weibke3 obtained solidus arrest temperatures of 29°C for Cu-Ga alloys from 60 to 90 pct Ga, 0.8C lower than the generally accepted melting point. This may be the effect of a eutectic close to gallium, or, more likely, the result of impurities, or experimental error. The seven elements listed in Table I whose effects were not known were of potential interest if they lowered the melting point of gallium. Their effects were determined experimentally for this reason. Binary alloys containing nominally 2 pct of each of these elements were prepared in the form of 2-g melts by placing the components in a graphite crucible and holding them in an argon atmosphere at 370°C for 5 hr. These melts were then subjected to thermal analysis. In all cases. the solidus temperature was the melting point of gallium. Since these elements (As, Ca, Ce, Mg. Sb, Si, and T1) did not lower the melting point of gallium, they were not considered further as components of a eutectic-type alloy. Ga-Sn-Zn Alloys Preliminary considerations of this system for low-melting alloys were encouraging. All three binary systems were of the simple eutectic type. The composition and melting points of the eutectics were as follows: Sn-9 pct Zn (199°C), Ga-8 pct Sn (20°C), and Ga-5 pct Zn (25°C). Therefore, the probability of a ternary eutectic was high. For reasons to be discussed later, aluminum could not be used as an alloying constituent, leaving the Ga-Sn-Zn system as the only one of interest for low-melting gallium-

Jan 1, 1953

By S O’Connell, M Scholz, A Robertson, M L. Bloss

The value created in any mining operation is a function of the mine plan. The quality of this plan is dependent on the strategies employed during definition drilling, resource estimation and mine planning. This paper presents opportunities to improve the value of an operation through better strategic management of these core activities. Case studies undertaken recently at Olympic Dam are presented to support the conclusions presented in the paper.CITATION:Bloss, M L, O’Connell, S, Robertson, A and Scholz, M, 2016. Do we maximise the value of our operations through our definition drilling, resource estimation and mine planning strategies? In Proceedings International Mine Management Conference, pp 9-20 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By M. Ye. Melnikov

The report is about oceanic ferromanganese crusts ? covers of iron and manganese hydroxides developed over an opened rock of seamounts and rises. Ore bed parameters of crusts are understandable as their thickness and content of main economic components ? manganese, cobalt and nickel. All known results of research activity on ferromanganese manganese crusts point to that crust are characterized by notable variability of thicknesses and composition. It is possible to separate few levels of variability. The most evident is the first level of parameters variability, which is manifested in various regions of the Ocean, and connected first of all, with an age of submarine mountains, a host objects for a crusts. It was proved by many authors, that most powerful crusts are connected with submarine mountains of Cretaceous age. [1]. Crust thickness at the Magellan Seamounts reaches, for example 12-15 cm, sometimes exceeds 20-22 cm. Thicknesses of Hawaii Archipelago or Tuamotu crusts in 3-4 times less. Biostratigraphy studies of crustal sections at the Magellan Seamounts already show, that its main part started to form in the Late Paleocene. Four layers with well expressed features in structure and composition of a layer are separated in the section. From foot to top: Late Paleocene ? Early Eocene layer I-1, Middle-Late-Eocene layer I-2, Miocene layer II and Pliocene ? Quaternary layer III. Relics of more ancient Campanian ? Maastrichtian ore layer [2, 4] were discovered. It is evident for example, that Oligocene mountains could not be a host for two lower layers in the crust section.

Jan 1, 2010

Gold and copper mineralization in the Parkes area is hosted by a meridional sequence of Late Ordovician to Early Silurian igneous and sedimentary rocks on the central northern edge of the exposed Lachlan Fold Belt. The mineralized area straddles two zones separated in part by the Parkes Thrust and exhibiting different styles of deformation and mineralization (Figure 1). The western zone is characterized by gently folded rocks, with shallow dips and weak to non-existent axial plane cleavage. Faulting is restricted to directions oblique to bedding. Numerous occurrences of minor copper mineralization are known, but of recent national importance is the discovery of the Coradgery- Goonumbla porphyry copper-gold deposits by Geopeko Ltd. A resource in excess of 250 million tonnes has been delineated (Jones, 1985), and this represents the first porphyry deposit of sufficient grade and tonnage to be potentially mineable in New South Wales. The eastern zone is much more strongly deformed. Folding is tight with strongly developed axial plane cleavage. Faulting is abundant both parallel and oblique to bedding. Quartz veining is also abundant, and a narrow belt of gold mineralization adjacent to the Parkes Thrust stretches from Forbes in the south, through Parkes and Peak Hill, to Tomingley in the north. Over 31 tonnes of gold have been produced from this gold belt, mostly before 1914, and now three deposits show good potential for redevelopment - Peak Hill, and the London-Victoria and Lachlan lines of lode.

Jan 1, 1987

By Donald S. Cameron

By dispersing gold in high surface area form supported on metal oxides, its inert character can be transformed to make economical, effective catalysts. Gold has already been demonstrated in a number of fuel cell applications such as gas phase catalysts, electro-catalysts, and electrical connectors. In this paper, the various types of fuel cell systems are reviewed, and several opportunities for gold identified. Low temperature fuel cells, including alkaline and solid polymer electrolyte types rely on high surface area platinum group metal catalysts which are highly susceptible to poisoning by low concentrations of carbon monoxide in the fuel supply. Hydrogen is frequently obtained by steam reforming hydrocarbons, followed by the water gas shift (WGS) reaction. A promising initial use for supported gold catalysts is in catalysing this WGS reaction. Research has shown that gold supported on iron oxide (Au/a-Fe2O3 ) WGS catalysts are more active than the current commercial copper oxide / zinc oxide catalysts, and effective at temperatures as low as 120oC. Products from reformer/ water gas shift reactors can be further purified by removing traces of carbon monoxide. If a small proportion of oxygen is introduced into the fuel gas stream, carbon monoxide can be preferentially oxidized to carbon dioxide even in the presence of hydrogen. Gold nanoparticle catalysts on iron oxide support (Au/a-Fe2O3 ) have exhibited higher activity than commercially available platinum on alumina (Pt/?- Al2O3 ) preferential oxidation catalysts. The low temperature of this reaction may make it feasible to incorporate these catalysts within the fuel cell itself. Proton exchange fuel cells provide several possible applications for catalytically active gold and its alloys. Carbon supported platinum group metals would benefit greatly from improved electrical conductivity if gold replaced some or all of the carbon support material. As electrode current densities are raised, electrical resistance constitutes an increasing proportion of voltage losses within the fuel cell. Dramatic reductions in cell stack voltage losses have already been demonstrated by reducing inter-cell contact resistance using gold plating. The low temperature oxidation properties of gold catalysts have been investigated in controlling gaseous emissions from direct methanol fuel cells, and gold also provides essential catalysis in building direct borohydride oxidation fuel cells. The prospect of a range of other applications for gold in fuel cells to contribute useful improvements in corrosion resistance and conductivity is assessed. Globally, fuel cells have been developed for a wide range of applications including stationary generators, cars and buses, industrial vehicles and small portable power supplies, each of which represents a substantial market. Hence there are likely to be many and varied opportunities for gold catalysts to contribute to the performance and economics of the systems being commercialized.

Oct 1, 2003

By M. J. Ferrante

New data on zirconium tetraiodide (ZrI4) have resulted from high-temperature enthalpy and X-ray powder diffraction studies conducted by the Bureau of Mines. These studies were undertaken as part of the Bureau's efforts to provide important thermodynamic data essential to the advancement of mineral resources technologies that can be employed with minimal energy requirements and minimal environmental degradation. Enthalpies were measured with a copper-block drop calorimeter. No transitions or other anomalies were found. Tabulated values are given from 298.15 to 772 K for relative enthalpy, heat capacity, entropy, and Gibbs energy function. Enthalpies are expressed in equation form and combined with data from the literature to calculate values of the standard enthalpy of formation and the Gibbs energy of formation. X-ray powder diffraction data indicate that ZrI4 is primitive cubic with a lattice parameter of 11.79 A and is isostructural with stannic iodide (SnI4).

Jan 1, 1980