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By Paul Piercy

Bougainville Copper Limited operates a porphyry copper mine in Papua New Guinea. The waste dumps will contain 400 to 500 million tomes of rock at the end of nine life. The paper describes investigations carried out over a period of en years and highlights the problems associated with waste lump leaching in a tropical and seismic active region. Aspects discussed include mineralogy, chemical reaction, leaching rates, microbiological activity, dump stability, dump structures, effects of tropical conditions, seismic activity and topography.

Jan 1, 1981

By S. Glen

Cyanide management practices on modern gold plants are becoming more onerous, due to environmental pressures, particularly for signatories to the International Cyanide Management Code. Operations are therefore seeking to reduce levels of weak-acid dissociable (WAD) cyanide reporting to spigot discharge as well as to any eventual discharges from the tailings storage facility (TSF). Current gold industry standard processes primarily include the oxidation of cyanide by means of sodium meta-bisulfite (SMBS, or SO2) with air, Caro&apos;s acid (H2SO5) or hydrogen peroxide (H2O2). These processes require the transport and usage of expensive oxidizing reagents, along with the safety and environmental issues associated with these corrosive and toxic chemicals. Maelgwyn Mineral Services (MMS) has developed the MMS CN-DTM process, which utilizes the Aachen ReactorTM, a high-energy mass-transfer superoxygenation system, in conjunction with an activated carbon-based catalyst and no additional reagents, to increase the rate of cyanide oxidation to cyanate, the thermodynamically more stable form. Testwork conducted at the Maelgwyn Australia testwork facility in Perth Australia is described, at both pilot scale and continuous bench-scale, on a sample of tailings effluent obtained from an Australian gold plant. WAD cyanide is demonstrated to be lowered using the MMS CN-DTM process from an influent of 130 mg/L to the required levels for discharge to TSF (<50 mg/L). The continuous test results showed stable operation over three residence time turnovers. The pilot-scale results demonstrated the efficiency of the process at the reasonably large scales required for engineering cost estimation.

Jan 1, 2011

By Travis Q. Lyday

During 1983, Ecuador&apos;s gross domestic product (GDP) decreased by a reported 3.3% in real terms, the second consecutive decline in the economy after more than a decade of growth generated mainly by petroleum export revenues. The slowdown was due, in part, to the effects of the world recession, lower foreign demand for oil, depressed world oil prices, and reduced demand and prices for Ecuador&apos;s traditional agricultural exports. Inflation accelerated to an estimated 55% annual rate. The sucre was devalued in March, for the second time in less than a 12-month period, by 27% after remaining unchanged during the previous decade. In addition, continuous adjustments were made every weekday, effectively devaluing the sucre another 30% by yearend. Ecuador&apos;s production of crude petroleum increased almost 12% in 1983 compared with that of 1982. Average daily production was 237,100 barrels per day (bbl/d), up from 211,300 bbl/d in 1982.

Jan 1, 1985

The history of the down draught Dwight- Lloyd system of iron ore sintering in Australia is developed. Characterisation of the broad process is given for one plant, and regional divergences from the reference practice are noted and briefly analysed. The subject of the development of high basicity sinters is introduced, and regional differences in approach and results are Examined.

Jan 1, 1972

By Ronald B. DeDiemar

This paper will present the intrinsic factors of a cone crusher that affect performance, develop and define an ideal feed gradation for a cone crusher and, finally, bring out an important new development in computer design of crushing chambers and show an ability to predict crusher performance without trial-and-error methods.

Jan 1, 1979

By S. A. Vorobyev, Yu. L. Mikhlin, Ye. V. Tomashevich, A. A. Karacharov, M. N. Likhatski1, A. S. Romanchenko, S. V. Saikova

"A set of state-of-the-art methods have been applied to study ultrafine particles and nanoscale species arising on mineral surfaces upon milling, interaction with flotation reagents, and leaching of base metal sulfide ores in order to gain insights into interfacial mechanisms. The fine fractions produced by ball milling of a Pb-Zn Gorevsky ore and four Cu-Ni sulfide ores studied with laser diffraction, dynamic light scattering, zeta-potential measurement, Xray photoelectron spectroscopy (XPS), SEM, TEM and other techniques. The particle size distributions had, aside from the peaks at 20-60 ?m, maxima near 1-2 ?m; the flotation was considerably suppressed when the yield of positively charged ultrafine particles approached tenths % (several kg per ton). High-energy XPS and X-ray absorption spectra revealed that sulfide minerals depleted in metal in air and aqueous solutions were composed of outer “polysulfide” layers, strata with disulfide species, and heavily defective underlayers, and “passivation” was explained by stability of the metal-deficit structures. Dixanthogen at pyrite and copper-activated sphalerite, dixanthogen and then cuprous xanthate on chalcopyrite, and chemisorbed xanthate at galena were specified as the main interfacial products using cryo-XPS of fast-frozen flotation slurries. The particle size, zeta-potential and behavior of colloids of Cu and Pb xanthates and dixanthogens were largely determined by the initial ratio of a cation and collector; the properties of copper xanthate nanoparticles were also affected by incorporated dixanthogen (about 15 wt.%). Submicrometer gas domains of 3-8 nm in height and “hydrophobic” forces upon the probe retraction were found on xanthate-treated minerals using atomic force microscopy and spectroscopy; their impact on flotation is briefly discussed.INTRODUCTIONInterfacial phenomena play a key role in flotation, leaching, water purification and related environmental processes. The mineral processing and extraction of metal from sulfide ores commonly involves milling the ore, which produces, along with the particles of 20 µm to 100 µm, mineral entities ranging from micrometer to submicrometer and nanometer scale. Furthermore, ultrafine particles of flotation reagents, products of metal sulfide oxidation, and so on may form spontaneously and accumulate in production water, flotation froth, deposit on mineral surfaces, affecting the flotation performance, and then enter waste waters, mine and natural drainage, polluting soils, surface- and ground waters (Miettinen et al., 2010; Wang et al., 2014). The efficiency of flotation and hydrometallurgical recovery of values, environmental issues are crucially dependent on the state of mineral surfaces. Particularly, it is generally accepted that the surface non-stoichiometry of sulfide minerals induced by oxidation and leaching should affect their hydrophobicity and reactivity, including so-called “passivation”, but the nature of such surface layers are still a matter of controversy (see, for example, Holmes and Crundwell, 2013). Another phenomenon attracting rapidly growing interest in several areas is low-dimensional gas species (“nanobubbles”) at hydrophobic surfaces that may play a decisive role in particle-bubble attachment in flotation but remains scarcely investigated up to now (Xing et al., 2017). Here, we survey our recent results on the abovementioned problems applying a series of rather new methods and approaches; more details can be found in refs. Karacharov et al., 2016; Mikhlin et al., 2015; 2016; 2016a; 2016b; 2016c; 2016d; 2017; 2017a; Vorobyev et al., 2017."

Jan 1, 2018

By Christopher J. Bise

The objectives for the research project, "Coal Mine Injury Analysis: A Model for Reduction Through Training," were to identify and develop a means to indicate deficiences in human performance, job skills, and/or knowledge at a given mine site that are amenable to alleviation through training or job redesign, and to provide ;I set of analytical tools and training resources that will enable mine training personnel to effectively incorporate the noted deficiencies into a personalized model training program. The findings of this research project are contained in Light separate volumes. Volume I represents the Executive Summary of the study and provides a broad overview of the project&apos;s individual areas of emphasis and deliverables. The additional eight volumes provide greater detail on the development of a Model Mine Training Program based upon Professional Database Analysis, Incident Reporting, Loss Control, Job Safety Analysis, Risk Assessment, Cost/Benefit Analysis, and Mine Safety Management.

Jan 1, 1993

By M. Lohk, Y. -. R. Pastarus

Oil shale industry of Estonia provides a significant contribution to the country’s economy, but causes a large number of different problems. In spite of high economical parameters of the current underground mining (room-and-pillar) technology it is not effective. Backfill technology will be applicable in condition of Estonian oil shale mines. Nowadays attention has been focused on the use of combustion and mining by-products as filling materials. Use of ash and limestone in mining industry is treated as a part of mining technology, not as a waste disposal. Underground utilization of wastes reduces the volume and area required for surface disposal, environmental taxes. It improves the quality of mining works. The use of backfill technology has great impact on mining practice in Estonian oil shale industry.

Jan 1, 2011

By R. D. Nelson, F. E. Bowman

Evidence has been found for a (010)a?(111)B[102]a /,11[341]/B crystallographic relationship between the monoclinic a and B phases of plutonium during the a?B transformation. The results of an X-ray diffraction study, where [010] fiber textured a samples were used in the absence of suitable single crystals indicate that the (OIO)a planes become (111)B planes upon transformation under near-equilibrium conditions. The transformation strain along the fiber axis, which was the [010] direction, was measured dila-tomekically; the measured 8.5 pct expansion compares favorably with the 8.44 pct expansion in the in-terplanar spacing represented by the (010)a?(111)B relationship. From plots of the atom positions in each of the related planes, a correspondence was deduced between the [102]a, direction and the [341]B direction. Further analysis of the two lattice structures in the light of this relationship revealed a rotation about the [102] direction of 1 deg 43 min and a slight shearing in this same direction of about 30 min. THIS paper discusses the (B crystal structure of plutonium and the orientation relationship existing between the monoclinic a and B phases during the a?ß transformation. The kinetics of the a?ß and (3 — a transformations have received extensive consideration, and because of the crystallographic complexity of these phases, the question of the mechanisms by which these transformations occur is especially intriguing. Nelson and Shyne1 evaluated the existing experimental evidence and concluded, from the indirect evidence available, that both the ß ? a and a ? ß transformations occur by a martensitic process. Their data reveal the anisotropic nature of these transformations which suggests the existence of specific crystallographic relationships between the parent and product phases. In this paper, we are concerned with the confirmation of the existence of such a relationship resulting from the a ? ß transformation and the derivation of the crystallographic details necessary to specify it. EXPERIMENTAL RESULTS X-ray diffraction and dilatometric data were obtained from samples of a plutonium having a [010] fiber texture. These cylindrical specimens, approximately 1 cm in diam, were prepared by transforming the ß phase to a under the influence of a uniaxially applied compressive load.&apos; The [0l0] direction is parallel to the direction of applied stress; it is also perpendicular to the (010) planes. This correspondence between the plane normal and the direction having the same indices is, in the monoclinic a plutonium structure, restricted solely to this (010)[010] combination. Such a specimen was mounted in an evacuated, elevated temperature specimen holder on an X-ray dif-fractometer so that the diffracting surface was perpendicular to the fiber axis. The a diffraction pattern, Fig. 1, taken at about 115ºC, revealed the predominance of the (020) reflection. This monoclinic, P 21/rn space group yields no (0k0) reflections when k is odd. The temperature was raised slowly to 160°C to effect the complete transformation to the phase; then it was lowered to 120°C so that a diffraction pattern of the ß could be obtained near the a = ß equilibrium temperature for direct comparison with the a at the same temperature. The (3 diffraction pattern, Fig. 2, obtained under these conditions showed a (222) reflection relatively much more intense than in the random pattern. The other reflections appearing with sig-

Jan 1, 1970

By Martti Hagfors, Mervi Hokkanen

The Finnish Defence Forces has destroyed obsolete and spoiled ammunition in open surface mass detonations at Hukkakero fell, in municipality of Kittilä, in Lapland since 1988. The de-struction method was learned from Sweden in 1987. The disposal camp is organized every au-tumn and it lasts four to six weeks. A gross weight of an average charge varies from 150 to 250 tons and the net weight of explosives from 15 to 25 tons. As a booster there have been used 2 to 3 tons of emulsion explosives. The explosives mainly consist of trinitrotoluene (TNT) containing smaller a mounts of amatol and hexotol. The Finnish Defence Forces Tech-nical Research Centre (PVTT) has studied the environmental effects of these mass detona-tions since they began in 1988.

Jan 1, 2011

By Helder da Fonseca Nunes

Na última década, com o crescente aumento da demanda na produção de aço, as usinas siderúrgicas estão, cada vez mais, procurando soluções que tornem seus processos mais ágeis e economicamente competitivos, sem perder qualidade do produto final. O presente trabalho visou a uma avaliação post mortem dos tijolos refratários utilizados em carros torpedo. Esse estudo foi feito através das técnicas de difração de raios-X (DRX) e microscopia eletrônica de varredura (MEV) associada à espectroscopia de energia dispersiva de raios-X (EDS), com o intuito de se avaliar as modificações estruturais nos materiais em estudo (refratários TCP e TCE). Com base nos resultados obtidos foi possível verificar modificações estruturais mais significativas nos tijolos refratários TCE após o uso com base na incorporação de material associada à escória na sua superfície, o qual contribui para um aumento significativo na sua densidade.

Aug 16, 2017

By W. G. Schultz

"Sylvite's potash mine, which produces 8,000 tons of ore per day, probably ranks as one of the most highly mechanized and automated mining operations in the world. Employing, on a normal 10-hour production shift, one supervisor and a crew of seven operators, Sylvite is able to mine at an average rate in excess of 600 tons per hour. The ore is produced by two Marietta miners weighing 258 tons, the largest and heaviest pieces of equipment ever taken underground. The ore produced by these two Marietta miners is conveyed to the shaft area, cycled through a 15,000-ton storage system and hoisted to surface completely automatically. The operation of all equipment in the mine can be monitored and controlled from a central control panel located underground. Because Sylvite's mine is a new operation with equipment of a new design, the full potential of the operation has not yet been realized. The ultimate capability is clearly evident from the success Sylvite has had over the past year as the average mining capability has risen from 100 tons per hour to 600 tons per hour."

Jan 1, 1973

By H. K. Fouad, L. A. Guirguis

The starting mill strip solution· for this study· is an ammonium uranyl tricarbonate solution of pH 8.2 containing 20g uranium/liter, after a DEPA/TOPO extraction process from sulfuric acid leaching liquor. To the first portion of the concentrated acidified strip solution, hydrofuoric acid is added at 95°C in reduced condition to obtain uranium tetrafluoride. The second portion of the uranyl carbonate strip is subjected to a precipitation step by admixing 0.3 volume of non-solvent precipitating agent such as acetone per volume of uranium. ·Uranium oxide (U30 8) is obtained from this precipitate by calcination for half an hour at 800°C in air. The third portion of the strip solution is neutralized to a pH 6.5 with sulfuric acid to precipitate iron and other contaminants. The solution is further acidified to a pH 1.85 with continuous air bubbling to remove CO2, followed by H2Ch precipitation at pH 3.5 to obtain uranyl peroxide. The latter is reduced by stannous chloride to obtain uranium trioxide dihydrate UO3. 2H20. Identifications, characterization· and purity of these products are carried out by complete chemical analyses, Scanning electron microscope study, tap density determination, X-ray diffraction and infrared spectroscopic investigations. The achieved results agreed well with that of the published data for these nuclear grade purity products.

Jan 1, 2000

By W. G. Matteson

THE origin of the salt domes of the Gulf coastal plain has been investigated by many of the most able geologists, but the problem cannot be said to have been satisfactorily solved. Since 1860, numerous theories have been presented, only to be discarded, at least in part, as more complete information revealed their fundamental weakness. Real progress toward solution dates from 1902, when Hill&apos; advanced the theory of secondary deposition of the domal materials from saturated solutions of hot saline waters ascending from great depths under hydrostatic head along structural lines of weakness. Shortly thereafter, Harris,2 using Hill&apos;s hypothesis as a basis, explained the doming and pronounced uplift associated with these salt cores as the result of forces exerted by growing salt crystals. This was a marked advance over the ideas of Coste3 and Hager,4 since no. evidence of igneous intrusives, as they assumed to explain the uplifts, had been found associated with the domes. Harris5 developed his theory until it offered such apparently plausible explanations of so many details of dome phenomena that his hypothesis and conclusions received widespread acceptance, despite some serious objections, and today his theory, somewhat modified, is considered by many able investigators to be the best explanation of, the origin of these domes. The immense production of oil per acre, the recognition of the high lubricating quality of the oil, the development and recognition of the efficiency and advantages of oil-burning vessels, with the, subsequent

Jan 2, 1921

By Jon Y. Kaneshiro, Gregory E. Korbin, Stephen J. Navin, Larry J. Stout

Sewage presently being discharged into the Tijuana River Valley pollutes the valley as well as the beaches in the South Bay of San Diego, making the beaches unusable nearly year round. The SBTO will convey flows down a 8.5 m (28 ft.) by 58 m (190 ft.) deep drop shaft, through a 3.35 m (11 ft.) by 5.8 km (3.6 mile) long tunnel, and up a 46 m by 2.7 m (150 ft. by 9 ft.) riser shaft connecting to a 1.5 km (0.95 mile) of seafloor pipeline and 1.2 km (0.76 mile) of diffusers on the ocean floor. The drop shaft will be sunk through 38 m (125 ft.) of saturated sands and gravels and 20 m (65 ft.) into the dense fine sands of the San Diego Formation. The tunnel liner has been designed as a five piece, single pass, gasketed, bolted, reinforced concrete liner designed to withstand an external head of 76 m (250 ft.) of water and internal operating head of up to 27 m (89 ft.) and to accommodate movement at the numerous fault crossings. The tunnel is contemplated to be driven with a state-of-the-art Earth Pressure Balance Machine (EPBM) or slurry shield machine through a wide range of conditions from clay to gravel with boulders.

Jan 1, 1995

By D. M. S. Bhatia, Richard D. Hagni

Five sulfide minerals from the Magmont mine, southeast Missouri were sampled for 31 trace elements in over 300 samples by laser microprobe spectrographic analysis of polished sections. The concentration of several trace elements shows a pattern of progressive variation with depth (space) and variation with different paragenetic stages (time) of each mineral. Factor analysis of the geochemical data shows sympathetic correlation both in space and in time of Bi, Cd, Ge, and Sn in galena and sphalerite, and Ni and Co in sphalerite and marcasite.

Jan 1, 1981

By N. R. Zehr

El presente texto describe los problemas de desague y ventilación que corresponden al túnel Graton en Casapalca. En ese sentido, Antonio Raimondi menciona que probablemente fue Gratón, el primer túnel de desagüe en Casapalca: «la veta de San Antonio es drenada mediante túnel socavado hace poco tiempo y recientemente terminado. Esta conecta con áreas de trabajo situadas por debajo de las ya inundadas de modo que, para efectuar el desagüe, solo tendrá qµe perforarse en plano inclinado. Los túneles Graton tendrán poco más de 11 km, los cuales pueden perforarse desde accesos en el Valle del Río Rimac, poco más arriba del pueblo de San Mateo, en un punto denominado "Carbonyacúpalabra" quichua que significa «agua de carbón». Asimismo, estos túneles gemelos se terminarán bajo el pozo de la mina Aguas Calientes de Casapalca. Una vez terminado, una perforación servirá para desaguar las áreas de trabajo y la otra, para la respectiva ventilación.

Jan 1, 1969

By P. Somasundaran

Gangue minerals can often have severe adverse effects on selective value mineral separation. Such effects can be mediated through a variety of pathways or mechanisms. One popular mechanism is that of ?slime coating? or heterocoagulation, wherein the gangue mineral fines are believed to coat the value mineral surfaces and thereby reduce selectivity and floatability. Another pathway that has received relatively little attention is that mediated through the effect of gangue minerals on pulp rheology, and consequently selective separation. Our recent work in developing a scientific understanding of these effects has highlighted the prevalence and importance of this pathway. In this study, the impact of shape and morphology of serpentine gangue minerals on suspension rheology and selective Ni flotation from ultramafic ores was investigated. We found strong evidence for micro- and macro-network formation in the presence of acicular (needle-shaped) or fibrous minerals, which impacted pulp rheological properties. Results also supported the hypothesis that morphology has a greater role to play than mere shape. The size of the network ranged from 5 microns to 2 cm depending upon the amount and aspect ratio of fibrous minerals. These networks impede many flotation sub-processes, such as gas dispersion and bubble-particle interactions. Additionally, the small pore size of the networks prevents bubble penetration leading to a large transport of the gangue minerals to the concentrate via lifting of the entire network by bubble flux, which resulted in a significant grade dilution. Based on the scientific insights generated in this study various techniques have been developed to improve selective value mineral separation. Keywords: fibers, aspect ratio, microstructures, networks, pulp viscosity, gangue transport

Sep 1, 2012

By A. C. Lawrence, B. Econ, D. Com

The importance of human factors in mining productivity by A. C. Lawrence, D. Corn., B. Econ. (Member) The paper outlines some of the views on the relationship between work attitudes and performance, and examines evidence derived from relevant research done in the mining industry. It is suggested that higher productivity within any given system of mining can be attained if attention is paid to the four factors that represent the CORE of human work performance: Competence, Opportunity (or Organisation), Recognition (or Rewards), and Expectations (or Enrichment).

Jan 7, 1974

By Sadan Kelebek, Gerhard W. Heinrich, Peter F. Wells, Peter J. Whittaker

"Based on plant mineralogical data & circuit modelling, a pilot plant campaign was conducted at Strathcona Mill to identify options for improving the performance and operating flexibility of the copper-nickel separation circuits. Emphasis was given to options for combined treatment of the two feed streams (primary nickel ore rougher concentrate and copper ore circuit concentrate) to obtain more flexibility in the use of existing column flotation capacities. The pilot test results demonstrated that circuits which incorporated preconcentration prior to column flotation gave the best metallurgical results. Maximum column carrying rates were also related to the preconcentration. Predictions that increased circulating loads from the column scavengers would improve copper-nickel separation performance were confirmed.IntroductionThe copper-nickel separation circuits at Falconbridge's Strathcona Mill produce a high grade (>30% Cu) copper concentrate most of which is treated at the Falconbridge Kidd Creek smelter near Timmins. The remaining nickel concentrate which still contains approximately 20% of the feed copper is combined with other lower grade nickel/copper concentrates and shipped to the Falconbridge nickel smelter. The separation is required because of the limited capacity for copper processing in and downstream from the nickel smelter. Since no nickel is recovered at present in the Kidd smelter, the challenge is to minimize the nickel content of the copper concentrate.At present there are two independent separation circuits treating the rougher concentrates from the copper and nickel circuits as shown in Figure I. The minerals treated are mainly chalcopyrite and pentlandite but there is up to 25% of the copper present as cubanite in the copper ore. The circuits were kept separate because the flotation rates and froth characteristics were very different, probably because of the presence of cubanite and the large difference in the concentrate grades feeding the circuits."

Jan 1, 1995