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By W. E. Johnston

At last year's Annual Meeting a paper by Haultain and Johnston was presented entitled Is the Gold in Tellttrides Soluble in Cyanide? Since then the writer has continued the study of various phases of this problem. Samples and specimens of ore from some of the Kirkland Lake mines have been studied and non gold-bearing tellurides have been found in these that are not soluble in ordinary mill solutions. Samples of tailings, both old and recent, from this district have been examined with apparatus and methods that have proved very successful in detecting the presence of extremely minute quantities of tellurides. Tellurides, both base-metal and gold-bearing, have been discovered in these tailings, but only in such minute quantities that their presence would not affect the ordinary assay results. More free gold particles have been found in the tailings than gold-bearing tellurides. Much experimental work has been done on tellurides, concentrated from high-grade material and from ordinary run-of-mine ore. The gold-bearing tellurides behave very much as does gold itself. Finely divided particles are dissolved fairly rapidly, coarser particles more slowly. All the tellurides are soft and brittle and also have a high specific gravity, with the result that they are extremely finely divided in ordinary mill practice. The ordinary high-lime solution of Kirkland Lake practice is suitable for the dissolving of the gold tellurides. Oxygen is necessary, but apparently not more so than in dissolving gold. Some particles have been found that appear under the microscope to be ordinary metallic gold particles, but on heating they show a small telluride content. These appear to dissolve more slowly than gold. There is considerable variation in the ratio of tellurides to gold from different points in the mines. So far the writer has failed to find any connection between this ratio and the richness of the ore. Generally speaking, the base-metal tellurides predominate. Some of these contain gold but this may be due to a mixture of tellurides in the one particle.

Jan 1, 1933

By L. R. Plitt

A new simple correlation has been developed to evaluate the performance of classifiers. The new correlation has been tested on existing data from 150 different hydro-cyclone classification tests. It is shown that this model provides a meaningful improved method of mathematically describing the classification process.

Jan 1, 1971

By Shinji Muraishi, Shinji Kumai, Yasutaka Kedo, Takashi Kambe

"Magnetic pulse forming (MPF) is one of the extreme high-speed forming processes. A metal sheet which is accelerated by electromagnetic force is collided onto a mold and fine and sharp details of the product can be obtained. The deformation mechanism of the MPFed metal cannot be understood only by the microstructure observation of the deformed metal. The deformation behavior of the metal should be investigated also by considering the local microstructure change with strain, strain rate and temperature change during deformation. Numerical analysis is an effective method to achieve this requirement. In this study, pure Al and Cu sheets were deformed by MPF. Impact velocity of the metal sheet was calculated by using ANSYS Emag-Mechanical. Based on the obtained impact velocity, the deformation behavior of the metal sheet was reproduced, and local strain, strain rate, and temperature were analyzed by using ANSYS AUTODYN. The relationship between the local microstructure change of Al and Cu sheets and the deformation parameters was examined.INTRODUCTIONMagnetic pulse forming (MPF) is one of the high-speed forming processes using electromagnetic force. Fine and sharp details of the product can be obtained, and springback after deformation is extremely reduced in comparison to the conventional forming processes(Psyk, Risch, Kinsey, Tekkaya, & Kleiner, 2011). Figure 1 shows a schematic diagram of MPF. A metal sheet is placed over the coil in the discharge circuit. The discharge current runs through the coil, and magnetic fieldis producedaround the coil. An eddy current is inducedin the metal sheet. Interaction between magnetic field and eddy current creates electromagnetic force. The metal sheet accelerated by electromagnetic forcecollides ontothe mold. Forming is completed in a few tens of micro-seconds.MPF is suitable for metals with a high electrical conductivity like Al and Cu.The MPFed metal may have characteristic microstructure because of high strain rate deformation."

Jan 1, 2018

By M. R. Khalesi, S. Bellec, C. Bazin, D. Hodouin

Batch grinding tests conducted on a gold ore indicated that gold is not randomly distributed within the size fractions of the ground ore. Since gold leaching performances were found to be dependent of the size of the gold carrying particles an integrated gold ore grinding-leaching simulator should incorporate a method to predict the gold size distribution of a ground ore. The paper describes the results obtained from batch grinding tests showing the non random distribution of gold within the size intervals of a ground ore and the initial developments of a grinding model to predict the gold size distribution in a batch grinding product.

Jan 1, 2011

By Naizhong Xu

During the past 30 years, fully mechanized caving mining has played a positive role in the improvement of the efficiency of coal production, but which has also had a great influence on the mining environment, especially to environment damage of shallow mining areas in the central and western regions of China. The surface subsidence parameters are the basis of the surface environment evaluation and governance. During 1980~1990s of the last century in China, fully mechanized mining subsidence laws were researched more fully, however, since coal caving technology is affected by many factors, and researches on its mining subsidence laws (parameters) were found to be grossly inadequate. Through actually observed in recent years, it is considered that coal caving mining subsidence laws (parameters) can use fully mechanized mining law (parameters) for reference. Based on fully mechanized mining laws (parameters), this paper reveals the similarities and differences of the surface subsidence laws between fully mechanized caving mining and fully mechanized coal mining, which can guide the work of coal mining under buildings, water bodies and railways in new mine area and mine collapse governance.

Aug 1, 2013

By P. E. Walker, M. E. Reed, R. C. Sims, B. Snowdon, D. E. Fallas

An advanced Flash Furnace feed system is the key to improving furnace performance. Clyde-WorleyParsons has developed a revolutionary pulseless pneumatic injection feed system technology, capable of delivering a range of benefits to operators of Flash Furnaces. The solution was created by combining the pneumatic conveying and injection knowledge, expertise and technology of Clyde Materials Handling with WorleyParsons' flash furnace process and operating experience. Optimal furnace burner performance requires the feed material to be presented to the burner as a stable, pulseless and accurately controlled flow, distributed evenly around the burner tip circumference. These simple requirements appear obvious, but are extremely difficult to satisfy in industrial environments and are not achieved by conventional feed systems. Our analysis of existing operating furnaces has identified the link between pulses in concentrate feed rate caused by conventional drag chain conveyors and rapid fluctuations measured in the furnace pressure. These fluctuations occur at a timescale close to the reaction shaft residence time and lead to unwanted instability in the primary furnace reaction zone - the flame. Through the use of the solution created by Clyde-WorleyParsons, it is predicted that the much more accurate control of feed rates achieved can lead to substantial improvements in furnace output, increased oxygen efficiency and better control of the composition of furnace liquids, such as matte, blister or slag. All these improvements lead to significant increases in smelter output and efficiency, and deliver high economic value compared to the cost of the feed system. Clyde-WorleyParsons' solutions can be deployed on greenfield sites or retrofitted, and therefore, have the capability to improve feed control at both new and existing smelters. This paper will discuss the field test work undertaken to date, the impact of findings and the ongoing analysis of linkages between instabilities in the various components of conventional feed systems and furnace pressure stability.

Jan 1, 2007

By D Martín, G. Díaz, F. Cubeddu, A. B. Mejias

The Modified ZINCEXTM Process (MZP), developed by Técnicas Reunidas, is an industrially proven flexible process. It can handle a wide range of primary and secondary raw materials, producing SHG zinc. The core of the Modified ZINCEXTM Process is the zinc solvent extraction unit. This unit is an effective barrier for any leachable impurities present in the raw material. As a result of this an ultra-pure zinc solution is always obtained. The high versatility of the process makes the application of the technology in different scenarios possible. MZP can be effectively applied when developing a whole new plant (Skorpion) or adapting its scheme to an existing refinery (Akita), in both cases giving the same results. Flexibility in terms of capacity of the plant is a great advantage of the MZP, there is the possibility to adapt the global process to a wide range of production capacities. Zinc production capacities of over 150 000 t/a may be achieved with a single solvent extraction plant train. The robustness of the Modified ZINCEXTM Process has been recently proven on two new plants currently in operation: Portovesme (Italy) and Horsehead (USA) after start up during 2013. The status of both plants is described in this paper.

Jan 1, 2014

By John Blackshaw

NEW sources of supply of tungsten concentrates became necessary when the flow from the Far East was blocked in 1942. In Canada, one source has been noted in the workings of the Hollinger mine at Timmins, Ontario. For many years, a small amount of scheelite had been removed with the gold ore, and an appreciable tonnage of scheelite still remained in the mine. At the request of the Dominion Government, a plant was built to recover this scheelite in the form of a concentrate that could be used by the alloy-steel industry without further preparation. The plant began operating early in March, 1942, and a small tonnage of ore, carrying scheelite and gold values, has been treated daily since then. The possibility of recovering the scheelite had been considered on several previous occasions. Each time the proposal had been given up because the total profits from the enterprise were estimated to be insufficient to repay the capital cost of building the recovery plant. At the time the plant was built, additional information had been gathered about the tonnage and grade of the scheelite ore in the mine, and several thousand tons of ore grading higher than 0. 25 per cent WO3 (tungstic trioxide) were known to be available.

Jan 1, 1943

By J. Mrozowski, R. Kurowski, A. Chmielarz, Z. Szolomicki

PbSO4 is a commonly encountered component of the materials used in lead recycling (e.g. battery paste) and in by-products of metallurgical processes (e.g. residues from zinc hydrometallurgy, dust from copper smelting). Smelting of battery paste results in SO2 emission and in generation of significant amounts of hazardous ‘white slag’. Those adverse phenomena can be eliminated by removal of sulphur from the paste. Lead-bearing by-product materials are of polymetallic character with usually low Pb content, which makes lead recovery technologically difficult and uneconomic. However it can be successfully achieved by extraction of lead sulphate from solid phase with triethylenetetramine (TETA) water solutions. That compound has capability for selective solvation of a whole lead sulphate molecule. Virtually pure lead carbonate can be precipitated by means of saturation of lead-loaded aqueous TETA solution with carbon dioxide, and complete regeneration of the extractant is achieved by fixing of sulphate ion into gypsum through operation of calcium hydroxide suspension. The paper presents results of the lab and pilot scale studies into process of battery paste desulphurisation and recovery of lead from the residue of zinc calcine leaching.

Jan 1, 2014

By G. Titichoca

Modification of the blasting process considers that any increase in the energy consumption generates greater benefits if done in the later stages (associated with a larger decrease in energy consumption). Therefore, although the blasting cost is doubled, generating a greater proportion of fines in addition to a weaker ore (because with greater loads and appropriate distribution of explosives a greater number of internal cracks is generated), the reduction of the unit cost that occurs in the grinding stages (SAG and ball mills) generates a positive balance in the overall size reduction process. Codelco Chile, Division Andina, has developed an extensive experimental plan to evaluate the concept of blasting modification applying greater energy. This was implemented in two stages, each including a specific mine sector: La Union and Don Luis. This paper reviews the experience of implementing such blasting modifications at the La Union mine and its impact on the design concepts and the operation of the SAG mill plant

Jan 1, 2007

Lonmin RoM ball mills are treating two types of feed ore produced by conventional mining and mechanised mining methods. It was reported that reduction in mill throughput was observed when treating the mechanised mining ore. Detailed grinding surveys were conducted for troubleshooting. Ore samples were collected for breakage characterisation using a JKRBT based on different particle density components. XRD analysis was conducted to investigate the association of minerals with density components. The plant surveys and the breakage characterisation tests all suggested that the two mining methods did not significantly affect either the ore breakage properties or the RoM mill performance. Instead, the mill discharge open area exerted a remarkable influence on mill throughput. The RoM ball mill operated at Lonmin K4 Concentrator has been proven to be a versatile mill that performed stably with variations in feed size distribution and feed ore changes by different mining techniques. The reasons are elucidated by the multi-component breakage characterisation and the plant surveys data.

Jan 1, 2012

By J. Butra

The underground research presented in this paper was carried out in the two Polish copper mines: Rudna and Polkowice-Sieroszowice. The aim of the research was to determine stress field parameters. The measurement method and measuring positions are described as well as the measuring technique adapted to the geological and mining conditions of the Rudna mine and the Polkowice-Sieroszowice mine. The identified values and directions of principal stresses and horizontal stresses and their importance for optimization of mining operation and safety improvement are discussed.

Aug 1, 2013

By A. Warczokand

The cleaning of copper smelting slag requires magnetite and cuprous oxide reduction. The slag reduction with coke, injected coal powder or bunker oil is strongly endothermic and requires heat generation by fuel combustion or the use of electric energy. The reduction of fayalitic slag with calcium carbide is slightly exothermic and the formed calcium silicate modifies the slag. Thus, the additional energy is required only for covering furnace heat losses. Results of crucible scale tests showed the rate of slag reduction approximately five times higher in comparison of the slag reduction with coke under the same conditions. It seems that the effect of exothermic reaction and slag modification with CaO at the reaction interface results in very high rate of slag reduction. Industrial scale tests carried out in the Anglo-American Chagres Smelter demonstrated the possibilities of effective reduction and cleaning of the slags from a flash smelter and Peirce-Smith converters in a Teniente Slag Cleaning Furnace. The slag reduction was carried out without any reductant or stirring gas injection, simply by calcium carbide charging through a furnace mouth, and was very fast.

Jan 1, 2007

By M. I. Kalashnikova, Y. M. Shneerson, M. V. Keskinova

Interaction between mattes having various compositions and solutions with a wide range of free acid and non-ferrous metals concentration have been studied in terms of chemistry, mechanism and kinetics. The solution acidity and oxidizers to reducers ratio in the matte-solution-gas phase system have been demonstrated to be the major factors determining the process behaviour. It was found that the types of copper and nickel secondary sulphides resulted from nonferrous metals precipitation from solution, depend on of the solution and initial matte composition. Based on these studies, technologies of matte leaching and nonferrous metal precipitation in the form of rich sulphide concentrates are developed.

Jan 1, 2004

By R. E. Phelan

Introduction The Flin Flon deposit was discovered by Tom Creighton, an experienced prospector and trapper, who in 1914 made his headquarters at The Pas, Manitoba, and still lives there. The discovery was made in the fall of 1914, and Creighton and his associates spent the next summer in investigating the find. In August of 1915 the first claims were located. The property was optioned to Hayden Stone & Company, and in the spring of 1916 they started a diamond-drill campaign. Hayden Stone spent $50,000 on the property and, among other things, completed over 7,500 feet of diamond drilling. The ore not being as high grade as expected, and also being complex in character, Hayden Stone then abandoned their option. In the spring of 1917, Messrs. Earle, Faskin and associates took an option on the property and started an extensive drilling campaign. This campaign accomplished approximately 18,000 feet of drilling and secured for the Faskin interests a 32 per cent interest in the property. In 1920, W. B. Thompson and The Mining Corporation of Canada secured an option, and, while this option was in force, sunk two shafts in the ore-zone and did a considerable amount of drifting and cross-cutting in the ore to study the manner in which it occurred in place, and, by actual channel sampling, to check the grade indicated by the previously accomplished diamond drilling. All of this work had indicated that an ore-body existed on the property containing at least 18,000,000 tons of ore, assaying as follows: gold, 0.074 oz./ton; silver, 1.06 oz./ton; copper, 1.71 per cent; and zinc, ). 45 per cent (1). Complete analyses of composites from the drill holes showed that the ore was very complex in character. It contained the above values in gold, silver, copper, and zinc, as well as large amounts of sulphur and iron, and traces of lead, arsenic, antimony, cobalt, and various other metals. Although the ore was obviously pyritic in character, pyritic smelting, the usual method of treating this class of ore, could not be used to beneficiate the ore with any reasonable expectation of making such a venture a financial success, since coke and coal landed at Flin Flon would be expensive, and siliceous flux was known to be scarce locally and low in grade. The property therefore lay idle until 1925.

Jan 1, 1935

By Jan W. Merks

The objective of metrology in mineral exploration is to derive unbiased confidence limits for masses of metals contained in reserves and resources. Sets of test results for gold and silver determined in pairs of interleaved bulk samples give unbiased confidence limits for the central value of each metal. The same sets of test results show how to verify spatial dependence by applying Fisher?s F-test to the variance of a set and the first variance term of the ordered set. A significant degree of spatial dependence gives a higher degree of precision for the central values of gold and silver. Plotting variance terms of an ordered set against the variance of the set and its lower limits of asymmetric 99% and 95% confidence ranges gives a sampling variogram. Sampling variograms put in plain view where spatial dependence in sampling units or sample spaces dissipates into randomness. The application of statistical methods to test results for sets of ordered core samples within boreholes, and for sets of ordered ore volumes within profiles, plays an important role in defining reserves and resources.

Oct 1, 2009

By J. N. Van der Merwe, M. Mathey

"The development and mechanical characterization of coal-crete, a composite material generated from coal fragments and some binder material, is described in this paper. Coal debris was obtained from a colliery in South Africa. The binder used in the study basically consists of cement and water, and further ingredients are added to the mixtures, such as sand, fly ash and polymers, in order to investigate alterations of the mechanical properties of coal-crete.Results from over 220 mechanical tests on coal-cretes with various binder mixtures give consistent trends for the material’s behaviour. Linear relationships are suggested between the uniaxial compressive strength, Young’s Modulus and the indirect tensile strength of the coal-crete.It is shown that mechanical properties comparable to coal can be achieved. Coal-crete is therefore suitable for physical modelling of mining situations in experimental studies and for use as backfill in underground coal mines. The latter application is particularly attractive when refuse coal is used as aggregate material. The indicated trends in this study may be used as a guideline for individual coal-crete design needs. However, some uncertainty remains as to the influence of particle shape, size and gradation, coal rank and age of the coal-crete. These aspects are recommended for further research."

Jan 1, 2015

Energy benchmarking is widely applied across industries to determine the potential to improve energy performance. Unlike the many technologies for which energy benchmarks and efficiency rating systems are already in maturity, benchmarking of mining processes is still in its infancy. Benchmarking energy usage in mining operations, where energy costs are high and represent a significant portion of overall operating expenses, is challenging due to the uniqueness of each mining operation. Mines vary in terms of geology, geographic setting, ore body geometry, mineralogy which impact the mining method, material handling, processing and waste management. In order to gauge the opportunity for reducing the energy intensity of individual operations and also to compare the energy performance of operations on a global scale, the deployment of new benchmarking methodologies, models and frameworks is necessary. As a step towards the establishment of an accurate framework for benchmarking the energy consumption of mining operations, comminution, one of the more energy intensive mining sub-processes, was selected as the focus of a new energy benchmarking method. The methodologies and processes used to onset fragmentation in a rock mass to the crushing or grinding of rock to a size that is suitable for economic extraction are predominantly dependent on the ore properties. For this reason, site specific factors, such as the size reduction requirements and ore hardness were included in an energy benchmark model so that the energy performance of comminution processes at different operations could be normalized and compared on a global scale. Single particle compression breakage has been identified by several prominent researchers in the field of comminution as the upper limit of energy utilization in size reduction processes. For this reason single particle compression breakage was proposed as the basis of a work index for ores to be used as an input for the benchmark model. Overall, the new method showed that the energy benchmark for mineral comminution can be normalized and subsequently compared for a range of mining operations once the ore hardness has been appropriately characterized.

Aug 1, 2013

By G. Roy, D. R. Lentz, A. O. Wills

"Abstract - Diamond-drill hole DDH-B357, located 1.5 km north of the Brunswick No. 6 Zn-Pb- Cu-Ag volcanic-sediment-hosted massive sulfide (VSHMS) deposit, intersects three exhalative horizons within variably altered felsic volcanic rocks of the Nepisiguit Falls and Flat Landing Brook formations. These three petrographically indistinguishable iron formation intervals (Fe2O3T = 21.4 wt.%) likely represent cogenetic hydrothermal sedimentary units because they display a common geochemical signature: Fe2O3T = 42.9 ± 10.5 wt.%, MnO = 5.4 ± 3.1 wt.%, elevated base metal values (Zn+Pb = 1999 ± 1091 ppm), strong enrichment in additional exhalative components (CaO = 5.3 ± 3.9 wt.%; P2O5 = 1.43 ± 1.00 wt.%), oxidized signature (Fe/Mn = 10 ± 6), as well as a common immobile element signature (Zr/TiO2 = 0.025 ± 0.007) representative of a pelagic source. The calc-alkaline to transitional host volcanic rocks can be discriminated by Zr/TiO2, and to a lesser extent by Th/Nb: Nepisiguit Falls Formation: Zr/TiO2 = 0.053 ± 0.004, Th/Nb = 1.08 ± 0.37; Flat Landing Brook Formation: Zr/TiO2 = 0.107 ± 0.043, Th/Nb = 0.86 ± 0.17. A symmetrical repetition of the footwall-iron formation-hanging wall stratigraphic sequence is observed in DDH-B357, with distinct felsic volcanic rock domains separated by the three iron formations. This is best explained by parasitic F2 folds on the west flank of the south-plunging Brunswick antiform, similar to the fold closures known to host massive sulfide accumulations in the Brunswick No. 6 and No. 12 mines. Iron formation geochemistry and felsic volcanic rock chemostratigraphy from drill core sampling can provide an effective mineral exploration tool for the structurally complex rocks of the Bathurst Mining Camp. Sommaire - Le forage au diamant DDH-B357, situé à 1.5 km au nord du gisement de Sulfures Massifs à Encaissant Volcanique et Sédimentaire (SMEVS) de Zn-Pb-Cu-Ag Brunswick No. 6 recoupe trois horizons exhalatifs au sein des roches volcaniques felsiques diversement altérées des formations de Nepisiguit Falls et de Flat Landing Brook. Ces trois intervalles de formation de fer, impossibles à distinguer pétrographiquement les uns des autres, représentent vraisemblablement des unités sédimentaires hydrothermales cogénétiques sur la base de leur signature géochimique commune: Fe2O3T = 42.9 ± 10.5 % poids, MnO = 5.4 ± 3.1 % poids, des teneurs élevées en métaux usuels (Zn+Pb = 1999 ± 1091 ppm), un fort enrichissement en composantes exhalatives additionnelles (CaO = 5.3 ± 3.9 % poids; P2O5 = 1.43 ± 1.00 % poids), une signature oxydée (Fe/ Mn = 10 ± 6), ainsi qu’une signature d’éléments immobiles communs (Zr/TiO2 = 0.025 ± 0.007) indicative d’une source pélagique. Les roches volcaniques encaissantes calco-alcalines à transitionnelles peuvent êtres reconnues par leur rapport Zr/TiO2, et à un moindre degré par leur rapport Th/Nb: Formation de Nepisiguit Falls: Zr/TiO2 = 0.053 ± 0.004, Th/Nb = 1.08 ± 0.37; Formation de Flat Landing Brook: Zr/TiO2 = 0.107 ± 0.043, Th/Nb = 0.86 ± 0.17. Une répétition symétrique de la séquence stratigraphique Mur-Formation de Fer-Toit a été observée dans le forage DDH-B357, avec des domaines distincts constitués de roches volcaniques felsiques séparés par les trois formations de fer. La meilleure explication est que le flanc ouest de l’anticlinal Brunswick à plongée sud est affecté par des plis parasites F2, similaires aux zones de charnière contenant les sulfures massifs des mines Brunswick No. 6 et No. 12. La géochimie des formations de fer et la chimiostratigraphie des roches volcaniques felsiques en forage peuvent fournir un outil d’exploration minérale efficace dans les roches structuralement complexes du Camp Minier de Bathurst."

Jan 1, 2006

By Y. Chengxian

Many factors about the HIC (hydrogen-induced cracking) resistance of pipelines are discussed in this paper. The main factors that influence the ability of HIC are environmental and material factors. The chemical compositions, non-metal inclusions and microstructure are discussed in detail, while a group of tests on HIC resistance are done according to varying C, S, Mn and P contents in pipeline steels, different experiment time and different strength to the coupon. It is concluded that decreasing the amount of C and S can obtain good HIC resistance; the test time has an effect on the different microstructure of X70; microstructure is the most sensitive factor for the initiation processes of HIC.

Jan 1, 2005