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By Thorndycraftm R. B.

"PURPOSEThe purpose of this presentation to the Canadian Mineral Processors is to review gold heap leaching systems currently in use and discuss their applicability to Canadian ores. The author's experience with the development and operation of heap leaching spans the past four years at. Pinson, and visits to many ether heap leaches in the western United States.INTRODUCTIONBy way of introduction to the heap leaching system, I will describe in slight detail the method used at Pinson Mining in northern Nevada. This will be followed by a discussion of optional methods in use at other operations visited.The Pinson orebody is a finely disseminated, well-oxidized hydrothermal deposit. Gold particles are finer than 20- microns. The orezone hostrocks are metamorphosed and silici¬fied limestone and shale. Sulfides and carbonaceous materials are negligible.The Pinson open-pit mine has operated since June 1980. It produces 1500 tpd of C.I.P. mill feed averaging .10 oz gold per ton, and 1500 tpd of heap leach material averaging .025 oz gold per ton. Cutoff grades are 0.04 for mill feed, and 0.01 for heap leaching. Stripping ratio is 9 tons of waste and leach grade to 1 ton of mill feed.The project is located in northern Nevada at 4900 feet above sea level.,Winters are fairly severe, with freezing conditions affecting operations from early December through April. Although officially designated as ""high-mountain desert"" country, snow and/or freezing rain occur almost every week of the winter.To date, all Pinson production-scale heap leaching has treated run-90,000 tons of ore are stacked on 300 foot square clay leach pads. Cyanide leach solution is applied through ""wobbler"" sprinklers at .0025 gpm/sq ft for 60 to 90 days. The pregnant solution flows from the heap by gravity to plastic-lined ditches, into a collection sump and then through buried piping to the 2.2 million gallon pregnant solution pond."

Jan 1, 1984

By D. Moradkhani

The heap leaching of oxide copper ores with copper cathode recovery by solvent extraction and electrowinning is now well established as a low-cost method of copper recovery. The main purpose of this study was to extract copper from the copper low-grade oxide ore of Chodarchaei mine using column leaching. The copper oxide ore contained 1.1% Cu and 1.75% Fe. The mineralogical analysis indicated the malachite (Cu2(OH)2CO3) was mainly composed of oxidized phases. The sulfuric acid leaching experiments were performed under the laboratory conditions. The influence of several parameters on the course of the reaction such as particle size, acid concentration, flow rate, and time was examined. The optimum collective extraction of copper and iron was obtained at a particle size of +10-15 mm for a leaching duration of 3 days with sulfuric acid concentration of 100 gpl and using a flow rate of 2.5 cc/min. Under these conditions, the recovery of copper and iron were 98.54% and 41.99%, respectively. Keywords: column leaching, copper, iron, working diagram.

Sep 1, 2012

By B. J. Scheiner

The presence of organic materials in gold ores interferes with gold extraction by cyanidation. The carbon contained in the ore has been shown to adsorb gold cyanide complex from solution. Removal of the carbon content by roasting or chemical oxidation prior to cyanidation results in gold extractions of 85 to 95%. This paper discusses how the mineralogy of the carbonaceous gold ores affects gold recovery by cyanidation. It also discusses the advantages and disadvantages of roasting and chemical treatment to render the ore amenable to cyanidation.

Jan 1, 1987

By A. I. Krynitzky, Henry S. Rawdon

The most commonly used material for terminals in spark plugs is commercial nickel wire, because of its relatively high temperature of melting, excellent heat conductivity, and slow rate at which the metal is oxidized, even upon continued heating at high temperatures. The grade commonly used for this purpose averages 97 per cent. nickel, the remainder being manganese, cobalt, iron, copper, with traces of other impurities always found in commercial nickel. A peculiar and interesting type of deterioration that occurs in these nickel terminals during the service life of the spark plug was recently brought to the attention of the Bureau of Standards. Commercial spark plugs vary greatly in their size and shape and the terminals differ considerably as to their relative size, shape, number, and arrangement with respect to one another. Although this defect was studied in detail in only one form of spark plug, the deterioration is a characteristic of the material, i.e., of nickel wire, rather than of the particular type of spark plug in which it was noted and studied. The mechanical features of the plugs, however, have a considerable bearing on the time required for the deterioration to become serious. The results of this study of the deterioration of nickel terminals in service should be of value to the makers of all types of spark plugs in which the terminals are made of this metal. CharacteR of Deterioration of WIres During Service Macroscopic Appearance and Properties of Changed Wire.—The nickel terminals in which the deterioration was studied were taken from spark plugs having a central terminal with the ground or side terminals attached firmly at both ends to the shell of the plug. In some of the plugs, two side terminals were used, one on each side of the central one. Although both terminals were found to have deteriorated to some extent, the attack of the central one was quite negligible compared to that of the side ones. These latter wires had developed, in service, transverse cracks that, in many cases, were as sharp and definite as a knife-cut. After a separation occurred, the breach widened by loss of material from the

Jan 1, 1921

By Ellis S. Hertzog

The material published in this report is part of a special study of some of the chemical and physical properties of Alabama coals. The complete study included friability and grindability determinations, high and low temperature assay distillation tests, and ash fusion-temperature determinations. Proximate and ultimate analyses and. calorific values of the coal samples also were obtained. This paper is concerned only with grindabilities, although proximate analyses have been included to give a better picture of the problem as a whole. The growing interest in grindabilities of coals is a result of the increase in use of pulverized fuel in rescent years. The tenative ball-mill grindability method D408-35T4/ was used in making all the determinations. The method of sampling and the technic of the testing procedure is described in Considerable detail in this report because the procedure was established quite recently. The ball-mill grindability index is a measure of the ease with which coal may be ground, which may be an important factor in estimating pulverizing costs. Up to the present time few data on the grindability of Alabama coals have been published. The data in this paper show that the Warrior and Cahaba fields exhibit a wide range of grindability in their coals. The mines tested are well distributed throughout the productive areas of these fields, and it is possible to make rough estimates of the grindabilities of coals not listed in this report from the data given for mines situated in the same vicinity.

Jan 1, 1938

By F. Y. Kang

There are rich resources of natural graphite in China. It would be a good opportunity to upgrade national graphite industry if natural graphite with modification is used in lithium ion battery. Micro-crystalline graphite in high purity was coated with a carbon film on the surface. The initial cycle efficiency was improved to be 89.9% and cycle stability was remarkably improved. The experiments proved that microcrystalline graphite with carbon coating have excellent electrochemical performances at low cost as anode materials for lithium-ion battery. In addition, H2SO4-GIC technique was used to prepare the natural flake graphite powders with mild-exfoliation. Sub-micro and nano pores were found in the graphite samples. In correspondence the reversible capacity, rate capacity and cycle life were improved, which would meet the demand of high-power lithium-ion battery. Natural graphite is the most promising anode material for large-scale lithium-ion batteries. The demand of modified graphite grows up greatly in the market. Microcrystalline graphite with surface coating and flake graphite with mild-exfoliation are the promising commercial anode materials for the industry of lithium ion battery.

Jan 1, 2014

By Peter Rubie

For many years, optimising the relining of hard rock grinding mills has been complicated by: ?? the large number of variables; ?? the low frequency of relines (slow feedback loop); ?? the potential economic risk associated with some changes. A technology that has its roots in the automotive manufacturing industry is being utilised to construct a statistically accurate, configurable, and dynamic simulation of the mill relining process. The effects of various mechanisation and process changes can be rapidly modelled and compared. This technology will provide mill maintenance managers and contract relining companies with the opportunity to benchmark current performance against world?s best practice. It will also provide an opportunity for concentrator plant designers and mill manufacturers to plan for maximum plant efficiency, by designing an infrastructure and equipment combination that maximises annual plant availability. This simulation tool and its associated data set, has been developed using recent grinding mill performance data from mills of varying dimensions, liner configurations, mill relining equipment, operator and tool variables. The simulation will provide an output that the various stakeholders can utilise to make optimal decisions within the given financial, physical and technological constraints of the individual concentrator plant.

Jan 1, 2012

By A. W. Dougall, T. M. Mmola

"SynopsisThe global resources and commodities market has become highly competitive. While southern Africa’s abundance of minerals resources is still unrivalled, it has lost considerable dominance in terms of production output. The sustainability of southern Africa’s mining industry is increasingly becoming dependent on its ability to manage the performance of its operations well. A valuable tool for monitoring and managing performance is the use of key performance areas (KPAs) – which are those areas of performance that are reflected explicitly or implicitly in the vision and strategies of an organization and reflect the critical success factors of the organization. This paper is a review of key performance areas in the southern African mining delivery environment. The KPAs discussed in this paper have been identified by comparing KPAs of the several mining houses engaged in surface mining operations in southern Africa and then extracting those KPAs that are common to most of them. Although the authors support the view that each organization should develop KPAs to specifically fit its needs, the study reveals that five KPAs – safety and health, costs, product quality, fleet management, and delivery should form a default list that covers the key areas that any organization should consider when choosing KPAs. KPIs are those subsets of KPAs that we measure in order to manage KPAs.IntroductionThe global resources and commodities market has become highly competitive. While southern Africa’s abundance of minerals resources is still unrivalled, it has lost considerable dominance in terms of production output. The sustainability of southern Africa’s mining industry is increasingly becoming dependent on its ability to manage the performance of its operations well. A valuable tool for monitoring and managing performance is the use of key performance areas (KPAs), which are ‘those areas of performance that are reflected explicitly or implicitly in the vision and strategies of the organization’ (Barker, 1997). The terms KPA and KPI (key performance indicator) are often used interchangeably – whether correctly or erroneously is debatable. KPIs are ‘quantifiable measurements, agreed to beforehand, that reflect the critical success factors of an organization’ (O’Neill, 2007). Each KPA probably has multiple KPIs associated with it."

Jan 1, 2015

By H A. Challenor

Eyewash safety showers located in remote hot environments may be unsafe to use due to excess water temperature and high risk levels of water borne bacteria such as Legionella. Australian Standard AS 4775 specifies that dispensed water shall be bacteria free and have a maximum temperature of 37.8°C. Legionnaires disease is contracted when water aerosols containing Legionella bacteria are inhaled.Laboratory tests show 30 to 70 times more aerosols are generated by showers operating at 38°C than with showers operating at 25°C. Furthermore, excess temperature in flushing water can cause burn injuries leading to hospitalisation, skin grafts and/or permanent scarring. Excess temperature also increases the rate of reaction to corrosive substances, opens pores in the skin to allow greater dermal penetration and can cause dizziness and fainting by dilating blood vessels and reducing blood pressure.CITATION:Challenor, H A, 2017. Managing excess temperature and high risk levels of Legionella bacteria in eyewash safety showers, in Proceedings Iron Ore 2017, pp 337–346 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By H. C. Van Der Merwe

In the 21st century, dynamic, accurate digital 3-D geological models are essential to the pursuit of safe, efficient and profitable mining. This is particularly true for the deep-level underground mines in South Africa. The Sirovision® solution is a collaboration project between the Australian CSIRO (Commonwealth Scientific and Industrial Research Organisation), Datamine Software Ltd. and AngloGold Ashanti Ltd (AGA). The purpose of the project is to provide a fully integrated digital rock face imaging, geological mapping and modelling system for the AGA gold mining operations. The CSIRO-developed Sirovision® Stereo Camera Rig (SCR) consists of two digital cameras, alighting system, a laser guidance system and image processing software. The imaging system works on the principles of photogrammetry, i.e. overlaying of two 2-D images with a central focus point, with mathematical algorithms extracting 3-D information from the 2-D image pair. The output from matching several image pairs is a computer-generated, full 3-D, virtual copy of the mining excavation. The image resolution and relief ares of sufficient quality to distinguish different rock types and structural contacts. Functionality within Datamine Studio3 is used to add geological intelligence to the 3-D images provided by Sirovision®. The geologist identifies and ?draws? lines representing geological features directly onto the image. By utilizing the inherent ?topography? of the 3-D image, the software is able to convert the lines into 3-D surfaces, ready for use in the 3-D geological model. Subsequent to promising underground test results from AGA?s Sunrise Dam Gold Mine (SDGM) in Australia and other mining operations worldwide, it was decided to test the Sirovision® system in the South African deep-level gold mines. The first underground tests at Moab Khotsong Mine began in January 2009. The objectives of these tests entailed the capturing of 3-D images of selected development ends, mapping of geological features onto the 3-D images and integration of the mapping data with the 3-D geological model. Some downsides have cropped up during the feasibility testing, related to practicality of the SCR for acquisition of 3-Dimagery in the deep-level underground operating environment. These constraints will have to be addressed prior to operational implementation. Facing such difficulties is not unusual when attempting to implement new technology in such a challenging working environment and testwork is still in progress at the mine in order to prove the concept of using this technology in a Witwatersrand underground gold mine. The great advantage of the Sirovision® solution is that it offers the geologist the opportunity to work remotely on a 3-D virtual copy of a mining excavation, without the heat, humidity, hazards and time constraints associated with physical mapping in an underground workplace.

Jan 1, 2009

By J. E. Dutrizac, Alba Sunyer

The factors affecting the precipitation of arsenic-free alunite (KAl3(SO4)2(OH)6) were investigated in a series of laboratory experiments. Although the amount of alunite precipitated increased with increasing retention time, temperature, solution pH and the concentrations of Al(SO4)1.5 or K2SO4, the composition of the products remained nearly constant. The preferred conditions identified for the precipitation of arsenic-free alunite were then used to assess the behaviour As(III) and As(V) during alunite precipitation at 98°C. Increasing additions of As(III), as NaAsO2 or As2O3, resulted in a slight increase in the amount of precipitate formed at pH 2.80. However, X-ray diffraction analysis showed all the precipitates to be alunite, and <0.2% As(III) was detected in the products. In contrast, increasing additions of As(V), as KH2AsO4 or As2O5, resulted in significant increases in the amount of precipitate formed at pH 2.80 or 3.00. Furthermore, the arsenate (AsO43-) contents of the precipitates increased up to 15%, and the sulphate contents decreased, as the As(V) concentration of the synthesis solution increased from 0 to 9 g/L. X-ray diffraction analysis of the products detected only alunite, but there was a progressive expansion of the alunite cell with increasing arsenate content. The implication is that arsenate substitutes for sulphate in the alunite structure. Preliminary observations on the environmental stability of the arsenate-bearing alunite using the TCLP protocol gave solubilities <0.4 mg/L from a precipitate containing 8.5% AsO4 and 7.8 mg/L from a product containing 19.5% AsO4. Thus, it appears that alunites containing less than -10% AsO4 would be an acceptable vehicle for the disposal of arsenic from hydrometallurgical processing solutions.

Jan 1, 2011

By Al Romphf

Managing blasting-induced air overpressure levels is a key compliance requirement for most blasting operations. Regression analysis, plotting overpressure amplitude vs cube root scaled distance, will often present a level of scatter which should be considered unacceptable. Relying solely on regression-based predictions can lead to overly conservative restrictions that may negatively impact other key performance indicators. Improved methods are needed for accurate overpressure prediction. The Heelan-Blair wavelet has been shown to closely resemble the overpressure waveshape produced when a single charge is fired under typical confinement conditions. The amplitude of a single-hole overpressure wave is influenced by factors such as proximity to the receiver, charge mass, orientation, and confinement both at the collar and face. Additional factors, including timing sequence, barrier effects, wind direction and velocity, must also be considered. The linear superposition method, commonly applied for ground vibration prediction, can be adapted for air overpressure modelling. In blast design software, this approach can consider all relevant parameters and environmental interactions. Given the uniform nature of air compared to rock, linear superposition using realistic elemental wavelets may replace the need to fire a signature hole. Data from 38 single-hole blasts conducted at quarries and mines throughout North America were used to develop and calibrate a linear superposition model. This model reasonably reproduces air overpressure results from full-scale production blasts, offering a practical approach to overpressure compliance and prediction.

Jan 26, 2026

By Michael D. Loy

This paper examines the computerization steps of United Coal Company of Bristol, Virginia. OVERVIEW Producing close to 7,000,000 tons per year, United Coal Company is one of the most interesting mining companies in the east. Their approach to mining reflects a dedication to modern technologies and extraction methodologies. With varying amounts of production coming from four divisions (a fair amount of production comes from contract operators) and over a billion tons in recoverable reserves, United rests heavily on the planning and engineering efforts of a centralized engineering group. Although each division relies on its own engineering personnel for day-to-day management and operations, long range planning and reserve management is conducted at the corporate engineering level. This group, while extremely competent and efficient, is relatively small (7 people), when compared to the needs of a large mining company.

Jan 1, 1985

By A. Bruynesteyn

Most ores and coals contain sulphide minerals such as pyrite, FeS2, the sulphur portion of which is a ready substrate for a variety of sulphur oxidizing bacteria. Although there are several bacteria capable of oxidizing sulphide minerals, the most often discussed culprit is Thiobacillus ferrooxidans.. Oxygen from the air slowly oxidizes pyrite into sulphuric acid, but T- ferrooxidans can increase this reaction rate several 100,000 times.

Jan 1, 1991

By Augusto Weberbauer

El presente texto revisa la geografía e hidrografía del Perú. El territorio peruano forma parte de dos sectores fundamentales del continente sudamericano: los Andes y las Llanuras Bajas del Oriente. Asimismo, nuestra geografía se divide en tres zonas, una occidental, otra media y otra oriental, denominándolas respectivamente: Costa, Sierra y Selva. Las llanuras y colinas de ambos lados, el del Océano Pacífico y el de Amazonía, pertenecen a la "Costa" y "Montaña" respectivamente, en las que se encuentran las partes inferiores de las zonas andinas. Dentro del sistema de los Andes tenemos : Los Andes del Titicaca y de las mesetas volcánicas, los Andes del Apurímac, los Andes del Alto Marañón, Los Andes del Chamaya. En el sector Occidental tenemos la cuenca de Titicaca y Cordilleras orientales y el Nudo de Vilcanota. De otro lado, dentro de las condiciones orográficas e hidrográficas se divide la Costa en cinco partes: de Arica a Pisco, Pisco a Trujillo, Trujillo a la Punta Pariñas, la Punta Pariñas a Tumbes y de Tumbes a Zarumilla.

Sep 1, 1974

By G. Mark Aylmore

Various processes have been developed using a combination of elevated temperature and chemical treatment processing to recover Li from silicate minerals. To facilitate further process development, a comprehensive understanding of the deportment of Li and associated minerals in ore bodies is essential to allow the industry to predict the response of ore reserves to metallurgical treatment options. This paper describes results from the integrated use of the John de Laeter Centre’s state of the art analytical and mass spectrometry techniques to characterise a selection of Li bearing ore bodies and determine their amenability to potential processing options for the extraction of Li. The mineralogy, mineral associations, and liberation characteristics of ore-bearing and gangue minerals were characterised using a combination of the TIMA and XRPD studies. The Li content and distribution within minerals were defined using LA-ICPMS and field emission scanning electron microscopy techniques (EBSD, ToF-SIMS) and atomic probe microscopy.

By Shi Guan-Yong, Niu Li-Ping, Dou Zhi-He

"In the preset work, the viscosity model (named modified KTH model) proposed by Sichen Du and S. Seetharaman et al and extended by Shu Qi-feng was applied to the ESR slag systems. A correlation to predict the viscosities of CaF 2-(CaO)-Al203 slags using interaction coefficients of different cations in the presence of oz-and viscosity interaction coefficients between oz-and F in the presence of different cations has been developed. The interaction coefficient between oz- and F- in the presence of Al3+ was determined from the experimental data as shown in known literatures. The good agreement between the calculated viscosities and the experimental data in the CaF2-(CaO)-Al203 systems has indicated that this approach can be successfully employed to predict the viscosities of ESR slags.IntroductionReliable viscosities data of high-temperature slag melts are important for the modeling and design of high temperature metallurgical processes. Although a number of experimental measurements have been carried out, the available viscosities data is still scarce compared to the needs of today's technology, especially in the case of complex melts. In process simulations, the needs of viscosity descriptions for complex systems which could enable the extrapolation of the data as functions of temperature and composition is strongly felt today."

Jan 1, 2013

By R. D. Yancich

A case study of longwall mining surface subsidence was performed at a mine in Southwestern Pennsylvania. The mine operated in the Pittsburgh coal seam which averaged 70-72 inches with 6-8 inches draw slate in the longwall location. The average overburden depth ranged from 625 8eet to 660 feet. Three adjacent longwall panels were studied and classified as Panel 1, Panel 2, and Panel 3. The following is information on each and can be seen on the General Mine Map (Fig. 1).

Jan 1, 1984

By F. D. Delve

RECENT studies by the author on the reduction of titanium from TiO2-bearing slags have been accompanied by difficulties that are attributed to

Jan 1, 1959

By Yuri Hovanski, Jingyi Zhang, David P. Field, Piyush Upadhyay

Friction stir welding has gained wide interest in industry and drawn large research attention due to its high level of automation and superior joint performance. In this study we further expand the welding parameters to be of magnitudes higher than those previously reported to lower the cost and enable high volume joint production. Sound butt-joints were produced with aluminum alloy 6111-T4 blanks with welding speeds up to 6000 mm/min. Tensile tests of the joint pieces show >97% joint efficiency in terms of ultimate tensile strength. The T4 natural aging and grain refinement is found to contribute to the superior joint properties. Electron backscatter diffraction (EBSD) analysis is used to qualitatively study the local shear texture inside the nugget zones of the welds. The shear texture result is a good indicator of the material flow directions in the nugget zones. The flow directions behind the rotation tool are found to be flattened towards the top surface of the workpiece when the welding speed is increased, suggesting intense material mixing and transportation along the longitudinal welding direction (WD).

Mar 1, 2018