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By S. A. Ghoreishi-Madiseh

Underground mines, with their relatively high ground temperature and their extensive backfilled stopes provide a great opportunity for producing geothermal heat. The novel idea of installing a network of heat exchange tubes into stopes prior to backfill placement converts each mine stope into a heat producing battery. In this system, backfill plays the role of the heat exchange medium conducting heat from the surrounding rockwalls to the heat exchange tubes. This geothermal heat can be used for heating: mine facilities and buildings, the intake air, a close-by mineral processing plant, or even nearby communities. This paper investigates the possibility of extracting renewable geothermal energy from backfilled mine stopes by means of closed-loop geothermal cycles. To simulate realistic operational conditions a heat transfer model is developed and solved numerically. To evaluate the numerical results, a small scale physical model is constructed and the experimental results are compared with the simulation results. The study estimates the sustainable rate at which heat can be extracted from a typical underground mine stope, the resulting outlet temperature and performance of the geothermal system. The results show that mine stopes are capable of sustainably producing geothermal heat not only when the mine is active, but also after the depletion of the ore body. Therefore, an underground mine will no longer be perceived as an enduring economic liability, but as a long-lasting source of clean, renewable, and inexpensive low-grade geothermal heat.

Aug 1, 2013

By P. J. Finnis

This paper describes the use of wire rope on open-pit mining equipment, giving specifications and examples of the performance achieved. Installation methods are also discussed, making the paper of considerable practical use to mine operators.

Jan 1, 1973

By Laurence D. Burke

The electrocatalytic behaviour of gold in aqueous media is surprisingly complex and a novel view of gold electrode surfaces is proposed to explain the observed electrochemical responses. The metal surface is considered as a chemically (or redox) modified electrode, with equilibrated, low energy, surface gold atoms functioning as a relatively inert support and low coverage, high energy, protruding gold atoms (or minute clusters of same) functioning as electrocatalytic redox mediators. The protruding atoms are viewed as surface active sites and the complex electrocatalytic behaviour is attributed to the basic instability of the mediators, the diversity (and poor control) of same, and the acid/base (or hydrolysis) behaviour of the oxidized states of the mediators. It is assumed that major advances in the application of gold in the heterogeneous catalysis of gas phase reactions will be accompanied by similar advances in the use of gold in the electrocatalysis area; however, this will require considerable work of both a practical and theoretical nature.

Oct 1, 2003

By Margaret Armstrong, Chris Roth

Abstract -Estimating ore reserves for vein type deposits is a two-stage procedure: first, calculate the geometry of the vein system, and second, estimate the grades within this system. The grade estimation can only be consistently performed if the vein geometry - its size, shape and orientation - has been correctly characterized. Getting the size and shape of the different veins right means that the ore tonnages will not be artificially inflated, e.g., by falsely classifying host rock as veins. Similarly, correctly estimating their orientation and location helps mine management decide on the appropriate mining technique, selective or not. When applying geostatistics to estimate the vein geometry all available information needs to be used and not just the standard lithologic indicator of being or not being in a vein.

Jan 1, 1998

By C. J. Edmonds

Of the gold mined in Canada over 90 percent is extracted from the ore by the process of "cyanidation". In this process crushed ore is treated with lime to provide "protective alkalinity" and cyanide, usually in the form of sodium cyanide. The gold is dissolved in the cyanide solution, which after further treatments for clarification, is precipitated by the addition of zinc dust. Wastes from the process consist of tailings which will contain cyanides. Water consumption, mill size, effluent quantity and quality are depicted in transparency (1). It should be noted that as far as the wastes are concerned it has been impossible to postulate a typical situation. Variation from the above data will occur. A summary of data from tailings pond effluents is presented in transparency (2). The figures in parentheses indicate the usual range of values for the parameter.

Jan 1, 1973

By O. Benavente, M. C. Hernández

Selenium is obtained mainly from copper anode slimes, which is a by-product of the copper electrorefining process. Selenium is present in copper anode slimes as silver and copper selenides. Traditionally, selenium has been obtained by pyrometallurgical processes; however, hydrometallurgy has now been incorporated either full or partial to the conventional process. Some hydrometallurgical processes are been developed and used at laboratory level an industrial scale. This document describes theoretical background and results of characterization and dissolution of selenium from a decopperized anode slimes in an alkaline oxidizing system. The results have indicated that the oxidizing leaching process reaches a practically complete dissolution of selenium (up to 90 %); the undissolved portion is due to the generation of a AgCl around the particle surfaces that delays the progression of the reaction. The results indicated that 90% of selenium extraction can be obtained by dissolution under moderate conditions of pH, temperature and reagent concentration in oxidizing medium. INTRODUCTION Selenium is distributed in the earth's crust in most rocks and soils. Selenium is essential, as it has wide range of applications in the medical and food industries as well as, used in semiconductor, sensors and photochemical devices. Selenium is rarely found in the native state, 90% of selenium is obtained from copper anode slimes, which is a byproduct of the copper electrorefining process (Lu, Chang, Yang, & Xie, 2015; Xiao et al., 2017; Yang et al., 2018). In anode slimes, selenium is present as an intermetallic compound, as Ag-Cu selenides. Currently, selenium is recovered from the anode slimes via hydrometallurgical and pyrometallurgical processes (Lu et al., 2015). The traditional pyrometallurgical method recovers selenium effectively, but faces difficulty as a result of increased energy costs and strict environmental regulations associated with the process (Li, Yang, Jin, Chen, & Tong, 2017). Therefore, hydrometallurgical processes are proposed in oxidizing medium such as nitric acid, alkaline leaching with sodium nitrate, wet chlorination and pressure leaching, amongst others (Hait, Jana, & Sanyal, 2012; Kim & Wang, 2010; Xiao et al., 2017; Yang et al., 2018).

Jan 1, 2019

By E. Bratygin, G. Gazaleeva

"The article describes the analysis of methods and criteria of selectivity of optimal ore preparation schemes. Traditional criteria based on study of physical-mechanical properties of ores give the comparison of obtained figures with a reference standard or statistic data and the selection of the ore preparation scheme is made on a basis of a similar scheme from the existing production.Further on estimation is given to different criteria of the crushing selectivity, the new criterion is offered, the definition of which is done by results of an optical microscopy– the estimation of a valuable mineral release degree. The final estimation of the crushing process selectivity L? is performed by a calculation of a ratio of the valuable mineral free grains quantity in a desired size grade of a crushed material to the valuable mineral free grains quantity in a desired size grade of a raw product.Besides, optimality assessment of using the specific crushing unit is preliminary performed according to a maximum crushing degree of a material, however, the priority is given to the maximum selectivity criterion. The check of the proposed criterion was done when comparing the crushing of niobium bearing ores of the Vishnevogorskoye deposit in cone inertial and centrifugal impact crushers. Different operation modes of crushers were also checked. The comparison of the crushing selectivity criterion L? showed that the centrifugal impact crusher (CC) has the value of the selectivity criterion lower than the cone inertial crusher (CIC). For the crusher CC the criterion L? is 0.82 – 0.87 units, whereas for the crusher CIC – 1.43-1.755 units. The best crushing mode for the crusher CIC-300? is as follows: turning angle of debalance is 120°, peripheral speed of a cone rotation – 1,420 rpm, specific energy consumption – 6.99 kW?t/t.INTRODUCTIONIt has been shown that the most efficient techniques of mineral raw materials disintegration are selective crushing enabling to produce liberation of particles at maximum use of destruction techniques by borders of minerals cleavage. These days, such techniques are usually called special disintegration techniques (Jankovic & Valery, 2015), and they are used in 3–4 crushing stages. The selection of optimal crushing techniques is performed based on the following main parameters:- degrees of crushing, calculated based on granulometric features of raw and crushed products;- selectivity criterion defined according to useful mineral release and slime ability degree; and- traditional criteria (Gazaleeva et al., 2015) of choice based on study of physical-mechanicalproperties of ores gives the comparison of obtained figures with a reference standard or statistic data and the selection of the ore preparation scheme is made on a basis of a similar scheme from the existing production."

Jan 1, 2016

By S. Dessureault, M. Yildirim

More mining companies are now investing in IT, including updating one of the traditional IT process control tools used in the mining industry: real time in-pit truck allocation control and monitoring systems, or fleet management systems (FMS). These systems have been used to maximize the overall mine production by improving equipment utilization and reducing production costs. Most modern operations monitor the in-pit operations using GPS and wireless communications to produce data. Improvements in bandwidth, sensors, and computing power are causing modern systems to become more complex and generate more data. However, human analysis by simple regression or table generation in spreadsheets of the data is becoming impossible. Data mining solves this data management problem. Data mining finds patterns and relationships in very large data sets. This paper describes the application of modern data mining techniques on truck dispatching systems in a real open pit hard-rock copper mine. The analyses conducted included determining how the trucks performed under particular conditions and allocation systems. The long-term benefits of this work are to identify strengths and improvement opportunities in truck assignment systems and establish the skill sets and IT infrastructure needed in undertaking more complex datadriven technology such as a truck dispatcher trainer.

Jan 1, 2007

By Jeffrey S. Loen

"The size, morphology, surface texture, per cent mineral inclusions, and bulk chemistry (Ag and trace elements) of placer gold particles vary systematically according to transport distance from source rocks, as indicated by a case study from the Pioneer district in Montana, and data from the literature.Placer gold samples show a rapid decrease in mean and maximum particle length, and a gradual increase in flatness index (F.I. = length + breadth/2 x thickness) from about F.I. = 2 in bedrock deposits, to as much as F.I. = 45 over transport distances of several tens of kilometers. Primary mineral inclusions (mainly quartz, sulfide minerals, and iron oxides) are mostly lost within 10 km to 20 km of fluvial transport; this loss of quartz and trace metals causes a major change in bulk chemistry of placer gold samples. Following the loss of inclusions and the development of flakes, edges of flakes are folded and the mean number of folded edges in a sample increases with distance. When viewed under the electron microscope, surface textures of placer gold particles also become progressively more pitted with distance.Analysis of placer gold particles can be used to help evaluate placer source-area problems (placers with no known hard-rock gold deposits). For example, coarse placer gold containing abundant inclusions indicates a proximal source. On the other hand, an abundance of thin flakes is evidence of a long transport distance and possible reworking from older gravels. Placer gold characteristics can therefore provide information on distance to mineralized source rocks."

Jan 1, 1995

By D. Neely, D. Milne, L. R. Feldman

"Resin-anchored rebar is commonly used for rock support in mining. The rock properties and environment determine the average bond strength, allowing mine engineers to select the appropriate length and installation pattern for the support. In weak material such as potash, the average bond strength tends to be lower than for a typical hard-rock installation. Determining the failure mechanism by which the support fails in soft-rock applications could lead to improved bond strength and better calculated installed support capacity. This paper reports on research conducted at a potash mine in Saskatchewan and analyzes the failure mechanism of the support.RÉSUMÉ Dans les mines, les barres d’armature enduites de résine sont fréquemment utilisées pour soutenir le roc. L’environnement et les propriétés du roc déterminent la résistance moyenne d’adhésion, permettant ainsi aux ingénieurs miniers de choisir la longueur de barre appropriée et le diagramme d’installation du soutien. Dans des matériaux faibles, tels que la potasse, la résistance moyenne d’adhésion tend à être plus faible que pour une installation typique dans de la roche dure. La détermination du mécanisme de rupture selon lequel le soutien fait défaillance dans des roches tendres pourrait conduire à une meilleure force d’adhésion et à un meilleur calcul du soutien installé. Le présent article fait état de la recherche effectuée dans une mine de potasse en Saskatchewan et analyse le mécanisme de défaillance du soutien. ,"

Jan 1, 2016

By G. J. Borbely, E. A. Devuyst, V. A. Ettel

"A new method for oxidative destruction of cyanide in industrial waste waters and slurries, such as gold mill barren liquors, tailing slurries and flotation tailings has been developed at the Inca research laboratories. Rapid decomposition of cyanide and related species is attained by treating the waste waters with a mixture of S02 and air at controlled pH and in the presence of a small amount of copper which acts as a catalyst. The approach selectively oxidizes cyanide and metal cyanide complexes, and also removes iron cyano complexes which are not removed by alkaline chlorination.The new method is shown to be less reagent intensive and therefore more economical than alkaline chlorination for treating gold mill and flotation waste waters. INTRODUCTIONOver 90% of the gold mined in Canada is extracted from the ore by ""cyanidation"". Wastes from the process consist of tailings which contain free cyanide, cyanide combined with heavy metals, thiosalts and thiocyanates. Because of the concern over the effect of toxic cyanides on the environment, all cyanide containing effluents will have to be treated in the future to meet certain government set concentration limits."

Jan 1, 1982

By E. C. Keeley

THE property of Buffalo Ankerite Gold Mines, Limited, is in Delora township, Porcupine area, Ontario. The southwestern part of the property is ground formerly owned by Marbuan Gold Mines, Limited, which was acquired by Buffalo Ankerite in January, 1936. Until 1938, the Ankerite (or North) mine and the Marbuan (or South) mine continued as separate operations, each developed through a surface shaft and winze to the 1050 level and each having its own mill. This meant high hoisting costs, which, in 1936 and 1937, amounted to 36 cents per ton. In 1938, the underground workings of the two mines were connected on the 1050 level, and ore from both mines was hoisted at the main, or No. 2, shaft of the North mine, location of which is shown in Figure l. This shaft was discontinued at a depth of 1150 feet because, owing to the soft nature of the talc (serpentine) rock in which it was sunk, it had to be concreted throughout, and also because of its great distance--1,100 feet and 1,400 feet, respectively-from the North and South orebodies.

Jan 1, 1945

By S. F. Guo, Z. F. Zhan, X. L. Huang, Y. Zou, S. W. Qi

"FLAC3D is an important numerical analysis software to study dynamic response of rock slope. In application of the program, the common issues such as absorbing boundary and the method to apply wave have been well studied. However, effects of model mesh size, damping and width of slope are still unknown. In order to make the result more convictive, this article has discussed the above issues systematically. It found that when the maximum mesh size is smaller than 1/10~1/8 of the smallest wavelength, the mesh size is smaller, the computational accuracy is higher. Meanwhile, values of damping and width of slope have no effect on the result. Additional, results of FLAC3D modeling on wave transmission across rock joints agree well with analytical solutions, so it has verified the capability and accuracy of FLAC3D on dynamic response of rock slope.INTRODUCTIONChina is a mountainous country accompanied with many earthquakes. Thousands of geological disasters are triggered by the Wenchuan Earthquake in Sichuan Province, and the majority of the disasters are landslides induced (Xu et al., 2009). Meanwhile, the paper (Li et al., 2003) points out five significant issues about dynamic loading in the area of geotechnical engineering, which includes the study of rock slope stability under earthquakes, and the dynamic response of rock slopes is one of its important study issues."

Jan 1, 2015

By J. Poplawski

In mineral processing plants, cyclones typically perform the classification duty prior to the downstream recovery process. Particle size distribution of the cyclone overflow is an important parameter and can be viewed as the product of the comminution process. Too coarse of a product will likely have poorly liberated valuable minerals and make recovery difficult. Too fine of a product may represent a missed opportunity to increase plant throughput and/or also result in low recovery due to poor kinetics. “Near-line” particle size measurement instrumentation has been in place for several decades, its availability and low measurement frequency have typically been inadequate for reliable use in automatic control. CiDRA Minerals Processing has developed a novel and robust technology that provides a highly reliable and low maintenance system for “on-line” measurement of the particle size in the overflow of individual cyclones. The system is based around a wetted sensor design with no moving parts and provides a real-time trend of the desired target grind size parameter. The system does not require sampling and associated sample transfer piping that is prone to plugging, thus avoiding high maintenance requirements. Plant data and benefits realized from the latest installations of the CYCLONEtrac PST will be presented. INTRODUCTION Impact-based real-time hydrocyclone particle size measurement Acoustic impact-based particle size tracking is a unique method for measuring and controlling the particle size in cyclone overflow streams. The implementation of this technology is centered upon a sensor probe that is inserted into the overflow slurry stream via a two-inch (50 mm) hole in the overflow pipe (Figure 1). Particles within the slurry stream impact the surface of the probe generating travelling stress waves within the probe. A sensor converts these travelling stress waves into an electrical signal and proprietary signal processing techniques convert these signals into a particle size measurement that is output every four seconds. The sensor is constantly in contact with many particles in the slurry stream, thus obtaining information from orders of magnitude more particles than traditional sample-based technologies. The sensor has no impact on cyclone performance because it is located downstream of the hydrocyclone and the presence of an air core ensures there is no change in the back pressure seen by the hydrocyclone.

Jan 1, 2019

By Z. Bibak, S. Banisi, A. Ghasemi, E. Nematollahi

"The use of large AG/SAG mills in the mineral industry has been on the rise recently due to a significant reduction in the capital and operating costs for achieving significant increases in plant throughputs. The major reason for downtimes in these mills is the time taken for the replacement of broken or worn liners. This loss of “availability” of these units has a significant impact on the productivity of these plant operations. The ability to predict liner life time and its evolving shape could help to optimize these comminution operations. In the past decades, various models have been proposed to estimate liner wear rate, but because of their empirical nature they could only be used within certain limited operating conditions. In this research, a phenomenological model which could predict the liner wear rate was proposed and tested. This model considers parameters such as; operating conditions, liner hardness, pressure on the lifter, and, relative velocity of particles and mill shell. Data from industrially measured liner profiles were taken during the liner life time at the Sarcheshmeh and the Gol-E-Ghohar SAG mills to provide a solid base to calibrate and validate the model. The comparison of the model predictions with the actual measurements of the liner wear rate showed that the results were in a good agreement at both, the Sarcheshmeh (R2=0.94), and the Gol-E-Ghohar (R2=0.97) concentrators.INTRODUCTIONAG/SAG mills are one of the most important technologies in the mineral processing industry in the recent decades. The “Availability” of these units in a plant operation is one of the most important economic parameter for evaluating their performance. The major reason for the downtime of these mills affecting their “availability”, is the time required to change worn or broken liners (Yahyaei, Banisi, & Hadizadeh, 2009; Maleki-Moghaddam, Yahyaei, & Banisi, 2012). The knowledge about the magnitude and profile of liner wear not only enables more accurate liner life estimation to prevent unwanted interruptions of the SAG milling in mineral processing plants and more strategically plan the scheduled mill outages for liner changes. It also could provide key information needed to select an appropriate liner design (Yahyaei et al., 2009; Rezaeizadeh, Fooladi, Powell, & Weerasekara, 2010a)."

Jan 1, 2016

By Fathi Habashi

"On August 3, 1888, German Patent No. 43977 entitled ""A Process for the Production of Aluminum Hydroxide"" was issued*. The discovery which led to the patent was made by the Austrian chemist Karl Josef Bayer (1847-1904) (Fig. 1) who was at that time in Russia, and the process became known as the Bayer Process in his honour(1)(2)- The process imediately achieved industrial success, displacing the pyrometallurgical process that had been used until that time to produce alumina. The Bayer Process involved the pressure leaching of bauxite with NaOH solution to obtain sodium aluminate solution from which aluminum hydroxide was precipitated by seeding. Today bauxite is not only the principal source of aluminum but also of gallium, both metals being effectively recovered by the Bayer Process. The purpose of this paper is to outline the historical background of this discovery and its importance to hydrometallurgy."

Jan 1, 1999

By A. Kapoor

Gold mill effluents contain toxic pollutants such as cyanide (CN), thiocyanate (CNS), ammonia (NH4-N), and a variety of toxic metals. Various practical and economical technologies are in use for the removal of CN and toxic metals from gold mill effluents, however, the removal of CNS and NH4-N is challenging. The presence of CNS and NH4-N may make effluents toxic to aquatic life. The new Canadian Metal Mining Effluent Regulations will require mine effluents to be nontoxic. As a result, there is a need to develop practical and economical technology for CNS and NH4-N removal. The Mine Effluents Program in the Environment Group is presently evaluating biotechnology processes for the removal of CNS and NH4-N from gold mill effluents. The processes being evaluated are attached growth systems such as a Rotating Biological Contactor (RBC) and completely mixed suspended growth systems such as a Sequencing Batch Reactor (SBR) operating in a batch mode. The research to date at MMSL has shown that the RBC is very effective in removing CNS and NH4-N from simulated effluents. The NH4-N removal project showed that the RBC is capable of removing 0.8 g NH4-N/m2 of RBC disk area per day at an average temperature of 4.5 oC and hydraulic loading rate of 0.02 m3/m2/d. The RBC was also found to be very effective in removing CNS (feed = 200 mg/L and effluent < 1 mg/L) at 8 oC and a hydraulic loading rate of 0.02 m3/m2/d. The SBR was effective in removing CNS and NH4-N (generated from CNS degradation) at SBR operating conditions of two-12 h treatment cycles and a temperature of 12 oC. The end product of CNS and NH4-N oxidation was NO3-N, which is relatively non-toxic.

Nov 1, 2002

By Davis. B. R.

There are a number of hydrogen storage systems proposed for automotive applications. However, all of the current suggestions fall short of the DOE targets for storage density and volumetric density. The DOE has suggested that only through radically new ideas will a practical solution to hydrogen storage for automotive applications be realized. This paper provides some background in chemical hydrogen storage and discusses roadblocks to the implementation of some proposed technologies.

Jan 1, 2005

Between 1993 and 2003, a series of AG and SAG mill pilot plant trials were conducted using Hardinge Ical pilot plant scale SAG mills on numerous ore samples and ranging across a wide variety of operating conditions. The data from these tests were used to evaluate the design of SAG and AG mill circuits for over a dozen projects, of which about half were eventually constructed and commissioned. The data were also used in the development of SAG mill modelling, scale-up and simulation procedures by several consultants who had access to part of the data set. Recently, we have had the opportunity to bring this data together and further analyse the consolidated dataset. This paper reports on the outcomes of this analysis that has identified the impacts of different AG/SAG circuit flowsheets and operating conditions on energy efficiency and operating cost.

Jan 1, 2012

By L. Chunpongtong

ABSTRACT Oil sands production occurs on a massive scale, making orebody estimation a challenge. In rainy conditions, operators can have difficulty accessing ore at the mapped location. Without enough inventory as a buffer, the high-cost stockpile is depleted quickly, necessitating the removal of significant amounts of overburden and interburden to meet plant feed requirements. The inventory curve—a plot of ore inventory on a period-by-period basis—plays an important role in selecting an appropriate scheduling scenario. This paper presents a programmable method for creating an inventory definition by using a pit optimization tool.

Jan 1, 2014