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By R. L. Grayson

Following lip on a USBM-sponsored research project, the authors have utilized the knowledge-base structure and system concepts from the Sun Sparcstation-based worker scheduling system of the Mine Management Support System to develop a PC-based application. The new software adopts the nested-window concept to facilitate data collection and modification on personnel, their availability on a shift, and work priorities for a shift as well as to allocate manpower optimally on a work shift and delineate supervisory training responsibilities. The various components of the software are described in detail, along with enhancements made to the original system.

Jan 1, 1996

By Paul Laforest, Michael Moats, Daniel Majuste

The interaction of anode and electrolyte chemistry in copper electrorefining is complex. This is especially true with regard to the behavior of Group 15 elements (As, Sb, and Bi). To better understand this system, laboratory electrorefining experiments were conducted using commercial anodes with As/(Sb + Bi) molar ratios of 0.54 and 3.8 and an electrolyte collected from a commercial refinery. The effect of adding thiourea during plating was also examined. Twenty-one hour copper deposits were produced in the laboratory to simulate starter sheet production. The mechanical properties of the electrodeposited copper as measured by an industrially relevant empirical bend test and a one-point bend test developed by UFMG are reported. The crystal structures of the samples were also examined.

Mar 1, 2017

By C. Tong, B. Hilscher

"Sensor based ore sorting is being rapidly adopted by the mining industry. The ability to boost mill feed grade by rejecting waste grade rocks early in the process has proven revolutionary for some operations.This paper briefly reviews the current position of ore sorting in the industry, as well as abridged results from specific operations such as Barrick, McEwen, New Gold, and two others. The paper also introduces the concept of “Profit Recovery™”, the measuring of recovery based on rock profitability rather than just metal content.IntroductionSensor based ore sorting is being rapidly adopted by the mining industry. The ability to increase mill feed grade by rejecting waste grade rocks early in the processing stage is proving to be revolutionary for some operations. These potential outcomes have been too invaluable to be overlooked by both producing operations and prospective projects, thus leading to a wide range of studies on ore sorting. In addition, the advent of ore sorting has also called for a new standard of recovery analysis. The answer to this is the creation of a new term and concept - Profit Recovery™.This paper evaluates the most recent results of ore sorting in the mining industry, and presents the results from five different mining operations. Additionally, this paper will discuss and evaluate the Profit Recovery™ of each of these operations. The goal of this paper is to address common concerns regarding ore sorting rejects and their actual impact on project economics.State Of The ArtOre Sorting is a sensor-based sorting and pre-concentration technology implemented before the processing stage that is used to reduce the amount of waste reporting to the mill feed. This technology can also be utilized to recover ore from previously uneconomic waste, as well as reduce the mill energy and reagent consumption (Tong, 2012). In greenfield projects, sensor-based sorting can further provide value by reducing processing capital costs. The decline of available high grade orebodies and decreasing head grades has further increased the attractiveness of pre-concentration, and subsequently ore sorting (Lessard et al., 2014).There are currently two notable types of sensor-based sorting: bulk and rock-by-rock. Bulk sorting consists of live, high tonnage sorting that can be installed on a scoop or on a conveyor belt with a diverter. Rock-by-rock is a selective sorting method that scans and sorts individual rocks on a conveyor belt, and rejects rocks using air jets or mechanical levers. Figure 1 shows a diagram for a typical air jet sorter."

Jan 1, 2018

By E. Bonsall, J. J. Brummer, A. R. Graham

"A method and device are described for sampling diamond-drill core by cutting a continuous fillet of constant cross section from the cylindrical surface of the core throughout appropriate sample lengths. The apparatus employs a tapered, abrasive-set, cutting wheel, the conical cutting surface of which projects slightly into a rectangular core-guiding trough set parallel to the axis of rotation. The depth of fillet and thus the amount of sample per unit length can be regulated by adjusting the core guides. The freshly cut fillet itself, by engaging in a guide beyond the cutting wheel, acts to prevent rotation of the core during operation of the device.The cuttings which form the sample are normally collected in a tray below the cutting-wheel and appear at about 80 per cent -100 mesh. They require little or no further treatment or comminution before analysis. Speed, economy and convenience of sampling are thus greatly increased as compared with conventional sampling by im-1>act breaking or sawing, followed by crushing, grinding and sub division for assayAssays from fillets (about 1/20 the cross-sectional area of the core) and from 180-degree segments, from the same ninety-three core-samples, representing 431 feet of nickel-copper mineralization, gave the following results:"

Jan 1, 1968

By Qingyun Huang, Junyi Xiang, Xuewei Lv, Chenguang Bai

The extraction of vanadium from mechanically activated converter slag was studied in dilute sulfuric acid solution. The effects of roasting and leaching parameters were investigated. The results show that Ca/V mole ratio, roasting temperature, leaching temperature, liquid-solid ratio, and particle size all have significant effects on vanadium leaching efficiency from calcification-roasted converter slag.

Mar 1, 2017

By Raymond L. Jones

With the inauguration of open-pit copper mining in Bagdad, Ariz., plans were formulated for a large scale leaching operation. Dump stockpiling was started almost immediately, but actual production was not initiated until spring 1961.

Jan 9, 1977

By A. Erdem

In this study, approximately 3 tons of coal sample taken from thickener entrance was prepared by mineral processing techniques and cleaned by gravity methods. The samples were classified to 5 size fractions by wet screening. The size fractions of +1mm and -1 +0.500 mm were chosen for direct consumption or cleaning by spirals. The studies by Multi Gravity Separator (MGS) were carried out with the -0.500 +0.280 mm and -0.280 +0.020 mm size fractions where the -0.020 mm fraction does not used in the experiments. The clean coal fractions of +1 mm and -1 +0.500 mm obtained by classification were subjected to lower calorific value (LCV), ash and total sulphur analyses. The results were 4168-4946 kcal/kg (on dry basis), 31.01-38.54 % ash and 4-4.27 % total sulphur content respectively. The results of the clean coal concentrated by MGS experiments in -0.500 +0.280 mm fraction was found 5918 kcal/kg LCV, 19.82 % ash content and 80.47 % combustible recovery. The results for the -0.280 +0.020mm fraction were 6004 kcal/kg LCV, 19.19 % ash content, 80.47 % combustible recovery respectively. With reference to the above experimental results, pre-economic evaluation studies were completed and decided to construct an additional unit to the plant. Capacity of the constructed unit is 75.000 t/y which corresponds $ 2.600.000 income in a year. General Directorate of Turkish Coal Enterprises concluded to apply this project to the other coal washing plants in the country due to the successful results of this study and laboratory studies has been going on by MTA currently. Keywords: coal tailings, mgs, recovery, washery, pre-economic evaluation

Sep 1, 2012

By E. A. Twichell

An entirely new concept in the effective utilization of magnetic, energy has resulted in a major break-through in the design of magnetic separation equipment. One of the first applications of this concept has resulted in the development of a Permanent Magnetic Wet Drum Separator with strength .and operating characteristics equal to Electro Wet Drum Separators. Prior to this development when strength and adjustability were required, electro wet drums were specified even with all their drawbacks. The electros, by nature, are subject to coil failure or burnout, over-heating and loss of strength, high power consumption and generally high maintenance. Now the high strength and the adjustability, formerly the exclusive property of electros, has been engineered into permanent wet drum separators. These units combine maximum field strength in the separation zone with strength adjustment to suit changing conditions. Adjustment can be effected while the drum is in operation without stopping either the feed or the drum.

Jan 1, 1967

Drilling underground can be a hazardous undertaking in many circumstances. Raiseboring and boxhole boring underground could form an integral part of the block caving production methodology and getting the right mix of technical capability, ergonomics and economical viability has been the goal of many machine manufacturers. With the introduction of the Terratec Universal Boring Machine concept, flexibility of raiseboring, downreaming and boxholing has been enhanced by the introduction of a single machine that will perform all three processes. In addition to its technical flexibility, additional safety features have been introduced that will eliminate many sources of injury by mechanising most of the operational procedures. Together with the one-man remote operation, this machine design addresses and solves many of the safety issues. This paper outlines the machine concept, details its safety features and shows the techno-economic advantages for use in the block caving environment. Block caving is a distinct caving method applied mostly to large massive orebodies because of the inherent low costs and high production capabilities. Areas of sufficient size are mined by undercutting so that the mass above will cave naturally. Extraction of the caved ore at the bottom of the ore column causes the caving action to continue upward until all of the ore above the undercut level is broken into sizes suitable for handling (Figure 1).

Jan 1, 2000

By Paul C. Schmall, Kevin Clarke, Paul J. Lewis, John M. Stanbury

"The $200M rehabilitation of the more than 100-year-old Gowanus Flushing Tunnel and pumping station located on the Gowanus Canal in Brooklyn, NY required deep excavations in an extremely congested urban environment. The environment posed significant challenges, including: support of excavation for protection of existing structures, excavation through man-made fill while eliminating groundwater inflow due to potentially contaminated groundwater chemistry; discharge and disposal impacts; and potential settlement of surrounding structures. This paper will present the design and construction challenges associated with the construction of a new combined sewer overflow (CSO) chamberwhich included a jet grout bottom seal, to mitigate groundwater inflow during excavation. The foundation for the finished structure also included a unique system incorporating the jet grout bottom seal elements with deep jet grout columns (piles) acting as the foundation system for the final structure. Design and construction challenges included highly variable soil conditions such as man-made fill, obstructions from previous construction, presence of an organic stratum, and conflicts with existing timber foundation piles. The jet grout bottom seal was constructed in loose sands with the deeper jet grout foundation elements extending to bear on a dense sand stratum. Challenges associated with the bottom seal included grid spacing and construction sequencing. Wet in wet sequencing was used to mitigate potential windows in the bottom seal further complicated by shadowing from existing timber foundation piles.Introduction And BackgroundModernization of the Gowanus Tunnel Pumping System required deep excavations in the extremely congested urban environment of Brooklyn, NY. The project location is shown on Fig. 1 and 2. The focus of this paper is to present the design and construction challenges associated with the support of excavation, control of groundwater, and ultimate foundation support for the combined sewer overflow (CSO) bypass chamber extension. The project site was tightly constrained by adjacent, active roadways and underground utilities, as well as residential and industrial structures. Therefore, excavation support was required to limit ground movement and maintain the integrity of the surrounding facilities. Excavation depths to as much as 16 ft below ground level, 8 ft below groundwater, required that seepage and groundwater be controlled so as to minimize pumping and disposal of groundwater and maintain the surrounding groundwater levels to avoid potential settlement of adjacent roadways, utilities, and structures. In addition, the subsurface conditions required that the proposed CSO bypass chamber extension be supported on a deep foundation to avoid differential and total settlements that may be detrimental to the existing and expanded structure. A plan view of the existing CSO bypass chamber and the proposed extension is shown on Fig. 3."

Jan 1, 2016

By V. M. Sokolov, Jr. DuPlessis

The technology for recycling fine wastes, grinding sludges or swarf, and solids such as slag that contain a high content of metallic material needed improving. The objective was to produce a master alloy that met the tight requirements of the Western manufacturers and achieve improved yields of the valuable elements, nickel and cobalt, to over 90%. The alloys from the production of Alnico. magnets were chosen for this work. A process is proposed .that is able to recycle all kinds of Alnico wastes. This process is able to reduce all detrimental elements, which are contained in the wastes, to within acceptable levels. Molybdenum, if present, is an exception. Depending on the levels of contamination of undesirable elements different recycling strategies are proposed. The majority of the wastes can be recycled by melting and refining with a liquid slag layer using unique melting furnaces that are relatively unknown in Western nations. The proposed technologies allow the reelamation of over 95% of the cobalt and nickel from any kind of Alnico waste, and there are no limitations on the proportion of different kinds of wastes in the charge. The proposed processes and technologies could also be applied to the recycling of grindings, turnin

Jan 1, 2000

By P. A. S. Manning

Eastern Jamaica consists predominantly of non-carbonate rocks reaching elevations of over 2200 m. The area is drained by a well established river network which supplies close to 30% of the sand and gravel used by the building and construction sector. Present high extraction rates and slow rates of replenishment will result in early exhaustion of this source of aggregate. A number of volcanic and carbonate rocks are being examined as a possible source of high quality aggregate which meet the requirements for all types of construction. Preliminary evaluations show a dacitic deposit to be the most suitable source for aggregate use.

Jan 1, 1998

By Lztok Peruš, Goran Kugler, Matevz Fazarinc, Milan Tercel

"Hot deformability of M42 tool steel additionally alloyed with cobalt and molybdenum was investigated. Hot-compression tests were carried out in the temperature range 850 °C -1200 °C, at strain rates range 0.001--6s-l up to strain of0.9. Field-emission scanning electron microscope and optical microscopy were used for characterization of microstructure of deformed samples, which revealed a very complex precipitation of carbides that strongly depends on the soaking temperature, the soaking time, the stress state, the deformation temperature as well as on the strain rate. Gathered data was used to calculate the processing parameters such as process maps, apparent activation energies and strain hardening exponents. For better understanding of thermodynamical properties of the studied steel a simultaneous thermal analysis was conducted. Furthermore the analysis of phase equilibrium was calculated using Thermo-Cale software. On the basis of these studies the optimal soaking temperature and process windows were determined.IntroductionHot workability ofledeburitic tool steels is important economic factor. This means that for each tool steel individuallysafe range of hot working parameters should be revealed. Publications in the literature with regard to the hot workability of tool steels are rare and therefore more information from this research area is desired.The relatively low hot workability of ledeburitic tool steels, i.e. steels in which the solidification is completed by a eutectic transformation of the residual interdendritic liquid to austenite and various alloy carbides (ledeburitic carbides), is usually characterized by the production of surface and internal cracks during the hot deformation."

Jan 1, 2013

By Jurgen Hahn

The paper reports on both, the design and decision making for the filters in a backfill plant in Europe as well as more then 10 years of operation and maintenance experience of the vacuum disc filters installed. It begins with the first step, the filter sizing based on a sample provided by the customer, followed by the commissioning of the filter units and reports on the development of the filter performance during the following 10 years of operation. Based on the physical properties of the sample and the process targets of the client for the backfill plant, the paper shows the logic steps taken in the laboratory to ensure the target moisture, determine the required filtration area and filter size as well as the selection of the ancillary units and the formulation of the performance guarantee. The paper discusses some issues with filter operation during the commissioning phase and the actions taken. Finally, the paper concludes by highlighting the gradual change over the more than 10 years of operation and how this change affected filter performance and operating costs.

Feb 1, 2024

By P Valenzuela

Joint mapping is a fundamental input for rock mass characterisation and slope stability analysis. The usual way to do it is using a compass in the field or digitising structures on a screen, with a software package.In this paper a method to identify and map joints automatically along a rock face is presented; it is called the Concentric Shells (CS) algorithm. The method scans a point cloud sequentially, tests if selected points are ‘true pivots’ within an inner shell, and then it searches for points inside a wider sphere (outer shell).The algorithm, developed by the author, was applied in real data. It reproduces the main features obtained from conventional (compass) and digital mapping (software package). Execution times are approximately 45 seconds for two point sets holding of 3.1 million points. Obtaining the same results via digital mapping takes approximately 3–4 working days.Key advantages of this method are: significant time reductions; elimination of mapping bias; and the ability to manage very large data sets (>2 million points) without the need of scanning the cloud on the screen. These advantages make this method an attractive tool for engineers and geologists wanting to increase productivity.CITATION:Valenzuela, P, 2017. Automated joint mapping using the concentric shells algorithm, in Proceedings Tenth International Mining Geology Conference 2017, pp 257–262 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By Adrian Dance

Newmont Ghana Gold Limited?s Ahafo operation have been working with Metso Process Technology & Innovation (PTI) since early 2009 to increase mill throughput from a combination of controlled blasting practices and optimised primary crusher and grinding circuit conditions. For such Mineto- Mill projects, PTI?s methodology is termed Process Integration & Optimisation (PIO). Ahafo operate a SAG mill, ball mill and pebble crusher (SABC) circuit that processes a range of primary ore of varying hardness from different pits which is blended with soft oxide material. The PTI study focussed on ball mill limited material from the Apensu open pit. Following a benchmarking study of all blasting, crushing and grinding practices in January 2009, PTI recommended changes in both blasting and crushing conditions in order to generate a finer feed size to the SAG mill. Additional operating changes in the grinding circuit were recommended. A series of trials were conducted in November 2009 where three blasts were fired using a different blast design (hole diameter and explosive type) in the same area of the Apensu pit as the benchmarked material in January 2009. Top and bottom benches (or flitches) from each blast were sent exclusively to the grinding circuit and the material was tracked using PTI?s SmartTag? system. The results from the six trials showed a significant increase in primary ore throughput at a reduced blend of oxide material. Ahafo have since standardised on these modified blasting conditions for all Apensu ore zones and have been able to sustain higher throughput compared to historical performance on similar material. This paper summarises the phases of the PIO project, the changes made in operating practices and the outcomes of the blasting trials that validated the predicted increase in mill throughput.

Jan 1, 2012

By Hani S. Mitri

Strainbursts in brittle rock are common to deep underground mines. The state of stress at the boundary of mine openings is dictated by a biaxial stress/loading condition. This paper reports the results of a series of biaxial compression tests carried out on 100 mm cubic samples of norite rock, under different horizontal-to-vertical stress ratios. The results indicate that the biaxial compressive strength is considerably higher than the uniaxial one. It is found that the norite sample behaviour under biaxial loading mirrors field behaviour where shearing and progressive spalling of the opening boundary are observed prior to strainbursting. Sample failure is initiated by rock spalling at the sample free faces, i.e. in the plane of biaxial loading. Finally, it?s the out-of-plane shear failure mechanism that causes the sample to collapse. Shear failure takes place violently and abruptly and is accompanied with considerable audible noise.

Apr 1, 2005

By Tiejun Chun, Gutian Mu, Jiaxin Li, Hongming Long, Zhengwei Yu, Ning Li

The basic characteristics of iron ore, including assimilation, fluidity, cohesive phase strength and the ability to produce calcium ferrite, are often used to evaluate the sintering properties of iron ore and guide the optimization of iron ore blending. Six kinds of common iron ore used in a steel company in China were selected in this work. The basic characteristics of the single iron ore and blended iron ores were studied, as well as the difference between weighted averages of basic characteristic index of single iron ores and the real value of basic characteristic index of blended iron ore under different ore blending ratios. The results shew that the liquid phase liquidity, cohesive phase strength and calcium ferrite formation ability had a significant linear positive correlation with SiO2 content. The weighted average of basic characteristic index of single iron ore cannot fully reflect the actual blended iron ore properties. The optimization of the blending ratio can be achieved through the detection of the basic characteristics of the mixed iron ore, combined with the basic characteristics of iron ores.

Mar 1, 2018

By P. Songfack

In this work, the slurry flow in the ball mill is solved with Navier-Stokes' equations and the marker and cell technique (MAC), which tracks the fluid-free surface. Considering different planes in the radial and axial directions, this numerical approach leads to the direct calculation of the slurry velocity profile, mill holdup, and volumetric flow in the ball charge and pool. The MAC technique takes as input, the results of a direct three-dimensional simulation of the motion of grinding media, and in turn, provides a detailed knowledge of the hydrodynamics of slurry flow through the porous structure of ball load. This technique is a new approach to the mass transport problem that overcomes the limitations of indirect studies such as residence time analysis and holdup measurements.

Jan 1, 1994

By Y. Y. Li, Q. Chen, Y. X. Cai, Q. Zhang, S. Mao

"Due to the influence of combustion conditions, the fly ash produced by some power plants has the problem of high-carbon content. The unburned carbon in fly ash can be removed by flotation, and the decarbon tailings should reach the national standard level I fly ash. The fineness of the requirement is one of the important indicators and is also an important factor affecting the tail ash activity. In this paper,adopting two methods investigate the effect of particle size on the flotation index: one is direct flotation of fly ash, and the other way is wet grinding + flotation of fly ash, comparing the two methods and selecting the appropriate process,which provides a way for the effective utilization of fly ash. INTRODUCTION Fly ash is a solid waste discharged from coal-fired power plants. The annual amount of emissions of fly ash are very large in China. The amount of fly ash were discharged from coal-fired power plants are increasing gradually, and the amount of fly ash stored has exceeded 2.5 billion tons, but the comprehensive utilization of fly ash is not high, which brings about a huge environmental problems( Lu et al.,2011). Carbon is a harmful component of fly ash in cement and concrete application (Zhang et al.,2008). Fly ash decarburization is an essential link to improve the utilization efficiency of fly ash and the reduce pollution ( Yang et al.,2012). Carbon is selected from fly ash to make full use of fly ash resources and improve utilization of fly ash (Li et al.,2008). In this paper, the flotation decarburization of high-carbon fly ash is studied, through comparing the grinding and not-grinding processes, optimizing the separation process of fly ash, which provides a way for the effective utilization of fly ash."

Jan 1, 2018