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Based on the examination of thirty sets of contiguous matte and slag samples taken from industrial nickel smelters a relationship is predicted between oxidic nickel in slag, oxygen in matte and the Ni/Fe ratio in the matte. Oxidic nickel in the slag is found to increase with an increase in oxygen content of a matte of constant Ni/Fe ratio, and it is proposed that the relationship may be used to predict nickel solubility in slag from a knowledge of matte composition alone.

Jan 1, 1980

By Pat McLaughlin

Blast design in the construction industry has often been based on past practice or powder factors. This is to some extent understandable, since construction projects do not have the longevity of mining or quarrying operations and therefore have less opportunity to pursue potential improvements. The main concern of the operator is whether or not the technique will work, and at what cost to the downstream processes. Time, not long term savings, is of the essence.

Jan 1, 1994

Present roof bolting practices in the collieries of Australian Iron and Steel Pty. Ltd. are outlined. Roof support has been improved since introducing roof bolts and it is hoped to increase the reliability of the bolts still further.Expansion-shell, and split and wedge roof bolts five to eight feet long are placed by "Atlas Falcon" and "Fletcher" roof bolters. Both anchorage and tightening have presented some problems.Good panel supervision is required if systematic roof bolting is to be properly co-ordinated with coal production without unnecessary delay to either. Successful roof bolting can only be the product of conscientious men and supervisors who are all convinced of its value. A rigid operational code should be established early and maintained.INTRODUCTIONRoof bolting is a method of support which is permanent and reduces or eliminates the need for other support; The method was pioneered in America and was first experimentally investigated in Australian collieries at Elrington in 1949 (McKensey, 1953). Pneumatic installation methods were employed. Subsequently, a method of using standard hand-held electric coal drills was developed at John Darling Colliery (Horseman, 1954). Pneumatic roof bolting equipment was first operated in the collieries of Australian Ironand Steel Pty. Ltd (A.I. &. S.) in 1951. Since then various hydraulically operated mobile machines have been installed in Australian collieries and these, together with improved pneumatic equipment, form the two present basic methods of placing ,roof bolts. Roof bolt anchorage is achieved by either split and wedge or expansion-shell bolts.The two broad types of roof bolting are 1. consolidation of strata, and 2. suspension support.

Jan 1, 1961

By C A. Fleming

Gold extraction is largely driven by mineralogical factors, which often cause gold losses to various tailings. Mineralogical factors affecting gold recovery include grain size and shape, surface coating or rimming on gold particles, the presence of cyanide or oxygen-consuming minerals or preg-robbers, the presence of slow-dissolving gold minerals and the refractory nature of submicroscopic gold. Among these factors, locking of fine gold particles in sulfide, silicate and other minerals, either as visible, fine-grained gold inclusions and/or as invisible submicroscopic gold, is by far the most common factor leading to poor gold recovery in gold ore processing. This paper discusses the mineralogical characterisation of gold lost in tailings and its metallurgical implications. The techniques used in characterising the un-recovered gold are also briefly introduced.

Jan 1, 2007

By P. Wittke-Gatterman

ABSTRACT: A three dimensional constitutive law for swelling rock is presented. It can be applied to the osmotic swelling of mudstone as well as to the swelling of rocks containing anhydrite. It describes the development of time-dependent strains and stresses due to swelling considering elastic and viskoplastic behaviour. Furthermore an anisotropic swelling behaviour can be considered. This constitutive model was implemented within a numerical computation program according to the finite element method and calibrated on the basis of the results of measurements in the investigation drift of the Freudenstein tunnel which is completely located in the unleached Gypsum Keuper. A parameter combination could be found which results in a good agreement between numerical solutions and results of measurements. Therewith an analysis procedure which enables the design of tunnels in swelling rock is available. ZUSAMMENFASSUNG: Im vorliegenden Beitrag wird ein dreidimensionales Quellgesetz vorgestellt, das nach derzeitigem Kenntnisstand sowohl auf das osmotische Quellen von Tonsteinen als auch auf das Quellen anhydrithaltiger Ton- beziehungsweise Schluffsteine anwendbar ist. Das Stoffgesetz wurde in ein Finite-Elemente-Programm implementiert und anhand von Meßergebnissen des im unausgelaugten Gipskeuper liegenden Untersuchungsstollens des Freudensteintunnels kalibriert. Es ist gelungen, eine Kennwertkombination zu finden, mit der alle Meßergebnisse gut beschrieben werden können. Damit steht ein Bemessungsverfahren für Tunnel in quellfähigem Gebirge zur Verfügung. RÉSUMÉ: Dans l'article présent un loi de gonflement à trois dimensions est présenté, qui peut être appliqué aussi bien au gonflement osmotique de l'argile compactée q'au gonflement de l'argile compactée ou du limon compacté contenant de l'anhydrite. Le loi de comportement était implémenté dans un programme numérique d'éléments finis et calibré avec des résultats de mesures de la galerie de recherche du tunnel de Freudenstein, situé dans le Keuper de gypse non lessivé. On est réussi à trouver une combinaison de paramètres avec laquelle tous les résultats de mesures peuvent être bien décrits. Par ce moyen, une méthode de dimensionnement existe pour des tunnels dans de la roche capable de gonfler.

Jan 1, 2003

By Shirleny Fontes Santos

Muscovite mica crystals lower than 15 mm diameter are discarded as waste in the mining area of Borborema-Seridó (BRAZIL). The objective of this work was the ore dressing and purification of this waste to be used in the preparation of pearlescent pigment. Muscovite was dry ground using knife mills and an ultrasound treatment. It was possible to achieve 67% of mica with particle size lower than 100 µm. This product was used in the preparation of brilliant pigments based on muscovite flakes covered with rare earth oxides (CeO2, PrO2, Ce0,95Pr0,05O2). The pigments were characterized by X-ray diffraction, thermal analysis and scanning electronic microscopy. The color of the resulting pigments was analyzed using the CIELAB method and it showed the following colors: muscovite-CeO2 ? yellow, muscovite-PrO2? black and muscovite-Ce0,95Pr0,05O2 ? orange. Those results have shown that ?trash mica? is suitable for use in pigment preparation.

Jan 1, 2010

By N. T. Lowe

The National Institute for Occupational Safety and Health (NIOSH), Spokane Research Laboratory (SRL), investigated a means to evaluate the potential impact of surface conditions above underground mines on emergency response activities. Recent events have highlighted the need to conduct critical emergency operations on the surface above underground work areas. Accessibility and usability of the surface, such as the ability to drill holes or deploy seismic monitoring or through the earth communications systems, are an important consideration for emergency response planning. This paper identifies critical surface conditions such as: surface waters, valley fill, highways, railroads and significant structures that must be considered in emergency response planning and in the conduct of emergency operations as they relate specifically to the seismic detection of trapped underground miners. Results of case studies indicate a need to consider the impact surface conditions may have on emergency response capabilities.

Jan 1, 2009

By Bryan Ulrich

Rroundtable 2009, a Knight Piésold and Co.-hosted roundtable discussion on mine closure and cover design was held at the Red Lion Inn and Casino in Elko, NV on Feb. 12, 2009. Knight Piésold?s Bryan Ulrich and Steve Boyce, as well as Knight Piésold representatives Cynthia Parnow and Corey Conrad from Denver, CO, and Rick Frechette from the Tucson, AZ office were on hand to help facilitate the discussion. The meeting played host to approximately three-dozen attendees from four states. Attendees included personnel from seven mining properties and attendees from corporate offices. The majority of attendees were people directly involved with environmental work on a day-to-day basis. Other attendees were project managers whose jobs involve some level of environmental focus. The purpose of Roundtable 2009 was to exchange ideas and information pertaining to mine closure and cover design associated with almost any aspect of a mining operation. This type of forum provides a less inhibited format for discussion, when compared with traditional conferences and symposia. In the roundtable format, lively discussions are encouraged. This discussion was the fourth in the series of Elko Roundtable events. Previous roundtables pertained to heap leach pad design, construction and operation; design, construction and operation of tailings storage facilities and site-wide water considerations. The initial subtopics for Roundtable 2009 included:

Jan 1, 2009

By John Gamble

This paper summarizes the weight of epidemiological evidence to evaluate the hypothesis that asbestos exposure is causally associated with increased risk of gastrointestinal (GI) cancers as suggested by Selikoff in an early study of insulation workers. This review looks at populations that develop GI cancers, namely stomach, colorectal, colon and rectal. Guidelines for assessing causality are strength of association, biological gradient and consistency of the associations. Exposure?response (E?R) was evaluated using three methods to estimate exposure. Rate Ratios (RRs) for lung cancer and percent of mesothelioma are used as surrogate measures of asbestos exposure for all the cohorts of exposed workers. Quantitative or semi-quantitative estimates of cumulative exposure to asbestos were also used to assess E?R trends and were compared to E?R trends for lung cancer and mesothelioma in individual studies. Surrogate measures are important since there are few individual studies that have assessed E?R. None of the various methods to estimate asbestos exposure yielded consistent E?R trends and the strength of the associations were consistently weak or non-existent for the four types of GI cancers. The epidemiological evidence detracts from the hypothesis that occupational asbestos exposure increases the risk of stomach, colorectal, colon, and rectal cancer. Findings are briefly summarized below. © 2007 Elsevier Inc. All rights reserved. Keywords: Asbestos; Colon cancer; Colorectal cancer; Gastrointestinal cancers; Ingestion; Lung cancer; Mesothelioma; Rectal cancer; Review; Stomach cancer

Jan 1, 2007

THE art of mine surveying has made very great progress in recent years, and is still advancing, perhaps faster than any other branch of surveying. The scope of the mine surveyor's duties has greatly increased, his instruments and methods have improved, the responsibility of his position is greater, and the end is not yet in sight.It might be supposed that such a steadily growing subject would have an adequate literature, but this is by no means the case and outsiders commonly judge mine surveyors by their text-books. Hardly any condemnation can be too strong for most of these books. The English books truckle to the antiquated and crude methods apparently still in use in England, and thereby largely aid in perpetuating them; they commonly in illustrative examples give the distances in fathoms, feet, and inches; they spend page after page discoursing on instruments that should have been forgotten long ago; they try to antagonize theory and practice by detailing such calculations as that a certain vein will contain 2,003.907 pounds of galena per square fathom, and then reduce this amazing quantity to hundredweights, quarters, and pounds. Nothing can be more unscientific, or, for that matter, less businesslike, than unwarranted assumptions of accuracy; it is, perhaps, the greatest curse of applied science. Here we have a calculation to thethousandth part of a pound, when there is probably an unavoidable error of two hundred pounds. What shall we say of a man who explains how to measure the depths of shafts to the hundredth part of an inch by means of short brass rods screwed together...

Jan 1, 1909

By F. Grajales Muñoz

The Ciénega project, now under construction by Peñoles group, is located in the mountains of northwest Durango, Mexico. The gold and silver deposits are found in a 4-km (2.5mile) long system of veins. An underground operation will be built. The planned 1 kt/ d (1100 stpd) process plant will contain a countercurrent cyanide circuit for oxide ore and a flotation circuit for sulfide ore. Considerable resources have been devoted to the development of infrastructure in the isolated location, as well as for the mitigation of environmental impacts. Startup is scheduled for the third quarter of 1994. Ciénega’s ore bodies consist of quartz veins containing gold, silver, lead and zinc values. The vein thicknesses vary from 2 to 10 m (6.5 to 33 ft) with a northwest trend and nearby vertical dip. Veins are hosted in Tertiary volcanic rocks. The district has intermittently been explored since 1971 by Penoles. After the third series of diamond drilling and direct development work on vein, Peñoles decided to begin project construction.

Jan 1, 1994

This paper describes certain analytical methods used at the Rosepery Mine and Treatment Plant of the Electrolytic Zinc Co. of Australasia Ltd., which are not generally in use and may therefore be of more interest than a description of the normal routine methods which are used in most of the mining assay laboratories of the Commonwealth, and which have been published previously.The ore mined and treated at Rosebery is of a complex nature and demands closer control in the concentrating plant than is necessary on some other similar mining fields.It is necessary for the mill shift supervisors to keep constant control on the grade of lead and zinc concentrates produced on their respective shifts, and further, it is essential to maintain an economic compromise between grade of concentrates and the recovery of the particular concent:t:ate. This necessitates a more frequent check on concentrate grade tp.an is provided by the daily assays carried, out by the assay office. Rather than employ trained ,assayers on shift work, "quick methods" of analysis, which could be carried out by the operators, 'were adopted.'In such methods, it is desirable that the necessary manipulation should be reduced to the following:-a. Taking the sample, drying and mixing.b. Weighing the necessary amount of sample-for assay.c. Adding the reagents for use in the assay without change of beakers.d. Titration and calculation.Such a contraction of, the normal technique would be impracticable for many determinations, but in the case of lead...

Jan 1, 1949

By M. H. Solomon

After the global financial crisis of 2008, African mining is entering anew phase of development. The rapid withdrawal of emerging market funding from the critical exploration and development industries provided a hiatus in funding, a gap which was quickly filled by Chinese and other Asian investors. While the continent is still economically dependent on its extractive industries, the prevalence of Dutch Disease has undermined Africa?s ability to benefit fully from its mining, oil, and gas industries. While the extractive industries are closely related to many of the more fragile and failed states in Africa, it is equally true that the strongest states in Africa have mining-based economies. This paper explores the possible linkages between mining, strong and weak political economies, and poverty in Africa. It draws the conclusion that neither Dutch Disease nor Resource Course is a given in resource-endowed countries, and that it can be avoided if the mining economies in these countries are actively integrated into their respective broader economies and used to foster economic diversification. The author asserts that given the capacity constraints of many African governments, it is contingent on mining companies to become integrally involved in catalysing diversification around their infrastructure and supply chains.

Jan 1, 2011

? CONSTRUCTION AND MINING COSTS ARE HIGH IN THE ARCTIC ? VERTICAL KIMBERLITE PIPES WITH HIGH STRIP RATIOS ? SITE SPECIFIC GEOMETRIC CONSTRAINTS ? OPEN PIT FOLLOWED BY UNDERGROUND MINING ? HIGH KIMBERLITE UNIT COSTS TRACK INSTALLED ON PIT WALL ? INTENDED TO REPLACE MAIN HAUL RAMP ? 5 MIN HOIST CYCLE TIME ? KEY ADVANTAGES - REDUCED CYCLE AND STRIPPING RATIO ? TECHNOLOGY EXISTS IN OTHER APPLICATIONS

May 1, 2003

Small scale' table concentration tests have many critics. Many metallurgists consider that such tests are of problematical value because of the difficulties involved in conducting and interpreting them.Many kinds of small-scale ore dressing tests are difficult to conduct, and there is, perhaps, good reason for thinking that table concentration tests are amongst the most difficuIt.Interpretation of results from small-scale tests is the responsibility of the metallurgists and engineers in charge, and it is often held that small-scale table concentration tests are particularly difficmlt to interpret.TESTING FOR TABLE CONCENTRATIONOn analysis it appears that the difficulties encountered in conducting small-scale table concentration tests are of three fairly distinct kinds. Firstly, there are difficulties due inherently to the smallscale nature of the operations; for example the smaller width of all mineral bands on the table and the less complete separation due to the shorter length of travel between the feed and discharge points.Secondly, there are the effects of batch operation owing to the fact that the mineral particles behave differently during the initial period when the sample is just beginning to spread over the table, the middle period when feed and discharge are even and continuous, and the final stage, when the last of the sample has been added and the table is beginning to empty itself.

Jan 1, 1954

Trends in Test Filtration to Respond to Decreasing Sample Size There has been a steady decline in the quantity of samples available for testwork when developing new mining processes due to the maturing mining technology and the increasing costs of pilot testing. Larox, a supplier of filtration equipment and its co-operation partner Lappeenranta University of Technology (LUT) have been actively developing new equipment, testing methodologies and tools to plan test campaigns with the objective of being able to determine the optimum filtration technology and the parameters for sizing full scale equipment with a minimum sample size. With smaller sample sizes, the test scale diminishes from pilot scale to bench scale, and the small equipment size has implications for scale-up. Redesigning the equipment to simulate full scale equipment rather than to match filtration theory has led to some interesting developments. Comparisons between bench scale equipment and production units help identify the limitations of bench scale testing. The nature of filtration is such that it is unreliable to estimate filterability theoretically, and different testing methodologies have been investigated to be able to test the feasibility of filtration from samples as small as few grams. While not optimising the filtration technology, these methodologies provide an adequate level of accuracy for scoping studies. Together with improvements in equipment, a software tool has been developed to reduce the number of tests necessary to optimise filtration technology and parameters for sizing.

Sep 13, 2010

By Mark McComb, Geoffrey R. Lane

"Over the years many differing approaches have been developed to clearly understand the nature, mode of occurrence, associations and deportment of both free-milling and refractory gold in a wide variety of differing geologic environments and plant products. Many approaches can be taken to characterize the ore which may occur as complex fine grained gold, ultra-fine grained gold, coarse nuggetty gold, complex Asrich refractory gold and double-refractory gold. The approach taken in assessing small drill core composites from Novo Resources Beaton Creek Paleoplacer gold project located in the Pilbara region of Australia was complicated by the nature of the ore, the small amount of sample available from current exploration work, and the gold grade and the grain size distribution. In this case the scope of the study was limited by sample availability although significant amounts of valuable information was also gained. This gold characterization study included the following elements:??Size fraction assays??Ore microscopy??Preparation of heavy mineral concentrates from sized fractions (screening) of crushed or milled head using heavy liquids and Superpan table.??Systematic scans of the heavy mineral concentrate, middling, and tailing fractions using TIMA Automated Scanning Electron Microscopy integrated with an Energy Dispersive Spectrometry to provide semi-quantitative elemental analysis of the individual grains found in the sample.The unique methodology employed to detail the gold deportment was the combination of the Tescan Integrated Mineral Analyser (TIMA) and the Oxford INCA GSR software. This technique not only allowed us to document the deportment of gold but recognize other associated minerals, which included gersdorffite, chalcopyrite, uraninite, coffinite, brannerite and several Rare Earth-bearing minerals.INTRODUCTIONGold deportment studies are commonly carried out on preliminary gold exploration projects in order to determine the various limitations, which may effect processing of the potential ore. This is often because it may be expected that there may be a refractory component to the gold, which may limit physical separation techniques and suggest more costly hydrometallurgical techniques. Often when carrying out gold deportment studies the mineralogical methods may be limited to assuming that the gold will be fine and easily found using standard techniques of optical microscopy or Scanning Electron Microscopy. This may not always be the case as various geological environments may pose their own individual problems to determining the deportment of the gold grains."

Jan 1, 2015

By Hasan Nizamoğlu, Z. Abidin Sarı, Aslıhan Demiraslan, M. Deniz Turan, Tolga Depci

In this study, recovery of copper from solid material (obtained by leaching of chalcopyrite with oxalic acid in the presence of hydrogen peroxide) with a copper oxalate structure was carried out selectively using HCl. The chemical composition of the solid was as 29.3%, 9.7%, and 13.3% for Cu, Fe, and S, respectively. Selective recovery of copper by degrading the copper oxalate structure with a low-solubility product (Ksp = 4.43 × 10−10) was performed by conventional leaching in the presence of HCl. The optimum leaching conditions were determined as 5 M of HCl concentration, 318 K of leaching temperature, 120 min of leaching time, 25 ml/g of liquid–solid ratio and 400 rpm of stirring speed. Under these conditions, approximately 77% of copper and 3% of iron were taken into the solution. According to the characterization of the leach residue that was obtained, the oxalate structure was degraded. Moreover, the results of XRD analysis showed that the sulfur (S) and cubanite (CuFe2S3) phases were mostly observed in leaching residues, and this was supported by the SEM-EDX data. Based on the results, it may be stated that selective copper extraction can be obtained from a chalcopyrite concentrate by a two-step leaching method using a conventional hydrometallurgical technique.

By Steve Chorley

Open-type, or main beam, tunnel boring machines (TBMs) can achieve impressive rates of production. This type of TBM typically outperforms other types of TBMs currently in use around the world. In good ground conditions, main beam machines have achieved production rates of more than 1 km/month (0.6 miles/month). However, installing effective ground support in poorer rock conditions on main beam machines can be a major cause of concern. The design of main beam machines is such that installation of ground support equipment, particularly at the front of the machine in what is commonly known as the L1 support zone, has traditionally been limited to rock drills and basic working platforms. Personnel working in the L1 zone have, until recently, been protected by roof supports and extended fingers, often with restricted access to working areas.

Jan 1, 2011

By D. Scott Scovira, Ruilin Yang

Blast vibration in the highwall from a cast blast in open pit mines or in the hanging walls from a stope blast in underground mines is a common concern. Vibration in such cases is a typical near-field situation where the distance from a blasthole to a point of interest varies significantly compared to the distance between the blast as a whole and the point of interest. Most existing blast vibration models are designed for far-field vibration using a single seed wave to represent all blastholes within a blast and do not simulate wave shape change over the distance.

Jan 1, 2010