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By D. C. Lynch

While a sizable amount of data exist as to the activity and distribution of minor elements between matte and metal, there has been no unifying theory presented delineating the form of dissolution of these elements in molten sulfides. In order to alleviate that deficiency the literature concerning the behavior of As, Sb, Bi and Pb in mattes is reviewed. Models present in the literature, regarding the thermochemical behavior of minor elements, are tested, and new models are presented and evaluated using thermodynamic theory. The results of those analyses are used to predict optimum conditions for the volatilization of minor elements. The dearth of data on the behavior of minor elements in nickel mattes requires that this review focus on copper- iron mattes. An effort is made, however, to utilize basic knowledge regarding nickel sulfides and the interaction of nickel with the minor elements to predict the behavior of those elements in nickel-copper and nickel-iron mattes.

Jan 1, 1993

By D Craw, P Whigham, C Rufaut

Geographic Information Systems (GIS) are computerised management systems for spatial data, offering improved data management, extensive data manipulation techniques and greater understanding of data. At the Wangaloa Coal Mine, South-East Otago, ArcGIS is being used to manage, integrate, analyse and visualise the diverse range of datasets being generated from an interdisciplinary research team. GIS will assist with identifying spatial and temporal patterns associated with the current site rehabilitation strategy. This paper will present an overview of how GIS can be a useful tool for understanding ecological recovery during mine site rehabilitation.   The Wangaloa opencast coal mine, owned by Solid Energy NZ Ltd, was closed in 1989 after more than 40 years of operation. Rehabilitation efforts involving more than 60 000 native plants began in October 2001. At Wangaloa sample points were randomly selected at 100 m intervals and recorded using a differential GPS. Plant, soil and invertebrate data have been collected at each sample point. Plots of 8 - 9 plants have been established within approximately 5 m of each sample point. Since September 2003 seasonal monitoring of plant growth and survival has been carried out. Chemical and physical datasets have been generated from soil collected in June and December 2003 for each sample point. A more restricted dataset is being generated for soil collected on a seasonal basis from March 2004. Plant and soil characteristics from these datasets have been attached to each sample point and GIS layers have been created. Relationships between data layers can be explored based on their spatial patterns. Examples presented from Wangaloa include distribution of planting success and temporal variation; temporal change in pH; interpolated pH map; digital elevation model; relationships between planting success and growth with pH and organic matter. GIS is proving to be a valuable tool on the integrated project at Wangaloa.

Jan 1, 2004

By W. F. Watts

This report describes a statistical analysis of 41,502 respirable quartz dust samples collected from 1974 through 1981 in metal and nonmetal mines and mills. The goal of this Bureau of Mines study was to identify commodities and occupations associated with high quartz dust exposure so that future enforcement and research activity can be focused on the high-exposure areas. For this analysis, the Bureau used its computerized Mine Inspection Data Analysis System (MIDAS), which contains data on nearly 350,000 air samples, including data for 61 contaminants in 45 commodities. The samples analyzed were collected by inspectors of the Mine Safety and Health Administration (MS HA). The data were entered into the MIDAS computer and coded according to commodity, occupation, location, and other categorical information. Occupations an. commodities with high quartz dust exposure were identified by grouping the data by code categories. Workers at sandstone, clay and shale, and miscellaneous nonmetallic mineral mills had the highest quartz dust exposures. Within these mills, occupations with high exposures were baggers, general laborers, and persons involved in crushing, grinding, and sizing operations. Dust concentrations in these mills were not necessarily the highest, but because the dust contained a high percentage of quartz, the health risk from dust exposure was the greatest.

Jan 1, 1984

By C. F. Cornell, R. C. Emmett, D. A. Dahlstrom

FOR many years the disk-type and cloth-covered drum filters have found widest application in liquid-solids separation, which uses continuous filters. The disk type is less expensive, occupies less floor space per square foot of filtration area, and requires negligible down time for filter media changing. However, because filter cloth is billowed out by the blowback in the cake discharge, it is very short-lived if the scraper blades are set too close. Consequently cake weight is very important in assisting cake discharge, which normally necessitates a minimum cake thickness of 3/8 to ½ in. Also, the vertical position of the disks eliminates the possibility of efficient cake washing for removal of soluble values. The disk-type filter is generally limited, therefore, to applications that require no cake washing and form relatively thick cakes within the normal range of filter cycle times. The conventional cloth-covered drum filter is a more flexible unit, permitting wider variation in the percentage of cycle time devoted to cake formation, dewatering, or washing, as required by the application. Thinner filter cakes can be discharged because a horizontal line across the filter medium at the location of the scraper blade is equidistant from the edge of the blade at all points. The scraper blade therefore may be set a short distance from the filter medium or, where wire winding is not used, a floating scraper can be utilized so that the contour of the cloth can be followed. The drum filter is generally employed when there are difficult filtering slurries with resultant thin cakes or when cake washing to recover soluble values must be practiced. Difficulties sometimes encountered in continuous filter operation can be summarized in the following four categories: 1) Low filtration and/or washing rates due to blinding of the filter medium. 2) Poor cake discharge resulting from sticky cakes, filter medium blinding, or too thin a cake for the particular type of filter. 3) High filter media costs caused by short life and frequent down times for cloth changing. This results from blinding or from abrasion by the scraper blade when cakes are thin. 4) Blowback of filtrate at cake discharge because not enough air passes through the cake to purge the drainage area and filtrate lines during dewatering. To reduce or eliminate blinding tendencies several modifications have been tried, for example, cover-cleaning showers, blowback under the feed slurry, and snap-blow cake discharge. In many cases, however, this simply retards the rate of blinding, since the filter medium is kept clean at its outer surface only by these methods. As blinding usually occurs within or on the back of the medium, the operator is finally forced either to remove the cloth and scrub the medium intensively with a cleaning solution or acid-rinse it on the filter—all resulting in down time, short cloth life, and additional costs.

Jan 1, 1959

By R. A. D. Pattrick, R. A. F. Ixer

Paper presented at Mineralisation in the Caledonides, the Mike Gallagher memorial meeting held in Edinburgh, 27-28 June 1996. At Calliachar Burn, 14 steeply dipping quartz-sulphide veins, with and without gold, infill master joints that crosscut gently dipping metasediments and metabasics of the Pitlochry Schist Formation. The wallrock is extremely bleached and enriched in sericite, chlorite and carbonate. Gold grades vary from high with quartz-galena-pyrite to low with galena-chalcopyrite; the gold forms electrum inclusions smaller than 20 micrometres in pyrite or, rarely, arsenopyrite. At Urlar Burn, gold is present in small amounts in 4 quartz-galena-chalcopyrite veins. Although much of the mineralogy is similar to that at Calliachar, there are significant differences in Sb-, Te-, Bi- and Hg-bearing phases. Fluid inclusion data suggest mineralisation occurred over the range 320-140 degrees C, from fluids with significant CO2 and 2-13 wt% equiv. NaCl. Mantle-derived fluids appear to have been generated during the late Caledonian and focused by the Urlar Burn fault

Jun 19, 1905

By Charles Stone, Madan Naik, Drupad Desai, Karel Rossler

Planning of New York’s new subway line dictated the location of shallow underground station caverns and track crossovers. Clear span openings ranging from70 feet to 100 feet and lengths in excess of 1000 feet, coupled with low rock cover ranging from 25 feet to 40 feet required judicious selection of construction methods, equipment, and proper sequencing of the excavation stages. Rock classifications alone could not predict the behavior of the rock mass during construction. A robust design procedure that considered most of the important aspects of rock behavior and elements of shallow tunnel design, minimized the negative impacts of variable geotechnical data. This paper describes the intricacies of the planning and design of the $16 billion Second Avenue Subway with insight into how to overcome the design complexities and construction challenges of the urban underground.

Jan 1, 2005

Project developent proceeds by increasingly detailed studies addressing overall project returns through an analysis of the substance, risks and costs associated with the following elements: ò Reserves ò Mining ò Processing ò Infrastructure ò Environmental Impact ò Product Market Computer-based expertise has a potential to ò Capture perishable expertise, making this available for shared access and so reducing the cost of human experience ò Consolidate know-how for optimising process operations, bringing consistency of judgement and advice to decision- making by making the rules, facts and preferences explicit ò Allow assignment of the basis and authority of decisions, so experts can pass routine expertise down the line, freeing their time to generate more. ò Force a review of expertise when creating the knowledge base.

Jan 1, 1989

By Sam Spearing

Free-standing supports are commonly used in coal mines in the USA, particularly when longwalling. A recent trend has been the development of prop supports. Prop supports have many advantages over bulky, crib-type secondary standing supports, particularly in regard to material handling and installation. The challenge in prop design has been to develop load capacities that can compete with crib type systems and to develop reliable (stable) yielding capability. This paper will focus on the design aspects of steel prop supports, specifically, and evaluate the various concepts that have been developed to provide easy height adjustment and sustainable stable yielding under load. The design and resulting improvement provided by recent support developments called the Quik Stik and Ball Buster are discussed in detail. Performance areas that still need improvement in the design and usage of free standing supports in general are identified and possible solutions outlined.

Jan 1, 2008

By George K. Clement

Manual estimating method through use of equations, factors and curves for preparation of feasibility type estimates for capital and operating cost of mining and primary beneficiation in the United States and Canada of various types of minerals occurrences, except fossil fuels, using state-of-the-art technology. User should have basic estimating experience in the mining industry and/or related fields. Primary usage of this handbook will be for the preparation of preliminary estimate within a reasonable degree of accuracy with relative small amounts of hard input data. Output may be used to determine if a more finite type of estimate should be produced.

Jan 1, 1978

By J. Jerome MacDonald, Stephen B. Flewelling

"In the base metals industry of today, operations required to continuously improve productivity and reduce unit production costs. Consistent with these goals is the improvement of the muck haulage cycle from open stopes with the No. 12 Mine.Existing haulage from open stopes occurs with LHD units experience at Brunswick indicates that LHD units have a higher unit cost per tonne mucked than loader-truck combinations when the haulage exceeds approximately 150 m.The reintroduction of open stoping at Brunswick made existing loader-truck combinations unsuitable. It was recognized that application of recent continuous loading technology could potentially result in significant unit cost savings and productivity increases.A review of the technology resulted in the testing of the Voest Alpine AL60 loader in the open stopes located on the 1000m Le vel. Testing began in January 1988 and finished in late November 1988. The test will provide experience as well as quantified production and maintenenace parameters f or the purpose of quantifying production unit costs and system productivity, ultimately resulting in a decision to further utilize or not utilize the loader as a primarymucking unit at Brunswick .INTRODUCTIONBrunswick Mining and Smelting Corporation Ltd. produces approximately 10500 tonnes per day from the No. 12Mine located 35 km southwest of Bathurst, New Brunswick Mining is the largest (single mine) producer of zinc in the world having mined over 52 million tonnes since 1964. Many years of production still remain with proven and probable reserves in excess of 90 million tonnes. Reserves grade at an average of 3.65% Pb. 8.99070 Zn, 99g/mt Ag and 0.32% Cu . The operation employs 1446 people with approximately 800underground including operations and maintenance staff.In the No. 12 Mine two major mining methods are presently utilized . The primary method is Mechanized Cut and Fill (MCF) accounting for approximately 6500 tonnes per day from four major areas. The remaining 4000 tonnes per day is produced from open stopes with the majority of 2800 tonnes per day being produced by the 1000 level.The 1000Level contains 30 million tonnes segmented into open stope blocks 30 m high, 15m and 30 m on strike , with a transverse width of 10m to 50 m (Fig. I). Stopes are organized on a primary secondary stope arrangement along strike. Primary stopes are undercut and overcut full size with the back fully cablebolted. All stope and lateral development is driven 4.0 m high. All stopes to date are flat bottom (Fig. 2). Primary stopes are filled with cemented rock- fill , secondaries with conventional rockfill, Haulage from the stopes is primarily with 8-yard LHD units ; mucking is approximately 50% conventional and 50% remote. Haul distance to date has averaged approximately 150m with current stope haul distances of approximately 300m. Haulage is presently to a small jaw crusher situated on the 1000 Level. From August 1989on, haulage will be to a set of ore passes feeding to a large gyratory crusher situated on the 1200 Level. Start up of the gyratory crusher corresponds to an increase in tonnage from 1000 Level to 4100 tonnes per day."

Jan 1, 1989

By C. Dirscherl

"Declining ore grade, leading to increased material transport and plant throughput requirements, is one of the major challenges in the current mining environment. This is accompanied by rising energy and labor costs, decreasing plant productivity and the requirement for highest plant availability. Siemens’ answer is the latest gearless drive technology for grinding and conveying. Gearless drive solutions are surpassing the mechanical limits of conventional drive systems serving to utilize the principle of economies of scale. By elimination of various components of the drive train the maintenance activities and spare parts inventories are reduced. The advantages are culminating in the incomparable availability of the Siemens’ gearless drive technology of 99.46 to 99.71% - as confirmed by real operational data from the Antapaccay mine in Peru. It was the first plant worldwide to use gearless drives for both applications. KEYWORDS: Gearless Mill Drives, Gearless Conveyor Drives, Availability, SAG Mill, Ball Mill, Overland Conveyor, Antapaccay INTRODUCTION – THE GEARLESS PRINCIPLE The principle idea behind a gearless drive system is to reduce the number of components and diversity of parts. Especially those components that are at the edge of current manufacturing or power limits are eliminated. The used equipment provides the possibility to scale up and increase the power transmitted to the driven machine. This finally results in a possible increase of throughput respectively transported or processed material. In order to apply this principle of simplification we will take a look at the components of a conventional drive system consisting of: - Driven equipment (mill, conveyor, slurry pump…) - Components altering the rated speed (gearboxes, girth gear / pinion) - The electric motor - Starting devices for the motor (VSD, CCV, LRS, clutch…), which are necessary because a direct across-the-line start of high power motors with load would result in a significant drop in the line supply voltage - Alternatively a variable speed drive (VSD) or cycloconverter (CCV) to utilize the possibility of speed variation during operation - The electrical supply system (cables, switchgear, transformers, protection equipment) Intermediate gearboxes are not required when a motor is used with a rated speed that directly matches the speed requirement of the driven equipment. Furthermore the VSD can be used to smoothly start the motor and to vary speed during operation, which means that it satisfies both requirements."

Jan 1, 2015

By Roberto Busato Belger

- Fertilizer Business Overview - Supply -Demand Balance in the World - Supply -Demand Balance in Brazil - Brazilian Market Growth Opportunities - Fosfertil Operations - Fosfertil Expansion Plan - Salitre Project - Project Characteristics - Technical Challenges and Solutions - Technical Support Studies Conclusions

May 1, 2010

By Tom Dettweiler, Robina Sharpe, Wright. Michael

The International Seabed Authority and a number of countries have or are in the process of developing environmental impact assessment guidelines and legislation for seafloor mineral development. The formal decision to grant a project an environmental permit is based on an environmental and social impact assessment (ESIA), culminating in an environmental impact statement (EIS). The EIS needs to be supported by sufficient data upon which an assessment of impacts can be made and mitigation measures developed. Given the remote locations of many seafloor prospects, collection of sufficient environmental data to inform an EIS is often a difficult, expensive and lengthy process.

Sep 1, 2014

The Purification of Low-Grade Quartz Ore by Flotation and its Mechanism

Sep 13, 2010

By H. Soto, J. Jara, F. Nava

"A combination of oxidation and precipitation was used to eliminate cyanide from gold milling effluents. Preliminary laboratory work developed with both synthetic cyanide solutions and with industrial effluents indicated that ozone can easily destroy free cyanide and weakly complexed cyanide (i.e. copper and zinc cyanide). In this case the reaction is quite fast and seems to be controlled by the mass transfer of ozone to the solution. Experimental results indicate that free cyanide and weak-acid dissociable cyanide in mill effluents can be reduced to less than 1 ppm. However, the iron-cyanide complexes proved to be quite resilient to destruction with ozone and they remained in the solution even after most of the free and weakly complexed cyanide was destroyed with ozone. These results were confirmed in a pilot trial developed at the Sphinx plant in northern Quebec.To deal with the problem presented by the presence of the iron complexes two different approaches were studied: use of a combination ozone-ultraviolet light oxidation, and the precipitation of iron-ferrocyanide complexes in the residual solution after ozonation. This last method proved quite promising since reduced the total cyanide levels of industrial solutions assaying as much as 250 ppm to less than 1 ppm of total cyanide. Control of the · pH of the solution was the key to obtain the precipitation of the iron complexes. The use of iron to precipitate cyanide complexes has the advantage of being less expensive and less toxic than copper (used by the Inco process)."

Jan 1, 1992

In dealing with the pulverization and treatment of auriferous ores, it may be stated that there is not one system of treatment applicable to all classes. In the southern portion of New Zealand the ores generally contain free gold, with scarcely any impurity that is, it is found in an almost pure state, without any alloy, and its dissemination amongst the matrix is generally in tolerably coarse particles. The only difficulties the mill man has to contend with, are the economical concentration of pyrites, which in some of the lodes are rich in gold, and the extraction of the gold the pyrites contain. In some of the lodes there is what may be termed float gold, that is, the particles of the precious metal are so finely divided that it passes over the quicksilver tables, and, unless there are other appliances for saving it, this class of gold is entirely lost.Indeed it is only within the last five years that any attention has been given, in the southern portion of the colony, to saving the fine gold that has passed the amalgamating tables. In the North Island the ores are very complex there are scarcely two mines, although they may be adjoining each other, where the bullion is of the same character. On every field the gold is alloyed with silver', and in combination with other metals and mineral substances, such as copper, zinc, antimony, galenfl, iron, sulphur, arsenic, etc., and, in some instaaces, cinnabar, as in the case of the Champion lode at Tui Creek, Te Aroha. Ores of this class are extremly difficult to treat satisfactorily.

Jan 1, 1903

Keywords: Pyrometallurgy, furnace, Lonmin, platinum, PGM, UG2 Lonmin, earlier than any other primary platinum producer, had to deal with the concentrating and smelting of UG2-rich ores and concentrates respectively. Smelting was performed at a fairly modest scale compared to its industry peers in the Platinum Group Metals (PGMs) industry, and was focused on smelting concentrates obtained through low mass pulls while still maintaining high recoveries at its concentrators. Lonmin gradually smelted larger quantities of UG2 concentrates. Initially two 2.3 MW Infurnco furnaces were commissioned in 1982, followed by three 5 MW circular 3-electrode Pyromet furnaces in 1991. Deep electrode immersions and moderately high hearth power densities were used in all the designs. Lonmin decided to continue with circular furnace technology when it planned its new high-intensity No. 1 Furnace. Neither Lonmin nor the technology supplier and EPCM company foresaw the challenges that scale-up would bring when applied to the smelting of UG2-rich concentrate blends. Superimposed on the high chromite content, was the low base-metal loading, mineralogical difficulties, and fine particle size that came with milling of all concentrates (especially UG2 and recycle materials within the smelter). Through a process of fundamental diagnoses of furnace run-outs and wear patterns observed during repairs, the main challenges operating this high-intensity furnace were identified as sulphur vapour corrosion of the copper coolers, uneven and unpredicted movements of refractory bricks with associated copper cooler lift and matte tap-block movement, the formation of three-phase ?mushy? zones, high refractory and tap-hole wear rates, uncertainty in matte level and associated insufficient matte buffer height, and high furnace operating temperatures. These factors seldom worked in isolation and will be explored in more detail in the paper. The variability in furnace feed characteristics led Lonmin to re-design Furnace No. 1, to invest in back-up furnace capacity, and to invest in improved monitoring and control. These improvements consisted of online and high-frequency off-line feed chemistry and mineralogy monitoring, online pressure monitoring of water-cooled circuits, an alternative matte liquid level measurement in the furnace, and electrode immersion estimation. Improvements were also made at the converters by installing and utilising optical spectral analysis of the converter flame to characterise converter behaviour and achieve the desired iron end-point for white matte. This paper also briefly discusses the current and future expansion plans, as well as ancillary operations at the smelter such as flue-gas handling and materials handling.

Jan 1, 2011

IN a mine with any considerable output the economical handling and transport of ore underground is a matter of prime importance, and in the design or lay-out of a trucking system the question of what form the points and crossings are to take should be one of the first considered. Trucks may be moved from one line of rails to another by the following means: by flat sheets, with which may be coupled turn-tables, or by points and crossings. The latter class may be further divided into fixed and movable points.Flat sheets and turn-tables, owing to the time and skill needed by the trucker in using them, are seldom of great value with large tonnages, unless for purely temporary work, and the choice narrows down to one between fixed and movable points andcrossings. Both systems have their disadvantages - movable points being liable to jamb with dirt and get out of order, whilst with fixed points trucks may sometimes run over the points and capsize, or go on to the wrong line, though this is not of frequent occurrence. On the other hand. the fixed points are simple, easily laid, and strong, and there is no necessity for the trucker to work any levers, the truck being guided on to its new direction by screwing.Cast-iron points and crossings were first introduced into the North mine during the opening-up of the 950-ft. level, and the first arrangement was designed for a double turn-out in the main crosscut. Since then both the points and crossings have beenmodified several times, and it may be interesting to briefly outline the various forms through which they have passed, showing the reasons for the retention of some features and the rejection of others.

Jan 1, 1915

By John C. Nigro

Bench scale and pilot plant research was conducted using dolomites (CaO,MgO) lime as the basic additive in the preparation of self-fluxed pellets from a typical magnetic taconite concentrate (5.57 S_2). The specific objective of this investigation was to ascertain the viability of the magnesia lime pellets in high temperature oxidizing and reducing atmospheres. Pellet basicity and induration temperature were major parameters affecting fired pellet quality; temperatures ranging from 1,200° to 1,250" C appeared to be the most favorable for production of self-fluxed pellets with basesities (B) above 1.0. Comparison of the mechani¬cal and metallurgical properties of regular (acid) and self-fluxed pellets (B 1.55) produced under similar conditions in a modified grate pelletizing machine showed that the self-fluxed pellets were more resistant to abrasion and to high and low temperature reduction disintegration, an important consideration in commercial application. The Plus 3 mesh Linder index increased from 68 percent (regular pellets) to over 90 percent (self-fluxed pellets). The reducibility and swelling indices of the self-fluxed pellets were found to be comparable to the regular pellets.

Jan 1, 1972

By H. C. Counsell, R. Webber

"The mill at Denison Mines' Elliot Lake Operations started up in 1957, with a capacity of 6,000 tons per day. Over the years various plant modifications expanded th.is to 7 500 tons per day. In 1976, management decided to carry out a major expansion of the milling capacity, and during 1980 the grinding capacity was increased to 15,000 tons per day.The original comminution system consisted of a conventional crushing plant feeding minus S/s-inch material to rod and pebble mills, in closed circuit with mechanical classifiers. The key decision that had to be made was whether the expansion should include conventional or autogenous grinding flow sheets.During 1977, extensive pilot plant studies at Lakefield Research showed that two-stage semi-autogenous grinding, with some steel media in the primary mill and with pebble media in the second stage, produced stable grinding conditions. This type of circuit was selected by Denison for the expansion, and went into production in 1980. Primary millThe flow sheet of the semi-autogenous grinding circuit is shown in Figure 1. The primary grinding mill is a Koppers 28 foot by 10 foot mill, driven by a 4,000 h.p. synchronous motor. It is fed with a minus 8-inch run-of-mine ore, and 4-inch grinding balls are added as supplementary grinding media. There are two Koppers 15.5 foot by 22 foot secondary pebble mills, driven with 1500 h.p. synchronous motors. Each grinding stage operates in closed circuit with cyclones, and the primary cyclone overflow is the feed to the secondary mills. The circulating load in the primary stage can be controlled by adjusting the cyclone apexes."

Jan 1, 1984