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By Patrick E. Cavanagh

"A pilot shaft furnace was operated for one year at Steep Rock to produce special high-grade products from coarse ore, using lignite as fuel. The furnace is 10 ft in diameter and 60 ft high. When operated to heat coarse Steep Rock ore to drive off combined water and give a 64-per-cent-Fe product, the fuel consomption was 900,000 Btu's per long ton of product. The furnace was run in this way from September 1966 to January 1967 to establish the technique of feeding and discharging the furnace and controlling the gas composition and temperature. The furnace is similar in operation to a lignite water gas producer containing a large proportion of catalytic iron oxide. Steam injection is used to control the temperature. The product was tumbled in a rotary trommel to stabilize it. The resulting fines could be fed to the conventional pellet plant at Steep Rock. The furnace was next operated to make 77-per-cent-Fe metallized coarse ore. Several major modifications in de-sign were made and the furnace was successfully operated for short periods to maintain the required conditions to remove 75 per cent of the oxygen from the ore to give a 75-per-cent-reduced product at a grade of 77 per cent iron. The furnace cooling zone was operated under positive pressure, with internai alkaline water sprays to cool the charge. The product was discharged from the open bottom of the furnace without serions reoxidation. The metallized ore was magnetically separated from the discharge. Most of the charred lignite discharged along with the ore is re-cycled. Fuel requirement was 11,000,000 Btu's per long ton of product. This metallized coarse ore is intended for blast furnace feed. A short test run was carried out to establish the conditions for making a highly reduced melting stock for steel furnaces. To achieve 90 per cent reduction and over 90 per cent Fe, the furnace must be slowed down so that the production rate is about one-half the rate when making a 75-per-cent-reduced metallized product. Fuel requirement is 15,000,000 Btu's per long ton of product. The simple shaft furnace developed is similar to the top half of a blast furnace, with some major modifications to allow discharging into the open air. This Low Temperature Blast Furnace program has been technically successful and has resulted in making data available for the design of a commercial plant. Study of the commercial feasibility of large-scale production of metallized coarse ore at Steep Rock is still continuing."

Jan 1, 1968

By Alton B. Cook

In the Scurry Reef field, Scurry County, Tex., a study was made to determine the physical properties of the oil in all parts of the reservoir by a new method developed for this study. The method involved correlation of data from a survey 1 of the gravity of the produced oil, from measurements of gas-oil ratios on key wells selected to give representative data for the entire reservoir, and from laboratory analyses of reservoir oil samples. A field survey was made of the API gravities of the produced oil by testing oil samples from 107 key wells. Precise gas-oil-ratio tests were made on 45 key wells that were producing under comparable separator-operating conditions. Subsurface-oil samples were obtained from seven wells, selected to provide reservoir oils ranging approximately from a minimum to a maximum in saturation pressure. The physical properties of the subsurface-oil samples were determined, and correlations were made of these laboratory data with the field gas-oil-ratio test data. These correlations were then used to estimate physical properties of the oil throughout the reservoir. A logical procedure of determining the variations in physical properties of reservoir oils in most fields is to obtain and analyze subsurface-oil samples from enough key wells to provide an ample coverage of the field. Under this procedure, data from a large number of samples would be needed to provide the desired information on the Scurry Reef field, as it is one of the largest known in the United States.

Jan 1, 1955

By K. Turgeon, J. -F. Boulanger, L. Whitty-Léveille, C. Bazin

"Several companies targeting Rare Earth Elements (REE) around the world have completed a Preliminary Economic Assessment showing positive project financial results. Although REE ores may contain high REE value, financing these projects remains difficult in part due to the number of processes required to valorize the elements and the relatively low yield of these processes. Direct ore leaching without the production of a concentrate may reduce the capital and some operating expenditures through process simplification, and increase revenues because of REE recovery improvement.A silicate REE ore is used to test various hypotheses regarding whole ore processing and to develop a simplified flowsheet. An atmospheric leach (200 kg/t H2SO4) of crushed whole-ore containing 0,6% REE, followed by impurity removal and REE precipitation recovers 80% of the REEs in a solution containing REE and Th. The high value contained in most REE deposits makes whole-ore approaches worth considering for most projects, given the losses of valuable species typically associated with the production of a REE mineral concentrate from the ore. INTRODUCTIONRare Earth Elements (REE) find applications in modern and clean technologies, whether civil, industrial or military. With China producing more than 90% of the world’s REE, the embargo imposed by this country in early 2010 increased REE prices for a three year period. With prices having shrunk back many-fold from their peak value, projects put forward during the hike are struggling to secure financing. Owing in part to unconventional processes such as acid-baking and solvent extraction, REE plants are high capital cost and high operating-cost units, and present technological risks (Verbaan et al., 2014)."

Jan 1, 2016

By M. Savella

The Runruno Gold Project is located on the island of Luzon, approximately 200 km north of Manilla in the Philippines. The mine is a surface mine operation and use the proven BIOX® and carbon in leach processes to recover gold, and the ASTER™ process for detoxification of the CIL residue prior to discharge to the Residue Storage Impoundment (RSI). Work to date has defined a mineral resource of 1.39 million ounces of gold, and the operation will produce 96,700 ounces of gold per annum over a mine life of 10.4 years. The BIOX® circuit is designed to treat 140,000 tpa of concentrate with a design capacity of 404 tpd of concentrate at a design sulphide sulphur grade of 17% S2-. The Runruno project is the first BIOX® plant to implement the Generation III BIOX® design principles. As part of the Generation III BIOX® program Outotec supplied a turnkey, containerised metallurgical laboratory to facilitate the first four stages of the BIOX® and ASTER™ inoculum build up requirements. BIOX® inoculum build-up was started during early January 2015 with 5 litres of stock cultures shipped from South Africa. The BIOX® culture was successfully adapted to concentrate produced from the mini plant during March 2015. The ASTER™ inoculum build-up commenced during early August 2015 utilising 27 litres of ASTER™ bacterial inoculum already adapted to similar process conditions expected during commercial operation. This paper will detail the various stages of inoculum build-up through to commissioning and ramp-up of the BIOX® and ASTER™ Processes at the Runruno Gold Project. The paper will highlight some of the factors affecting the commissioning process as well as the improvements seen through the introduction of the Generation III BIOX® design principles.

Jan 1, 2017

By Norman A. Jull

"IntroductionThe scope of this paper is intended to deal mainly with cyclones in grinding circuits. However, the section on Cyclone Equipment, contains more general descriptions, to cover most of the cyclones used in mineral separation plants.Cyclones as heavy media separation vessels are discussed by Mark Freberg (this volume). Their use in tailings deslirning is discussed by P.C. Lighthall, eta/. (this volume).Cyclone EquipmentCyclone TerminologyApexObviously, the apex of a cone is the smallest end. However, with cyclones the term is usually used for the fitting which is attached there to control discharge of the underflow stream.Note that the cyclone need not be so mounted that the apex is the lowest point, although that is the most common method. Keeping the apex below the rest of the cyclone helps avoid plugging when the underflow contains very large particles and the tonnage of underflow solids can fluctuate.Various devices for adjusting apex diameter or otherwise controlling the underflow are discussed later under ""Cyclone Construction"".BypassingThe transport of a portion of feed slurry directly to underflow so that classification is bypassed by that portion of feed.This action is fundamental in any hydraulic classification, whether gravity or centrifugal, because the large particles going to underflow have some void volume between them, which remains filled with feed slurry.D50By definition, D50 is that particle size which has an equal probability of going to overflow or to underflow.It is calculated by drawing a curve of recovery vs particle size and noting the size at which 500Jo recovery occurs.This may be done equally with corrected or with gross recovery (see below) and the resulting value should therefore be identified as d50c (corrected d50) or as d500 (gross d50).Note also that it is common in industry practice to plot size analysis data on the retained size rather than on the average of passing and retained (the middle of the size band). To portray sizing alone it makes no difference, but to read a D50 value off a curve of corrected or gross recoveries, it is essential to plot those values on the average size of each band."

Jan 1, 1989

By Rudolf Fahn

Bentonites are best suited for the preparation of acid activated clays with efficient adsorption properties. They are weathering products of acid volcanic ashes and their natural deposits are world-wide spread. The main constituent of bentonite is the aluminium hydrosilicate nontmorillonite with a high ability to swell. Süd-Chemie owns bentonite deposits in Germany and subsidiaries in Italy, Mexico and Arizona.

Jan 1, 1979

By T. Emery, D. Sweet, J. Bourgeois, B. Seymour, D. Porter

Cemented rockfill (CRF) is being used to backfill primary and secondary stopes at the Eagle Mine, an underground nickel and copper mine operated by Lundin Mining. National Institute for Occupational Safety and Health (NIOSH) researchers from the Spokane Mining Research Division (SMRD) are conducting cooperative research with the mine staff to determine if the size of a CRF sample affects its measured strength properties. Based on previous research by NIOSH, cylindrical samples of CRF ranging in size from six to eighteen inches in diameter were cast at the mine and cured underground. The samples were later transported to the SMRD laboratory and the Michigan Technological University where tests were conducted to determine the strength and elastic properties of the CRF. To further analyze the relationship between backfill density and compressive strength, different ASTM International compaction techniques were used to cast the samples. For comparison, tests were also conducted on in-situ core samples that were drilled from a stope which had been backfilled with the same CRF mix. The data collected from this study not only improves our understanding of CRF in-situ properties but also helps optimize Quality Assurance/Quality Control (QA/QC) methods for backfill preparation and testing.

Feb 1, 2023

By L. A. Morley

Electricity is a major cause of lost-time accidents and fatalities in the mining industry. Major hazards and unsafe practices that contribute to electrical hazards are identified in this paper. Recommendations for reducing electrical accidents in surface mining are given and are directed toward the following three areas: preventing equipment contact with overhead lines, preventing maintenance related accidents, and defining system protection techniques.

Jan 1, 1986

By J. H. E. Jeffes, C. Diaz

The heat balance and chemical equilibria involved in the production of blister copper from a chalcopyrite concentrate in a single operation are examined. It appears that two stages—one oxidising and one reducing—will be required. The analysis indicates that on thermal grounds the process is possible with a dry, high-grade chalcopyrite concentrate, if oxygen enrichment to about 30 per cent is used, but that copper losses in the slag will be serious and will require a secondary recovery operation. More extensive data on the activities of copper oxide in slags are required to elucidate this point more effectively

Dec 1, 1971

By Messias dos Santos Machado, Renato B. Godoy, Roberta Lima, Andressa Silva, Francisco Valenzuela-Díaz, Rene R. Oliveira, Esperidiana Moura

This work aims to incorporate the Bof White Clay, from Boa Vista, Paraiba State, Brazil, as natural nanofiller in Ehylene vinyl alcohol copolymer (EVOH) and obtain flexible films. Nanocomposite was obtained using a twin-screw extruder, and film formed using a blow extruder machine. The flexible film nanocomposite was characterized, by tensile tests, XRD, DSC and their properties were evaluated. The results showed a good interaction between the clay and the EVOH resulting in an increase of properties of films nanocomposites as compared to films neat polymer.

Jan 1, 2015

By L. E. Murr

Solution flow in leach dumps and heaps or in columns of representative rock has been the subject of only limited studies. This is a regime involving unsaturated flow in semiconsolidated rock with a wide size distribution. Even the concepts of continuous flow systems are fairly recent, and have evolved from the search for better methods of operating industrial chemical reactors. (1-3) Waste rock consolidation and permeability play a key role in solution flow characteristics. Harris (4) suggested that bulk density variations in a leach dump could alter the particle-to-particle contact, and that large particle aggregates could act like single, large particles . In the limiting case where the bulk density approaches that of the undisturbed, consolidated rock, the entire waste unit would behave as a single particle. Roman (5) treated the phenomenon of bulk density and its effect on consolidation in terms of lixiviant flow paths or solution channeling in leach dumps. Like Harris, he assumed that no solution moved through particles or particle aggregates associated with zones of high bulk density. Solution flow paths are thus effectively separated by particle regimes, creating solution channels in the waste body. While some attempts have been made to describe solution flow in leach dumps and related systems by utilizing computer model approaches and laboratory- scale simulations (5,6), there have been no direct, large-scale observations of solution movement in channels or of the actual channel sizes and distributions within a waste body. This paper describes a series of experiments involving large-scale, controlled waste leaching tests, conducted over a period of several years, and aimed at providing some direct observation of the changes in waste consolidation and permeability, the size and distribution of solution channels, the movement of such channels with continued solution application, and other features relating to solution flow during the leaching of low-grade waste. These results are then combined with mineralogical information to explain observed leach behavior.

Jan 1, 1981

By Lazar Kricak, Vladislav Kecojevic, Dragan Bogunovic

In spite of many advantages explosives have, their usage may cause environmental problem such as seismic vibration. One of the solutions to this particular problem may be application of an artificial screen as a barrier to the seismic wave path. This paper presents the results of experimental research on the artificial screen concept, its characteristics and role in attenuation of seismic effects generated by blasting. More than 1,500 laboratory measurements were conducted with different combinations of screen sizes, positions of the screen to blasting source, and intensities of blasting impulses. The results of the study show a significant reduction of generated vibrations by employment of artificial screens.

Jan 1, 2007

By S Adamson

Morphological analysis of alluvial gold recovered from the same segment of a placer by four common commercial methods indicates that gold shape and the presence of quartz intergrowths or sulphide overgrowths substantially influence the recovery efficiency of each method. The amount and types of gold saved by each method varies according to the different hydrodynamic conditions under which each of the methods operates. Reverse circulation drilling has the lowest efficiency and preferentially loses moderate-high flatness gold and intergrown or overgrown gold particles with relatively low density. Gravity riffle, hydraulic riffle, and jigcentrifugal concentrator systems respectively save progressively more of these problematic gold morphotypes, but still lose significant and sometimes substantial amounts (of profit) to the tailings. Because of the differences in recovery efficiency, reverse circulation drilling probably underestimates the grade of most placers and may have resulted in bypassing several economic deposits. Losses to tailings by commercial recovery plants arise from inadequacies in fundamental plant design features. These inadequacies compromise plant efficiency by limiting the ability of plants to simulate the wide range of hydrodynamic conditions necessary to operate effectively throughout placer systems. Incorporation of sand pumps and multiple recovery methods into the more sophisticated plants only partly overcomes these inadequacies. At best, efficiency will be maximised in a few segments of the placer determined by individual plant design, and will decrease progressively upstream and downstream of those segments. Without prior knowledge of the morphological characteristics of the gold to be mined, it is difficult to choose the most appropriate plant design, or to estimate what proportion of the gold will be recoverable by any given plant. If the relevant relationships are not considered beforehand, the recovery plant is likely to lose a significant proportion of the gold, and sacrifice maximum profit.

Jan 1, 2001

By R. J. Howarth, P. L. Llowenstein

The errors resulting from field sampling, sample preparation and analysis are investigated for drainage sediments derived from homogeneous sandstone, shale, limestone, basic igneous and granite lithologies as a background to a primary reconnaissance survey of England and Wales. Emission spectrographic analyses of approximately 350 samples for Al, Ca, Fe, K, Si, Ba, Co, Cr, Cu, Ga, Li, Mn, Ni, Pb, Sc, Sn, Sr and V and atomic absorption analyses for Cu, Ni, Mn, Co, Zn and Pb have been treated statistically. For routine broad-scale surveys analysis of the unground -80-mesh sediment fraction proves satisfactory. Sampling error between localities in a stream is shown to be less than spectrographic analytical error for many of the elements considered here, except where mineralisation (contamination) occurs, but exceeds the atomic absorption analytical errors in most cases. Unless it it critical to reduce the amount of between-site variability (having regard to analytical errors) in the regional survey, there appears to be no advantage in the use of a more sophisticated sampling technique. The utility of moving-average maps in reducing the width of the confidence belt around the regional 'geochemical surface', and thus compensating to some extent for the sampling errors, is also demonstrated.

Dec 1, 1971

The Elgas Underground Storage Facility at Port Botany, Sydney, is the first purpose-built cavern of its kind in Australia and allows large capacity, safe and environmentally benign storage of Liquefied Petroleum Gas (LPG). The facility provides Elgas with the flexibility to source product at competitive prices and will ensure long-term security of supply. Construction has provided Orica Australia, formerly ICI Explosives, with a unique opportunity to provide a bulk explosive delivery system specifically designed to meet the exacting demands of the site (see Figure 1) and of the project.

Jan 1, 1999

The Arctic is a region of special economic, geopolitical, research, socio-ethnic, and defense interests of both Russia and other countries of the Arctic zone. Introduction of innovation technologies at ore-processing factories is a direct responsibility of the state and this problem should be solved on the basis of coordination of interests of different stakeholders. The task of elaboration of scientific principles of rational state regulation in the North is very topical. Innovations require considerable investments first of all from private capital. However as an investment object innovations are not attractive for investors as they require large expenditures for long-term projects, and they are connected to high risks because market incentives form striving to get quick profits of private companies and result in a certain behaviour strategy while innovations need ?long money?. Under such conditions without state regulation of investment and innovation activities development of the mining sector in the Arctic practically has no prospects. At innovation development of mining enterprises economic growth is provided at the expense of active state innovation activities. The elaborated strategy of ore-processing enterprises should correspond to the modern paradigm of the ore-processing industry development which is not only for extraction of minerals but also for multi-profile structure having comprehensive use of the resources on the rational basis intended for rational complex utilization of mineral resources of the AZR which by the definition includes maximally full use of the whole aggregate of resources on the economically rational basis with obligatory environmental with resource reproductive and socio-economic functions and deterrents. The main principle of creation of innovation technologies is to obtain more products of higher quality with minimal costs. This allows increasing ?productivity of the resources? several times. This principle makes increasing productivity of the resources the most important and in this case efficiency of use of the resources brings extra profits at the expense of lack of new costs such as payment for protection and utilization of wastes. According to the economic theory only ratio between demand and supply is able to fix optimal proportions in economy and to give necessary signals for investment activities of mining enterprises. In this context market for minerals and increase of mineral resources productivity do not create incentives for investment activities without which neither sustainable economic growth nor solution of macroeconomic tasks are possible. Nevertheless countries should not reject this idea in spite of economic efficiency of the enterprises. Extraction degree of useful components and especially oil in the Arctic zone is one of the lowest in the world. This can lead to crisis of oil industry and other mining sectors. The reason for that is lack of a state policy of realization of innovation technologies in the mining sector in the Arctic.

Jan 1, 2014

By K. Bunney, R. Pleysier

The deportment of a suite of elements through representative gold ore processing unit operations in cyanidation has been investigated. Chromium and lead are not soluble in alkaline cyanide solutions. Arsenic, antimony, cobalt, molybdenum, selenium, tellurium and vanadium are soluble, but typically do not adsorb onto activated carbon to any appreciable extent. Silver, copper, cadmium, mercury, nickel and zinc to varying extents report along with the gold to the carbon eluate. Cadmium, mercury and zinc can report to the carbon regeneration kiln off-gases. Strontium is soluble and adsorbs on carbon where it remgins.

Jan 1, 2011

By Akira Yazawa

In the field of pyrometallurgy, the equilibrium evaluation has recently become easy by use of thermodynamic software, but it is strongly desired to estimate the amounts of non-equilibrium minor components to simulate practical processes. However, simple physico-chemical technique can not be applied to evaluate practical non-equilibrium components for many reasons. As an engineering solution for postulated equilibrium system, the activity coefficient is modified and introduced as the simulation parameter referred to as the "adjustment coefficient." This modified thermodynamic calculations were adopted to various sulfide roasting processes where many solid phases are participating and the system is not necessarily in equilibrium. Successful simulation was realized by assigning suitable adjustment coefficients for minor components which form a pseudo solid solution in the calcine. Some examples from sulfation roasting and dearsenizing roasting were discussed. In the smelting system, the loss of copper in slag is caused by equilibrium and non- equilibrium reasons, that is, chemical dissolution and entrainment of copper in slag. The total copper content of slag was simulated by use of the adjustment coefficient for entrained copper.

Jan 1, 1998

By D. D. Gertenbach

"The successful commercialization of a pressure oxidation (POX) process for recovering metal values, including gold, copper, zinc, nickel and molybdenum, is the result of a carefully planned development program. The initial task involves developing one or more conceptual flowsheets, including the POX autoclave and downstream purification and recovery steps. A laboratory program is completed to determine the technical viability of the flowsheets, define the operating parameters for each step and provide information for an initial economic assessment of the process. The process is then confirmed during a continuous pilot plant program, providing engineering design data and other information for the commercial design. A well-thought-out development program has been shown to be critical for reducing the risk of commercializing POX processes. Experiences developing POX processes for refractory gold ores and copper concentrates are briefly discussed. IntroductionPressure oxidation (POX) has become a common commercial operation for processing sulfide-bearing feedstocks. These feedstocks include gold ores and concentrates; copper concentrates; nickel concentrates and mattes; zinc concentrates; and molybdenum concentrates. Drivers for the development and commercialization of POX processes include:• The high cost for pyrometallurgical processing of sulfide ores, much of which is attributed to environmental controls.• The motivation to implement safe and more environmentally attractive alternatives for sulfide ores.• The need to process increasingly difficult ores with complex mineralogy.• Improvements made over the last 25 years in POX equipment design and experience operating commercial POX plants.Although the capital and operating costs for commercial POX processing can be high, this technology is capable of rapid oxidation of most sulfides and arsenic minerals in the feed, with little noxious gases and environmentally stable iron arsenate and other iron compounds in the POX residue (Marsden and House, 2006).In POX operations, sulfides are oxidized to either sulfates or elemental sulfur in an autoclave at elevated temperature and pressure with oxygen gas. An example is the overall oxidation reactions of chalcopyrite when sufficient oxygen is present, shown in the following reactions:"

Jan 1, 2016

By A Price, D Okle, K Brooks

The operation of flotation plants has been improved over the years by use of fundamentally based design techniques, a better understanding of reagent chemistry, online metal analysis and the use of digital control systems. However, optimal operation of flotation banks is not consistently achieved using manual operation. The reason for this is that the system is a highly interacting one, with changes in air addition, cell interface level and reagent dosages all being available, without it necessarily being clear as to which change should be made for a particular situation.This situation is made more complex by the fact that the feed to a flotation bank can vary in flowrate, composition and density over a fairly short period of time. It is not possible for a human operator to reject these disturbances, given the extent of the operation that is typically being monitored.Model predictive control (MPC) is a control and optimisation technique, developed in the oil refining industry, that aims to manage just such interacting multiple input multiple output (MIMO) systems. This technology makes use of linear dynamic models of the plant, that are experimentally derived. These models are then used in a receding horizon strategy to determine an optimal trajectory of the inputs to the system.MPC has been applied to four areas of the lead zinc flotation unit at Mount Isa mines. A total of 31 cells are being controlled by the system, which varies air to the cells, levels and reagent addition on a minute-by minute basis. The MPC controls concentrate and tail grades, reagent dosages, as well as recoveries to ranges set by the plant metallurgists.The development of the MPCs is discussed, together with the benefits realised. The key factors in insuring an ongoing return on investment are described.CITATION:Price, A, Okle, D and Brooks, K, 2018. Glencore Mount Isa lead zinc flotation circuit – experiences from the implementation of model predictive control, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 101–110 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018