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By A. P. Yovanovic, P. Bonadia, M. N. Moraes, C. F. Matos

"The magnesite flotation operation of Magnesita Refractories, in Brumado – Brazil, has four parallel ball mills working in closed circuit with hydrocyclones to grind the ore for the reverse flotation of silicates in mechanical cells. The modification proposed here opens the circuit for three of the ball mills so that their products are collected together to feed a high frequency screen. The oversize of the screen feeds the fourth ball mill in closed circuit for secondary comminution. The product reports to dewatering and flotation. The undersize undergoes desliming and subsequent flotation operation. According to pilot tests performed, the modification on the magnesite flotation operation will promote a 20% increase in the productivity, 8.5% increase in mass recovery and a 26% reduction in water consumption. The gains are due to the fact that the silicates in the feed are concentrated in the smaller particles (<100µm) with over grinding in the existing closed comminution circuit, making it impossible to take advantage of this natural selectivity. The combination of open circuit, more selective milling, and the high frequency screen, ensures high efficiency particle size classification. This renders the process more effective, both to the screen undersize with its high contents of silicates and fines, and to the screen oversize, which is almost without fines and has a higher magnesite grade. This situation allows for the setting of specific parameters for the flotation of both the primary milling undersize and the secondary milling product.INTRODUCTIONMagnesita Refractories, with its operations site in Brumado, is the largest producer of high purity dead burned magnesia (DBM) in Latin America. The magnesite ore is extracted from an open pit mine, named Pomba, after which it is crushed and handpicked. Due to the presence of disseminated silicate the ore has to be ground and concentrated by means of reverse flotation, before feeding the high temperature kilns for sintering and conversion to DBM.The magnesite flotation unit has an impact crusher to reduce the size of the feeding ore, which is transported to the mills by conveyor belts. The milling operation is composed of four ball mills in closed circuit with hydrocyclones. The closed circuit generates a high circulating load with excess fines, which is detrimental to the selectivity of the desliming and flotation operations, reducing both mass andmetallurgical recovery.In the current scenario, the capacity of the flotation plant is insufficient to meet the demand of the DBM kilns, forcing the operation to work with high purity ores in order to attain the highest possible mass recovery in the concentration process. This is not an ideal situation as it requires the mining site to work with higher stripping ratios.The objective of this work was to improve the magnesite flotation unity to increase its productivity. After a detailed analysis, the milling was identified as the limiting process, which made the authors to focus on this operation."

Jan 1, 2016

By F. Q. Dong

According to the principle that should be originated from nature, compatible with nature, used in nature and back to nature and based on conception of designing of eco-material, the author combined the ideas of material, environment, zoology and healthy. Properties of natural mineral materials were used to produce micro-aggregate elements by bionic method, so its components and function could accord with living environment. Eco-mineral functional materials which can adjust, purify and optimize the microclimate were reviewed. The authors pointed out the multifunction, com-pounding, the compound characteristics and integration regularities of micro-aggregates. It was the first time in the world to put forward the ?gene? technique or ?material chip? technique of manufacturing function micro-aggregates and eco-function elementary materials. The results of this re-search supported by the national ?863? Hi-tech Project, mainly including the high-efficient air purifying mineral compound material indoor, the clay elementary antibacterial materials, the masonry cement/coating/putty/compound with preventing radon radiation, environmental friendly composite functional coatings, mosquito repellent and healthcare material and zeolite-based energy-saving composite materials, were introduced. Finally, the foreground of mineral materials in the field of future advanced eco-friendly materials was also discussed.

Jan 1, 2014

By N. J. Duncan

"Coal mining, whether surface or underground, has hazards that make it unique in the field of industrial safety and health. The often soft, faulted and folded sedimentary strata make wall or roof movement a risk to the safe and economic removal of the coal, while the extraction and handling of coal may create an explosion hazard even in surface operations, In Canada, these problems are compounded by the situation of the coal fields which range from deep undersea deposits in Nova Scotia to steeply pitching thick coal seams high in the Rocky Mountains. Climate too can create its own problems, particularly the effect of metals of minus 40°C temperatures, as crumpled dragline booms at prairie strip mines witness. Because of the difficult and sometimes hazardous conditions, Canada's underground colliery managers, in common with those of other Commonwealth coal-producing countries, must have a government ""certificate of competency"" before being appointed as mine managers. Certification of assistant managers (""under-managers"") and foremen (""fire-bosses"") is also a legal requirement for all of Canada's underground collieries, while the province of Alberta requires certification of surface management personnel. Electricians and mechanics who install and maintain the specially designed equipment underground and in hazardous areas of surface mines and processing plants, and mine surveyors who ensure accuracy of the location of underground workings, must also hold government certificates of competency. The requisites for all certification include a minimum work experience and knowledge of coal mining technology and mine safety and health legislation. Despite recognition of the hazards and increasing knowledge of methods of preventing explosions of flammable gas and coal dust in Canada's underground mines, there have been several disastrous explosions such as those at Springhill Colliery in Nova Scotia in 1891 with the loss of 125 lives, at Hillcrest Colliery in Alberta in 1914 with 189 dead, and more recently · explosions and fires in No. 20 and No. 26 Collieries in Cape Breton. Preventing explosions has required developing optimal ventilation techniques, reducing ignition potential, suppressing ignition at source, draining flammable gas before it can enter the air courses, and preventing, or sealing off, autogenous heatings with their associated carbon monoxide or explosion dangers."

Jan 1, 1985

By Kim B. Shedd, Erin A. McCullough, Donald I. Bleiwas

"The earliest known use of cobalt was to make blue glass in Mesopotamia before 2000 B.C.E. Since then, innovations across many diverse industrial sectors transformed cobalt into an essential commodity for contemporary society. The physical and chemical properties of the element cobalt and its alloys and compounds make them indispensable for a variety of applications, including aircraft engines, hybrid electric vehicles, machine tools, missile guidance systems, petroleum refining and smartphones. As a major industrialized nation, the United States is a leading consumer of cobalt and cobalt-containing products. However, with few exceptions, U.S. cobaltcontaining ore deposits are of low cobalt grade. Historically, U.S. cobalt mine and refinery output have not met domestic cobalt demand. As a result, U.S. cobalt chemical and alloy producers need to procure most of their cobalt from the international market, which can become susceptible to supply risk.The 1978 Cobalt Crisis illustrates supply risk. At that time, the Democratic Republic of the Congo (DRC) (then known as Zaire) was the world’s leading producer of mined and refined cobalt. An insurgent invasion of the country’s copper-cobalt mining region during a period of high cobalt demand and low producer inventories caused a temporary supply shortage in the international market. The monthly average cobalt spot price increased from $18/ kg ($8/lb) before the crisis to $99/kg ($45/lb) seven months later. The high price and concern about potential disruptions in supply prompted manufacturers to reduce or substitute for cobalt where possible, and encouraged increased recovery of cobalt from scrap. The DRC has regained its position as the leading producer of mined cobalt globally and continues to be characterized by high governance risks (U.S. Central Intelligence Agency, 2015; World Bank, undated). This article will present current and historical world cobalt production trends, which can help inform discussion about the variety of international supply chain risks consequential to its trade."

Jan 12, 2017

By Charles W. Perry

The options of enhanced oil recovery, coal syncrude, and shale syncrude are compared by approximately equivalent economics. The physical constraints for the major enhanced oil recovery processes are described, followed by new estimates of cost. The range for all three options in terms of light syncrude equivalent are $22 to $40 per barrel in 1980 dollars.

Jan 1, 1982

By Mattos J. L. C

Drilling and blasting with explosives in mining operations near communities require careful planning to mitigate socio-environmental impacts. Ground vibration, noise emission, flyrock, and dust dispersion are factors that may trigger conflicts with local populations. However, large-scale operations demand high productivity and intense material handling, making it essential to balance operational performance with impact control. The adoption of best practices, combined with advanced monitoring and mitigation technologies, enables sustainable mining even in proximity to inhabited areas. This study proposes the use of double and triple-deck blasting techniques with large-diameter boreholes (12 ¼” – 311 mm), addressing the sizing of charges and decks, as well as measures aimed at reducing noise perceived by nearby communities. The approach seeks to maintain the use of large drilling rigs already present in the operation, avoiding costs related to premature equipment replacement or expensive alternatives, while minimizing environmental and social impacts and promoting a more balanced and responsible mining model.

Jan 26, 2026

By M Berry, F MacCorquodale

The ownership, management and employment structures operating in the Australian minerals industry have dynamically evolved during the last 30 years. One of the most dramatic changes, from an exploration and mining geology perspective, is the reduction of in-house geological expertise and an ever increasing reliance on contract and consulting services.For all companies - big and small - two key issues resulting from these changes are the management of core geological intellectual property (IP) and competitive advantage. This is because there are less experienced geologists at exploration and mine sites, there are fewer head-office technical service teams to support mine sites, exploration teams are smaller with less specialists employed, and there is an ever-greater dependence on contract and consulting services.This paper reviews and explores these issues with an industry-wide geological context, then provides a case study of how Newcrest Mining Limited (Newcrest) has dealt with these issues in exploration. Newcrest has grown from a one-mine company with an Australian exploration focus, to a large global company with multiple operations and an extensive international exploration portfolio. NewcrestÆs management of its geological IP and competitive advantage has evolved as the company has grown and responded to market conditions, including its internal restructuring in mid-2013.CITATION:Berry, M and MacCorquodale, F, 2013. Managing geological intellectual property and competitive advantage - Newcrest Mining LimitedÆs experience, in Proceedings World Gold 2013 , pp 37-44 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By Juan J. Monsalve, Mario Karfakis, AMAN SONI, Nino Ripepi, Jim Hazzard

Pillar collapses are events that due to their severe consequences can be classified as high risk. The design of pillars in underground room-and-pillar operations should migrate to risk-based design approaches. The authors of this work proposed a risk-based pillar design methodology that integrates stochastic discrete element modeling for pillar strength estimation, and stochastic finite volume modeling (FVM) for stress estimation. This paper focuses on the stochastic FVM component for stress estimation. The mining and geomechanical aspects of a case study mine (CSM) are described and pillar stresses are estimated by using three approaches: (1) analytical solutions, (2) 2D finite element modeling, and (3) 3D finite volume modeling. This operation extracts a 30° dipping deposit, which makes current underground stone mine design guidelines inapplicable for this CSM. This work compares results from each stress estimation approach and discusses uses the point estimate method as a simplified stochastic approach to evaluate the effect of rock mass elastic properties variability on pillar stress distribution. Results from this work show that the three estimation approaches lead to different estimations, possibly, due to the wide range of assumptions each estimation approach considers. It was also determined that the horizontal to vertical stress ratio has a significant impact on pillar stress magnitude. Therefore, it is recommended to perform in situ stress measurements, or assume worst-case-scenario values to account and reduce uncertainty due to this parameter. The stochastic stress estimation approach used in this paper provides results that can integrate a risk-based pillar design framework.

Sep 24, 2022

By R. J. Henry

This paper describing the mining practices at the Teck-Hughes mines at Kirkland Lake, Ontario, is one of a series being prepared by the United States Bureau of Mines on mining practices, methods, and costs in various mining districts. HISTORY Prospecting was begun in the neighborhood of Kirkland Lake in 1906, but staking did not take place until 1911. Gold-bearing veins were discovered by surface trenching in 1913 on the mining claims which now make up the Teck-Hughes Gold Mines (Ltd.). A small mill was erected in 1916 after the completion of some underground exploration. A transmission&apos; line was built in 1917 to the camp to provide adequate power for a vigorous underground campaign. Also in 1917 the present management took control operations since 1916 have been continuous,&apos; with a steady increase in production to date.

Jan 1, 1930

By T. L. Joseph

"IntroductionThe efficiency of ore reduction in the blast furnace and fuel requirements depend upon the degree of uniformity with which reducing gases can be distributed through the stock column and upon the permeability of individual pieces of ore and sinter. If the ore is fine, the major problem in reduction is to get the ascending gas stream to the surface of the ore-Hard, dense ores of low permeability, mined in coarse sizes, tend to improve the permeability of the bed, but unless they are crushed to the proper size they reach the hearth unreduced.Surveys by the Bureau of Mines have shown conclusively that the gas distribution in the upper three fourths of the furnace is far from ideal. Furnace lines, top design, and methods of charging are important, but more thorough size preparation of the ore is necessary to eliminate size segregation at the stock line, which inevitably leads to non-uniformities in gas distribution.Because of the quantity of sinter now produced close study of the characteristics which determine its behavior in smelting is warranted. As the use of concentrates increases agglomeration will become more of a necessity. Improvements in the physical character of the ore burden are particularly important to plants using coke of poor physical quality. In addition to aiding reduction, improved physical properties of the ore burden will permit the use of higher blast heats, which is equally important.Reduction Tests on Fine Sizes of SinterPrevious reduction tests on minus 0.742— plus 0.525--inch pieces of commercial sinters revealed large differences in porosity and reducibility. The results have been published in a former report. 3 Although the physical properties of the sinter, particularly porosity, were found to be of major importance in determining the rate of deoxidization, it appeared that certain chemical properties of the sinter appreciably retarded the reduction of sinters high in silica. This was attributed to the presence of fayalite, which has been identified by Schwartz and by Luyken and Kraeber4 as an important constituent of sinter. Although furnace operators and metallurgists have assumed that iron silicate is more difficult to reduce than hematite or magnetite, definite data on the reduction characteristics of this material were not available. Tests were undertaken, therefore, to develop a method for de-termining the amount of iron silicate present in sinters so that its effect upon reduction could be observed."

Jun 1, 1934

By Peter Ay, Vincenz Mehlstaubl, Satyanarayana Narra

"This study gives an insight into non-destructive testing methods suitable for porosity analysis at a small scale, firstly summarizing relevant state-of-the-art technology and pending patents, secondly realizing and documenting the start-up of the VHX-2000 digital microscope by the manufacturer Keyence and thirdly demonstrating practical application with the extended analysis of three fundamentally different agglomerates for which important application-related parameters are determined. Various analysis procedures on the different agglomerates the efficient and timesaving operational features of the digital microscope are outlined. Firstly an analysis of flax fibre agglomerates determines the process conditions best suited to produce agglomerates with specific properties by determining sphericity, cubicity, density and porosity as well as fibre damage and alteration. Secondly the production of iron-hydroxide - hemp-fibre agglomerates serves to obtain information on porosity values as a result of a cauterization of the fibres. The third analysis provides estimations of porosity values for acid-treated lignin agglomerates. Measurements were carried out with compact dry agglomerates and with soaked, expanded agglomerates, determining factors for total water carrying capacity. Practicability of non-destructive testing by digital microscopy is demonstrated and explained concerning the applications in this study by obtaining definite structural findings about the analysed agglomerates. Information on its operation is made available by a practice-oriented manual for the VHX-2000 digital microscope. Further suggestions for more in-detail analysis results with different instruments are given."

Jan 1, 2014

By Satu Strömberg

A single-particle laminar-flow technique was used to study oxidation of two nickel concentrates and a granulated nickel matte (43 wt% of Ni). Experimental conditions were: reaction gas from N2 to N2 + 75 vol% O2; gas preheating temperatures ranging from 500 to 1100°C. The major nickel-bearing minerals in the two concentrates were pentlandite and violarite, respectively. Chemical analysis of the particles was used to determine the oxidation degree of the materials, and optical and scanning electron microscopy were used to detect their morphology and mineralogy. Total desulfurization of the nickel concentrates was achieved under the most oxidizing conditions, while the sulfur removal from the nickel matte was not as efficient, especially with the coarse size fraction. Pentlandite-based concentrate was found to be less reactive than the violarite-based.

Jan 1, 1995

By Stefan Larsson, Sadek Baker, Razvan Ignat

"This paper describes the execution of two full-scale field tests where a braced steel sheet pile wall interacting with rows of overlapping dry deep mixing columns was first excavated and then loaded to failure. The aim of the tests is to provide insight of the performance of dry deep mixing column rows located in passive zone and interacting with a retaining structure. The column rows were installed perpendicular to the sheet pile walls with two different area ratios, i.e. different distanced between the column rows. Both tests were extensively instrumented with inclinometers, pore pressure transducers, bellow-hoses, earth pressure gauges and strain gauges mounted on the struts. Results of the performedtests will serve as development of design methods for excavation support with columns.INTRODUCTIONDry deep mixing has been used with good results to strengthen the soil when excavations are to be performed in locations with thick soft clay deposits. An application that has increased in recent years is to install columns on the passive side of the retaining structure. Columns can be installed in different patterns but rows, grids or blocks are the most common arrangement. The use of column type ground improvement installed on the passive side of a retaining structure has been documented for a few field cases, Tanaka (1993), O’Rourke et al. (1997b), O’Rourke and McGinn (2006), Ou et al. (2008). By improving the soil on the passive zone, the passive earth pressure in front of the retaining structure is increased. This has proven to reduce the excavation induced deflections behind the retaining structure, reduce the structural forces (bending moment in the retaining structure, strut and anchor forces) and improve the safety against basal heave failure. The main focus of the conducted measurements within these cases has been on recording deflections and structural forces on the retaining structure and there is very little documentation available of the stress-strain behavior of the improved soil acting on the passive side of the retaining structure.Two full-scale tests of braced steel sheet pile walls interacting with rows of overlapping dry deep mixing columns were first excavated and then loaded to failure was conducted during the spring-summer of 2014. This paper briefly describes the test set up, instrumentation, test procedure and some selected results from one of the conducted tests."

Jan 1, 2015

By D. C. Durgin

Located near Ely, Nevada, the Robinson Mining District has produced gold since 1868 from the Ruth? porphyry copper system. Gold occurs in at least seven different deposit types, including porphyry copper ore, silica-pyrite replacements along favorable horizons, fault controlled silica bodies, intrusive breccias, stockworks in bornfels and in retrograde skarns. In all of these the primary controls localizing gold ore are structural .preparation and permeable hosts. Indicator elements associated with gold are Ag, As, Te, and to a lesser extent Sb and Tl. Pb, Zn and F are peripheral to gold or with it depending upon position within the system. The district has produced 87,000 kg (2.8 million ounces) of gold thus far. An additional 19,300 kg (620,000 ounces) of reserves are established, and well over 31,100 kg (1,000,000 ounces) of reserves are anticipated. I

Jan 1, 1989

By B Small

CSA Mine, named after the nationalities of the mines first owners being Cornish, Scottish, Australian, is one of Australia’s deepest and highest-grade copper mines. A combination of the modified Avoca method and shrinking was a standard practice where production rings were fired against and bogged to waste fill. This method resulted in dilution and involved rehandling of waste material to refill the bogged stopes in the Western region and the QTS Central. The introduction of pre-charging blastholes using a wireless initiating system (WebGen™) has enabled CSA to design and fire stopes in reverse. This involves the use of a pre-charged Temporary Rib Pillar (TRP) against the waste fill material in a previously mined stope. The temporary pillar reduces dilution and improves conventional bogging as material is blasted towards the drawpoint rather than towards the waste fill material. Additional drill, prep and blast re-work is reduced or completely removed as rings can be charged prior to, in conjunction with, or after, charging of the slot. This is a safer practice as the charge crew spend no time working adjacent to a brow or open void. A TRP trial was conducted in the western orebody at CSA. The risk of exposure to a brow or open void while charging underground, and the bogger rehandling of waste material was successfully eliminated. Once reverse stoping was established in modified avoca stopes at CSA, two TRPs were implemented in challenging ground conditions in the QTS Central region. The TRPs were utilised in a retreating four-way intersection to extract a central diminishing pillar to close the level out. The ore recovered in this stope provided 5 per cent of CSA’s copper for the year. Without pre-charging with a wireless initiating system, two 5 m pillars totalling 6936 t of ore at 7 per cent either side of the stope would not have been recovered. CSA has implemented the practice of reverse stoping in modified avoca stopes using TRP for ten stopes since the successful trial. The development of additional blasting techniques enabled by precharging with wireless initiating systems is currently underway in the QTS North orebody at CSA Mine.

Mar 29, 2023

By A. K. Raji, M. O. Ojumu

Robotic subsea dredging crawlers are dynamically and remotely controlled vehicles that are used for deep sea mining and recovery operations. These exploration machines are released from a mother ship and move around on the ocean floor using tracks. Current ocean crawlers such as the MK3 ROST are hydraulically powered. In this paper we develop a scaled-down model for simulating and performing static loading analysis of an electrically powered robotic subsea dredging crawler (EPRSDC). The modeling, simulation, and analysis were carried out using modelling software from Solidworks. The structural frame was assembled using the Tetrix max robotics kit. The kit’s structural components were produced from 1050 aircraft-grade aluminum. The results were used in optimizing and for considering other materials, and the to identify specific areas to be reinforced in future crawler designs.

Oct 3, 2023

By Clark F. Grain

The monoclinic to tetragonal inversion of zirconium dioxide was studied by single-crystal X-ray methods, high-temperature X-ray diffractometry, and differential thermal analysis. The unusual features of the inversion, such as no definite transition Lperature, hysteresis, and athermal kinetics, were confirmed for powders who mean crystallite size was greater than 1,000 A. Samples of mean crystallite size below 1,000 A displayed classical kinetics, obeying a logarithmic rate law. A detailed mechanism based on Ubbelohde&apos;s theory of continuous phase transformations was proposed which is consistent with all the experimental facts.

Jan 1, 1965

The man in the street (and no doubt most members of the Institute) thinks of wire, if he gives it any thought at all, as a most commonplace commodity. It is an accepted necessity, and like most necessities is taken for granted, unless a shortage in one or other of its multitudinous forms or products causes inconvenience.For many years Australia has &#183;been a large consumer of wire, particularly for fencing. With the rapid development of secondary industry the demand has increased in both size and character until at the present time much of the wire produced in this country is used as raw material for subsequent manufacturing processes. The call has been of so varied a nature that the Newcastle Wire Mills now turn out a greater variety of wire types than any other single plant in the world.In this paper, the aim is to provide a picture of the manufacturing, properties, and uses of wire. No attempt is made to cover the subject in any detail, as the field is much too broad for anything other than general treatment. Many phases, particularly in regard to manufacturing processes, are, therefore, dealt with cursorily, but it is hoped that the paper will, without delving too deeply into the technical aspects of Wire production, give a general appreciation of:- (a) How steel wire is made. (b) The remarkable physical characteristics obtained by judicious combination of chemical composition, heat treatment, and subsequent cold work. (c) The uses of steel wire.HISTORY.Best known of the early references to wire is that appearing in Exodus, where mention is made of gold wire being used for the sacerdotal robes of Aaron. However, the period in question, about B.O. 1491, is comparatively modern history as far as wire is concerned, for specimens believed to have been made about B.O. 4600 have been found. It is fairly certain that the Egyptians produced iron wire in B.O. 4000. Of particular interest is the

Jan 1, 1947

By W. Mueller, M. Rocheleau, E. Dimroth

The paleogeographic evolution of the Abitibi Belt is subdivided into three phases, namely: 1) a phase of the growth of a submarine volcanic chain, 2) a phase of the emergence and growth of volcanic islands and 3) a phase of uplif t and erosion of volcanic islands. Isostatic calculations suggest that the volcanic sequence in the south of the Abitibi Belt rests on oceanic basement or on the mantle; the volcanic sequence in the north of the belt rests on about 13-14 km of tonalitic basement. 10-15 km of plutonic material accreted to the volcanic islands during paleogeographic phases 1 and 2, and caused the uplif t during paleogeographic phase 3.

Jan 1, 1984

By A. J. Petrina

"At Craigmont Mines Limited, Merritt, B.C., tests were begun in March, 1965 to evaluate the use of shotcrete as a method of ground support m development headings; previously, ail drifts had. required support, which was accomplished mainly by timber and occasionally by the use of rockbolts. The tests demonstrated conclusively the effectiveness of shotcrete for supporting Craigmont's ground. Gradually, the use of timber for ground support was virtually eliminated in favour of shotcrete. This paper describes the equipment used, the operation of the equipment, pertinent cast data and opera ting details. Also discussed are other uses developed for the shot-creting equipment, the use of reinforcing bar rockbolts, and a method used at Craigmont for lining long vertical ore passes with steel plate and concrete as part of the raising cycle."

Jan 1, 1968