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By Peter Bryant

"The case for innovation in the mining industry has never been more compelling—whether you believe the industry is in a sharp dip in a significant ‘sawtooth’ cycle or in the midst of a bust — the imperative is the same. Despite record production levels and still above-average prices compared to the lows of 2000, the industry is struggling to make profits and provide the returns on capital that investors are seeking. This represents a large-scale destruction of value over the last 15 years.The last 10 years have seen a sustained rise of operation expenses and capital development costs while there has been a rapid decline in productivity. This trend is unsustainable especially against other key structural challenges and forces shaping the future of the industry:1. Despite short-term fluctuations, there is longterm sustained demand for commodities.• Demand is driven by relentless urbanization, population growth and a rapidly growing middle class.2. Environmental concerns continue to mount.• Existing mining methods and their environmental footprint are becoming increasingly unacceptable to society.3. Geopolitical pressures and community activism are growing.• An estimated $25 billion worth of projects are on hold due to community activism.• Increasing nationalism tendencies and government expropriations of close to $30 billion.• Social license to operate is being challenged.4. Finding, building, operating and closing a mine just keeps getting harder and more expensive.• Costs have been increasing at an annual rate of 10 to 15 percent for the last 10 years.• More assets are stranded as they become uneconomical to mine under current mining methods, e.g. Olympic Dam.• Ore grades continue to decline.• Declining productivity at an annual rate of more than 10 percent for the last 10 years.5. The industry has consistently underinvested in technology and innovation."

Jan 1, 2015

By A R. McKinnon

The recently opened Hera Au-Pb-Zn-Ag mine in central New South Wales has provided an ideal opportunity to demonstrate the calculation of sulfide ore mineralogy using normative methods. Normative mineralogy applies a set of sequential rules based on the species likely to be present to assign the chemical components of a sample to their respective mineral components. The dominant sulfide mineral assemblage present at Hera is galena, iron-bearing sphalerite, chalcopyrite, pyrrhotite and pyrite. A normative technique for estimating the relative abundance of each of these species from drill hole, grade control and metallurgical assay data sets has been developed. This includes a process for deriving a gangue iron value and differentiating pyrrhotite from pyrite using sulfur/iron ratios. A calculated total sulfide volume value has been utilised at the mine to improve interpretation of lode boundaries. Normative drill hole values have also been used for domaining within the orebody, with large scale mineralogical trends evident. Dry bulk density (BD) values calculated using a normative species-weighted method show good correlation with measured BD values (R2 = 0.895) and are a significant improvement on the Pb+Zn+Cu regression method (R2 = 0.646) previously used. Application of these calculations to identify errors in assay databases is demonstrated, with specific reference to the data set for the nearby Nymagee copper deposit. Validation of block model grades is also explored and a method to improve resource estimates using direct normative mineral interpolation is proposed. The integration of the normative data into the production and metallurgical data sets at Hera is described and the relationship of the normative minerals to other economic elements such as gold and silver is discussed.CITATION:McKinnon, A R, 2017. Application of normative ore mineralogy to geological and metallurgical data sets at the Hera Au-Pb-Zn-Ag mine, New South Wales, Australia, in Proceedings Tenth International Mining Geology Conference 2017, pp 63–74 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By P. D. R. Maltby

"The Canadian Institute of Mining and Metallurgy has undertaken to host the XIV International Mineral Processing Congress to be held in Toronto at the Royal York Hotel from October 10 to 16, 1982. The theme of the Congress will be ""Worldwide Industrial Application of Mineral Processing Technology."" The program will include 10 sessions and numerous field trips to the different mining areas of Canada.For prospective authors, the preliminary program includes sessions on,1. Flotation - plant practice, equipment design, simulation, control and economics.2. Comminution - plant practice, equipment, design, simulation, control, wear, energy consideration and economics.3. Round table seminar on large grinding mills.4. Round table seminar on modern and future plant design.5. Mineral processes to recover precious metals.6. Mineral processes to recover energy minerals (coal, uranium).7. Mineral processes to recover industrial minerals.8. Round table seminar on the environment and ecology and how the different countries cope with associated problems.9. Materials handling with an emphasis on agglomeration techniques ereconentration methods, solid-liquid separation.10. Open session to deal with topic emerging from general demand."

Jan 1, 1980

The use of belt air in underground coal mines has been a continuous discussion since it was first introduced in the Federal Coal Mine Health and Safety Act (Coal Act) of 1969. Although the Coal Act prohibits the use of belt air to ventilate active workings, there were two exceptions prior to the 2004 Final Rule. There have been several major studies/rule-proposals by MSHA since 1985 and the most recent of which is the Technical Study Panel (TSP) established by the Mine Improvement and New Emergency Response (MINER) Act of 2006 to study the use of belt air and related issues. This paper reviews the history of belt air use, its associated controver-sies, and more specifically, the 20 recommendations unanimously approved by the TSP.

Jan 1, 2009

By W. C. A. van Niekerk, M. H. Fourie

The carcinogenic potential of chromium (VI) has been the subject of numerous environmental and occupational studies, from which many regulatory efforts emanated. Besides the regulation of levels of known toxic substances (e.g. Cr (VI)), the classification of dusts for regulatory purposes has thus far depended on broad definitions of particle size, mainly used to distinguish only between inhalable and respirable particles. In the past, ultrafine particles (less than 0.1 µm diameter) (PM0.1) were often regarded as a non-issue, because it was believed that significant doses would not deposit in the lungs. A growing body of scientific data is indicating that ultrafine particles are more toxic than their coarse counterparts. Increased toxicity can be related to the unique dosimetric aspects of the deposition and disposition of inhaled ultrafine particles. Secondly, ultrafine particles have a larger surface area per given mass. The increased surface area can act as a carrier for co-pollutants, specifically transition metals (including chromium) that could form a coat on the particle surfaces during particle formation. This suggests that the presence of ?inert? ultrafine particles in the environment may enhance the potential for exposure to reactive airborne compounds, including Cr (VI). These factors are particularly important when information on occupational epidemiology is interpreted. It is desirable to consider the particle size distribution, for example when occupational exposure to hexavalent chromium compounds is assessed. Since ultrafine particles are more toxic than coarse particles with the same chemical composition, it could be speculated that cancer slope factors might be related to particle size distribution. This is relevant not only to carcinogenic chromium compounds, but also basically for any particle-associated toxicants. In general, the probability of developing health effects associated with occupational toxicants is likely to be higher when these are associated with the ultrafine particle range.

Jan 1, 2004

By J. A. L. Napier

The evaluation of stress distributions and deformations in the vicinity of tabular mine layouts has been carried out routinely for many years using the displacement discontinuity boundary element method (DDM). In this approach, mine layouts are approximated as irregular shaped planar cracks (or slits) where the ?width? of the crack, corresponding to the excavation height, is assumed to be negligible compared to the in-plane, lateral dimensions. Early implementations of this approach have employed square element tessellations with constant displacement discontinuity component values. This is generally restrictive when considering the analysis of irregular pillar layouts or the intersection of fault planes with excavations. This paper describes a general revision of this approach in which triangular or quadrilateral element shapes are introduced in conjunction with higher order variations of the displacement discontinuity shape functions. This facilitates an accurate evaluation of detailed stress and displacement components close to excavation surfaces and allows the investigation of local damage and failure behaviour associated with particular geological structures such as weak parting bands or weak layers. A method to embed these features in an efficient and accurate multi-level solution scheme is described. This formulation can be extended to allow the analysis of shallow-depth pillar layout problems, facilitating the assessment of the interactive response and stability of shallow depth pillar layouts. A simple deformation model is introduced to facilitate the assessment of pillar failure and bursting potential in shallow mine layouts. The computational techniques described here have been implemented in a computer code called TEXAN (Tabular EXcavation ANalyser) and are illustrated by the simulation of a particular multiple reef pillar mining problem in a shallow depth platinum mine.

Jan 1, 2007

By Troy Boisjoli, Sean Hillacre, Matt Batty

Discovered in 2014, the Arrow Uranium Deposit has undergone rapid development through successive drilling programs informed by geostatistical drill hole spacing studies. An independent third-party geostatistical drill hole spacing study was completed by Clayton V. Deutsch Consultants Inc. in 2017, evaluating the uncertainty of thickness, grade, density, and areal limit of the Arrow Deposit to determine a drill hole spacing suitable for Indicated Mineral Resources. Indicated spacing was defined to be 24 to 32 metres (“m”) to be within 15% of predicted for a nominal quarterly production volume with a probabilistic tolerance between 75 and 90%. The study not only defined the Indicated Mineral Resource resultant from the 2016 drill program, but also provided drill hole targeting criteria for subsequent drill programs aiming to convert Inferred to Indicated Mineral Resources. A subsequent geostatistical drill hole spacing study on the Arrow Deposit was completed by Clayton V. Deutsch with Resource Modeling Solutions in December 2018 to define Measured Mineral Resource spacing in support of the 2019 drill campaign. The study resulted in a drill hole spacing of 9 to 17 m to be within 15% of predicted for monthly and quarterly production volumes using an accepted industry probabilistic tolerance of 90%.

Jan 1, 2020

By John C. Adams, Darrel D. Porter

After conventional drill and shoot methods were determined to be unfeasible due the fractured nature of the ground, a "coyote" blast was designed to produce 250,000 tons of rock from Rhone-Poulenc's Maiden Rock silica pit located near Butte, MT. This paper will cover the design and excavation of the explosive drifts, the placement and priming of 190,000 pounds of explosives, and the backfilling of the drift to provide confinement of the charges.

Jan 1, 1993

By M. C. Tippett

The modern era of mineral exploration in Panama began in the late 1960's, resulting in porphyry copper discoveries at Petaquilla, Rio Pito, and Cerro Colorado. In contrast, Panama's early mining history (1503 to the early 1700's) was associated with gold. A single mine, Cana, in Darien Province, produced more than one Million ounces of gold in the colonial period. Except for episodic exploration activity by British and French interests, Panama's gold potential since the 1700's has been largely ignored.

Jan 1, 1989

By Ed Revoort, Robert Schippers

In Rotterdam in the Netherlands the project ‘De Zalmhaven’ is being developed. The project consists of the realization of houses, parking facilities, two residential towers of 70 m and a residential high rise of 215 m. An artist impression for the project is given in figure 1. For the high rise a new development in the use of large diameter, drilled piles with a steel casing has been successfully utilized. In this article the installation method of 65 m long steel drilled piles in two consecutive sections is presented. The settlements for the building (and the influence on its surroundings) have been analyzed in detail using 3D Finite Element calculations, which will also be discussed. Finally there is focus on the results of settlement measurements carried out during construction in relation to the settlement prognosis.

May 1, 2022

By J A. Cowburn

The high intensity zone within the Jameson Cell is the downcomer. It is largely external and separated from the flotation tank. This, together with operation of the downcomer under vacuum, rather than at elevated pressure and the absence of moving parts, allows ready access to the high intensity zone for measurement and analysis. Experimentation was conducted allowing measurements of recovery for residence times of between 20 milliseconds and ten seconds within the downcomer of a Jameson Cell. The affect of aeration rate on the recovery of different particle sizes was also studied.

Jan 1, 2005

By Jônatas Venancio Barbosa, Dagoberto Brandão Santos, Túlio Magno Füzessy de Melo

In this work, the mechanical and metallurgical behavior of titanium added ultra-low carbon (ULC-Ti) steel under hot and warm working conditions was studied by means of dilatometer compression tests. Double compression schedules were performed at temperatures between 700°C and 1000°C, inter-pass times of 0.5-100 s, and deformations of 0.5 and 0.3 in the first and second stages, respectively, with strain rate of 1 s-1. The analysis of the flow curves obtained allowed the evaluation of the softening characteristics of the steel. The softening and microstructure features indicate different restoration mechanisms depending on the temperature range. Static recrystallization with rapid microstructure restoration is observed at temperatures within the austenitic and intercritical field. Strain induced boundary motion and recovery mechanisms apparently control the restoration process in the ferrite region. In general, flow stress curves showed dynamic recovery behavior. Only the deformation in the intercritical region produced a peak in the flow stress curves. Isothermal holding tests associated with single hit compression indicated the presence of dynamic strain induced transformation, accelerating the softening kinetics at the intercritical region.

Oct 1, 2019

By D. J. Steynfaard

Sishen Iron Ore Mine is situated 280 km north-west of Kimberley in the Northern Cape Province of South Africa. The mine produces and sells high quality iron ore of various specifications to various national and international clients. The saleable product is derived from the blending and beneficiation of different types and qualities of hematite iron ore. This paper documents the new developments which were implemented (or are in the process of being implemented) on the mine in the long-term planning, medium-term planning, grade control and material tracking in the beneficiation plant with special attention being paid to the quality of the final, saleable product. The process starts with the long-term planning where the pit shell and pit optimization is determined by Whittle 4X. New developments include the introduction of a linear programming based scheduling system to enhance the long-term schedule generated by Whittle 4X. The LP route was decided on in order to take into account all the constraining factors of the final product that could not be configured in Whittle. To complement this the XPAC Auto Scheduler scheduling package was introduced to do the medium-term mine scheduling. This 18-month rolling plan includes cost parameters to enable the planner to extract a detailed operational budget from the scheduling while ensuring that production standards are maintained and grade constraints are met. The existing grade control system was enhanced with GPS capabilities and a computer system to do material tracking. The high precision GPS system introduced on the shovels allows for the accurate control of the loading procedures at the mining face. Because of the complicated geology and grade composition of blasting blocks it is imperative to accurately differentiate between different materials in the same blasting block and being able to excavate that with the loading equipment. The GPS system on the trucks allows for accurate location monitoring of dumping in order to keep track of specific material types. The state-of-the-art material tracking system developed for Sishen will enable the grade control officer to keep track and record various parameters of the material from its in situ position in the blasting blocks, through the crusher and onto different stockpiles, in various stages of the beneficiation process and onto the blending beds, into the dispatching trains and eventually into the ships for international distribution. These developments elevate the Sishen planning and grade control systems to a new level of service excellence from which management can obtain accurate and timely information on product status. It also enables Sishen to maximize resource utilization while still complying with the tough market constraints.

Jan 1, 2003

By R. E. Lindstrom

Effective separation of rare-earth mixtures is obtained using hydrogen as a retaining ion at 200° F with ethylenediaminetetraacetic acid (EDTA) eluant. Results obtained in Bureau of Mines bench-scale apparatus and large columns with hydrogen as a retaining ion closely parallel those obtained with copper as a retaining ion. The use of hydrogen as a retaining ion permits EDTA and water, collected before rare-earth breakthrough, to be recovered in a form that allows the material to be recycled without extensive processing. With the exception of yttrium and dysprosium, separation of rare-earth mixtures is improved and throughput is increased by elevated temperatures. Separation with 1,2-diaminocyclohexanetetraacetic acid (DCTA) eluant increases markedly on increasing temperature from ambient to 250° F; however, on the basis of separation efficiency, DCTA does not compare favorably with EDTA.

Jan 1, 1962

By C. A. Pickles, J. M. Toguri

The refining of two molten Ag-Cu alloys, containing 7.5 and 11.2 mass% Cu, with a borosilicate slag was investigated using both air and pure O2 to determine the effects of the following variables: flow rate of oxidising gas; injection time; mass of sodium borosilicate flux; and injection of the oxidising gas into either the slag or the metal. The results demonstrate that more than 90% of the Cu can be removed with Ag losses of less than 5% and that refined metal with a Cu content of less than 0.5 mass% can be produced. Ag losses to the slag increased with the amount of Cu removed, and a mechanism is proposed to account for this

Dec 1, 1995

The Aredor mine employs conventional dragline methods to exploit alluvial diamond deposits. Production began in 1984 with the policy of mining in the terrraces during the wet season and in the river flats during the dry season. Early production failed to meet predicted grades. A major geological programme to re-evaluate existing reserves was undertaken. This resulted in considerable increases in reserves in the river flats. Many of the reserve blocks included flats on both banks of the Baoule river. Methods of access into the river flats, normally flooded in the wet season, were developed to allow mining throughout the year. River diversions have been the main method used to provide access into the reserve blocks and, most importantly, to remove the risk of flooding. Aredor has carried out six main river diversions with a total length of 12 km. The diversions allowed production planning to be made on the basis of the economic evaluation of the reserve blocks, without undue regard to natural ground conditions or to seasonal factors. The Manning equation was used for the calculation of channel dimensions and gave satisfactory results. The practical aspects of the diversion preparations and flooding prevention are described

Sep 1, 1991

By G. Price

The Building Research Establishment installed a base load cell in a driven cast-in-place pile prior to it being tested under vertical load. The monitored base loads were found to be significantly less than could have been predicted by current design methods. The less than expected capacity was attributed to the drilling out procedure. An electro-level system installed in a second similarly formed pile, provided detailed information on the performance of the pile under lateral load. The information obtained was used to check several current design methods for laterally loaded piles. The findings show the potential dangers of attempting to improve design parameters from only limited performance data.

Jan 1, 2010

By H Zhang, A Lawrence

To accommodate the fast growing need for services in Singapore’s Marina Bay downtown area, Marina South, the construction of a common services tunnel (CST) was required. The CST includes various services such as telecom cables, power lines and water pipes. A deep excavation and temporary earth retaining system (TERS) was required to facilitate the construction of the tunnels. Marina Bay is reclaimed land over thick soft marine clay which is likely to be still consolidating. The deep soft marine clay poses a big challenge for deep excavations in downtown areas where highways and sensitive structures are close by. This paper presents a case study of part of the CST Phase 1B and 2 at Marina South, in particular a 26 m deep excavation supported by a 46 m diameter temporary caisson. The construction started in late 2006 and the basic structure was completed in early 2011. The caisson was formed by 1.0 m thick overlapping diaphragm wall panels with a capping beam and three ring beams at different depths. Two-dimensional finite element analyses were conducted to predict the ground settlement, lateral displacement, bending moment and hoop stresses in the diaphragm wall and ring beams during different excavation stages. A comprehensive instrumentation and monitoring scheme was established to verify the design predictions, control excavation safety and trigger the contingency plan to protect public safety. The impact of construction activity, unbalanced temporary stockpiles and adjacent deep excavation for a mole removal will be discussed.CITATION:Zhang, H and Lawrence, A, 2014. A case history of a deep excavation in a big circular shaft in Singapore marine clay, in Proceedings 15th Australasian Tunnelling Conference 2014, pp 581–588 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Edmond J. O’Donovan

South Bulga is a new longwall operation located in the Hunter Valley coal-mining region in Southeastern Australia. The mine’s objective is to achieve productivity levels significantly higher than the current industry average. From the day longwall production began, South Bulga’s output was below both budget and industry expectations, primarily because of the poor performance of the conveyor system. In the past, conveyor systems have been seen as an adjunct to the mine plan, not as an integral part. At past production levels, this approach may have been acceptable. In today’s mining operations, the conveyor system must be treated as integral and vital to the mining operation. The conveyor system is analogous to the vascular or circulatory system of the human body. Of itself, the system does not do anything, but if it is not functioning satisfactorily, the mine cannot operate.

Jan 1, 1996

By Donald D. Smythe

This paper describes briefly the topography and geology of the region where the mica-bearing pegmatites are found and discusses prospecting, the quality of the mica, its preparation, and evaluation of the deposits. Muscovite mica occurs in a number of widely separated localities in Brazil, but production has come largely from deposits in the southeastern and eastern part of the State of Minas Gerais (Fig. I). There the deposits form a discontinuous zone, which starts at a point go km. north of the city of Rio de Janeiro and extends north for some 500 km., roughly parallel to the coast. A maximum width of 180 km. is reached along the Rio Doce. To the west in Minas Gerais, and extending east into the states of Espirito Santo and Rio de Janeiro, the mica zone proper is fringed by areas in which there are scattered occurrences of mica-bearing pegmatites. A few of these outlying deposits have produced commercial mica, but most of them are unimportant. To the southwest, in the State of Sao Paulo, there are a number of mines, which at one time produced a very considerable amount of sheet mica, largely as a byproduct of kaolin mining. These deposits, and a few others lying between them and the main productive areas to the northeast, appear to be the southwestern continuation of the strong Minas Gerais mica zone. In the vicinity of Conquista, just north of the Minas Gerais boundary in the State of Bahia, and still farther north, near Jacobina, there are several known mica deposits. Their location indicates that they may be the northern continuation of the main mica zone. The major part of Brazilian mica production has come from four areas within the mica zone proper; from north to south, Governador Valadares, Raul Soares, Espera Feliz, and Muriaé.. The first is go km. from north to south and reaches a maximum width of 180 km. The Raul Soares area extends 135 km. from northeast to southwest, and in places is 80 km. wide. The Espera Feliz area is 100 km. from north to south, and reaches a width of 35 km. The Muriai. area extends 150 km. from northeast to southwest and its width reaches 40 kilometers. Between the known productive areas, and in the areas directly to the southwest and to the north of them, little mica has been produced. These gaps, as well as certain irregularities in the outline of the mica zone itself, are to be ascribed either to lack of prospecting or to conditions preventing the discovery of mica, rather than to its nonexistence. Elsewhere in Brazil mica has been reported from eastern Goiaz, Ceará, Pernambuco, Rio Grande do Sul, Matto Grosso, and Amazonas. Production from these sources is negligible at present. Because of the inferior quality of the mica from the more accessible of these localities, and the operational difficulties occasioned by the remoteness of others, it is improbable that they will become important producers for some time to come.

Jan 1, 1948