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By Philip J. Bangerter, Chris Twigge-Molecey

Design for safety is critical to metallurgical plants, due to the inherently dangerous nature of their processes. Two significant areas of concern are: 1. preventing catastrophic process failures that cause damage or injury; and 2. operational safety that directly affects those working in or living near the plant. Process safety involves human behaviour, but the designer can eliminate or control hazards by engineering approaches, and control impacts through the design of the operating procedures. The tools available to guide safe facility design include bowtie analysis, hazard analysis, and hazard and operability studies. Clean plant design principles can guide the design process to address in-plant occupational health and safety issues. Auditing and review is a key part of the overall design process.

Jan 1, 2015

By G. Hu, P. Chang

"As hydraulic fracturing is forbidden in some countries due to its accompanying environmental pollutions, microwave fracturing was proposed as a substitute technology to enhance coal seam permeability. Its mechanism includes: on the one hand, thermal stress caused by non-uniform microwave heating leads to fracture development in coal body, which increases coal seam permeability for gas; on the other hand, moisture within the coal body that hinders gas desorption and diffusion is removed during this process. To study the effect of moisture content on fracture development under microwave irradiation, high resolution photographs were taken before and after microwave treatment. These photographs were then binarized and skeletonized. Based on the processed photographs, the total area were calculated using ImageJ. The results showed that coal samples with 0% and 25% water saturation have more variation in fracture development as compared to that of samples with 50%, 75% and 100% water saturation. This study can be very useful in gas drainage and gas control in coal mines. INTRODUCTION Coalbed methane (CBM) is a clean energy source as well as a natural hazard to underground mining (Kurnia, Sasmito, & Mujumdar, 2014; Ranathunga, Perera, & Ranjith, 2014). One of the main goals of mine ventilation is diluting methane and removing underground contaminants (Xu, Huang, Nie, Chalmers, & Yang, 2017). Coalbed methane (CBM) has to be extracted prior and during underground mining to avoid methane outburst and explosion accidents. However, with the increase of mining depth, the coal permeability decreases significantly, which makes it hard to extract the methane (Huang, Xu, Hu, Kizil, & Chen, 2018). To enhance the coal seam permeability, many CBM recovery methods have been applied on-site, such as hydraulic fracturing and enhanced coalbed methane (ECBM). However, hydraulic fracturing is restricted due to environmental concerns and ECBM is only suitable for the coal seam with relative large permeability (Bustin, Bustin, Chikatamarla, Downey, & Mansoori, 2016; Huang, Xu, Chen, & Chen, 2018; Huang, Xu, Hu, et al., 2018)."

Jan 1, 2019

By Margaret Anne Stephenson

While the concepts of Aboriginal title share a similar jurisprudence in both Australia and Canada resource development regimes on Aboriginal title lands differ significantly. In Australia, the process is the right to negotiate with mining proponents. In Canada, the process is the duty to consult with government regarding mining projects. This paper compares and assesses the processes for ?consultation and negotiation? with Indigenous peoples when development actions (particularly in the context of mining resource development) impact Indigenous property rights and how agreement making can be progressed. This paper will question whether the resource development processes afford Indigenous people?s property rights full respect when mining developments on Indigenous lands are proposed.

Aug 1, 2013

By Eldridge Haynes

IF you ask the average American to define 'total war' he is apt to fumble for an answer. But in Britain everyone knows the answer, because Britain has mobilized its total labour force, including women. If we were to match, proportionately to our population, Britain's mobilization of labour, we should have 60,000,000 people working full time in the armed services, civilian defence, and war industries. Actually we have fewer than 35,000,000 so employed. In Britain two out of every three persons between the ages of fourteen and sixty-five are so engaged. For the first time in the history of any democracy Britain conscripts women for service in the army, navy, and air force. Two hundred thousand British women have been conscripted for the army, known as ATS, meaning Auxiliary Territorial Service. There are more women in the air force than the total personnel of the RAF at the outbreak of the war and almost all of the land base jobs of the British navy are now handled by women. In addition to cooking and office work, Britain's women soldiers and sailors are driving trucks and motorcycles, repairing motor vehicles, packing and repacking parachutes, installing, inspecting, and maintaining gun equipment and ammunition of combat planes after each raid, raising and lowering barrage balloons, forecasting weather, manning harbour craft, sending and receiving radio messages. A normal ack-ack unit is composed of 229 women and 189 men. The women man the gun height finders and predictors, give bearings, and signal to fire.

Jan 1, 1942

By Graham Swan

The case is presented for the development of a spray-on liner for ground support, but only in the context of a new mining system, consistent with the technical and business case advantages of liners compared to alternatives. Over the past 10 years much effort has been expended in specifying and testing the mechanical/environmental properties of various liners, without actually fulfilling any mining system requirements. The results have been generally disappointing, with no consistent and sustained application in a dayto- day production environment being achieved, anywhere. Central to this shortcoming has been the failure of mining/liner ma nufacturing companies to realise that screen/mesh or shotcrete cannot simply be replaced with thin, deformable liners: success will depend upon closely defining and evolving a new, liner- functional mining system. The paper begins with a discussion of some fundamental technical capabilities and constraints associated with 3M Canada?s liner material that has been developed in partnership with Falconbridge Limited. Intended applications for this liner include the support of bursting ground associated with deep mining conditions. With safe application and consistent performance in mind, the paper argues for a new mining system that derives in the first place from best quality drilling and blasting practices. Taking this as a given, a system for waterscaling and liner application prior to mucking out is proposed, followed by bolting through the liner while arranging for the bolts to be explicitly connected to the liner. Some logistical and equipment related challenges of such a mining system are then reviewed and discussed in the context of the business case for liners. It is concluded that this approach, if successful, will provide the greatest benefits in the areas of safer mining, due to reduction in worker exposure, and in reduced mining cycle times.

May 1, 2003

By D. K. Matlock, D. J. Hamre, J. G. Speer

Ultrafine ferrite (UFF) grains may be produced in surface layers of plate steels using controlled intermediate cooling followed by deformation. Experiments were conducted using a 0.12 C - 1.26 Mn steel on a Gleeble 1500 hot deformation simulator. Taguchi designed experiments were used to evaluate prior austenite grain size, intermediate cooling rate, intermediate cooling temperature, intermediate hold time and amount of reduction in order to observe the effects of variables and their interactions on the final microstructure while minimizing the number of required test runs. Evaluation of resulting microstructures and mechanical properties revealed a preferred thermal and mechanical history for developing ultrafine microstructures in surface layers of plate steels. Application of the fundamental concepts of phase transformations to industrial plate rolling is considered.

Jan 1, 2004

By J. P. Piguet, A. Hosni, J. P. Josien, H. Baroudi, R. Hadadou

"The iron ore mines in the Lorraine region of north-eastern France cover a surface area of approximately 3,900 km2 and involve more than 150 cities. A total extraction method was usually used during exploitation, but this technique was sometimes replaced by the room and abandoned pillar technique when it was necessary to protect surface buildings and infrastructure. Rooms and abandoned pillars were initially designed to ensure long-term mine stability. However, this aim was not always reached and numerous collapses occurred in the Lorraine iron basin, either during production or several years after closure. Several subsidence events were identified during a period of one century; the most recent event occurred in 2012. Two groups of events were identified. The first group represents events characterized by sudden surface movement, and the second group includes event characterized by progressive subsidence.Numerous studies conducted during the last decade helped improve our understanding the origin mechanism of spontaneous or progressive (slow) events. These studies led to identifying long-term potentially unstable underground zones (hazard zones), particularly deep zones located under buildings and infrastructure. The latest are currently monitored by microseismic networks. A similar high requirement level is needed for unstable zones without taking into account the kinetics of the subsidence, which is very important for safety. Thus, GEODERIS initiated this study, primarily to acquire a better understanding of the kinetics of the progressive events group and identify the main parameters that could explain why some pillars zones developed a maximum amplitude subsidence on surface within a few hours or days, while it took several weeks to months for others. In practice, the results of this study will facilitate adapting the requirement level of microseismic monitoring system to the kinetics of pillar collapse.To retrieve the real kinetics for each event, historical and sparse documentation was used. Firstly, archives research was conducted, especially testimonies and newspaper articles published during the events. This work helped to gather useful information that sometimes contained a precise description of subsidence duration. The archives research helped to classify some progressive events according to the subsidence kinetics. Secondly, a diagnostic of geotechnical and geomechanical parameters of historic events was realized, combined with a cross analysis of the data. The analysis took into account dimensions of underground workings (e.g., pillar lengths, widths, heights, introduction of a “pillar shape factor”, and stress amount). An original expression was highlighted to connect the pillar geometry to the stress state. The kinetics expression was calibrated to classify the historic events taken into account according to the kinetics of movements. The kinetic criterion was applied to predict subsidence kinetics for the potential unstable zones currently monitored by a microseismic system."

Jan 1, 2015

By D. R. Griffiths

"Oxidation of pyrrhotite prcxiuces sulphuric acid which in turn leaches out heavy metals, resulting in acidic contaminated seepages. The establishment of a marsh on top of the pyrrhotite would result in an anaerobic sediment, which should prevent further oxidation of the pyrrhotite. Initial data indicates that concentrations of sulphates and heavy metals in the seepage water are greatly reduced. Further hydrogeological studies are required however, to determine if metal and acidic loadings to the environment have increased.L'oxidation du sulfure de fer produit de l'acide sulfurique qui a son tour attaque les métaux ayant pour resultat une contamination d'acide et de métal des eaux d'infiltration. L'etablissement d'une couverture faite de boue et de vase au-dessus du depot du sulfure de fer réduit les effets de l'oxidation.Les données initiales indiquent que les concentrations de souffre et de métaux dans les eaux d'infiltration sent grandernent réduites.Des études plus poussées sent nécessaires pour déterminer si les quantités de souffre et de métaux dans les eaux d'infiltration ont augmentées.INTRODUCITONPyrrhotite tailings are readily oxidized through a combination of precipitation and atmospheric oxygen causing acidification of the unsaturated zone above the water table. This reaction is usually catalyzed by the bacteria, Thiobacillus ferooxidans. As the pH decreases, heavy metals become more soluble resulting in contaminated seepages to ground and surface waters.By creating a marshland on top of the pyrrhotite, an anaerobic intermediate layer should form between the organic covering and the tailings, preventing the oxidation process from progressing.In September 1986, Falconbridge Limited implemented a tailing reclamation project that involved creating a marshland on top of pyrrhotite tailings. The following paper will discuss and illustrate the preliminary results obtained during the sampling period of May to September 1987."

Jan 1, 1988

By T. Kho, W. Zhang, M. E. Reed

The control of flash furnace heat balances is critical. Suspension smelting control and stability comes from stable operation of the heat balance, and this leads to a stable reaction shaft exit temperature. A number of flash furnace operations have been reviewed to determine if the application of this approach is beneficial for their operation. The cause and effect relationship between reaction shaft exit temperature with uptake and throat buildup is being enhanced with this work program. Our operating personnel are exposed to the operational hazards of cleaning this buildup from the throat and it is imperative that as an industry we continue to look for repeatable solutions. WorleyParsons has reviewed operational data from a number of flash furnaces and looked at the possible improvements that can be made to decrease variation in the reaction shaft exit temperature. The data assessed for each operation illustrate the need to fully understand the process inputs to the particular operation and to ensure that the control changes are correctly impacted. In the plant data that have been assessed for a number of operations combinations of feed changes and inappropriate process decisions have lead to changes in reaction shaft exit temperature which impact the overall furnace operation and the uptake shaft condition, and ultimately the boiler. INTRODUCTION In 2016 WorleyParsons jointly prepared a paper outlining the effects of heat balance control on the Olympic Dam flash furnace (Reed et al, 2016). That paper investigated the importance of heat balance control in flash furnaces and demonstrated the changes made at the Olympic Dam operation to control the heat balance in the furnace and the impact that change had. The operation is still using the tool to assist in trouble shooting performance and pinpointing problems that may lead to issues in the furnace throat and Waste Heat Boiler (WHB). As a result of the interest in the methodology and due to the issues surrounding safety and process performance caused by WHB throat buildup and damage, WorleyParsons approached a number of flash furnace operators to discuss the application of the approach at their operations.

Jan 1, 2019

By Barry Hope, Javier Rico

"Goldcorp’s Hoyle Pond mine has recently completed several projects which have impacted the overall ventilation system. The project includes extending the Fresh Air Raise (FAR) to depth, development of a new Return Air Raise (RAR), and the installation of new sensors and ventilation controls throughout the mine. Two years after the completion of #2 Winze, the mine is ramping up its ore production to 1,300 tpd (up from 1,100). To ensure safe and profitable production, a reliance upon technology has been needed to provide the required ventilation to the work areas according to the mine plan. To systematically assess the mine’s ventilation in real-time, a significant increase in remote monitoring was required. This included installing additional flow, pressure, temperature and gas sensors. The first step in upgrading the existing monitoring was to purchase airflow and differential pressure monitors and install them in key areas of the mine. This paper presents the process of expanding the monitoring capability at Hoyle Pond mine, the selected equipment and the results of the implementation. The intended goal was to improve safety while minimizing capital and operation costs. The monitors were installed in strategic locations to provide immediate feedback on the impact of changes to the primary ventilation airflows. Comparing the available sensor technologies, installing them and systematically monitoring the ventilation served as a first step towards developing a mine wide Ventilation Control System. In addition, the initial state of the monitoring and control system, with final results and the chosen solution for the mine site, are presented. INTRODUCTION The Hoyle Pond mine is located in the City of Timmins, within the Porcupine mining district, Ontario, which has produced more than 70 million ounces of gold since 1910. Currently, approximately 60% of Porcupine Gold Mines gold production comes from the Hoyle Pond underground mine. Mechanized cut and fill and long-hole mining methods are used to extract the ore. The remainder of the ore comes from the Hollinger Open Pit mine. The Dome Underground mine ceased operations in 2017. Hoyle Pond is currently mining at 1820 meters below the surface and plans to go deeper. The average dry-bulb as wet-bulb temperature underground varies according to the depth and surface conditions which has extremes of –40°C in winter to +30°C in summer. The total airflow volume pushed down from surface is 240 m3/s to accommodate the diesel-powered equipment needed for normal operations. In order to improve the quality of air underground a program has been implemented to use diesel particulate filters, starting with the truck fleet and 6-yard scoops, followed by the intention to implement the rest of the functional diesel-powered equipment and eventually move to electric equipment."

Jan 1, 2019

By McNeely DuBose

INTRODUCTORY PROSPECTING for aluminum has always been, and still is, a peculiar combination of the technical with the physical approach, and 1 want to explain my conception of the term 'prospecting' when applied to aluminum, which differs in some respects from the ordinarily accepted idea of prospecting. In the early days of gold mining, prospecting was a search in the hills and the river beds for the metal, not for its chemical combinations. And so it was in the early days of aluminum, with the difference that the search for the metal was carried on, not in the hills and dales, but in chemical laboratories. Aluminum is never found in the elemental state and at that time the metal bad never been seen, but scientists of that day bad forecast that such a metal must exist and in 1807 Sir Humphrey Davy went so far as to give this unseen metal a name, aluminum, from the Greek word alumen. This word applies to our alum, and it was from alum that Davy sought to produce the metal. It is strange to think that, in laboratories throughout England and on the continent, prospecting for aluminum was busily under way by men who had never seen the metal they were searching for. Their situation was something like that of the fisherman and the 'big one' that got away. They could describe the metal, give its exact weight, and even name it, but they could not produce visual evidence of its existence. Eventually, however, the efforts of the scientist 'prospectors' were rewarded and in 1826 the metal was actually produced, possibly first by Wohler, though Oerstedt, a Danish chemist, is usually credited with the achievement.

Jan 1, 1951

By C. C. Li

Traditionally, strong and stiff devices, such as fully encapsulated rebar bolts and concrete lining and arches, are preferred for underground rock support. The attention is paid to the strength of the devices in such support designs. It has been observed in engineering practice that support systems composed of stiff devices are often subjected to premature failure in high stress rock conditions. In the past decade, yield support devices have been employed to improve the performance of rock support systems. A rock support system usually consists of both internal and external devices that are installed within the rock mass and on the free surface of the rock, respectively. Great efforts have been made to make support devices yieldable in the past years, but the efforts are focused on different aspects in the tunneling and mining branches. In the tunneling branch, the focus has been put on the development of external yield devices, such as Lining Stress Controller (LSC), Honeycomb element and compressible concrete, which are embedded in shotcrete liners, while in the mining industry the efforts has been on the development of yield rockbolts, such as the cone bolt and the D-Bolt. The internal and external support devices are not compatible in their deformation capacities in the current rock support systems even though yield devices have been employed. All the devices in a support system should be deformable and compatible in deformation capacity. With such a support system, premature failure of individual support devices could be avoided and the service life of the support system is prolonged. It is a trend at present to take into account the energy absorption capacity, instead of simply the strength, of support devices in rock support design.

Jan 1, 2015

By R. Darlington, S. Ji

"High pressure die casting is a promising process to make thin-wall components with high dimensional accuracy and excellent surface quality. However, the non-uniformity is one of the important features in castings. The inhomogeneity in tensile properties and microstructural characteristics were studied for the castings with different thicknesses made by high pressure die-cast Al-Mg-Si alloys. For the local mechanical properties in the die-castings, the casting skin provided the highest, whereas the casting centre provided the lowest yield strength, UTS and elongation. The yield strength, UTS and elongation were significantly decreased towards the casting centre. The microstructural inhomogeneity is characterised by the segregation of coarse fragmented dendrites, the reduction of solute concentrations of Mg and Si, and the increase of porosity level from the surface to the centre of castings. The growth velocities of eutectic a-Al phase estimated using the Jackson-Hunt model confirm that the growth variation is larger in the thin castings than that in thick castings.INTRODUCTION Inhomogeneity is an inherent characteristic in as-cast microstructures of a variety of alloys because of their non-uniform chemistry, microstructure, defects, topology and the resultant mechanical properties in the different ranges of localization (Campbell, 2003). Generally, three types of inhomogeneities characterise casting microstructures, which include (a) the casting defects of shrinkage and gas porosity, misruns, cold shuts, inclusions, hot tears and hot spots; (b) the non-uniform microstructure from the surface to the centre of castings; and (c) the non-uniform microstructure from the dendrites grown from primary solidification and the structure formed during the subsequent eutectic solidification in inter-dendritic regions. The chemical composition and the morphology between the primary dendrites and the inter-dendritic eutectics also differ in the as-cast microstructure. Obviously, the inhomogeneity is different in the castings obtained from different casting processes."

Jan 1, 2018

By David F. Machuca-Mory

Modelling the geometry of a vein is a crucial step in resources estimation. The resulting models are used as mineralization domain boundaries and have a direct impact on the tonnage of estimated resources. Deterministic models are often built using time consuming wireframing techniques usually based on hand interpretation of the drillhole intercepts. Another approach consists in coding the drillhole samples by a function of their distance to the veins contacts. The coding is subsequently used for modelling the vein contacts away from drillholes. This is a more efficient approach and is able to provide a measure of tonnage uncertainty. The use of location-dependent variograms improves the modelling by incorporating local changes in the anisotropy of the vein structure. This combined approach results in more realistic vein models, particularly when the geometry of the vein has been are altered by folding, shearing and other structural processes. The approach is illustrated on a realistic case study.

Oct 1, 2009

By K. N. Karparov

?Two highwall failures in a South African coal mine defied analysis by widely accepted limit equilibrium methods. ?The geological conditions were complex, with undulating coal-bearing strata overlying a karstic topography formed in underlying dolomite belonging to the Transvaal Supergroup. ?It was clear that the simplifying assumptions made by all limit equilibrium methods were inappropriate in the conditions.

May 1, 2007

Energy benchmarking is widely applied across industries to determine the potential to improve energy performance. Unlike the many technologies for which energy benchmarks and efficiency rating systems are already in maturity, benchmarking of mining processes is still in its infancy. Benchmarking energy usage in mining operations, where energy costs are high and represent a significant portion of overall operating expenses, is challenging due to the uniqueness of each mining operation. Mines vary in terms of geology, geographic setting, ore body geometry, mineralogy which impact the mining method, material handling, processing and waste management. In order to gauge the opportunity for reducing the energy intensity of individual operations and also to compare the energy performance of operations on a global scale, the deployment of new benchmarking methodologies, models and frameworks is necessary. As a step towards the establishment of an accurate framework for benchmarking the energy consumption of mining operations, comminution, one of the more energy intensive mining sub-processes, was selected as the focus of a new energy benchmarking method. The methodologies and processes used to onset fragmentation in a rock mass to the crushing or grinding of rock to a size that is suitable for economic extraction are predominantly dependent on the ore properties. For this reason, site specific factors, such as the size reduction requirements and ore hardness were included in an energy benchmark model so that the energy performance of comminution processes at different operations could be normalized and compared on a global scale. Single particle compression breakage has been identified by several prominent researchers in the field of comminution as the upper limit of energy utilization in size reduction processes. For this reason single particle compression breakage was proposed as the basis of a work index for ores to be used as an input for the benchmark model. Overall, the new method showed that the energy benchmark for mineral comminution can be normalized and subsequently compared for a range of mining operations once the ore hardness has been appropriately characterized.

Aug 1, 2013

By Hrayr Agnerian

The fair market value of an exploration property is determined by its potential to host a mineral deposit. This potential is gauged by the results of previous exploration, exploration stage, meaningful past expenditures and remaining targets that are not yet tested. Values of exploration properties can be viewed as distinct points in a three-dimensional space defined by orthogonal axes, namely: Exploration Stage (x-axis); Cumulative Expenditures (y-axis); and Property Value (z-axis). In general, these values are estimated by applying activity factors on previous exploration expenditures, e.g. an activity factor of 100% for an active property with good potential and a factor of 50% for an active property but past expenditures have not upgraded the property. At certain periods, a market factor may also be applied to reflect the activity of mineral property acquisitions. For properties that do not exhibit any exploration potential, only nominal values are applied.

Jan 1, 1996

By S. Borle

The microstructural features produced in friction stir welded AZ31, AZ80 and AZ91 alloys are examined when different welding parameters are applied. The microstructures primarily consist of a-Mg grains with a-Mg + Mg17A112 colonies, however melted films of Mg17A112 are produced in AZ91 alloy when high rotation speeds are applied. When the rotation speeds are slow, or the travel speeds are fast the Mg17A112 were incorporated into the stir zone, however they do not exhibit an elongated lamellar morphology associated with melted films. In the case of AZ80, the extruded base material contains a smaller fraction of Mg17A112 and few of these phases are observed in the stir zones. The results are explained based on the dissolution rate and melting temperatures of Mg17A112 controlling the overall morophology and fraction of phases in the stir zone.

Jan 1, 2011

By A. A. Sizikov, V. A. Sizikova

Key parameters to consider for any producer: bring down production cost and lead time; Lean production as a tool to achieve maximum efficiency; How to implement lean principles: discontinuous vs. continuous production (aluminum industry); About RUSAL: global top-three aluminum producer; Lean tools at use at RUSAL's production facilities; Pull system, Standardization of work, Just in time, Continuous improvement, Customer-Supplier relations, etc.

Jan 1, 2006

By Shuan-cheng Gu

Roof bed separation often occurred due to the deformation incoordination of surrounding rock following the excavation of mine roadway. Bed separation has effect on the bolts, and the estimation of the influence will directly affect the safety of support systems. In this paper, the hyperbolic function model to analyze the load transfer mechanism on the bolts was simplified as the exponential function form for easy calculation. An elastic-plastic analysis model of the bolt loading occurred by the bed separation was established. And the development low that the bed separation affected to the bolt loading was discussed. According to the parameters analysis of different separation values and locations, the influence law of the bolt loading caused by roof bed separation was summarized. Finally, the effects of bed separation were considered for the bolting design, it was able to provide a reference to the anchorage design of stratified rock.

Aug 1, 2013