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By C. E. Baltzer, W. H. Harper

"This study has been developed to illustrate the trend and pattern of distribution applying to the quantities and costs of the fossil fuels used, and the related amounts of electricity generated, in the thermal segment of the Canadian electric utility industry.Traditionally, Canada's requirements for electric energy have been preponderantly met by hydraulic power. The need for augmented supplies of thermally generated power has mainly developed since the close of World War Il-in an era that has seen drastic decline in the production of indigenous coal and buoyant expansion in the supply of oil and natural gas. Although coal currently is faced with serious competition from the fluid fuels, the utility industry in particular promises an advancing market for coal, because of its abundant resource, at prices less likely to show sharp increase. For Canada as a whole, this trend has been progressive since 1959, and, unbelievable as it may now seem, the extent of the advance by 1975, particularly in Ontario and the Prairie Provinces, may well be as much, or even more, than the present rate of consumption for all purposes.The text and the tables and charts are arranged to focus attention on: the growth of thermal genera ting capability; the historical trend in consumption of fuel and the related production of electricity; patterns of distribution by types of fuel and thermal capacity; the relationship of steam to other sources of thermal capacity; and the quantities, costs and related percentages of electricity generated by types and kinds of fuel used, both regionally and provincially."

Jan 1, 1966

By George H. Hope, Steve Ciccone

"The Red Dog Mine is both the largest known zinc reserve and the largest zinc producer in the world. The mine started in 1989, and by 1999 had increased production from approximately 300,000 tonnes per year (t/yr) of zinc concentrate to in excess of 900,000 t/yr. The VIP Mill Optimization Project further increased zinc concentrate production to 1.1M t/yr while improving both product quality and zinc recovery. The Mill Optimization project also addressed a number of issues related to risk reduction: power generation capacity, water treatment capacity and concentrate thickening. The project was faced with numerous challenges, the most daunting of which was the schedule. This US$105M project was executed, from conception to completion, inside of two years. Less than nine months elapsed from concept to delivery of materials and equipment to site. The project also faced a 100-day ice-free shipping window, the challenges of construction in an Arctic environment, and an extremely tight labour market for qualified craft personnel. These challenges were successfully addressed with several innovative approaches to project execution, including an Alliance contracting arrangement between the owner, engineer and contractor; full integration of the team; construction of modules in Anchorage; and fast-track engineering, procurement and construction.INTRODUCTIONThe Red Dog Mine, which began operations in 1989, is located above the Arctic Circle in Northwest Alaska, approximately 145 km north of Kotzebue (Figure 1). An 80-km road connects the mine site to the DeLong Mountain Transportation System (DMTS) port site. Red Dog is the largest known zinc deposit in the world, with known reserves totalling 94.5M tonnes, and is the largest zinc producer with a concentrate production rate of more than 1.1M t/yr.Open-pit mining is by typical drill, blast and load operation using moderately sized mining equipment. Ore is processed through conventional crushing, grinding, and flotation to produce separate lead and zinc concentrates. Filtered zinc and lead concentrates are trucked year-round to the DMTS port site, where they are stored in two A-frame buildings, 330 and 440 m long. A lightering barge system is used to transfer concentrate from the shallow water load-out to deep-sea vessels anchored approximately two miles offshore. Shipping is limited to a 100-day, ice-free window beginning in early July."

Jan 1, 2003

By A. Montera, M. Loken

"The process of blending consistent and predictable feed for the roasters is critical for optimizing product quality and controlling production costs. To assist in this process, online PGNAA slurry analyzers have been installed and evaluated at a Sudbury Ontario smelter. They are used to measure 100 % of the full process stream to obtain elemental composition data in real time. This paper explains the application details at Sudbury and the benefits achieved from their full stream, elemental slurry analyzers.INTRODUCTIONSudbury Integrated Nickel Operations (Sudbury INO), a Glencore Company, consists of two underground nickel/copper mines in Sudbury, Nickel Rim South and, Fraser, along with the Strathcona mill and the Sudbury smelter. The facilities are spread throughout the 60 kilometer-long, oval-shaped geological formation known as the Sudbury Basin (Figure 1). The company has been mining nickel-copper ores in the Sudbury area since 1929. Nickel and copper are the primary focus of operations at Nickel Rim South and Fraser. Other base metals such as cobalt and precious metals are also produced.The Strathcona Mill receives ore from Nickel Rim South, Fraser, and third-party miners to produce two concentrate streams. One is a nickel-copper concentrate for use by the Sudbury Smelter; the other is a copper concentrate which goes to other Glencore operations for smelting and refining. The Sudbury Smelter converts the mineral concentrate into a high grade matte containing nickel, copper, cobalt and platinum group metals. This matte product is shipped to Glencore's Nikkelverk refinery in Norway for further processing. In 2015, the Sudbury INO Smelter completed the first phase of the Process Gas Project (PGP); a series of process changes and capital investments designed to reduce sulphur dioxide (SO2) emissions in accordance with Ontario Regulation 194. A critical element of the planned emissions reduction was the elimination of a higher percentage of sulphur contained in input concentrate streams, which can then be captured and converted to sulphuric acid."

Jan 1, 2017

By F. Gaul, H. R. Manouchehri, A. Mosser

"Mining is a major energy intensive industry that contributes in consuming about 7% of the total world’s energy in which almost half in comminution. The underlying trait that drives energy consumption upwards appears to be somewhat persistent due to increasing in population, demands and growth rate. High grade resources have been/being depleted; consequently, low grade, high competent and complex ores with complicated geological structure are brought into perspective. For efficient extraction of values from such resources comprehensive multistage mining and processing strategies must be taken into account. Different treatment technologies, including ore sorting, must be considered to improve resource efficiency and productivity while taking into account the reduction in energy and water consumptions and related sustainability issues.The implementation of sorting technology in mining industry has a long past and its impacts on improving the overall efficiency of both mining and milling have been proven. However, the lack of complete understanding of its potential combined with ore complexity and low capacity of sorting machines have prevented the large scale application in mining industry. The application of X-Ray transmission sorting at Mittersill Tungsten Mine in Austria is presented and discussed herein. A technoeconomic analysis of the technology has revealed a significant potential of adding value to the concentration process. The rough feasibility study has given a strong feed-back on profitability and short time payback of about 2 years for the investment. Except the economic benefits the technology has positive environmental impacts. The potential for saving energy and water is large. The rough calculations have revealed that the energy saving can be up of 840MWh/annum. Furthermore, the ongoing cooperation between Mittersill mine and the sorting manufacturer is a good example on how the development of more competitive products, and product offerings, can be made."

Jan 1, 2016

By Eirik Sundvor, Hany Doss, Peter Vogt, Kathleen Crane

"Abstract - In 1989-1990, the SeaMARC II side-looking sonar (11 to 12 kHz) and swath bathymetric system imaged more than 80 000 km2 of the seafloor in the Norwegian-Greenland Sea and southern Arctic Ocean. One of our main goals was to investigate the highly oblique (115°) junction between the Mohns and Knipovich ridges, and to determine, using new morphotectonic data, whether or not this junction is stable or in a state of readjustment. These findings are presented in this paper.Along the northern Mohns Ridge, we observed a highly segmented rift valley undisturbed by transform faults. In contrast to the elevated Reykjanes Ridge, the Mohns Ridge is dominated by deep en echelon fault-bounded troughs, which are bordered by high rift valley volcanoes. These segment boundaries are interpreted to be sites of recent to present volcanic activity, based on their high acoustic reflectivity. The northwestern flank of the Mohns Ridge is marked by shallow quasi-linear ridges parallel to the present orientation of the Mohns Ridge. The orientation and geographic position of these ridges suggest that they were formed at the Mohns Ridge. Only in the northernmost cases are some of these off-axial ridges non-linear. The degree of the non-linearities increases slightly with proximity to the Mohns-Knipovich bend. In addition, because no transform fault was detected between the Mohns and Knipovich ridges, we conclude that the Knipovich Ridge must be obliquely spreading to the NW-SE."

Jan 1, 1999

By Maria D. Mastalerz, Wei Wang, Maria E. Holuszko, Amit Kumar

In this study, the micro-FTIR analysis was used to investigate in-situ surface properties of coal and its components (macerals) and these were directly correlated to the coal hydrophobicity as measured by the contact angle before and after reagent addition to understand the suitability of the reagent for flotation. The micro-FTIR technique can provide a semi-quantitative analysis of the chemical functional groups on coal surface, exactly where the contact angle is being measured. Selected functional groups and their ratios that provide information about aromaticity, the contribution of oxygenated groups, and aliphaticity are used to evaluate the reactivity between reagents and various coal components. The observations made in relation to the susceptibility of some reagents towards certain coal components should lead the way to a smarter way of using process design in terms of reagents selection for coal flotation.

Jan 1, 2017

By Andrew Bamber

The mining and beneficiation of minerals is the second largest end-use of electrical power on the planet, and comminution is by far the largest single contributor to this. Several jurisdictions, including British Columbia, have, in response to concerns about greenhouse gas emissions and climate change, adopted energy conservation legislation, including carbon taxes, carbon trading and conservation incentive schemes. Key to achieving conservation objectives is firstly an understanding of usage metrics across the various unit operations in the sector, and secondly an understanding of the conservation potential represented by available technologies and approaches in reducing end-use. This paper presents the results of a recent utility-funded study on energy use metrics and conservation potential at large open pit mines which are typical of the sector in BC.

Aug 1, 2013

By Dogan Paktunc, Larry J. Hulbert, Robert C. Carne, D. Conrad Grégoire

Abstract -A thin layer of stratiform Ni-Zn-PGE sulfide mineralization of sedimentary-diagenetic origin was deposited during the Middle to Upper Devonian in the euxinic "Nick basin". The mineralized unit (2:3 cm thick), which seems to have been developed over the entire sedimentary basin of >80 km2, consists of pyrite, vaesite (NiSi), and sphalerite. The average grade of the mineralization is about 5.3% Ni, 0.73% Zn, ?770 ppb (PGE+Au), and up to 61 ppm Re. Anomalous Se, As, Mo, P, Ba and U are present. A minimum of 0.90 x 106 tonnes of Ni were deposited in the basin (based on a bed thickness of 3 cm) during the Devonian. The unique metal association, extensive lateral distribution, persistent metal grade, mineralogical makeup, and stratigraphic control demonstrate that this is a new deposit type and a new geological environment for Ni and PGE +Au. The sulfide layer occurs at the base of a Phosphatic Chert Member which is underlain by a distinctive marker unit consisting of concretionary limestone structures. The limestone spheroids may represent a vent-specific carbonate facies developed adjacent to faults that emanated nutrient­ rich hydrothermal discharges just prior to the main mineralizing event. The suite of elements associated with the Nick mineralization suggests that the ore-forming metals were originally bound to organic matter derived from decaying marine organisms. Discharge of hot brines bearing organic­ matter-bound metals took place along numerous conduits within basin faults that are now manifest as bitumen veins. Our syndiagenetic model proposes that these fluids were discharged laterally from the conduits into the unconsolidated bottom sediment (ooze). The introduction of this metalliferous fluid, rich in organic matter, stimulated biological activity and bacterial reduction of its contained S04 to sulfide. Hot, dense, laterally migrating hydrothermal fluid precipitated thin sulfide-rich 1arninae within bottom sediment. Published thermodynamic studies suggest that the diagnostic vaesite­ pyrite assemblage crystallized at approximately 138°C. The ?34:S values range from -14.7 o/oo to-10.0 o/oo and are up to 34 o/00 lighter than locally surrounding sulfides and age-equivalent mineralized strata elsewhere in the Selwyn Basin. The ?13:C values of calcite in the footwall of the mineralized unit ( -12 o/00 to -6 o/00) are isotopically much lighter than regional values. The lighter isotopic character is attributed to the hydrothermal discharge of fluids enriched in organic compounds. Although geochemical profiles of the lower Earn Group sediments that host the Nick mineralization reveal that these black shales are not distinctive, the unusual Ni, Zn, PGE, U, Ba, and P elemental associations and their anomalous concentrations in stream sediments can be used to explore for this deposit type.

Jan 1, 1992

By Qiling Zhang, Zengqian Hou, Xiaoming Qu

Abstract - The Okinawa trough is an active back-arc-spreading center in which submarine hydrothermal exhalation (black chimneys) and sulfide mineralization are forming. Fluid inclusion composition in minerals of the hydrothermal feeder zones in the JADE field shows that the hydrothermal systems are extremely gas-rich. There are two independent and co-existing fluids, CO2-hydrocarbon and saline fluids. Microthermometry and Laser Raman Microprobe (LRM) analyses on individual fluid inclusions of the CO2-hydrocarbon type, dominated by CO2 and containing minor CH4, C2H4, C2H6, N2 and H2S, are almost equivalent to the fluid inclusion composition of a natural gas field. The saline fluid is mainly composed of H2O and contains minor Na+ and K+. It is close to a H2O-NaCl, or H2O-NaCl-KCl system, with salinities from 3.7% to 7.5% NaCl eq. Before venting on the seafloor, the fluids experienced immiscible separation. One of the end-member fluids is downward circulating seawater that interacted with sub-seafloor rocks. The other was gas (volatile)-rich fluid derived from a shallow magma chamber. The immiscibility separation of fluids resulted from the decrease of temperature and pressure of the hydrothermal system and continuous input of magmatic volatiles. The saline fluids in this system are discharging to form sulfide chimneys and black smoke. Meanwhile, CO2-rich fluid discharges as CO2 bubbles through hydrate pipes. A large amount of CO2-CH4-H2S gas or fluid in the upper part of the hydrothermal system, and reaction of this gas or fluid with saline fluids, finally enables the accumulation of metal sulfides.

Jan 1, 1999

Applying DEM to prediction of tumbling mill performance is challenging because several different modes of breakage are active in the process. As our knowledge of breakage and computational capacity improve, it is worth revisiting previous simulation tasks which did not produce a satisfactorily realistic description of a measured process. At SAG 2006, we reported the simulated and measured outcomes of treating a well characterised ore in a 1.2 m diameter mill. This well instrumented, pilot scale mill at the University of KwaZulu-Natal has been combined with some new approaches to ore testing to allow different modes of breakage to be tested. The mill design allows the rate of generation of fine material to be measured in close to real time for autogenous and SAG mill charges. The updated simulation model estimates mass loss with particle evolution and embeds the cumulative damage and breakage. The simulated results are compared with the measured results. Issues such as relating modelling inputs to particle breakage characterisation data and the accuracy of the predictions of the models are discussed.

Jan 1, 2012

By K. Scalise, M. Teixeira, K. C. Kocsis, J. Parrish

"This paper aims to introduce and discuss a newly developed algorithm, which can be uploaded on smart watches and other mobile devices to inform and protect underground personnel working in hot and humid environments. Using this algorithm, the metabolic rate (M) of a worker can be determined in “real-time”. In addition, besides warning signs and alarm signals emitted by the smart watch, the algorithm has the ability to determine work-rest time periods based on the worker’s physiological parameters (e.g. age, height, weight, gender) and the climatic parameters (Td, Tw, flow velocity). This paper also investigates whether a re-designed auxiliary ventilation system can provide appropriate work conditions in the production stopes. INTRODUCTION An underground environment with high temperature and humidity conditions generated from various heat and moisture sources can significantly affect the thermoregulation processes of the human body. This can lead to heat-related illnesses such as heat rash, heat cramps, heat exhaustion, and heat stroke. Heat stroke is a serious illness that carries a high risk of fatality, if the underground workers are not immediately treated and the climatic conditions are not corrected (McPherson, 1993). There are two methods used to control the climatic conditions in underground mines: (1) Using ventilation and cooling systems to reduce the thermal stress on the mine workers, and (2) Reducing the heat transferred to the ventilating air from major sources such as: strata, auto-compression, mining equipment, groundwater, blasting, etc. The heat from strata and auto-compression is transferred to the ventilating air at varying degrees, based on factors such as the virgin rock temperature (VRT), the thermal properties of the surrounding rock formations, and the surface air temperature. However, the use of mining equipment and blasting processes can be managed to reduce their contribution to the mines’ overall heat load. To provide appropriate work conditions, selecting the most suitable cooling method depends on the level of heat to be removed, the location of the problem areas, and economic constraints (Brake & Bates, 2002; McPherson, 1993). Because every mine is unique, it is essential to monitor the climatic conditions to select the most appropriate method of cooling. A majority of the time, simply adjusting or re-designing the auxiliary ventilation system can efficiently remove the heat and dilute the contaminants. This may involve moving the ducting system, changing the size of the duct, changing the size of the auxiliary fan, or switching from forcing to an exhausting fan arrangement. If the required air volumes are higher than the existing primary ventilation system can supply, other measures may need to be taken to increase the airflow delivery. This may include regulating the flow in some areas of the mine to increase airflow to the desired area, adding booster fans, or replacing the primary fans."

Jan 1, 2019

By Darrell McClarty, Roger Payne, Matt Haggis, Michael Courtin, Deborah Berthelot

"Over forty years of uranium mining in the Elliot Lake region of Ontario (I 956-1996) has resulted in the production of over 300 million pounds of uranium. With the completion of mining activity, Rio Algom Limited and Denison Mines Limited are utilizing progressive environmental technologies and management systems to reduce and manage the environmental risks associated with the 150 million tonnes of potentially acid-generating tailings in nine regional waste management areas. Water covers designed to reduce oxygen entry and thereby significantly inhibit acid generation have been applied at six of the sites with the Quirke site serving as a demonstration site for the Mine Environmental Neutral Drainage program. All five of Rio Algom Limited' s effluent treatment plants are monitored and controlled from a central control station utilizing a Supervisory Control and Data Acquisition (SCADA) system based on ""Fix Dmacs"" technology. Scheduling, auditing and reporting of plant operating and environmental monitoring programs for the entire watershed are controlled utilizing the Regional Environmental Information Management System (REIMS). Proper application of these technologies and management systems facilitates delivery of cost-effective environmental monitoring, care and maintenance programs at these sites and provides tools to demonstrate compliance with all environmental performance criteria.IntroductionCost-effective management of multiple tailings management areas distributed throughout a 35 km watershed requires the application of leading-edge environmental technologies. Long-term monitoring, care and maintenance costs must first be minimized through the application of decommissioning technologies that inhibit acid generation and minimize the release of contaminants from the sites. On-going operating costs must then be controlled through the application of environmental management strategies that optimize the allocation of resources while ensuring compliance with regulatory and Company environmental requirements.Using sites in the Serpent River Watershed as an example, this paper demonstrates the effectiveness of water covers as a decommissioning strategy to inhibit acid generation. In addition, the Telemetered Environmental Operating Control System and Regional Environmental Information Management System are reviewed as examples of the application of environmental technologies to the management of environmental programs."

Jan 1, 1998

By Robert A. Creaser, Iain Mitchell, Robert L. Linnen

Abstract - The Bermuda Zn-Pb showing is hosted by dolomitized Blue Fiord Formation of Devonian age, located east of the Ensorcellement dome on the Grinnell Peninsula of Devon Island. Fluid inclusions in hydrothermal calcite indicate that the mineralization precipitated from low-temperature, highly saline brines. The ?34S compositions of sphalerite, galena, and marcasite range from 16.1‰ to 35.2‰. Consequently, the Bermuda showing is interpreted to be Mississippi Valley-type (MVT) mineralization. The apparent age of mineralization has been determined by the Rb-Sr method from sphalerite separates, and a Late Devonian age of 357 ± 50 Ma (MSWD=65), with an initial 87Sr/86Sr ratio of 0.7083 ± 0.0020 is indicated. This date, within error, is the same as the Polaris deposit. This suggests that the mineralization formed during the Ellesmerian Orogen, although it is also possible that mineralization is associated with extension, related to the opening of the Sverdrup basin. The strontium and sulfur isotopes and fluid inclusion analyses indicate the involvement of a brine that acquired its salinity from interaction with evaporites, lower in the stratigraphic succession. The Polaris mine is the type deposit in the Cornwallis Zn-Pb district and is hosted by the Thumb Mountain Formation. The results of this study are significant because they demonstrate that regional brine movement is more widespread than previously recognized, and that MVT mineralization in the Cornwallis Zn-Pb district is not restricted to the Thumb Mountain Formation.

Jan 1, 2004

By Ainul Akhtar, Steve Cockcroft, Daan Maijer, Carl Reilly, Lu Yao, Jun Ou

A coupled thermal-fluid flow-multicomponent model has been developed to aid in understanding the melting/dissolution behavior of solid Al-rich Material (TiAl) in a liquid titanium pool produced by an electron beam. The model is capable of accounting for the significant phenomena present affecting heat, mass and momentum transport including thermal and compositional buoyancy and Marangoni forces, Darcy attenuation, evaporation, melting and solidification, and the associated release or absorption of latent heat. The modeling results have indicated the compositional fluid flow driving forces (compositional buoyancy and Marangoni forces) contribute significantly to the melting/dissolution process. The model is waiting for validation against empirical data.

Jan 1, 2014

By F. Hassani, R. Mikaeil, B. Ferdowsi

Two analytical solutions for estimating the ovaling deformation and forces in circular tunnels are widely used in engineering practice, due to soil-structure interaction under seismic loading. This paper discusses the discrepancy between the two analytical and finite difference methods. A comparison of the two analytical methods shows that the calculated forces and displacements are identical for the condition of full-slip between the tunnel lining and ground. However, the calculated lining thrusts differ by an order of magnitude when considering no-slip between the tunnel lining and the ground. The analytical solutions are compared to numerical analyses of the no-slip condition using the finite difference method to validate which of the two methods provide the correct method. To achieve the goal, numerical modelling, field data of the Kuhin railway tunnel and Manjil earthquake characteristics are used. Numerical analysis results agree with one of the analytical solutions that provides a higher estimate of the thrust on the tunnel lining, thus highlighting the limitation of the other analytical solution.

Jan 1, 2008

By I Wilkomirsky, F. Parada, R. Parra, E. Balladares

"The neutral roasting of As bearing copper concentrates is confirmed well established and promising option for the treatment of this type of complex concentrate. The AS elimination by volatilization allows subsequent treatment of the calcines produced in a conventional pyrometallurgical process, by blending this product with standard concentrates.Several tests were performed using the fluidized bed pilot plant at the University of Concepción with different types of concentrates. Calcines, fines from two hot cyclones and flue dust from the ESP were collected. These materials were characterized using QEMSCAN® and the results used for the development of a mass and energy balance which took into consideration the specific chemical transformations that occurred in the reactor.A physico-chemical/kinetic model is proposed to explain the formation of bornite, chalcopyrite and magnetite. The mechanism involves solid-gas reactions between chalcocite, pyrrhotite and gaseous sulfur that without the mineralogical characterization would not have been possible to propose"

Jan 1, 2014

By J. Severin

Surface mining operations are increasingly involving the design and development of deeper and larger open pits, often with plans to transition into underground mass mining operations. Experiences at the Palabora Mine in South Africa demonstrate the complex interactions between underground workings and the steep slopes above that may lead to slope movements that potentially pose safety and economic concerns. To properly assess the rock mass response to these interactions for planning of future developments, understanding the controlling influence of geological and geomechanical structures is crucial. Preliminary results are presented from a detailed review of historical slope monitoring data from the Palabora Mine, before and after the initiation of block caving 400-m beneath a 800-m deep pit. This paper demonstrates that a detailed analysis of geology and monitoring data can be used to better understand the kinematic controls of complex rock slope displacements and interactions between open pits and underground mines. This investigative treatment of the monitoring data is important in understanding the failure mechanisms prior to undertaking sophisticated 3-D numerical models.

May 1, 2009

By Michael Drozd

"The operation of an activated charcoal system has five separate unit operations. These unit operations have common points for CIP, CIL and CIS system, which vary widely in application.The unit operations are:a. Absorptionb. Desorption (Stripping)c. Acid Washingd. Reactivatione. Carbon Handling (carbon transportation, sizing, dewatering, etc.)Cost optimization starts with the basic operating parameters (design philosophy) set down at the time of engineering design. These parameters undergo almost immediate change due to site specific ore requirements, throughput changes, operator requirements or reagent availability.Activated charcoal is sometimes viewed as simple, uncomplicated reagent that requires not optimization. To some extent, this statement is true, but under most circumstances, if the time necessary to optimize the use of activated charcoal is available, the effort is rewarded with significant savings. CPL-Carbon Link has embarked upon a program of supplying technical support with its activated charcoal. Several operations in the United States have undertaken to have CPL-Carbon Link do an operational survey to determine if potential savings are possible. CPL-Carbon Link has offered to do these surveys for projects that are clients or simply would like to have CPL-Carbon Link review their operation. The information accumulated by CPLCarbon Link is being used to attempt to fashion industry standards so that a common reference point can be established for activated charcoal usage."

Jan 1, 2008

"Abstract - An estimation of resources of structurally complex gold lodes and stockworks represents a challenging task for geoscientists due to the complex geometry of the lodes and discontinuous grade. In the present case study, the resource of a gold stockwork has been estimated by uniform conditioning after the lode has been subdivided into geostatistically defined domains using the indicator probability model. The indicator probability model represents a powerful tool for structural interpretation of the mineralization and can be applied when traditional 3D volume constraining methods (wireframing) have failed to produce a unique, non-subjective model. For comparison, the resources of the same zone have been estimated without domaining. Results of the study clearly show that estimates obtained without domaining of the mineralization can yield a substantial error due to excessive smoothing of the grade.Application of uniform conditioning for modelling the grade distribution has a significant advantage over linear methods (e.g., ordinary kriging). Uniform conditioning enables estimation of local recoverable resources at different selective mining unit sizes that can be substantially smaller than the drilling density without creation of biases or over smoothed local values."

Jan 1, 2002

By Rita Aiello, Stan Mack, Peter Werth, Joseph McCarney, Jozef Stachulak

"Johnson Matthey has developed the first diesel particulate filter (DPF) for underground mining that controls particulate matter (PM) at the same time as maintaining emissions of NO2 at or below engine baseline levels. DPF technology is critical for controlling PM which is classified as a carcinogen, but passively regenerating systems rely on the use of oxidation catalysts that can potentially increase NO2 emissions. This paper reviews the development of low-NO2 PM control technology and the results from testing this technology underground on diesel mining equipment. KEYWORDS Decomposition catalyst, Diesel particulate filter (DPF), Diesel particulate matter, Mining Continuously Regenerating Trap (CRT®), NO2, SCR INTRODUCTION The introduction of diesel particulate filter (DPF) technology on heavy duty diesel (HDD) engines has been an important step towards addressing the clean air and health concerns for mining companies. Control of diesel particulate matter (PM) emitted from diesel engines is already being implemented for on- and off-road vehicles, and similar legislation is being prepared for mining equipment. In addition to PM, the diesel emission control strategies (DECS) also reduce carbon monoxide (CO) and hydrocarbons (HC). Some DECS control oxides of nitrogen, or NOx, which is composed of NO and NO2. Johnson Matthey has led the development of emission control technologies for diesel engines for almost 30 years. Over the last ten years alone JM has supplied over 3 million Continuously Regenerating Trap (CRT®) DPF systems for on-road vehicles, and over 200,000 systems for off-road vehicles. The patented CRT technology combines a diesel oxidation catalyst (DOC) with a DPF to effectively trap harmful PM from diesel exhaust, while removing CO and HC. The DOC converts part of the engine NOx to NO2, which reacts with the trapped soot to regenerate the filter. As engines become more fuel efficient, less waste heat enters the exhaust. This can be a disadvantage for after-treatment systems as it leads to lower catalyst operating temperatures. The CRT system regenerates passively, without addition of heat, at temperatures that are typical of diesel engine exhaust. JM recently launched the Mining CRT system which integrates CRT technology with NO2 abatement to reduce PM and tailpipe NO2 from underground diesel mining equipment. This is the first technology proven to control both PM and NO2 emissions for a cleaner, healthier working environment. The Mining CRT is also cost-effective compared to other technologies."

Jan 1, 2019