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By Mario E. Rossi

Geostatistical conditional simulations are becoming increasingly popular as tools that provide models of uncertainty at different stages of a mining project. They have been used as grade control tools in daily operations, to assess the uncertainty of minable reserves at the project?s feasibility stage, and to assess mineralization potential in certain settings. Other applications include assessment of recoverable reserves, resource and reserve classification, and drill hole spacing optimization studies. All large-scale applications of conditional simulations intend to benefit from the ?correct? (or ?accurate?) characterization of uncertainty, adequately describing the variability observed from the data and its impact on the final objective. The objective of this paper is to compare the ad-hoc ?uncertainty model? provided by a traditional classification scheme with the probability intervals resulting from a conditional simulation model. It is argued that the uncertainty model derived from the use of classification schemes is of little practical use to the mining company or operation. The paper emphasizes differences in uncertainty based on the size of the mining unit considered and the extraction method, and local geological differences. Most importantly, it discusses confidence intervals for these mining units, as compared to the relative precision envisioned by a typical classification scheme. The application described in this paper is taken from a medium-sized Cu open and underground mine in northern Chile, and it demonstrates the impact of several variables on the resulting conditional simulation models. It also compares a more ?traditional? resource classification scheme applied, and the wide difference in local confidence intervals for each mining unit.

May 1, 2001

By W. Dziurzynski, St. Wasilewski, T. Palka, A. Krach

"Air parameter monitoring systems, regardless of gasometrical protections, provide a significant number of measurement data. The obtained data broadens the knowledge on processes taking place in underground workings and shows the relationships and influence of machines and technological processes on the variability of ventilation parameters in the areas of longwalls. Nowadays, computer simulation methods are increasingly used to reproduce the flow of air and methane mixture in the area of longwalls equipped with shearers. The paper presents the results of a research experiment covering a long-term observation of a longwall area during mining with a shearer using sensors from the mine's monitoring system. Data from sensors for methane concentration, pressure and velocity were used and additional ventilation measurements were taken to determine the parameters characterising the air flow in the area. The influence of different machine cycles in the longwall on the changes of air parameters in the area of the longwall was shown. A numerical model of the ventilation area was developed and the computer program VentZroby was used for the calculations, which allows for the simulation of the process of ventilating the area of the active longwall during the extraction of coal with the use of a shearer and haulage of the run-of-mine. Computer simulation of the influence of the shearer's operation and the methane inflow associated with the distribution of the mixture of air and methane was carried out. The results of the simulation were compared with the data recorded by the monitoring system’s sensors during the measurement experiment. Comparison of the recorded methane concentration courses with the results of a computer simulation of the air and methane flow conditions in the mining area showed changes in the gassiness. INTRODUCTION Studies carried out in the Polish and global mining industry show that methane is an obvious factor in limiting mining production due to the loss of continuity in the operation of longwall complexes in hard coal mines under methane emission hazard (Schatzel et al., 2008). In addition, methane hazards have a significant impact on the safety of the operators of machinery in the longwall. The requirements of Polish regulations and the practice of safe operation of mining longwalls require correct determination of gas concentration, volume flow, as well as pressure and temperature of the flowing air. As part of the research undertaken in the Budryk (Wasilewski, 2010) and Bielszowice (Dziurzynski et al., 2009) mines to assess the methane hazard in the longwalls and workings in the vicinity of the longwall, research experiments were carried out, during which air parameters were recorded by the mine monitoring system and additional testing equipment in different cycles of shearer operation."

Jan 1, 2019

By A. J. Giroux

"The use of Ishikawa cause and effect diagrams in an analysis of requirements for improving safety and productivity at Falconbridge's Strathcona Mill is presented. The analysis lead to numerous small improvements being made with the cumulative effect being a significant improvement in both areas.INTRODUCTIONMill management in the 90's involves the major requirements to improve both safety and productivity in the workplace. These objectives, once seen as unrelated or even mutually exclusive, are now accepted as being complementary. Managers, trained either on the job (coming up through the ranks) or in an engineering discipline followed by first and second line supervisory experience are now turning to methods developed in consumer product manufacturing to ensure that all the components are in place to ensure the ore processing facilities are safe and efficient.This paper shows how management at Falconbridge' s Strathcona Mill used the Ishikawa ""fishbone"" diagram ( 1) , a method further developed by Deming(2), to put into place a comprehensive safety and productivity process. The Ishikawa/Deming concept is that no one element or program will itself continually improve a process or service. It is only by examining and then improving all the elements that are involved in the process or service that continuous improvement is obtained. The process was built on the Deming principle of worker ownership where management is the facilitator for putting into place the mechanisms whereby workers can themselves improve the operation. The process is illustrated mainly by examples of the changes made in the hope that these may be of direct help to other operations."

Jan 1, 1993

By M. El Tokhi, H. Arman, B. M. Amin

"This paper aims to overview some mechanical and physical features of the gabbroic rocks. The study has two phases: filed study/in-situ measurements and laboratory work. During the field studies, rock block samples were collected from different locations of the study area to represent the different types of the gabbroic rocks. Either core or rock samples for various tests were prepared from rock samples taken to the laboratory. The unconfined compressive strength (UCS), indirect tensile strength (ITS), point load index (PLI), Schmidth hammer rebound value (SHV), slake durability index (SDI), sonic velocity (SV) and unit weight (UW) test were carried out either on the selected rock block samples or core samples.INTRODUCTIONThe geology of the United Arab Emirates (UAE) has been divided into three major rock units (Lippard et al., 1986); an autochthonous succession, allochthonous units composed mainly of Mesozoic rocks and include the Sumeini Group (concomittent slope sediments), Hawasina Complex (basinal sediments) and the Semail ophiolite nappe (massive slice of former oceanic crust), that were emplaced as a series of thrust nappe in the Late Cretaceous and Neo-autochthonous sequence of Maastrichtian and Lower Tertiary sediments.The Semail Ophiolite (600 km long and up to 150 km wide) is thought by some authors (Glennie et al., 1990) to have been generated along a subduction related back-arc spreading axis during the Cenomanian-Turonian and was obducted onto the Arabian continental margin during the Campanian. Others, however, consider it to represent a primitive arc-spreading center related to oblique subduction Lippard et al., 1986). The Ophiolitic rocks in the study area comprise mantle and crustal sequences. The mantle peridotite and crustal gabbros are the dominant rock types of the exposed Semail Ophiolite north of the Hatta zone. This paper is only concentrated on the gabbroic rocks."

Jan 1, 2015

By E. Dalgaard

During linear friction welding of titanium alloy Ti-5A1-5V-5Mo-3Cr (Ti-5553), the weld zone exhibits beta (B) grain refinement and alpha (a) phase depletion that have the combined effect of deteriorating the mechanical performance of the weldment. In this work, linear friction welded Ti-5553 was subjected to pre- and post- weld heat treatments in order to determine the conditions under which a phase depletion could be mitigated in the weld zone and thermomechanically affected zone (TMAZ). The mechanical response of the welded samples to the heat treatments was determined by performing tensile testing at room temperature. While the pre-weld heat treatments had no significant effect, the post-weld heat treatments were instrumental in restoring the strength of the starting (heat-treated) material.

Jan 1, 2011

A series of field and laboratory evaluations were conducted in order to characterize the effects of a Mann+Hummel SMF-AR® diesel particulate filter (DPF) system on the aerosols and criteria gases emitted by diesel engines. This system, with a durable sintered metal filter media and available active regeneration via an on-board electrical heater, has been considered for retrofitting diesel engines used in light- and medium-duty underground mining applications. Two DPF systems were installed on a forklift and locomotive from the underground mining fleet of the Vale?s Creighton Mine and evaluated over a 1,500-hour trial. This evaluation was complemented with field and laboratory emissions tests. The field tests were performed on the vehicles while at the Creighton Mine surface shop. During those tests, the emissions were assessed for the engines operated at hydraulic stall, high idle, and low idle conditions. The laboratory tests were executed at the diesel engine emissions laboratory at the National Institute for Occupational Safety and Health (NIOSH), here the DPF removed from the forklift was further evaluated at four steady-state engine operating conditions as well as at transient conditions using a custom-designed duty cycle. Very similar methodologies were used during field and laboratory tests to measure concentrations of aerosols and criteria gases in the diesel exhaust, both upstream and downstream of the DPF system. The concentrations and size distributions of aerosols were measured using a fast mobility particle sizer spectrometer, in exhaust diluted by a partial flow dilution system. The concentrations of CO2, CO, NO, and NO2 were measured in the raw exhaust using a Fourier transform infra-red spectrometer. Both field and laboratory emissions tests showed that the evaluated DPF systems were very effective in reducing aerosol emissions from all tested engines, and for all test conditions. The systems were found to have minor effects on gaseous emissions from those engines. The findings from this study should help the mining industry to better understand the benefits and challenges of using DPF systems to control the exposure of underground miners to diesel aerosols.

Aug 1, 2013

By D. W. Duncan, A. Bruynesteyn

Acidic mine waters containing solubilized uranium have been observed in many uranium and some copper mines. In every case, the sulphide and iron oxidizing bacterium, Thiobacillus ferrooxidans, was also present. This bacterium provides the ferric iron required to oxidize u+4, both by oxidizing available ferrous iron and by oxidizing pyrite or other available sulphide minerals. This latter oxidation also provides sulphuric acid and may increase extraction by exposing more uranium. The enhancement of bacterial activity and the results of some field tests are discussed.

Jan 1, 1971

By S. Kelebek, E. Yalcin

"Diethylenetriamine (DETA) and/or triethylenetetramine (TETA) are reagents that can generally be categorized under ""flotation modifiers"". These polyamines are known to be effective for the deactivation/depression of pyrrhotite that is present in Canadian nickel-copper sulphide ores in large quantities. Recent bench scale testing on some of these complex ores indicated that chalcopyrite flotation can also be adversely affected under certain conditions involving polyamines, which may be taken to be an evidence of their specific affinity towards chalcopyrite. In general, DETA shows no significant depressant action on chalcopyrite while TETA's promotion of hydrophilicity for this mineral has been observed even in the presence of xanthate. This prompted an investigation on thermodynamic equilibria involving these polyamines and copper ions. Results serve a useful purpose to identify conditions for deactivation phenomena. CuDETA2+ and CuTETA2+ chelates as products of sequestration have large predominance areas covering a wide range of redox and pH conditions, where copper xanthate species are not stable, especially in the presence of TETA."

Jan 1, 2009

By S. Shairp

The first commercial application of the Dynatec two-stage zinc pressure leach process commenced operation at the metallurgical complex of Hudson Bay Mining and Smelting Co., Limited in Flin Flon, Manitoba in 1993. A key feature of the successful leaching operation is the presence of iron in solution, which facilitates oxygen transfer in the autoclaves and enables rapid oxidation of zinc sulphide minerals. At the same time, the solution from which zinc is recovered must be essentially iron free. Precipitation of iron from the solution starts in the autoclaves and is completed in subsequent atmospheric purification steps. Conveniently, these iron precipitation steps also remove nuisance elements such as arsenic and fluoride from the solution, while producing solids with good liquid-solid separation characteristics. This paper provides an overview of the current operations in Flin Flon, with particular reference to the behaviour and deportment of iron throughout the zinc plant.

Jan 1, 2006

By L. G. Morrell

Introduction A Self-Dumping cage which combines the features of a small skip and a cage has been used in a vertical winze between the 2,000 and 2,500 levels at the Coniaurum mine for the past three years, during which time its success has been demonstrated by uninterrupted service and low maintenance charges. lt was designed by John Reddington, mine manager, and was built under his supervision in the Coniaurum mine shops. Being new in many of its operating features, a small-scale model was made and tried before the final construction was undertaken. The mechanical performance of the model suggested a few minor changes that were incorporated in the final drawings. During its three years of use, the automatic dumping device has saved the expense of deck-handling of the cars. This actually represents a gross economy of something over four times the cost of construction and installation, which totalled $1,325. The cage, empty, weighs 2,200 pounds, of which 500 pounds represents the weight of the dumping accessory and necessarily heavier construction. Besides a considerable financial saving, the time saved in unloading increases the daily hoisting capacity of the winze. In raising ore from the 2,500 level, five minutes are required for a complete trip. Allowing one minute for the alternative of decking, we believe that the automatic dumping has increased the capacity of the winze hoist nearly 20 percent.

Jan 1, 1933

By E. Heikkinen, J. Suikkanen, T. Siren, J. Valli, M. Hakala

Diametrically faced borehole breakout observations are a fairly good indication of magnitude of the secondary stresses acting perpendicular to the borehole. In cases of low in situ stresses, where borehole breakouts are not observed naturally, it is possible to increase the prevailing stress state around the borehole by increasing the rock temperature. When the temperature is increased sufficiently, thermally induced borehole breakouts will occur. By implementing the temperature increase in boreholes located at excavated tunnels, it is also possible to study the effect of the near-field stresses caused by the excavation. The near-field stress state changes as a function of borehole depth, thus increasing the information available from experiment. To study the feasibility of this proposed low cost method, a Borehole Thermal Spalling (BTS) experiment was executed in ONKALO Underground Rock Characterization Facility, in Western Finland in 2014. The first borehole pilot test with the method was conducted in ONKALO at the POSE niche in already at May 2010, with the second pilot test following in August 2010 at Äspö HRL. The major objective of the experiments was to define the trend of the maximum in situ stress component, while also providing knowledge of the in situ spalling strength of the ONKALO rock mass. The stress state in ONKALO is nearly isotropic in horizontal layer, causing problems for the use of more traditional stress measurement methods. With boreholes heated over long interval, the weakest rock parts are observed to fail, thus providing statistical confidence. For these reasons, continuous test sections have an advantage in ONKALO, compared to spatially limited stress measurement methods such as overcoring and hydraulic fracturing. The BTS experiment is conducted in 9 meter deep vertical boreholes located at the POSE niche, situated -345 m depth below the ground surface. The boreholes used within the BTS experiment are located in migmatitic granite, in an experiment area where the surrounding stress state and the rock strength are fairly well known. The prior knowledge of the stresses is favourable for the experiment, as it requires careful planning and iterations to determine the appropriate heating power domain. Too low heating power will not be sufficient to cause borehole breakout, while too high heating power causes breakout in all directions thus making determination of stress direction hard or impossible. The initial state of the borehole and induced borehole breakouts will be monitored using acoustic televiewer logging (ABI) and optical borehole logging (OBI) imaging techniques. Fracture mechanics modelling is used in planning of the experiment, also in back-analysis to link the observed breakout angle to stress state. Both the pilot test in 2010 and BTS test in 2014 resulted in similar borehole breakout direction. The results are in line with so called EDZ & VT1 stress interpretation, revealed the maximum horizontal component bearing the magnitude of 21.5 MPa, with the trend of 166°.

Jan 1, 2015

By K. Mayhew, K. Murray

The CESL Copper Process was developed as a hydrometallurgical alternative to smelting and refining for copper sulphide concentrates. As the majority of such concentrates contain appreciable gold and silver values, effective recovery of these metals is essential to the economics of this technology. Unfortunately, conventional cyanide processing cannot be used on the residue from the copper process, clue to its unusual characteristics when compared with naturally occurring gold and silver ores. An abundance of elemental sulphur, as well as the presence of cyanide soluble copper, leads to the formation of both thiocyanate and copper cyanide which is detrimental to process economics clue to excessive cyanide consumption. This, however, can be reduced to acceptable levels by process innovations such as pressure cyanidation and cyanide recovery. This paper outlines the successful application of the CESL Gold Process to various gold-bearing copper concentrates from bench to demonstration scale.

Jan 1, 2011

Open pit production planning is a procedure consisting of multiple stages. Although all the planning stages rely on the geostatistical block models, long- to short-term plans each require their appropriate resolutions and levels of details. The main motives behind using different resolutions are the tractability of the models and the practicality of the generated schedules. The current approach in the mining industry is to use nested pits generated by Lerchs-Grossman as the basis for long-term planning and to use manually generated polygons, within those pushbacks, as the units of production control in mid- and short-term planning. However, the nested pits generated by Lerchs-Grossman algorithm and the polygons drawn by mining engineer do not provide control over the value and tonnage of ore and waste inside the planning units and therefore cannot lead to optimum solutions. In this paper, we first present a pushback determination approach which maximizes the profit of the mine with control over the tonnage of ore and waste within each pushback. We then propose a clustering approach with size and shape control that determines aggregates within those pushbacks; and finally, we introduce a mathematical programming model which uses the generated pushbacks and aggregates as the planning basis and generates production schedules that maximize the net present value of the operation and are practical from the operation?s point of view.

Aug 1, 2013

By M. H. ElMaghraby

This paper describes the development and validation of a strategy for vibration-based online detection of faults in a particular class of machinery commonly found in industry. This machinery is defined by two basic characteristics that preclude it from the application of standard online condition monitoring approaches. The first characteristic is that the machine is in a constant state of transient operation, thus making it difficult to differentiate between changes in transducer measurements that are due to variable duty and those that are due to machine malfunction or fault. The second characteristic is the fact that the machinery involves multiple sub systems that are subject to identical and simultaneous loading, operating environments and duty cycles. An example of such machinery is a system of multiple hydraulic pumps driving a common load. The monitoring strategy presented here employs an anomaly detection scheme together with methods of signal processing and feature extraction that exploit the parallel duty arrangements of this equipment. Preliminary data is collected from a pair or motor-gearbox assemblies used in a material haulage system in the mining industry. Testing and validation was performed on a mechatronic test bench with both healthy and faulted components. Experiments were carried out to investigate how various configurations of the system were able to detect different types of faults. The results indicate that this approach is effective and merits further investigation.

May 1, 2013

By Andrukaitis. E.

The increasing use of electronic equipment by the Canadian Forces has increased the importance of electric power. A power source that is packed with energy and yet light, small and durable is the common request of military users. However, this needs to be achieved while also addressing the requirements of safety, reliability and low temperature performance. The potential use of fuel cells in a military environment has become a possibility in several areas in the 21st century. Some examples of power source requirements and the materials related R&D required to give better, higher energy power systems in the future will be discussed.

Jan 1, 2005

By A. H. Duffield

"Forming part of the Prairie Evaporites, the sylvinite layer mined at Alwinsal underlies the Blairmore quicksands and the water-bearing Devonian formations. Production is achieved by a method of trackless, continuous mining of rooms, leaving pillars for natural support. The paper describes the development of the mine, and the equipment and organization employed in the operation and maintenance of the underground facilities."

Jan 1, 1972

By E. G. Baltuch

Natural Ventilation in mining and metallurgical processing applications is key to proper operation function. There are number of ventilator designs available to a project team or design engineers, the selection of which will affect both the type of building structure required, project costs and design performance which is difficult to rectify or re-engineer once implemented. Research and applied results, such as that performed by Air-Therm Inc., demonstrates that computational fluid dynamic simulation allows for 5 dimensional observation, analysis and optimization at significantly lowered cost than previously possible. These results have been fully implemented on a number of mining and metallurgical applications and the company continues to study, optimize and innovate as new tools become available to provide the best possible engineered solutions for particular applications.

Aug 1, 2013

By J. A. Finch

The metallurgical performance of a flotation cell is strongly influenced by the features of the bubble population, characterized by the gas dispersion properties, a collective term including bubble size, superficial gas velocity and gas holdup. It is required that gas be well distributed throughout the cell. Gas distribution is estimated here by simultaneous measurement of gas velocity (Jg) at different distances from the center (radial Jg mapping). This communication describes a technique to perform radial Jg mapping together with fundamentals for the interpretation of the data.

Jan 1, 2009

By L. Szecowka, M. Poskart, Siwka M. . J.

Oxides of nitrogen, created during combustion, are the most hazardous components of atmospheric pollution. However, it is possible to limit the negative influence of hazardous components on the natural environment. An experimental appartatus was built to determine the influence of the following "primary methods" on the reduction in concentration of NOx: air staging, reburning and flue gas recirculation. The influence of the simultaneous usage of the primary methods on reduction in NOx emissions was also examined. A significant increase in the efficiency of NOx reduction was achieved in two cases.

Jan 1, 2004

By J. Petit

"In July 2004 workers at the ABI Smelter in Bécancour (Quebec, Canada) went on strike. Contingency plan were ready to face the situation and plan was done to operate one potline out of three. Two lines were stopped; keeping in mind the restart on cold metal after the strike was over. The subject to be presented and shared includes a summary of work organization including training, schedule of restart, pot cleaning, pot preparation, crash start method, follow up after crash start, safety and environment. This major project has been a very big challenge. It shows that people involvement is a must and the key success. It is then true to say : ""People who believe in success will work and act in order to get there"" and ""People who don't believe in success will act in such a way to fail"" Then both will prove they were right to think their own way ! Sharing such experience can be interesting because it's a true story and people like true stories."

Jan 1, 2006