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By J. Y. Kim

This paper presents a novel action recognition method for observing human workers using interactions between actions and related objects on an internal construction site. This method can be used to measure work rates for labour productivity monitoring. This monitoring is critical because the performance of a construction project is significantly impacted by labour productivity. However, construction sites are generally crowded with a large number of workers and objects. Such congestion disrupts the accurate, automatic recognition of construction workers? actions. This congestion is one reason that existing automatic action recognition studies of construction areas mainly focus on workers? actions themselves. However, the crowded conditions mean that sites could offer a great deal of clues that could be used for automatic action recognition. According to psychological studies, interactions clearly take place between human actions and related objects, such as between hammering and a hammer. Humans use these interactions to recognize actions or objects more accurately. On the construction site, workers, materials, tools, and equipment are carefully planned out ahead of actual construction. The categories of workers and objects are pre-defined and, as noted, specific interactions define relations between worker actions and objects. In this paper, the interactions are limited to human workers and their hand-held objects. Action recognition results can be combined with hand-held object information to improve recognition accuracy. With the limited interactions, experiments in this paper show a significant improvement in action recognition. This paper describes the utilization of these interactions to improve construction action recognition accuracy based on human skeleton data and 2D color video from Microsoft KINECT sensor.

Aug 1, 2013

By L. Xia, B. Hart, J. Nigim, Z. Chen

"Grinding ore is an important step in the flotation process. Not only does grinding reduce particle size and liberate minerals, it also creates conditions for reactions to occur on particle surfaces that can aide or inhibit flotation. There have been numerous studies examining various grinding regiments and the effect on flotation pulp chemistry, including autogenous grinding and using media of variable composition. There have been however, few studies looking at the effect of variability in grinding media size on pulp chemistry and subsequent flotation. This study attempts to link changes in pulp chemistry in response to variations in grinding media size to flotation recovery. It uses probes mounted in the grinding chamber (pH, Eh, DO, and conductivity) to monitor pulp chemistry changes during grinding of a Cu-Zn ore. Surface chemistry analysis by ToF-SIMS was performed on sphalerite from the mill discharge. Activator and depressant species were monitored on the mineral surfaces and their presence was evaluated in the context of variability in pulp chemistry linked to differences in grinding media and its ball size.INTRODUCTIONIt has been widely recognised that not only does grinding reduce particle size and liberate minerals but the grinding environment has a large effect on the flotation of sulphide minerals. This effect is attributed to Eh change, iron hydroxide coating on surfaces, oxygen reduction, precipitation from solution and galvanic coupling (Grano, 2009). As early as 1960, it was reported that after grinding the ores in an iron mill the natural floatability of sphalerite was reduced significantly (Rey and Formanek, 1960). Kocabag and Smith (1985) studied on the industrial circuits showing that the depression of sulphides flotation in a steel mill is possibly due to the coating of iron oxidation products. Peng, Grano, Fornasiero, and Ralston (2003a, 2003b) found that iron contamination from grinding media plays a dominant role in depressing galena and chalcopyrite flotation. Huang, Grano, and Skinner (2006) reported the same observation in the flotation of arsenopyrite."

Jan 1, 2016

By Troy Boisjoli

Since its discovery in February 2014, the Arrow Uranium Deposit has undergone rapid development through aggressive and systematic drilling programs and is now being progressed through advanced engineering and permitting. Based on the 2018 NI 43-101 Technical Report, the Probable Mineral Reserve estimate totals 234.1 million (“M”) pounds (“lbs”) triuranium octoxide (“U3O8”), contained in 3.43 M tonnes at an average grade of 3.09% U3O8. The proposed processing plant at the Rook I Project (the “Project”) will be capable of producing up to 31 M lbs of U3O8 per year, with a projected mine life of nine years based on the Probable Mineral Reserve estimate, although NexGen is permitting a 24-year operating life at the Project assuming the majority of Inferred Mineral Resources are upgraded to Indicated Mineral Resources with continued mineral resource development drilling. The Project will be developed through transverse and longitudinal longhole mining methods, pairing primary and secondary stoping techniques with a high degree of equipment mechanization which will provide a combination of good productivity, high extraction, and stable back support. This next generation of uranium operations combines the use of advanced tele-remote equipment and instrumentation with a low-cost bulk mining method and a best-in-class tailings management practice, effectively reducing operating costs and setting a new standard for elite environmental and social practices.

Jan 1, 2020

By LUKE O. LINDOE

A major clay products industry in the Medicine Hat area since before 1910 has maintained a continued interest in the clays of the Cypress Hills. For the first forty years the materials used were local red-burning Cretaceous and Pleistocene clays and sands and high-quality stoneware clays of the Whitemud Formation at Eastend, Saskatchewan. Recently a much broader spectrum of raw materials has been brought into use. Including the exposures of the Eagle Butte structure, the Cypress Hills present a 1200 m section of clay-like sediments. Of this 1200 m about 94 per cent, the high montmorillonite shales of the Upper Cretaceous, can be considered useless, or nearly so; the remaining six per cent, all fresh-water beds, presents a wide variety of potentially useful materials. The development of these clay resources is complicated by deep surface creep on the south flank of the Cypress Hills, by largescale slumping on the north flank and by a structural complex in the Eagle Butte area.

Jan 1, 1984

By R. Roufail

Mineral liberation is accomplished by comminution and is the first step towards achieving successful downstream processes such as flotation or leaching. In metal mining, one of the most effective comminution methods that is used to grind particles below 10 microns is stirred milling. In this paper the study of particle breakage mode vs. mill operating parameters is addressed. Stirred mills' grinding action is mainly attrition, but operation can be manipulated to include breakage by compression or impact loading. Macro and micro analysis of particle breakage and grinding mechanisms are correlated. Macro analyses convey information that relates grinding mechanism to particle size and shape. It is speculated that the breakage mechanism in the horizontal stirred mills is massive fracture for the coarsest particles and attrition (abrasion) close to the grinding limit where the size reduction ratio approaches 1.0. For micro analysis, the particle breakage mode has a direct impact on fracture type either transgranular or intergranular. Intergranular particle breakage leads to higher mineral liberation compared to transgranular breakage. Similar minerals would have more homogeneous properties that convey a stronger bond compared to dissimilar, heterogeneous mineral bonds. Transgranular fracture requires higher energy than inter granular fracture; trans granular fracture toughness of pure single phase mineral is about 10-14 % higher than the intergranular fracture toughness. This communication presents the results of an investigation to assess how operating conditions can affect trans- vs. inter-granular breakage.

Jan 1, 2009

By P. Turcotte, E. Karampinos

"Construction of underground excavations in squeezing ground conditions faces several technical challenges that can result in delays in production and high costs due to rehabilitation. A review of the behaviour of drifts under squeezing ground conditions was undertaken at the LaRonde mine. In particular it focused on implemented strategies to control the observed large deformations. The mine experiences a large range of squeezing ground conditions, mostly driven by the presence of foliation and high stresses. This results in large deformations over one meter in radius. A comprehensive ground control strategy has been implemented with the aim to manage, rather than arresting drift closure. The evolution and effectiveness of the employed support strategy are discussed based on documented field observations. In complement to the field implementation numerical models are used to provide further insight on the observed squeezing conditions.INTRODUCTIONThe development of underground excavations under squeezing ground conditions is usually associated with excessive rehabilitation and significant failure of ground support due to large deformations. Cost research case studies have concentrated on squeezing ground conditions in tunnelling. An overview of the methods used for the identification and quantification of squeezing and the numerical methods for the simulation of these conditions in tunnelling has been provided by Barla (2002). Numerous support systems that can manage ground deformation are available for civil engineering tunnelling. Nevertheless, the use of these systems in mining would result in high support cost and production delays. Mining operations have higher development rates and shorter service life. This study focuses on the behaviour of underground excavations under squeezing ground conditions in hard rock mining.In a mining context, the magnitude of deformation is usually higher than in civil engineering tunnelling as there is a higher tolerance for operation purposes. Potvin and Hadjigeorgiou (2008) noted that in mining, squeezing is encountered when the total displacement of an excavation reaches at least tens of centimeters over the life expectancy of a supported drive and is associated with considerable damage to the ground support."

Jan 1, 2015

By K. Johanson, M. Hubert, C. Eckert, D. Ghose

The mining industry routinely processes material with different particle sizes. Coal, nickel ore, copper ore, lignite, shale, and phosphate ore are all examples of materials with wide particle size distributions. It is often assumed that these materials are homogenous and that any particle size distribution has the same chemical activity and composition. It is entirely possible, and quite likely, that chemical composition is a function of particle size distribution. In addition, particle size distributions in ore materials are often responsible for the difference in flow behavior in process equipment. This is evident in coal electrical production facilities. Fine coal may have the same ash content, sulfur content, and BTU value as coarse coal. However, all electrical production facilities know the extreme flow problems that result when attempting to handle wet fine coal. Segregation of these bulk materials is an important issue that must be understood to prevent these cohesive flow problems. Additionally, fertilizers are mixtures of particles with different shape and sizes. These mixtures must remain homogenous to optimize fertilizer performance. Segregation leads to poor product quality. This paper presents a method of measuring the magnitude of sifting segregation occurring in bulk material and the relationship between the strength of the bulk material and the separation tendency. It shows an inverse relationship between the yield strength of the material and the bulk segregation.

Jan 1, 2004

By M. Hozayen, Q. Ni, E. S. Radwan, P. Nawrocki, A. Jebbouri

"A major geomechanical study was conducted for one of the UAE onshore oil fields with the purpose of studying reservoir rock properties and stress distribution, based on which a 3D coupled reservoir geomechanical model was built. This model was later used for wellbore stability analysis and for analyzing the effect of fractures on future reservoir production performance, including fracture deformation and permeability evolution occurring due to reservoir depletion and resulting changes in local stress field. The subject of this study was a complex fractured Upper Cretaceous carbonate reservoir characterized by high degree of heterogeneity, both vertically and laterally. Wellbore instability related drilling problems were encountered while drilling the wells in this field. The problems were mainly in drilling the horizontal wells, including breakouts and mud losses. Experimental results of laboratory tests used in this study are summarized in Part I of this paper whereas wellbore stability analysis and formulation of a3D geomechanical model that was built for that purpose is summarized herein.A 3D geomechanical reservoir model was developed, which included natural fractures. The mechanical properties of the reservoir rock, such as Young’s modulus, Poisson’s ratio, UCS, friction angle and tensile strength were populated based on the correlations established in Part I of this paper and the developed model was then used to simulate the 3D mechanical-property distribution and the evolution of the in situ stresses in the field due to depletion from 1983 to present-day. Based on the full field model, mud weight cubes were developed to predict the safe mud weight windows in different drilling directions. In addition, well stability prediction for two planned wells was performed using a 3D near-borehole model. Firstly, the computed stress state and mechanical properties simulated in the full field model were extracted along the well trajectory of an existing horizontal well which was drilled recently and then, a3D near-borehole model was constructed along the well trajectory. The wellbore stability analysis along the well trajectory, including stress state, strain distribution and displacements, was performed to identify the instability events along the well trajectory. It has been seen that the presence of natural fractures is closely related to the recorded borehole instability incidents. The computed plastic strains which indicate the wellbore failure were consistent with the recorded wellbore instability events in the FMI image logs, what provide further verification of the developed model. Then, this 3D near-borehole model was applied to two planned horizontal wells and the wellbore stability analysis for the two wells was carried out.The results showed that drilling vertically in the reservoir is safer than drilling horizontally. However, the drilling mud weight window in the vertical direction is narrow, being as narrow as 18.7 pcf or 0.299 sg locally. Drilling horizontally is less stable towards the maximum far field stress direction than towards the minimum far field stress direction. The mud weight cubes were used to identify the optimal well placement and well trajectory. For planned well trajectories, this technology can also be used to determine the optimal mud weight."

Jan 1, 2015

By Wei Yingchun

Based on the deep burial depth of coal deposits in Huainan-Huaibei coalfields, Anhui Province, China, this paper puts forward the concept of partitioning of coal deposits according to occurrence conditions. This process is controlled by tectonic forces. The classification scheme of coal deposits exploration types is presented according to occurrence and mining conditions of coal deposits as viewed from the perspective of deep coal exploration properties. The principles underlying geological exploration services for the resources development are incorporated. There are six exploration types of coal deposits in the Huainan and Huaibei coalfields. Exploration models tailored to different types of exploration have been established and exploration strategies corresponding to different exploration models have been proposed. Steady-state temperature must be measured for the deep heat-harm type of coal deposit. The sealing coring of mine gas samples should be performed for the high mine gas type of coal deposit. For coal deposits with complex structures, such as those located beneath nappes, coal-controlling structural styles must be performed. Existing data on shallow districts are very important to the research of folds and fault-block types of coal deposits beneath and peripheral to old and existing coal mine areas. For the types of fault-block coal deposits hidden by thick Cenozoic cover, particular attention must be paid to comprehensive use of research on regional coal occurrence law and geophysical methods. The present work promotes the exploration level of coal deposits in Huainan-Huaibei coalfields to best meet the need for sustainable development of the coal industry.

Aug 1, 2013

By G. P. Gu

The in-service 90/10 cupro-nickel tubes in a water-chiller system suffered from severe corrosion damage during their relatively short service life causing unexpected down time. In addition to downtime, the environmental risk associated with losing refrigerant was also a concern that initiated this investigation, Microstructural investigation using SEM and electron microprobe indicated that pitting corrosion had resulted in local nickel depletion, During the corrosion process, copper appeared to have re-deposited around the corrosion pits accelerating the local corrosion.

Jan 1, 2005

By W. G. McBride

The mining industry has already become highly technical in all its branches and this has brought about specialization in mining engineering. Increasing demand for mineral products, exhaustion of high-grade or easily worked deposits, and narrowing of the fields for exploration and development, are forcing mines to greater depth and to working material of lower grade and more complex composition. The Robinson Deep at its Turf shaft has reached a depth of 7,640 feet and expects to go to 8,500 feet; Miami Copper, under normal market conditions, profitably mines ore running only 16 pounds of copper to the ton; Alaska Juneau is making a profit on ore running about $1.15 per ton in gold; and many mines are handling ores of an extremely complex nature. In each case, the success of these operations has depended upon the application of sound scientific principles and good business methods to the problems involved. It may be safely assumed that mining at great depth and the exploitation of low-grade, or complex, ores will become more and more important as time goes on, and this means that greater and greater demands will be made upon the technical skill and business ability of the mining engineer. To meet this condition, the more or less haphazard methods of training the young engineer that have prevailed in the past will have to be replaced by a careful and well-ordered system of engineer-training. Upon the industry and the older mining engineer falls the duty of providing means to assist the deserving student to prepare himself properly to meet the increased demands that are falling upon his profession. Consideration of the training of the mining engineer involves a decision as to what constitutes his field of usefulness. Technical control of methods and processes obviously falls upon the engineer, but there are still many who doubt his usefulness in the executive field, particularly in positions involving close contact with the men and work. Many engineers have failed as shift-boss or foreman, but this has been generally due to fault in the management in using men who were temperamentally unfit to lead others or who lacked the necessary preliminary training.

Jan 1, 1932

By Eugene Larochelle

The serpentine of the Eastern Townships of Quebec is more or less seamed and impregnated with chrysotile asbestos, of which we note two types: the cross-fibre and the disseminated fibre. The cross-fibre type always appears in fibres or crystals arranged parallel to one another, and disposed at right angles to the walls of the matrix serpentine. The length of fibre of these veins, which run in every conceivable direction, even crossing ?one another, varies from microscopie dimensions to three and sometimes four and even five inches. It is the principal form of asbestos found in the serpentine of Thetford Mines, Black Lake, Coleraine, and Asbestos. The disseminated-fibre type, which is the main product of the serpentine of Broughton township, in which ate located the mines at East Broughton, does not form veins, but occurs in the serpentine without any definite arrangement. There is a difference in the toughness and hardness of the rock of the two types, the Broughton serpentine being softer than that at Thetford. The disseminated-fibre section of the serpentine belt is probably more regular in its content than is the cross-fibre section. Nevertheless, it contains no 'crude,' which is the most valuable of asbestos, and the fibre is usually shorter than the cross-fibre average.

Jan 1, 1928

By R. M. Berry

A brief outline of refining methods used to (1) upgrade yellowcake to nuclear purity and (2) convert the uranium to the chemical and physical forms required by the fuel fabricators is presented. The uranium hexafluoride (UF6) production facility now under construction at Eldorado, Port Hope, is discussed. Technological improvements in uranium refining are considered.

Jan 1, 1969

By A. Vervoort, A. Govaerts

Geostatistical concepts are often difficult for students to understand, even those with a strong mathematical background. One of the main problems is the link between the variation of the parameter value in space or time and the calculated experimental semivariogram. Another challenge is differentiating between directional and omnidirectional semivariograms and their interpretation. For these reasons, interactive tools were developed based on the free public domain software R. The use of these interactive tools is limited to educational situations only (i.e., to visualize basic concepts). The interactive modules can be accessed at www.bwk.kuleuven.be/geostatistics.

Jan 1, 2014

By Joel Werner

Weak metal prices, declining head grade, and increased operational costs are forcing many open pit mining companies to look to their balance sheets for significant cost reductions in order to remain competitive. Maintenance continues to represent a significant proportion of the total operating costs in the mining industry. Compared with the other major cost components of the mining process very little effort has gone into maintenance optimization. The potential payoff from maintenance optimization on the cash cost of the commodity is enormous. A large percentage of these costs are incurred in unscheduled maintenance events, which typically cause serious disruptions to the production process. These maintenance induced production losses can be a significant contributor to the overall operating costs. A structured proactive maintenance approach using the latest advances in technology can achieve dramatic cost reductions and productivity improvements. Remote condition monitoring systems are becoming increasingly commonplace and have the potential to identify problems prior to failure. Detection of equipment degradation prior to failure will enable repairs to be scheduled thereby reducing costs and interruptions to production. Remote condition monitoring technology has evolved rapidly in recent years, with a host of new tools becoming available to assist mine operators in improving their maintenance operations. These tools have capabilities such as: remote real-time vital signs and performance monitoring, alarm/event handling, trend analysis, and maintenance workflow management. When these monitoring tools are used in conjunction with a mine management system the vital signs data can be integrated and associated with maintenance history, predictive maintenance data, operational information, and geographical information. This integrated approach to the management of vital maintenance data will help shift the mobile equipment maintenance paradigm from reactive to proactive. This paper will introduce a proactive approach to the management of the maintenance process and the tools required to facilitate this process.

May 1, 2003

By C. Ciriello

Six Sigma methodology, as applied within Xstrata (formerly Falconbridge and Noranda), involves a disciplined approach to managing projects, solving problems, improving performance, and leveraging information. The four (4) cornerstones of Six Sigma are the use of Philosophy (customer driven, desire to improve and discipline), Metrics (measurement systems), Methodology (scientific method and sequence of deliverables), and Tools (such as statistics, change management, and root cause analysis). This paper will outline the general steps of the Six Sigma methodology and demonstrate how each phase directly applies to a real plant metallurgical project aimed at reducing nickel losses of the rougher flotation circuit at Raglan. The main concepts of Six Sigma are described, along with the specific challenges, successes, and deliverables related to the project. It is also the authors' aim to demystify the basic Six Sigma principles.

Jan 1, 2007

By S. Gößling-Reisemann

Most copper ores contain valuable co-products such as molybdenum, gold, silver, nickel, etc. Sulphuric acid and steam are valuable by-products, which are generated dur¬ing copper production. The environmental impacts from mining and refining therefore need to be shared between these by-products and co-products, an issue in Life Cycle As¬sessment (LCA) referred to as allocation. There are different, recognised methodologies for doing so: burdens can be allocated based on the market values of these commodities, they can be allocated by mass, volume, molar amount, functionality, or other physical, technical or economic factors. All of these methodologies have their respective merits and restrictions, and the choice is usually case specific. Nevertheless, the choice between alternative methodologies can have dramatic effects on the LCA results. Recycling in LCA has to be handled in a similar way, as it essentially constitutes a special case of co¬production. The existing standards (ISO 14040 ff.) allow different methods for imple¬menting recycling and allocation into metal LCAs (open loop, closed loop, value cor-rected substitution, etc.), which are still a subject of discussion in the scientific community. However, the methodology used can significantly influence the ecological profile of copper and copper products. We will present an overview of the different methodologies available for including recycling and allocation and give an analysis of how the meth¬odological choice affects the final LCA results. This work will be followed up by quantitative case studies.

Jan 1, 2007

By Alex MacEachern

Air is the gaseous substance that envelopes the earth and forms its atmosphere. It is remarkable in the constancy of its composition; for while this is being continually changed as the result of the respiration of men and animals, and by addition of gases arising from organic changes and the products of combustion, it is ever being brought back to normal and the proper balance restored by the processes of plant and vegetable life. Nature sees to it that the air in which we live and breathe is kept purified. This does not apply to the air in a coal mine, where there are no natural forces to change and make use of the different gases formed or evolved, and where mechanical ventilation is the only effective means of keeping the air pure. The atmosphere consists of oxygen and nitrogen, not in the combined state but merely mixed. By volume, the composition is: oxygen, 21 percent, nitrogen, 79 percent, there being included with the latter small quantities of such substances as water vapour, carbon dioxide, nitric acid, ammonia, ozone, argon, neon, and organic gases. Of the two principal gases which form air, oxygen alone supports life. When air is inhaled into the lungs the oxygen is absorbed by the blood, which carries it through the body to nourish and energize it. Exhaled air consists of water vapour and about 4 per cent carbon dioxide, with from 16 1/2 to 17 per cent oxygen and 79 per cent nitrogen; the oxygen alone having been drawn on to any considerable extent.

Jan 1, 1930

By Brian Putland

Single stage semi-autogenous / autogenous (S/AG) milling has become a common design for a variety of ore types with the advantages of being comparatively low capital cost and flexible for future expansion. The single stage SAG/AG milling option is ideal for starter projects with significant exploration and expansion potential. Currently a number of the largest SAG mills designed are installed in single stage configuration. This paper discusses the challenges associated with the process design of single stage SAG/AG milling circuits, the design flexibility required to ensure a robust circuit and the operating techniques adopted at successful installations.

Jan 1, 2012

By J. Dubinski

This paper describes the key circumstances of the underground coal gasification (UCG) process, which is planned to be carried out in the Polish hard coal mine ?Wieczorek?. The construction and field tests of a UCG pilot plant have key issues that need to be addressed to realize the research project goal: the elaboration of a highly effective technology of fuel and electricity production. The project will conduct several monthly tests of gasification in the pilot geo-reactor, which will be constructed based on the results of laboratory tests. The realization of the process requires numerous appropriately prepared actions adjusted to natural conditions in the hard coal deposit. Based on scientific principles, it is necessary to elaborate the procedures related to the location of the UCG installation (including its legal and safety aspects), and to perform a technical risk analysis. In addition, it is necessary to determine the required mining, geological, technical, economic and organizational circumstances, while at the same time considering the real but constantly changing process conditions.

Aug 1, 2013