The use of packed sphere modelling for airflow and heat exchange analysis in broken or fragmented rock

Airflow and heat exchange characterizations through large bodies of fragmented rock in mines, such as those at Creighton and Kidd Creek Mines, reveal them to be still fundamentally only empirical in nature. Analysis of the accepted methods for the design and understanding of geometric properties such as the heat exchange area or the length or shape of airflow passages known to affect heat transfer in, for example, heat exchanger design do not appear in the ‘design’ equations for those bodies of broken rock. This thesis couples a method of discontinuum porous media modelling (referred to as a packed sphere model, abbreviated PSM) with a computational fluid dynamics (CFD) code to develop a proxy methodology for analysis of porous media that incorporates variables of airflow, heat transfer, and geometry (including porosity and tortuosity). Material property values for equivalent continuum fluid dynamics models are established and are found to follow formulations for airflow branches used in mine ventilation network analysis. Laboratory experiments of airflow and heat transfer with the PSMs were compared to CFD results for the same models on a 1:1 scale, to verify the approach and CFD results. Three separate approaches were investigated for the scaling of the results of the PSMs for use in large scale (~1km3) CFD simulations of industrial situations. The result of the work presented in this thesis is a verified methodology for establishing CFD airflow and heat transfer parameters for large bodies of broken and fragmented rock from knowledge of the particle size distribution parameters or the body porosity. The application of the methodology is illustrated with reference to the so-called Natural Heat Exchange Area at Creighton Mine, Sudbury, Ontario.Doctor of Philosophy (PhD) in Natural Resources Engineerin

Laboratory Determination of Coal Dust Cleaning Efficacy of a Fibrous Filter for Flooded-Bed Dust Scrubber

Fibrous-type dust filters are used in flooded-bed dust scrubbers to capture dust from underground room and pillar mining atmospheres. They have 10–30 layers of finely woven strands that trap particles through the interception and impaction process. A full-cone water spray is installed upstream of the filter, which floods the screen. A scrubber’s efficacy is usually measured and reported in terms of reduction in gravimetric dust concentration at a known location in a mine. This paper reports the particle-size-dependent dust removal efficiency of a fibrous filter obtained from an instrumented test-set up. A variable frequency drive and an inline flow control knob were used to control the airflow through the filter and water flow onto the filter. Optical particle counting of coal dust particles upstream and downstream was carried out to determine the cleaning efficacy. Experiments showed an increase in cleaning efficiency for all the dust particles with their size. A progressive decrease in dust concentration downstream of the filter with an increase in water flow through the nozzle affirmed the capture of dust particles by water sprays

Data Management System for a Semiautonomous Shuttle Car for Underground Room and Pillar Coal Mines

In recent years, autonomous solutions in the multidisciplinary field of mining engineering have been an extremely popular applied research topic. This is a result of the increasing demands of society on mineral resources along with the accelerating exploitation of the currently economically viable resources, which lead the mining sector to turn to deeper, more-difficult-to-mine orebodies. An appropriate data management system comprises a crucial aspect of the designing and the engineering of a system that involves autonomous or semiautonomous vehicles. The vast volume of data collected from onboard sensors, as well as from a potential IoT network dispersed around a smart mine, necessitates the development of a reliable data management strategy. Ideally, this strategy will allow for fast and asynchronous access to the data for real-time processing and decision-making purposes as well as for visualization through a corresponding human–machine interface. The proposed system has been developed for autonomous navigation of a coalmine shuttle car and has been implemented on a 1/6th scale shuttle car in a mock mine. It comprises three separate nodes, namely, a data collection node, a data management node, and a data processing and visualization node. This approach was dictated by the large amount of collected data and the need to ensure uninterrupted and fast data management and flow. The implementation of an SQL database server allows for asynchronous, real-time, and reliable data management, including data storage and retrieval. On the other hand, this approach introduces latencies between the data management node and the other two nodes. In general, these latencies include sensor latencies, network latencies, and processing latencies. However, the data processing and visualization module is able to retrieve and process the latest data and make a decision about the next optimal movement of the shuttle car prototype in less than 900 ms. This allows the prototype to navigate efficiently around the pillars without interruptions

Rupturas y continuidades del modelo asilar : Relato de una experiencia desde el trabajo social

En el presente texto se propone desarrollar algunas reflexiones, producto del trayecto profesional propio, en una institución dependiente del Ministerio de Desarrollo Social de la Nación: ex “Instituto Torcuato de Alvear”. En el mismo se aportarán algunos elementos de reflexión en relación a las prácticas institucionales, problematizando el lugar de las ciencias sociales en general y el Trabajo Social en particular, y de este modo, analizando rupturas y continuidades en relación al modelo asilar. Al finalizar el texto, se recupera una experiencia de intervención desde el Trabajo Social, llevada a adelante por dos Lic. en Trabajo Social. (Párrafo extraído del texto a modo de resumen)Eje temático: Acción Política - Historia reciente, memoria colectiva y trabajo socialFacultad de Trabajo Socia

Rupturas y continuidades del modelo asilar : Relato de una experiencia desde el trabajo social

En el presente texto se propone desarrollar algunas reflexiones, producto del trayecto profesional propio, en una institución dependiente del Ministerio de Desarrollo Social de la Nación: ex “Instituto Torcuato de Alvear”. En el mismo se aportarán algunos elementos de reflexión en relación a las prácticas institucionales, problematizando el lugar de las ciencias sociales en general y el Trabajo Social en particular, y de este modo, analizando rupturas y continuidades en relación al modelo asilar. Al finalizar el texto, se recupera una experiencia de intervención desde el Trabajo Social, llevada a adelante por dos Lic. en Trabajo Social. (Párrafo extraído del texto a modo de resumen)Eje temático: Acción Política - Historia reciente, memoria colectiva y trabajo socialFacultad de Trabajo Socia

Rupturas y continuidades del modelo asilar : Relato de una experiencia desde el trabajo social

En el presente texto se propone desarrollar algunas reflexiones, producto del trayecto profesional propio, en una institución dependiente del Ministerio de Desarrollo Social de la Nación: ex “Instituto Torcuato de Alvear”. En el mismo se aportarán algunos elementos de reflexión en relación a las prácticas institucionales, problematizando el lugar de las ciencias sociales en general y el Trabajo Social en particular, y de este modo, analizando rupturas y continuidades en relación al modelo asilar. Al finalizar el texto, se recupera una experiencia de intervención desde el Trabajo Social, llevada a adelante por dos Lic. en Trabajo Social. (Párrafo extraído del texto a modo de resumen)Eje temático: Acción Política - Historia reciente, memoria colectiva y trabajo socialFacultad de Trabajo Socia

Managing and Utilizing Big Data in Atmospheric Monitoring Systems for Underground Coal Mines

Underground coal mining Atmospheric Monitoring Systems (AMS) have been implemented for real-time or near real-time monitoring and evaluation of the mine atmosphere and related parameters such as gas concentration (e.g., CH4, CO, O2), fan performance (e.g., power, speed), barometric pressure, ambient temperature, humidity, etc. Depending on the sampling frequency, AMS can collect and manage a tremendous amount of data, which mine operators typically consult for everyday operations as well as long-term planning and more effective management of ventilation systems. The raw data collected by AMS need considerable pre-processing and filtering before they can be used for analysis. This paper discusses different challenges related to filtering raw AMS data in order to identify and remove values due to sensor breakdowns, sensor calibration periods, transient values due to operational considerations, etc., as well as to homogenize time series for different variables. The statistical challenges involve the removal of faulty values and outliers (due to systematic problems) and transient effects, gap-filling (by means of interpolation methods), and homogenization (setting a common time reference and time step) of the respective time series. The objective is to derive representative and synchronous time series values that can subsequently be used to estimate summary statistics of AMS and to infer correlations or nonlinear dependence between different data streams. Identification and modeling of statistical dependencies can be further exploited to develop predictive equations based on time series models

Scale and numerical modeling to determine operating points of a non-clogging Vortecone filter in mining operation

Numerical and scale modeling studies of Vortecone, a pressure-driven wet-scrubber device for the efficient capture of over-sprayed paint in the automobile industry, are presented. In this manuscript, Vortecone was tested for removing dust particles from underground mining operations. The pressures required to operate Vortecone and the airflow rates through the Vortecone are the two most important factors for mine ventilation systems. This study used dry, no-particle conditions to obtain relationship between these two parameters and then designed a Vortecone filter ventilation system for mining operations. Commercial software, SC/Flow, was used to generate the CFD model with unstructured meshes and a series of numerical calculations were accomplished. Included in these were calculation of a 1/3rd scale model of Vortecone along with experimentation that was accomplished to validate the numerical predictions. The experiments were conducted to measure pressure drops for known airflow velocities at critical points within Vortecone. The scale model experimental results agreed very well with the CFD numerical calculations. For scaling the performance of the 1/3rd scale model to full scale, the scaling laws were developed using the law approach; they are discussed along with the feasibility of the Vortecone filter system for underground mining operations

Condiciones laborales de lxs trabajadores sociales : Desafíos del Colegio profesional: distrito Mercedes (Bs. As)

En el presente trabajo proponemos aportar algunos elementos de reflexión en torno a una investigación realizada desde el Colegio de Trabajadorxs Sociales del distrito Mercedes. La iniciativa de presentar nuestro trabajo en esta jornada, tiene como propósito, socializar resultados preliminares sobre las condiciones sociales y laborales de lxs Trabajadorxs sociales del distrito de referencia, y además plantear interrogantes en cuanto a la centralidad del Colegio Profesional en este proceso. (Párrafo extraído del texto a modo de resumen)Eje temático: Trabajo - Informalidad, precarización y explotación laboral.Facultad de Trabajo Socia

Condiciones laborales de lxs trabajadores sociales : Desafíos del Colegio profesional: distrito Mercedes (Bs. As)

En el presente trabajo proponemos aportar algunos elementos de reflexión en torno a una investigación realizada desde el Colegio de Trabajadorxs Sociales del distrito Mercedes. La iniciativa de presentar nuestro trabajo en esta jornada, tiene como propósito, socializar resultados preliminares sobre las condiciones sociales y laborales de lxs Trabajadorxs sociales del distrito de referencia, y además plantear interrogantes en cuanto a la centralidad del Colegio Profesional en este proceso. (Párrafo extraído del texto a modo de resumen)Eje temático: Trabajo - Informalidad, precarización y explotación laboral.Facultad de Trabajo Socia