Evaluación de la técnica DEM para estudio de altura de columnas altas en minería de block caving.
Loading...
Date
2024
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Universidad de Concepción
Abstract
Las operaciones de Block Caving se están volviendo más desafiantes a medida que la minería se lleva a cabo a mayores profundidades, en rocas más competentes y con requerimientos de producción más elevados. Dado esto existe la tendencia de aumentar la altura de columna para este tipo de operaciones, tendencia que presenta ventajas como la reducción de los costos de preparación minera y desventajas como altos esfuerzos por sobrecarga. Este aumento en la altura de columna tiene un efecto en el flujo de material granular, por lo tanto, es necesario estudiar el comportamiento del flujo gravitacional a altura de columnas altas (<500 [m]). Siendo los métodos de elementos discretos (DEM) una herramienta importante para el estudio de flujo gravitacional dado que permite un análisis en detalle de las micro y macro interacciones entre partículas.
Para realizar el estudio de flujo gravitacional en altura de columnas altas (<500 [m]) mediante DEM, se lleva a cabo un plan experimental. Esto se realizará mediante un modelo numérico basado en un modelo físico de escala 1:200 mediante el software Ansys Rocky. El plan experimental considera experimentos de tiraje aislado y tiraje múltiple con una granulometría utilizada en el modelo físico. El experimento de tiraje aislado consiste en cuantificar la geometría de flujo, mientras que el de tiraje uniforme se busca cuantificar la geometría de pilar remanente.
Para realizar los experimentos, primero se calibra el modelo numérico. Para ello, se calibra el material utilizado en el modelo físico mediante ensayos de caja de corte y ángulo de reposo con el software Rocky DEM. Una vez realizada la calibración del material, se lleva a cabo los experimentos de tiraje aislado y múltiple.
Se realizaron simulaciones con altura de columna de 200 [m], tanto para los experimentos de tiraje aislado y tiraje múltiple uniforme. En el tiraje aislado, la calibración no fue exitosa debido a la alta energía cinética inicial y que no se logró utilizar los parametros de calibración debido a los altos tiempos de simulación. En el experimento de tiraje múltiple, al aumentar la masa extraída, el pilar remanente disminuye gradualmente. Comparando ambos métodos de extracción, el tiraje aislado genera un pilar remanente mayor.
Se concluyó que no es posible realizar un estudio de altura de columnas altas, siendo la altura máxima posible para estudiar de 200 [m]. En el experimento de tiraje aislado dado que no se logra la calibración debido a alta energía cinética y tiempos de simulación, esto da a conocer la importancia del ángulo de fricción interna para la calibración. Para el experimento tiraje múltiple el tamaño del pilar remanente por tiraje aislado es mayor debido a que su ángulo de flujo es más agudo.
Block Caving operations are becoming increasingly challenging as mining takes place at bigger depths, in more competent rocks and with higher production ratios. Because of this, there exists a trend toward increasing the column height for the types of operations, a trend that presents advantages such reduced mining operation costs and disadvantages like high stresses due to overburden. This increment in the height affects the granular flow of material, making it necessary to study the behavior of gravitational flow in high columns (< 500 [m]). Since discrete element methods (DEM) are an important tool for studying gravitational flow, as they allow a detailed analysis of the micro and macro interactions between particles. To study gravitation in high columns (< 500 [m]) using DEM, and experimental plan is developed. This will be carried out through a numerical model based on a 1:200 scale physical model using the software Ansys Rocky. The experimental plan includes isolated draw and multiple draw experiments, utilizing the same particle size distribution as in the physical model. The isolated draw experiment seeks to quantify the geometry of the draw flow, while the uniform draw seeks to quantify the geometry of the remaining pilar. To carry out the experiments, first the numerical model is calibrated. To achieve this, the material used in the physical model is calibrated through direct shear test a repose angle test using Rocky DEM. Once the material is calibrated, the isolated and multiple draws are experiments are carried out. The simulation where conducted column height of 200 [m] for both experiments. The isolated draw, the calibration was not successful due to high initial kinetic energy and the inability to use the calibration parameters because of the high simulation time. In the multiple draw, as the mass extracted increased, the remaining pilar gradually decreased. When comparing both extraction methods, the isolated draw generated larger remaining pilar. It was concluded that it is not possible to conduct a study of high column height, with the maximum height being 200 [m]. In the isolated draw, calibration was not achieved due to high kinetic energy and simulation times, but this highlights the importance of the internal friction angle for calibration. In the multiple draws, the size of the remaining pillar in the isolated draw was larger due to its steeper flow angle.
Block Caving operations are becoming increasingly challenging as mining takes place at bigger depths, in more competent rocks and with higher production ratios. Because of this, there exists a trend toward increasing the column height for the types of operations, a trend that presents advantages such reduced mining operation costs and disadvantages like high stresses due to overburden. This increment in the height affects the granular flow of material, making it necessary to study the behavior of gravitational flow in high columns (< 500 [m]). Since discrete element methods (DEM) are an important tool for studying gravitational flow, as they allow a detailed analysis of the micro and macro interactions between particles. To study gravitation in high columns (< 500 [m]) using DEM, and experimental plan is developed. This will be carried out through a numerical model based on a 1:200 scale physical model using the software Ansys Rocky. The experimental plan includes isolated draw and multiple draw experiments, utilizing the same particle size distribution as in the physical model. The isolated draw experiment seeks to quantify the geometry of the draw flow, while the uniform draw seeks to quantify the geometry of the remaining pilar. To carry out the experiments, first the numerical model is calibrated. To achieve this, the material used in the physical model is calibrated through direct shear test a repose angle test using Rocky DEM. Once the material is calibrated, the isolated and multiple draws are experiments are carried out. The simulation where conducted column height of 200 [m] for both experiments. The isolated draw, the calibration was not successful due to high initial kinetic energy and the inability to use the calibration parameters because of the high simulation time. In the multiple draw, as the mass extracted increased, the remaining pilar gradually decreased. When comparing both extraction methods, the isolated draw generated larger remaining pilar. It was concluded that it is not possible to conduct a study of high column height, with the maximum height being 200 [m]. In the isolated draw, calibration was not achieved due to high kinetic energy and simulation times, but this highlights the importance of the internal friction angle for calibration. In the multiple draws, the size of the remaining pillar in the isolated draw was larger due to its steeper flow angle.
Description
Tesis presentada para optar al título profesional de Ingeniero Civil de Minas
Keywords
Minería por derrumbe, Industria minera, Simulación por computadores