Análisis y mejoramiento del modelo numérico hidrogeológico de la Unidad Minera Apumayo para la evaluación del impacto ambiental al acuífero, por actividades mineras
The present work denominated "Analysis and improvement of the hydrogeological numerical model of the Mining Apumayo Unit for the evaluation of the environmental impact to the aquifer by mining activities" has as objective to predict more accurately the possible impact to the aquife...
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| Format: | master thesis |
| Publication Date: | 2017 |
| Country: | España |
| Institution: | Universitat Politècnica de València (UPV) |
| Repository: | RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia |
| Language: | Spanish |
| OAI Identifier: | oai:riunet.upv.es:10251/89488 |
| Online Access: | https://riunet.upv.es/handle/10251/89488 |
| Access Level: | Open access |
| Keyword: | Flow Hydrogeological Simulation Modelo Simulación Transporte Hidrogeológico Flujo Model Simulació Transport Hidrogeològic Flux FISICA APLICADA Máster Universitario en Ingeniería Hidráulica y Medio Ambiente-Màster Universitari en Enginyeria Hidràulica i Medi Ambient |
| Summary: | The present work denominated "Analysis and improvement of the hydrogeological numerical model of the Mining Apumayo Unit for the evaluation of the environmental impact to the aquifer by mining activities" has as objective to predict more accurately the possible impact to the aquifer by elements from the process of extraction of silver and gold through the mining components such as the cyanide leach pad and the sterile tailings from the slits. The Mining Unit is located in the department of Ayacucho of Peru at 4000 masl, south central of the Andes, being thus, the mentioned mining components are in the head of microcuencas that are tributaries of superficial channels of which they are supplied for livestock use and agrarian some towns located in the area of indirect influence of the Mining Unit. In order to obtain environmental certification and initiate mining operations, the hydrogeological numerical model of the aquifer was executed in the Project area as part of its Environmental Impact Study (EIA) in which, according to the requirements of the legislation environmental, the flow and movement of particles was simulated. However, the revision of the numerical model shows that the groundwater flow model does not represent the actual conditions of the aquifer, so that in order to have a better representation of this, the design of the numerical model was modified through the variation of hydraulic parameters and boundary conditions; Likewise, sensitivity analysis and transit simulation were performed, which was not performed in the EIA model. As for the transport of pollutants, the movement of cyanide and cadmium was simulated as non-conservative but considering its hydrodynamic transport, using the software MT3DMS, which was also not executed in the EIA model. The improvements made in the numerical flow model, such as the outlining of the boundary conditions, adjustment of the steady-state calibration, sensitivity analysis and transient calibration, have allowed to obtain piezometric levels closer to those observed than in the numerical model of the Environmental Impact Study (2015) of the Apumayo Mining Unit, since there are no problems of flow output above the ground level that were in this model, not being representative of the reality, besides the calibration of better fit had a standard root mean square (RMS) of 2.6% which is lower than the normalized RMS of 8% of the numerical model of 2015. The potential negative impact of groundwater on an event of infiltration in the leach pad is not highly significant in the short term, because in none of the established scenarios the presence of the contaminant was detected after 30 years in the APU 9 piezometer located at 750 m downstream of the mining component, so it can be said that the process of movement of the pollutant pen is very slow, considering that it was considered as a conservative pollutant. Also, according to the results of the transport simulation, the diffusion process in this case is significant due to the low permeabilities in a large part of the domain of the model, reason why the movement of the pen is slow generating in the beginning an accumulation in the area of the entrance of the pollutant, so this type of behavior could generate a long-term risk, so it would be important to carry out a simulation for more than 50 years in the event that some type of event is similar to the scenario . |
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