Caracterización geológica del molibdeno en el yacimiento Radomiro Tomic, región de Antofagasta, Chile
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2020
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Universidad Andrés Bello
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El Molibdeno es considerado un importante subproducto obtenido de la minería del Cobre asociado a los pórfidos Cu-Mo, ya que agrega una gran ventaja económica a los procesos productivos. Debido a esto, un buen entendimiento del comportamiento de este elemento es necesario para sustentar modelos geológicos representativos y predictivos. Este estudio tuvo como objetivo caracterizar la ocurrencia de la mineralogía asociada al Molibdeno y su relación con los eventos de mineralización – alteración asociadas al Co-bre definidos en el yacimiento Radomiro Tomic, el cual corresponde a un depósito tipo pórfido cuprífero con importantes anomalías de Molibdeno de una ley media de 90 ppm. Este se ubica aproximadamente a 20 km al Norte de la ciudad de Calama, Región de Antofagasta. Para esto se realizó el mapeo de 22 sondajes diamantinos (4.614,65 me-tros) distribuidos en 4 secciones del yacimiento (13.400 N, 10.600 N, 9.400 N y 7.300 N) y análisis de laboratorio de 90 muestras, las cuales fueron estudiadas mediante cortes petrocalcográficos, DRX, FRX, TIMA e ICP. Los datos mapeados muestran que la mine-ralogía predominante (91.2%) asociada al Molibdeno corresponde a Molibdenita y en menor medida a óxidos de Molibdeno como Powellita, Wulfenita y Ferrimolibdita, para estos minerales se observó nueve tipos de ocurrencias, las cuales corresponden a; ve-tillas lixiviadas, óxidos de Molibdeno, brechas hidrotermales, vetillas del tipo A, B, de Molibdenita, Sericita gris verde (SGV), Cuarzo – Sericita (QS) y las vetillas llamadas en este estudio como RT Norte. Estas ocurrencias evidencian que la mineralización del Mo-libdeno se encuentra desde el evento tardimagmático hasta hidrotermal principal, donde el evento hidrotermal temprano representado por las vetillas B corresponde al principal contribuidor de Molibdeno al sistema. Las vetillas RT Norte ubicadas en la sección 13.400 N posiblemente representarían un evento distinto asociado a un aporte de fluidos hidrotermales ricos en Molibdeno que fueron transportados mediante la permeabilidad de estructuras asociadas a la falla Kala. Además, se observó que el Molibdeno no se concentra de manera sustancial por los procesos supérgenos (en comparación con lo que si ocurre para el Cobre), debido a que existen grandes concentraciones de este elemento en la zona lixiviada, evidenciando poca movilidad del elemento en condiciones ácidas, sin embargo, los análisis estadísticos muestran una disminución de este elemento en la zona lixiviada y una mayor concentración en la zona de enriquecimiento supérgeno y bornítica. El principal control geológico de la distribución del Molibdeno es-taría asociado a los sistemas estructurales transcurrentes dextrales NS Kala, Ckaari y NE Kalatche por sobre el control litológico.
Molybdenum is considered an important by-product obtained from copper mining asso-ciated to porphyry Cu-Mo, since it adds a great economic value to production processes. Because of this, a good understanding of the behavior of this element is necessary to support representative and predictive geological models. This study aimed to characte-rize the occurrence of mineralogy associated with Molybdenum and its relationship with the mineralization - alteration events of Copper defined in the Radomiro Tomic mine, which corresponds to a porphyry Copper deposit with important Molybdenum anomalies of 90 ppm average. Which is located approximately 20 km North of Calama city, Antofa-gasta Region. For this, a mapping of 22 diamond drill core (4.614,65 meters) distributed in 4 sections of the deposit (13,400 N, 10,600 N, 9,400 N and 7,300 N) was carried out and analysis of 90 samples were tested in the laboratory, which were studied by thin and polished section, DRX, FRX, TIMA and ICP. The mapped data shows that the main mi-neralogy (91.2%) associated with Molybdenum corresponds to Molybdenite and to a les-ser extent to Molybdenum oxides such as Powellite, Wulfenite and Ferrimolibdite, for these minerals nine types of occurrences were observed, which correspond to; leached veins, Molybdenum oxides, hydrothermal breccia, A veins, B veins, Molybdenite veins, Gris Verde Sericite veins (SGV), Quartz-Sericite veins (QS) and late Quartz veins call it in this study as “RT north veins”. These occurrences evidence that Molybdenum minera-lization is found from late magmatic to principal hydrothermal events, where the early hydrothermal event represented by B veins corresponds to the main Molybdenum contri-butor to the system. The RT Norte veins located in section 13.400 N would represent a late event associated with a contribution of hydrothermal fluids rich in Molybdenum that were transported through the permeability of structures associated with the Kala fault. Futhermore, it was observed that Molybdenum is not substantially concentrated by su-pergene processes (compared to what happens for Copper), due to the fact that high concentrations of this element have been found in the leached zone, showing the lack of mobility of Molybdenum in acid conditions, however, statistical analyzes vary a decrease in this element in the leached zone and a higher concentration in the supragenic enrich-ment and bornitic zone. The main geological control of the distribution of Molybdenum would be associated with the Kala, Ckaari and Kalatche structural systems over litholo-gical control.
Molybdenum is considered an important by-product obtained from copper mining asso-ciated to porphyry Cu-Mo, since it adds a great economic value to production processes. Because of this, a good understanding of the behavior of this element is necessary to support representative and predictive geological models. This study aimed to characte-rize the occurrence of mineralogy associated with Molybdenum and its relationship with the mineralization - alteration events of Copper defined in the Radomiro Tomic mine, which corresponds to a porphyry Copper deposit with important Molybdenum anomalies of 90 ppm average. Which is located approximately 20 km North of Calama city, Antofa-gasta Region. For this, a mapping of 22 diamond drill core (4.614,65 meters) distributed in 4 sections of the deposit (13,400 N, 10,600 N, 9,400 N and 7,300 N) was carried out and analysis of 90 samples were tested in the laboratory, which were studied by thin and polished section, DRX, FRX, TIMA and ICP. The mapped data shows that the main mi-neralogy (91.2%) associated with Molybdenum corresponds to Molybdenite and to a les-ser extent to Molybdenum oxides such as Powellite, Wulfenite and Ferrimolibdite, for these minerals nine types of occurrences were observed, which correspond to; leached veins, Molybdenum oxides, hydrothermal breccia, A veins, B veins, Molybdenite veins, Gris Verde Sericite veins (SGV), Quartz-Sericite veins (QS) and late Quartz veins call it in this study as “RT north veins”. These occurrences evidence that Molybdenum minera-lization is found from late magmatic to principal hydrothermal events, where the early hydrothermal event represented by B veins corresponds to the main Molybdenum contri-butor to the system. The RT Norte veins located in section 13.400 N would represent a late event associated with a contribution of hydrothermal fluids rich in Molybdenum that were transported through the permeability of structures associated with the Kala fault. Futhermore, it was observed that Molybdenum is not substantially concentrated by su-pergene processes (compared to what happens for Copper), due to the fact that high concentrations of this element have been found in the leached zone, showing the lack of mobility of Molybdenum in acid conditions, however, statistical analyzes vary a decrease in this element in the leached zone and a higher concentration in the supragenic enrich-ment and bornitic zone. The main geological control of the distribution of Molybdenum would be associated with the Kala, Ckaari and Kalatche structural systems over litholo-gical control.
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Yacimientos Minerales, Molibdeno, Toma de Muestras, Industria Minera, Aspectos Económicos, Impacto Ambiental, Chile