South Africa has an array of mining commodities which all play an integral role in our everyday surroundings, income, and most importantly, in the economy of the country. These mining activities also produce vast amounts of discard material, better known as tailings material, which is stored in different ways after extraction has taken place. Usually, storage entails the construction of tailings storage facilities, normal discard or tailings dumps. The upper surfaces of these anthropogenic structures are usually unstable and are, in most cases, characterised by different forms of erosion. This can be due to the chemical and physical properties of the materials of which they are constructed, but mainly due to unstable construction geomorphology, steep slopes, which leads to poor water run-off management and subsequent instability. Therefore, these structures need to be actively managed in order to increase and maintain their stability. Grass establishment, as a stabilisation technique, is the most effective out of all of the techniques, but there are certain constraints regarding this method (Titshall et al. 2013). The most costly constraint is nutrient supplementation during aftercare phases. In order to minimize this cost, new and innovative technologies need to be explored, and trialled. The contribution of soil biological processes in this regard was assessed, in order to minimise anthropogenic inputs. These biological processes refer to the fixation of atmospheric nitrogen by nodular root bacteria that grow on a group of plants referred to as legumes. These bacteria, also known as rhizobia, live in a symbiotic relationship with the host plant where they receive energy in the form of nutrients by trading nitrogen, which is an essential plant nutrient. Nine different tailings materials from different commodities available from South African Mines were selected. For a control medium, a well-drained soil type with an apedel structure and a clay content of approximately 6% was selected in order to promote optimal natural growth. These materials were chemically and physically analysed in order to develop a more holistic understanding on a micro scale level, as well as to ascertain possible constraints in this regard. Pot trials were selected as the experimental method in order to apply more specific control over root growth, plant development and growing conditions. The experimental data were collected over one growing season for both live forms. For this study, seven legume species were selected for establishment in the tailings materials in order to investigate their establishment potential in the growth mediums and their ability to fixate nitrogen. Based on the data, specific species were identified as viable options to include in future tailings amelioration projects; it can be assumed that the nitrogen produced by these species will be available in the growth medium for uptake by neighbouring plants that lack this biological function. These plants will also play a vital role in the long-term sustainable development of vegetation in the anthropogenic growth mediums. Sericea lespedeza had the highest enrichment ability during this study. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

South Africa has an array of mining commodities which all play an integral role in our everyday surroundings, income, and most importantly, in the economy of the country. These mining activities also produce vast amounts of discard material, better known as tailings material, which is stored in different ways after extraction has taken place. Usually, storage entails the construction of tailings storage facilities, normal discard or tailings dumps. The upper surfaces of these anthropogenic structures are usually unstable and are, in most cases, characterised by different forms of erosion. This can be due to the chemical and physical properties of the materials of which they are constructed, but mainly due to unstable construction geomorphology, steep slopes, which leads to poor water run-off management and subsequent instability. Therefore, these structures need to be actively managed in order to increase and maintain their stability. Grass establishment, as a stabilisation technique, is the most effective out of all of the techniques, but there are certain constraints regarding this method (Titshall et al. 2013). The most costly constraint is nutrient supplementation during aftercare phases. In order to minimize this cost, new and innovative technologies need to be explored, and trialled. The contribution of soil biological processes in this regard was assessed, in order to minimise anthropogenic inputs. These biological processes refer to the fixation of atmospheric nitrogen by nodular root bacteria that grow on a group of plants referred to as legumes. These bacteria, also known as rhizobia, live in a symbiotic relationship with the host plant where they receive energy in the form of nutrients by trading nitrogen, which is an essential plant nutrient. Nine different tailings materials from different commodities available from South African Mines were selected. For a control medium, a well-drained soil type with an apedel structure and a clay content of approximately 6% was selected in order to promote optimal natural growth. These materials were chemically and physically analysed in order to develop a more holistic understanding on a micro scale level, as well as to ascertain possible constraints in this regard. Pot trials were selected as the experimental method in order to apply more specific control over root growth, plant development and growing conditions. The experimental data were collected over one growing season for both live forms. For this study, seven legume species were selected for establishment in the tailings materials in order to investigate their establishment potential in the growth mediums and their ability to fixate nitrogen. Based on the data, specific species were identified as viable options to include in future tailings amelioration projects; it can be assumed that the nitrogen produced by these species will be available in the growth medium for uptake by neighbouring plants that lack this biological function. These plants will also play a vital role in the long-term sustainable development of vegetation in the anthropogenic growth mediums. Sericea lespedeza had the highest enrichment ability during this study. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

La presente tesis se estudia el fenómeno de licuefacción del material de relave en la presa zona norte en la mina cobriza, considerando que está sometida a una carga sísmica, valor obtenido a partir de un análisis de peligro sísmico considerando las fuentes sismogénicas históricas de la zona y posteriormente se determina una aceleración mínima necesaria donde iniciaría el proceso de licuefacción. Esta tesis tiene por objetivo identificar los factores que influyen en la falla por licuación en el material de relave Zona Norte en la mina Cobriza para evitar problemas de contaminación de suelos, calidad de agua y la posibilidad de ocasionar problemas en la planta concentradora que se encuentra al pie de la presa. Asimismo, se presenta información de definiciones sobre el fenómeno de licuación de suelos y mencionan casos históricos conocidos tanto a nivel mundial como en el Perú sobre los efectos ocasionados por este fenómeno. Posteriormente, se mencionan los estudios realizados para el reconocimiento y caracterización geotécnica del material de relave, así como el procesamiento de dicha información para poder evaluar el potencial de licuación donde se obtiene un factor de seguridad, el cual es un número que representa el potencial de licuefacción en el suelo. Finalmente, se concluye que los resultados demuestran la existencia de un alto potencial de licuación del material de relave en la presa zona norte en la mina cobriza considerando una aceleración de las fuentes sismogénicas históricas y se calcula un factor de seguridad de licuefacción de valor promedio de 1.3, con la finalidad de determinado la aceleración mínima necesaria donde iniciaría el proceso de licuefacción del material de relave. This thesis studies the phenomenon of liquefaction of tailings material in the dam in the northern copper mine is studied, considering that is subjected to a seismic load value obtained from a seismic hazard analysis considering the historic earthquake of gene sources area and then a necessary minimum acceleration which begin the process of liquefaction is determined. This thesis aims to identify the factors that influence the failure by liquefaction in the North Zone tailings material in the Cobriza mine to avoid problems of soil pollution, water quality and the ability to cause problems in the concentrator plant found at the foot of the dam. Also, information on the definition of soil liquefaction phenomenon occurs both known and mentioned about the effects caused by this global phenomenon and Peru historical cases. Subsequently, studies for the recognition and geotechnical characterization of the tailings material and processing of such information are mentioned in order to assess the potential of liquefaction where a safety factor, which is a number that represents the potential is obtained soil liquefaction. Finally, we conclude that the results show that there is a high potential for liquefaction of tailings material in the dam north in the copper mine considering an acceleration of historical seismic sources and a safety factor of liquefaction average value is calculated 1.3, in order to set the required minimum acceleration which begin the process of liquefaction of tailings material.