The Twangiza mine is located in the Mitumba mountain range, in the western part of the Albertine Rift Valley, just 20 km East of Itombwe Nature Reserve. A biological inventory was carried out within the mine’s decade...The Twangiza mine is located in the Mitumba mountain range, in the western part of the Albertine Rift Valley, just 20 km East of Itombwe Nature Reserve. A biological inventory was carried out within the mine’s decade-old progressive ecological rehabilitation sites. This inventory covered insects, amphibians, reptiles, birds and small mammals. The main objective of the inventory was to assess the level of animal recolonization in the 100-hectares’ restored areas. A total of 22 insect genera, 4 amphibian species, 11 reptile species, 43 bird species and 11 small mammal species were found. All of them were strongly settled in the core area within the afforested sites. Prior to the start of the Twangiza mine activities and 4 years before the ecological rehabilitation in the area, the avifauna was depauperate, both in number of species and their abundance. By then, no mammals or reptiles were recorded within the footprint area. The environmental and social baseline assessment identified 38 bird species in 2008, mainly grassland and mobile species, which were using scrub along valley streams as a refuge, outside the current mine footprint. Our results clearly demonstrate the positive impact of the afforestation on insect, amphibian, reptile, bird and small mammal’s diversity in this area.展开更多
From a harmonized structural map at the scale of a portion of SW Burkina Faso (90 × 80 km2), we targeted prospective zones on the basis of structural criteria and structure-geology relationships. The map was cons...From a harmonized structural map at the scale of a portion of SW Burkina Faso (90 × 80 km2), we targeted prospective zones on the basis of structural criteria and structure-geology relationships. The map was constructed from an aeromagnetic image, and the geology was deduced from old geological maps. The procedure involved extracting the magnetic fabric and deducing the deformation gradients, which led to the identification of shear zones. Analysis and interpretation of the structural geometry of the obtained structural pattern led us to target areas of interference between structures or geology-structures interplays, which are conducive to the deposition of metallic elements. The subsequent overlay of known gold prospects and deposits documented in the region revealed the validity of the predefined prospects. This result reinforces the applicability of the methodology as a first-order regional approach to mineral exploration.展开更多
The main objective of this study is to determine the hydrogeochemical specificities of the groundwater of the Angovia mine operating permit, located in the Yaouré mountains in the center-west of Côte d’Ivoi...The main objective of this study is to determine the hydrogeochemical specificities of the groundwater of the Angovia mine operating permit, located in the Yaouré mountains in the center-west of Côte d’Ivoire. To do so, descriptive and multivariate statistical analysis methods with the SOM (Self Organizing Maps) algorithm were applied to the physicochemical parameters of 17 boreholes using the calcite (ISC) and dolomite (ISD) saturation indices. The results obtained have shown that the groundwater in the Angovia mine operating permit area has an average temperature of 27.52°C (long rainy season) and 27.87°C (long dry season) and has an average pH of 7.09 ± 0.35 during the main rainy season and 7.32 ± 0.35 during the main dry season. They are mineralized with an average electrical conductivity of 505.98 ± 302.85 μS/cm during the long rainy season and with 450.33 ± 233.74 μS/cm as average during the long dry season. The main phenomena at the origin of groundwater mineralization are water residence time, oxidation-reduction and surface inflow. The study of the relative age of the water shows that the groundwater in the Angovia mine operating permit area is mainly undersaturated with respect to calcite and dolomite. They are therefore very old in the aquifer with a slow circulation speed during the long rainy season and the long dry season.展开更多
文摘The Twangiza mine is located in the Mitumba mountain range, in the western part of the Albertine Rift Valley, just 20 km East of Itombwe Nature Reserve. A biological inventory was carried out within the mine’s decade-old progressive ecological rehabilitation sites. This inventory covered insects, amphibians, reptiles, birds and small mammals. The main objective of the inventory was to assess the level of animal recolonization in the 100-hectares’ restored areas. A total of 22 insect genera, 4 amphibian species, 11 reptile species, 43 bird species and 11 small mammal species were found. All of them were strongly settled in the core area within the afforested sites. Prior to the start of the Twangiza mine activities and 4 years before the ecological rehabilitation in the area, the avifauna was depauperate, both in number of species and their abundance. By then, no mammals or reptiles were recorded within the footprint area. The environmental and social baseline assessment identified 38 bird species in 2008, mainly grassland and mobile species, which were using scrub along valley streams as a refuge, outside the current mine footprint. Our results clearly demonstrate the positive impact of the afforestation on insect, amphibian, reptile, bird and small mammal’s diversity in this area.
文摘From a harmonized structural map at the scale of a portion of SW Burkina Faso (90 × 80 km2), we targeted prospective zones on the basis of structural criteria and structure-geology relationships. The map was constructed from an aeromagnetic image, and the geology was deduced from old geological maps. The procedure involved extracting the magnetic fabric and deducing the deformation gradients, which led to the identification of shear zones. Analysis and interpretation of the structural geometry of the obtained structural pattern led us to target areas of interference between structures or geology-structures interplays, which are conducive to the deposition of metallic elements. The subsequent overlay of known gold prospects and deposits documented in the region revealed the validity of the predefined prospects. This result reinforces the applicability of the methodology as a first-order regional approach to mineral exploration.
文摘The main objective of this study is to determine the hydrogeochemical specificities of the groundwater of the Angovia mine operating permit, located in the Yaouré mountains in the center-west of Côte d’Ivoire. To do so, descriptive and multivariate statistical analysis methods with the SOM (Self Organizing Maps) algorithm were applied to the physicochemical parameters of 17 boreholes using the calcite (ISC) and dolomite (ISD) saturation indices. The results obtained have shown that the groundwater in the Angovia mine operating permit area has an average temperature of 27.52°C (long rainy season) and 27.87°C (long dry season) and has an average pH of 7.09 ± 0.35 during the main rainy season and 7.32 ± 0.35 during the main dry season. They are mineralized with an average electrical conductivity of 505.98 ± 302.85 μS/cm during the long rainy season and with 450.33 ± 233.74 μS/cm as average during the long dry season. The main phenomena at the origin of groundwater mineralization are water residence time, oxidation-reduction and surface inflow. The study of the relative age of the water shows that the groundwater in the Angovia mine operating permit area is mainly undersaturated with respect to calcite and dolomite. They are therefore very old in the aquifer with a slow circulation speed during the long rainy season and the long dry season.
