Resilience of Building Structures in Mining Communities in Ghana

Ground vibrations produced by mine blasting negatively impact nearby structures. In Ghana, there have been allegations of blast induced ground vibrations resulting in building cracking in communities around mining pits. A pre-mining building condition survey was undertaken in selected mining communities in Ghana, a total number of 1904 buildings were surveyed in five mining areas. The results show majority of the building are not engineered and the thickness of the foundations are less than 450 mm. The age distribution of the building is between 1 and 100 years. Sandcrete blocks are the main wall cladding with a percentage of 60%, landcrete wall cladding are about 24%, cement rendered landcrete blocks are 11% and wood cladding are 5%. The commonest defects identified with structures includes the crocodile skin crack, surface cracks, horizontal cracks, vertical cracks, through cracks and diagonal cracks, and spalling-off of the mortar from the walls due to improper bonding. The study showed that, most of the structures are not designed to withstand the mine blast induced ground vibrations. It is recommended that blast designs should take into consideration the conditions of buildings within mine pit environs and comply strictly with blasting regulations to avert confrontations with local communities.