Use of computer softwares and geomatic techniques for reclamation study of environmentally degraded mined lands in Benin City, Nigeria

Land degradation in the form of creation of massive pits, and deforestation of land are some adverse impacts associated with open pit mining activities. Benin City and its environs have witnessed a high proliferation of open pit sand and/ laterite mining activities popularly called borrow pits in recent times, with its associated environmental risk. This research is carried on five selected sand mines in Benin City to estimate the cumulative land area degraded as a result of sand mining operations, thus it determines the level of environmental damage done and quantity of material required for refilling and reclamation. The method involves the use of a GPS based geomatics technique to acquire GIS data of five selected open pit sand mines, as well as computer softwares for the analysis, and area and/volume studies. The result showed that sites A, B, C, D, and E deforested a land area of 17,923.125, 33,991.803, 36,038.761, 13,212.545, and 2,882.046 m2 respectively; while the volume of excavation created by the five sites are respectively 1,792,154.644, 4,992,730.898, 2,701,846.644, 9,878,111.857, and 134,258.932 m3. Thus, a cumulative area of 104,048 m² of land was deforested in the five sites while 19,499,102.98 m³ of excavation was cumulatively created which requires refilling and total reclamation.