Multi-Temporal Change Detection at a Limestone Mining and Cement Production Facility in Central Nigeria

Limestone mining and cement production at Yandev, Nigeria commenced in 1980 without an environmental impact assessment (EIA) to ascertain the extent of impact these activities could bring to bear on the physical and living conditions of the host environment. This study was carried out to assess the impact that mining of limestone and production of cement has inflicted on the quality and density of vegetation within the study area about 32 years since production commenced. Multi-temporal satellite imageries of the study area (Landsat for 1976, 1986, 1996 and Nigeriasat-1 for 2006), ILWIS Academia 3.3 and SPSS Version 15 were used for data analyses. Landuse and landcover (LULC) change detection; land surface temperature (LST) extraction; and normalized differentials of vegetation index (NDVI) estimation were carried out. The paired t-test was used for landcover data analysis. The study discovered first, that LULC changes occurred with built-up area increasing from 0.05 km2 in 1976 to 1.51 km2 by 2006, thus representing the landcover category with the highest gain. Conversely, thick vegetation declined from 4.30 km2 in 1976 to 1.51 km2 in 2006. Thick vegetation category lost to all other landcover categories while gaining only 0.07 from water bodies. The projected LULC of the study area by 2015 reveal an expected expansion in built-up area from 1.51 km2 in 2006 to 1.90 km2 by 2015, whereas thick vegetation is expected to further decline from 1.51 km2 in 2006 to 0.80 km2 by 2015. Second, the LST have risen over the study epochs (1976, 1986 and 1996) while NDVI signifies decline in quality and health status of vegetation cover over the study period (1986, 1996 and 2006). The study concludes that there is rapid decline in density and quality of vegetation cover within the study area. Ameliorative measures are recommended to include reforestation and improvement in limestone mining methods/techniques amongst others.