Remote Sensing (NDVI) for Vegetation Assessment | Talis GIS Spatial Intelligence

Gold Fields Ltd – St Ives Gold Mine

Remote Sensing (NDVI) for Vegetation Assessment| Talis GIS Spatial Intelligence

Regular vegetation monitoring is undertaken by St Ives Gold Mine in the areas surrounding their mining operations. 

Traditionally, vegetation monitoring was achieved by regular field surveys undertaken on the ground by botanists and environmental scientists. While this approach provides a range of site information, the method is recognised as being onerous given the broad areas that need to be assessed and is not considered to be an appropriate method of capturing all changes in vegetation health and cover over multiple years.  

Talis was appointed by Gold Fields Limited in 2015 to undertake a multi-spectrum satellite imagery analysis of the St Ives region, working to observe any changes in the spatial extent of vegetation assemblages over time. 

As recommended by Talis, the analysis calculated the Normalized Difference Vegetation Index (NDVI) for the area surrounding the site tailings storage facility – a study often conducted as a remote measure of vegetation distribution and health. This method determines the amount of visible-spectrum radiation (light) that is being absorbed by vegetation in a given area, which is a robust indicator of photosynthesis and, in therefore vegetation density and health. 

The assessment utilised archived multi-spectral imagery dating back four years, which provided a useful baseline and historical measure of changes to vegetation over that time. This was supplemented by a new satellite capture using the WorldView platform, which was then compared at both a regional and site level to the previous year’s captures. This approach provides a useful broad-scale measure of vegetation health, and reduces both the costs and risks associated with sending personnel into the field to undertake on-ground assessments. 

Talis maintains a close ongoing relationship with St Ives and Gold Fields Limited, and remain a consultant of choice.