Regular vegetation monitoring is undertaken by St Ives Gold Mine (SIGM) in the areas surrounding their mining operations, which is driven by both their environmental approval conditions and their corporate drivers to be responsible environmental stewards for the areas in which they operate.
Traditionally, vegetation monitoring was achieved by regular field surveys undertaken on the ground by botanists and environmental scientists. Whilst this approach provides a range of site information, the method is recognised and being onerous given the large areas that need to be assessed, and is not considered to be an appropriate way of capturing all the changes in vegetation health and cover over a number of years. SIGM therefore appointed Talis to undertake a multi-spectrum satellite imagery analysis to capture the changes (if any) in the spatial extent of vegetation assemblages over time.
As recommended by Talis, the analysis calculated the Normalized Difference Vegetation Index (NVDI) for the area surrounding the TSF4, which is often used 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 4 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 years 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.