[mass noun] Kimberlite that is exposed at the surface and has become yellow as a result of atmospheric oxidation.
- ‘This type of deposit is called eluvium and is commonly known as "yellow ground" in mining terms.’
- ‘It is mined from a matrix of weathered clay-like rock (kimberlite) called "yellow ground."’
- ‘Quarry operations at the PPC Limeacres limestone mine revealed a small kimberlite pipe, allowing a good view of yellow ground.’