Press release analysisWhen hot, acidic, sulphide-rich fluids eat away at some carbonate rock and replace it with sulphides the carbonate has to go somewhere. It forms "fugitive" carbonate veins which can form at a considerable distance from the point of liberation. These fugitive carbonate veins are often loaded with Manganese and glow under long wave UV as "BBQ rock". They can also contain small amounts of gold and silver.
You never mine the fugitive Calcite veins. You can use them to do a mass balance calculation. If you have a million m3 of fugitive calcite then you have a million m3 of massive sulphides somewhere.