Translations:Mining/64/en
From Vintage Story Wiki
To interpret the information, one must understand that this mode does not detect the actual presence of ore blocks, but detects the chance that ores are present (in permilli). The game uses randomly generated ore density maps whenever a chunk is generated. These determine the chance for ores to appear. Even if a player removed all the ores from a chunk, the prospecting reading would remain the same. Additionally, some ores are not detected by prospecting with this mode, like quartz or surface copper.