Drawn as a prospect: a shallow pit or trench dug to test for ore, not a working mine. The ore color stands for clay. Federal records note the kind of operation and its status, not its depth or layout, so this is a typical example rather than a survey of this site.
This location is classified as a mineral prospect or occurrence — a site where minerals have been identified but no significant mining has taken place. These sites typically have minimal environmental impact but indicate the presence of mineral deposits in the area.