Drawn as a mineral occurrence: a place where a geologist noted the mineral, with no mining recorded. The ore color stands for thallium. 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.