The two Minamikayabe lithocaps may have formed above telescoped porphyry systems. Mitsumoriyama, the western lithocap, is of particular interest and shows prominent alteration zoning and associated strong gold and multi-element anomalies, including an historic gold-mineralized drill intercept reported by the MMAJ. This higlights the potential for a disseminated gold-silver resource within the lithocap and an associated porphyry copper-gold deposit beneath this lithocap. Only the eastern edge of the Mitsumoriyama lithocap lies within Japan Gold’s application area. There is additional potential for high-grade gold veins between the two lithocaps within the project area. Based on the alteration and metal zonation patterns interpreted by Japan Gold’s consultants, the causal porphyry intrusions associated with the Minamikayabe lithocaps are interpreted to lie between 1 to 2 km depth below the present-day land surface.
The porphyry copper potential at Minamikayabe is supported by a 2014 report published by the USGS that assesses the porphyry potential of Japan. The project lies on a Late Miocene to Plio-Pleistocene segment of the Northeast Japan Arc hosted by calc-alkaline, andesitic-dacitic volcanic rocks. The USGS report documents that this arc segment, characterized by exposed advanced argillic alteration systems, is permissive for undiscovered porphyry copper deposits at depth.