No known historical gold production records exist for the pre-WWII era Kamitsue mine workings however Wantanbe, 20053 notes the presence of at least 40 mine portals and associated workings.
Exploration was undertaken from 1990 to 1992 by MMAJ as part of a regional metallogenic study which included regional gravity surveys, surface sampling (semi-regional and prospect scale), culminating in scout diamond drilling. Chronologically this included:
1984: Sumitomo geological sampling of historical mining portals.
1990: Geological mapping, geochemical sampling (300 rock chip samples) and alteration mapping.
1991: Prospect-scale rock chip sampling (399 samples) collected. This and previous work identified two distinct coincident clay-alteration / geochemical anomalies including a 5.5km by 1.5km east-west trending zone with anomalous gold, silver, arsenic, antimony and mercury and a smaller 1.5km by 0.5km zone with anomalous gold, silver, arsenic and mercury. A single inclined drillhole (3MAKC-5, 400m depth) targeted a Au-Ag-As rock geochemical anomaly and intersected a 1.6 m wide quartz vein zone which assayed 0.12 g/t Au & 11.1 g/t Ag from 341.9m (4METI, 1991).