Excavation at the Besshidozan copper mine in Iyo was started in the 4th year of Genroku, which was during the lifetime of Tomoyoshi SUMITOMO, a grandchild of Riemon Tomomochi SUMITOMO.
住友理兵衛友以の孫にあたる住友友芳の代には、元禄4年に伊予の別子銅山の開堀に着手。