About IMAI A
About Geological Survey of Japan, Ibaraki, JPN
About ISHIZUKA O
About Dowa Engineering Co. Ltd., Tokyo, JPN
About YAMADA R
About Akita Engineering Co. Ltd., Akita, JPN
About MIYAMOTO H
About Akita Engineering Co. Ltd., Akita, JPN
About Resource Geology
About metal ores
About 褐色鉱
About Metallic ore deposit
About 日本
About 黒鉱
About 鉱床
About 褐色
About 鉱
About 産出