Old mine - Kyuko

...However, the basis is to explore the surface and investigate the distribution of the strata exposed on the surface, and it is not uncommon for a single boulder picked up in a riverbed to be the starting point for the discovery of a large deposit. Re-investigations of old mines that were abandoned long ago and reviews of ore deposit quality maps from that time can also provide important clues. Other effective methods of mineral deposit exploration include geophysical exploration, which determines the underground structure by observing how sound waves are transmitted inside the earth's crust and the state of electric currents flowing underground, and chemical exploration, which examines the water quality of rivers flowing on the surface and trace elements in the soil to analyze the geological situation.

*Some of the terminology that refers to the "old mine" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…しかし，地表を踏査して地表に露出する地層の分布を調べることが基本であり，川原で拾った1個の転石が大鉱床発見の端緒となることも珍しくない。古くに見捨てられた旧坑の再調査や，当時の鉱床品位図の見直しといったことも，重要な手掛りを与えることがある。地殻内部での音波の伝わり具合や地下を流れる電流の様子をみて地下の構造を判断する物理探鉱法(地球物理学的探鉱法)や，地表を流れる河川の水質や土壌中の微量成分を調べて地質状況を解析する化学探鉱法(地球化学的探鉱法)の技術も，鉱床探査の有力な手段である。…

※「旧坑」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報