• 鉱山こうざん — mine
• 鉱石こうせき — ore stone
• 鉱脈こうみゃく — mineral vein
• 採鉱さいこう — mining
• 炭鉱たんこう — coal mine
• 鉄鉱てっこう — iron ore
• 鉱業こうぎょう — mining industry
• 鉱油こうゆ — mineral oil

The left part represents metal, while the right part relates to colored stones. The character originally referred to naturally occurring ore such as copper or gold before refining.

この鉱山こうざんでは 金属きんぞくが 採とれます。
Metals are extracted from this mine.

その鉱石こうせきは 銀ぎんを 含ふくんでいます。
That ore contains silver.

Commonly read as “こう” in compound words like 鉱山 and 鉱業. The kun-yomi “あらがね” is rarely used today and typically appears in classical contexts.