Copper Mineshaft

Generates at deepslate level, this mineshaft is mostly oxidised. Copper bars spawn instead of fences. There might also be Furnace Smelting Rooms. The starting piece has a gravel floor.

Edit: Initially, the block to replace oak fences was going to be copper grates. After snapshot 25w32a, the block to use instead of oak fences was copper bars due to the similar block states of both copper bars and oak fences.