"Ore Shoot" is a colloquial term in mining and geology to describe a long seam of mineral or metal bearing rock that can be profitable to extract. The term may have originated in the 17th and 18th centuries when various theories existed on the origins of ore deposits, including some that suggested they grew like trees.
Tabular or sheet-like deposits of metalliferous ores often contain areas of enhanced metal content that are larger in one dimension than another. A structure may contain multiple ore shoots. A "vein," "lode" or other mineral-bearing structure could be 5 to 20 feet (2 to 6 m) thick, steeply inclined within the host rock, persisting for hundreds or thousands of feet horizontally and vertically. Such a structure could contain an area of enhanced metal content extending 100 feet (30 m) horizontally and 500 feet (152 m) vertically. This would be termed an "ore shoot." The existence of the ore shoot could be recognized visually in a tunnel or "drift" excavated along the structure, or by the assaying of rock samples cut from the walls and roof of the tunnel. (Wikipedia)