On his historic journey through the gap in 1750, Dr. Thomas Walker made note of a spring coming from a cave. In his journal he noted that "the spring is sufficient to turn a mill." In 1819, a blast furnace was built on the stream below the cave, now known as Gap Cave. Large, sandstone blocks were used from nearby and fire brick was used to line the inside of the furnace which was used to smelt iron.
Iron ore was mined nearby, limestone was added in the process, and firewood was made into charcoal for use as fuel. Water from the stream powered large bellows and a massive hammer mill.
Each day 625 bushels of charcoal (approximately 52 trees), 6 1/4 tons of iron ore, and 1,563 punds of limestone were used to produce approximately 3 tons of iron. The furnace, which was known as Newlee's Iron Furnace, operated throughout the 1800's. Some of the iron was sold to local blacksmiths. Some of the iron was shipped in the form of ingots or "pigs" down the Powell River to Chattanooga, Tennessee