Beginning the process during the bats' stay would disturb them needlessly and could jeopardize their survival. In the late 1800s, a vertical shaft was constructed at Bracken Cave to extract the guano. Unskilled laborers worked inside, shoveling the harvest into buckets, which were then hoisted up through the shaft. In areas of the cave not easily accessible to humans, a large hose attached to an industrial vacuum truck is inserted through the shaft, and the cave floor is vacuumed. This method is automated and fast, requiring little manual labor.
Workers shovel the guano into a hopper attached to a pipe that leads to an air compressor above.
The compressor creates a vacuum and sucks the guano from the hopper into large bags at the top of the shaft. One day's work will typically result in 200 bags, or roughly 8,800 pounds, of guano. It takes about 21 days to complete the harvest. Malcolm Beck probably couldn't have imagined back in 1959 that the cave his friend casually mentioned would eventually become the source of a purposeful new career. Today he harvests, markets, and sells up to 50 tons a year of Bracken's bounty.