200 dives a day, lets say they are super and work a 10 hour day (for easy math). That's 20 dives an hour or one every three minutes. Diving down 40 feet and br

200 dives a day, lets say they are super and work a 10 hour day (for easy math). That's 20 dives an hour or one every three minutes. Diving down 40 feet and bringing up a 3 gallon bucket of sand, once every three minutes for 10 hours straight again seems... very difficult (or maybe a bit improbable). Perhaps it's a special kind of sand and they get more money for it so they don't have to do quite that much?