In the article, the guy that dived for sand bringing it up in a bucket made $16 dollars a day. He had to dive about 40 feet down. Someone else hauled the sand up that he dove for. This person made less.

So lets say between the two and maybe a boat, $25-35 a day. I looked up how much concrete sand costs... in the US at least I found it for $7 a ton. Are they able to bring up 3 or 4 tons a day per two man team diving down 40 feet? I am skeptical, but maybe there is something I don't understand.