Once I had a plumber looking for the main sewer line in the front yard of a house, near the front property line, after a few days of getting evasive reports from him, and him saying that he still hadn’t found it, I went to check on him.
While the sewer line would have been about 4 or 5 feet deep, for some reason he picked a certain spot and just kept digging as he looked for it vertically, somehow he had dug a 21 foot deep hole, by himself, I don’t even know how he handled doing it, removing the dirt and so on, but I didn’t want to embarrass him with questions, and I merely showed him where the pipe was most likely to be, and set him back to work.
He was working on that gold vein he came across.