Why did Dan BLANKENSHIP focus so intently on 10x, rather than other spots?

Dan BLANKENSHIP seemed to be a determined, hard-working, intelligent and resourceful man. He kept thorough records. Why did he focus so much on well 10x? He found the 10x location via "dowsing," which is not proven as a way to locate underground water. Even if it were a proven technique, the presence of underground water doesn't mean that the treasure is located there. Yes he did find some interesting things in 10x, such as pieces of metal. (I've corrected spelling of the word dowsing thanks to "Hiya")