Farmers accidentally found salt in well water, so they have been digging deep wells. During the Eastern Han Dynasty, when farmers in Zigong were drilling wells, they found that the groundwater here was salty and bitter, and there was no way to provide normal fresh water. However, Zigong farmers later discovered that edible salt can be extracted from these groundwater after boiling, and edible salt can be used as a condiment for people's normal diet. This is how salt is produced. After that, Zigong farmers have been mining well salt.
However, as well salt is used less and less, Zigong farmers can only decide to dig deep wells. Well salt has been mined on a large scale for thousands of years. By the middle and late Qing Dynasty, there was actually not much well salt buried on the surface, and only a very small amount of edible salt could be extracted. The difficulty of mining has also led to a sharp decline in the salt production provided by Zigong, which has caused many Zigong farmers to fail to obtain enough economic benefits to maintain their lives. Under the pressure of survival, farmers thought of digging deep wells to extract more edible salt.
Zigong farmers rely on their hands and brains to accomplish seemingly impossible things. In fact, in ancient times, it seemed impossible to dig thousands of meters of deep wells. After all, there was no advanced technology in ancient times. But in order to survive, they finally invented the impact drilling and sinking method through various means and methods, and chiseled the first thousand-meter deep well in human history.