An 18.4-meter-tall shelf is used to fish for brine at the Shenhai salt well in Da'an district, Zigong city, Southwest China's Sichuan province, on April 25, 2017. [Photo by TG/ provided to chinadaily.com.cn]

Workers at the Shenhai salt well in Da'an district, Zigong city, Southwest China's Sichuan province, still use a traditional salt making method, which dates back to as early as 2,000 years ago in China.

After drawing underground brine through the wells, the workers filter and purify it, which will be later boiled in iron pots. The salt is produced after workers boil brine in the pots for seven to eight hours.

Today, the Shenhai salt well maintains a daily salt production of around two tons, maintaining eight iron pots.

The salt well, dug in 1835, also boasts being the oldest in the world, with a depth of more than 1,000 meters.

Earlier in 2017, the salt well underwent renovation.

"The protective renovation gave some absent craft and relics a restorative reappearance, which allows visitors to experience the whole process of drawing and carrying brine, and producing, storing and transporting salt," said an insider responsible for cultural relic administration at the well.