According to the Lanzhou Morning Post, there are three caves in turn at the foot of Baigong Mountain Mountain, with the largest cave in the middle, and the other two caves have been buried by collapsed rubble. The reporter saw that the middle hole is about 2 meters from the ground, the depth of the hole is about 6 meters, and the highest point is about 8 meters. The cave is pure sandstone with no impurities except sand. Surprisingly, a large iron pipe with a diameter of 40 cm was inserted obliquely into the hole from the top of the mountain. Due to years of corrosion, only half of the pipe wall can be seen now. Another iron pipe with the same caliber enters the ground from the bottom wall, only the nozzle is exposed, and its size can be measured, but its length cannot be known. There are more than ten iron pipes at the mouth of the cave, the diameter is between 10 and 40 cm, and the distance between the iron pipes is different. The pipe wall is completely consistent with the rock. It's not like drilling a hole before putting the pipe, but like an iron pipe directly inserted into hard rock. All the other iron pipes have this function.

About 80 meters opposite the entrance of the cave is the sparkling Tuo Su Hu. On the beach more than 40 meters away from the hole, there are many iron pipes scattered on the exposed sandstone. These east-west iron pipes are smaller in diameter than those at the foot of the mountain, ranging from 2 cm to 4.5 cm. Judging from the shape of the remaining iron pipes, there are straight pipes, bent pipes, crossed pipes and spindle-shaped pipes. , strange shape and diverse types. The inner diameter of the thinnest iron pipe is only the thickness of a toothpick. Despite years of corrosion and sand filling, the small tube has not been blocked.

Strangely, there are some iron pipes in the lake, some of which are exposed to the water and some are hidden in the salty lake, and their shapes and thicknesses are similar to those on the beach.