The Baigong Pipes

In an area of China not known to ever contain people, let alone industry, there are three mysterious triangular openings on top of a mountain containing hundreds of ancient rusty iron pipes of unknown origin. Some of the pipes go deep into the mountain. Some of them go into a nearby salt water lake. There are more pipes in the lake, and more still running east-west along the lake shore. Some of the larger pipes are 40 cm in diameter, are of uniform size and are placed in what seems like purposeful patterns
.Oddly, the pipes are clean of debris despite being older than Zeus. This suggests that they were not simply shoved into the ground for the hell of it, but actually used for something.

Oh and did I mention that the mountain that these pipes are found on are considered inhabitable?

What the fuck?