Mining Pipe is the pipe that a Mining Well uses to replace the blocks beneath it. When broken, it drops itself. The Mining Pipe is a pipe only in name, as it cannot be used as a normal pipe - nothing will flow through it, and its orientation will not change depending on the pipes next to it.
Mining pipe cannot be crafted.
Be careful if breaking mining pipes downward. They break faster than you fall, so you can take fall damage, and there is a chance that lava could be waiting at the bottom.