The pipe connections to the mining platform suffer from the restriction to maxium pipe network length, meaning that they "sometimes" cant be used to mine ores far away from their position in the other furnace platform dimension.
(This is with krastorio 2 spaced out and no other mods (base game, quality, rails, space age))

i didn't increase the length for anything else than pipes and fluid tanks, so if you link directly your pipes to a miner, flamethrower, ..., you need to put a pump.
I don't know why some entities force the value while other don't.

i may change it in the future for miners / foundry / chemical labs etc, but for now at least, you have the solution to use it (=use a pump)