Considering the amount of interactions the game provides with heat, I find it extremely odd that heat transfer is modeled very differently for mined/stored materials than it is for placed buildings and existing structures. To get to the point, examine this structure I built in sandbox mode:
Insulated Abyssalite walls, Tungsten Metal Tiles, Diamond Tempshift Plates, and 2500 K Liquid Iron. For control purposes, ensure that the internal atmosphere is a vacuum. (Dupes can't exactly work/perform setup in the bottom chamber for the second experiment otherwise.) Basically, this chamber's designed to superheat anything in contact with the Tempshift Plates.
Experiment 1: 'Placed' material test
Simply place (using sandbox mode) a nice 1 ton block of -200 C Ice over one of the bottom Tempshift Plates. Watch as it melts and turns to Steam in a matter of seconds.
Experiment 2: 'Mined' material test
Place a Tungsten Smart Storage Compactor over one of the Tempshift Plates, then spawn a Duplicant within the lower chamber and place/mine 2 tons of -200 C Ice. Have the Dupe place it within the Smart Storage Compactor... and watch the non-results. (Also, consider deleting the Duplicant when he's done.)
If you inspect the Compactor and its Ice (1 ton mass, since mined materials have their mass halved), you'll see that it slowly heats up by .1 C a tick on Fast Speed. Feel free to kick the Ice out of the Compactor (remove its storage permissions) - it'll still do exactly the same slow temperature crawl, despite being literally the same material.
Why is there such a dramatic difference in heat transfer? I've been wanting to build a Steam Turbine plant driven by meteor Regolith (which can be sufficiently hot), but the painfully slow transfer of heat prevents effective use of this strategy. It also prevents creation of an effective mined Ice 'melter' room. I used to think the problem was that I put too much Ice into a Storage Compactor, but this test proves that it's a different issue entirely.
Steps to Reproduce
See "Experiment 1" and "Experiment 2" above.
This issue has not been confirmed by a developer yet.