Yep, that must be you, EK. Based on the map, which I believe was used for the salvaged save file, the border pillars that I finally managed to place a couple of days ago are still there. I'd guess that if you see it on the map, it is there. I probably have to re-run my quarry's first run and re-mine the area near it to find all that tin that I finally found......now if I can only remember which level down my staircase I started mining at.....Not too big of a deal as I learned a few things while quarrying and mining that I will do differently (I just hope that I still have my diamond efficiency-3 unbreaking-3 pickaxe). I will have to go back and farm the blazes for a while again though. Next time I use a throw away diamond sword rather than the enchanted bloodwood one....knockback is bad for blaze farming).
So, neighbor, how nice of a shop do you have?
I think that mine just got reset back to zero.