I'm 99% certain it's completely removed. My miners have still found ZERO claims on Ark since the ore reshuffle. The small amounts you see in auc are probably just remnants of people's storage from before the change, or leftovers from their own crafting runs with imported materials. Quantium is a universal resource, so I believe it's under the sole control of MA to determine drop rate, and as they said, they do move these universals around between planets to "stimulate interplanetary trading". Now maybe quantium is only found in one square meter of the planet, at a depth of 1500m+ ... I admit, that IS a possibility
Back when it was just Caly Quantium was considered a rare. If they restructured it correctly here that we have progressive levels and rarity of ores now instead of everything can be found with a Z1 then quant should have found its way back into rare status. I would assume that it would tale a Terra4 or a 320 or bigger to find regularly if you know the areas from what it was back in the day.
Yes, that's how it is now. Certain minerals are only found at certain depths. A Z1 (or terramaster 1) doesn't find the same things that a terramaster 4 does.