While I can see some of it especially the missions and saddle bag physicalization. I am baffled as to why people thing the Prospector and MOLE will eject inert material when that is the role of refining. While I understand the confusion because of the ui when normally it would be expressed as a percent concentration. But the ability to spawn ore with different concentration is already sort of seen and I believe we will see far more of that in mining in the future as it has lots of knock on game loops like ore transport and refining and feeds nicely into the reward paths. It will lead to Prospector pilots more choosy in what ore they hoover up while allowing ships like the Orion to operate on economics of scale in having the refinery part of the process. It also gives value to the refinery ship operating in tandem with moles and prospectors capitalize on being able to discharge the inert material for hauling.
The reason people talk about the prospector ejecting inert material was because that was one of the features it was sold with (I'm not sure about the MOLE, but I don't believe that was one of its abilities) which allows the bags to be completely filled with the useful raw resources rather than wasting space to store valueless inert material:
Is the ore filtering the same refining technique that the Orion has, or just a first reduction step to do a coarse removal of useless rock?
The Prospector will only be removing things like useless rock, the processing equipment on the Orion is much more advanced.
Source:
https://robertsspaceindustries.com/comm-link/engineering/15319-Q-A-MISC-Prospector-Part-II
Refining is a different process, taking the lower value harvested ore and changing it to valuable useable materials (mined ore - > Metal Ingots, for example, or Quantanium-> Refined Quantanium) which can then be used for manufacturing with a higher profit for the miner. When you take a loaded Prospector or MOLE to a refinery, you can sell the raw harvested ore (and inert material), or refine it to turn it into a higher value resource that then needs shipping elsewhere to sell. At present, "refining" doubles the value of the mined material for a small cost, and with the loss of a varying amount of "SCU" (and time while it is refined) depending on the refining method used and location of the refinery.
For some reason, the mining outposts currently sell refined products for traders to buy and sell, but I'd expect once refinery ships arrive (expanse, etc.) they will be switched to selling the raw materials, with players able to buy, refine, and sell.
Edit:
To clarify, the removal of inert materials by the prospector is similar to the way the "FLTR" mining modules currently work, but rather than decreasing the collection of inert material (as the modules do), the prospector would remove that inert material that had been scooped up before storing the ore in the saddlebags. Using these modules with a Prospector could still have value, as they would limit the amount that required filtering by the ship, allowing it to fill quicker as a greater % of the "scooped" material would be going to the saddlebags rather than being filtered out by the ship.
