There are a bunch of factors that go into mining yields, but fortunately the various mining groups have mostly worked it out long since (example source). But the numbers you've quoted in this thread - getting between 3 and 10 tons from lasering an asteroid - sound like they are within the plausible range you should be seeing. The values are randomized within certain ranges.You mean, something like an artificial cap?
I hope it has nothing to do with my low level mining lasers, prospector or small refinery (A2). That would be super artificial (not to say downright daft).
But then I got both results with the same equipment...
For laser mining, both being in a pristine ring and being in a hotspot increase both the percentage and chance of finding valuable minerals in asteroids (hotspots specifically boost the listed mineral, of course). There may be other "astrophysical" factors that affect the base abundance from system to system too, because not every pristine ring is created equal by far. Then the amount of mineral per fragment is a random multiplier of that: in deep space where there are no REZ sites, you get between 50-100% of the amount listed in the asteroid scan. The number of fragments you will get is also randomized: with no REZ site and an A-rated prospector you will get between 28-42 fragments, with lesser quality prospectors giving fewer. Multiply all that together and a 30% Tritium asteroid can give you anywhere from 4 to 13 tons of refined product, but should generally average out around 7-9.
With the advent of new-style SSD mining, you can get much much more than this from a single asteroid. But asteroids with those deposits are much rarer than surface-minable ones. There's ongoing debate about whether doing one or the other or both is ultimately faster, so YMMV.