Theorhetically mini black holes are produced naturally all the time but they dissipate in nanoseconds. As I understand it, black holes require a certain ammount of mass for them to be sustained.
Yeah, but is that mass a rock, a planet, or does it require a whole galaxy? It's important to know these things.
That’s because of Hawking radiation. The smaller a black hole is, the quicker it evaporates. The rate of evaporation becomes exponential with mass loss, and anything lighter than about a mountain will not gain further mass because the radiation pressure will exceed its gravity. But at that point, it won’t last long anyway. Hawking theorized all this using generally-accepted physics.