The idea of "monster hunting" by going through rifts is workable. A lore notion:
Experimental tech is being developed to try to manipulate (and one day to close) enemy rifts, but it's been discovered that they can be pried open to become two-way.
Rifts could be natural/random, and maybe higher-level tech could be developed to tune those, but rifts which open during mining encounters could be more assuredly made a certain way since their difficulty level and portal types change during the encounter.
One of the interesting things about this portal/mining tuning concept is that it essentially becomes a magnet to draw players into the encounter and area, allowing them to cooperate to push it toward a major storm event. This could be one of the ways to draw-out a high class kaiju on purpose/early and before it might breach "naturally" with all its allies invading.
Experimental tech is being developed to try to manipulate (and one day to close) enemy rifts, but it's been discovered that they can be pried open to become two-way.
Rifts could be natural/random, and maybe higher-level tech could be developed to tune those, but rifts which open during mining encounters could be more assuredly made a certain way since their difficulty level and portal types change during the encounter.
One of the interesting things about this portal/mining tuning concept is that it essentially becomes a magnet to draw players into the encounter and area, allowing them to cooperate to push it toward a major storm event. This could be one of the ways to draw-out a high class kaiju on purpose/early and before it might breach "naturally" with all its allies invading.