Current questions and answers regarding the map editor.

Disabling the standard operation of the mine shouldn't prevent resource generation (if it's captured). And indeed, resources are calculated before the trigger for a new day activates.

It's a shame, although it makes sense. I just don't think these manipulations involving resource removal are the right solution.
However, based on my personal experience and the experience of everyone in this thread, sometimes there isn't a correct solution, or rather, there is one, but it's not feasible.
In any case, thank you; I won't waste time trying to bypass the Nival events.