An example of how to obtain skills and items

For example, let's say that exploration and mining are both at the same level, 300.
From exploration, you can obtain 30 iron keys at 1/10 of your skill level three times per season.
If you balance this, mining will start at the same time.
Iron at the same time as getting the iron key, same as skill level, 300 each
I think it would be appropriate to just get it.
It takes 15 iron to make one iron key, so it is inferior when converted to an iron key,
Iron has other uses, such as being made into iron cannon bullets, so it is better to use less iron.
It is considered that the balance is maintained. I hope this serves as a guideline.