Hi.

What is the proper way to model a relationship between a company and a regulatory license that they hold to conduct operations at a particular location (a mine site)?

The scenario is;

A company (mining company) must have a permit to prepare(construct roads, buildings, waste dumps etc.) a mine site (a specific geographic region within which deveopment is permitted) to the the point of the commencement of commercial operation.

I've tried a ternary relationship but I'm not sure that's right.

I've tried a 1-1 relationship between a permit and a mine but then how does the company fit in?

I've tried a 1-1 relationship between the company and the mine but then how does the permit fit in?

I've tried the license as an attribute class of the relationship between a company and a mine. Not sure if that's right either. This might be right except that there are instances where a company might not have a permit for a mine (this is certainly the case for legacy data)

I've tried the company as an attribute class of the relationship between a mine and a permit. That doesn't make sense to me becuase that would mean the company would only exist if the relationship between the mine and the permit existed.

Anyone with any ideas?