For this, you need a one (ore) to many (minerals) relationship. You can then display the related records in a portal. There are several options for how you'd link them depending on what your Mineral records represent. If one mineral record can be listed for many different Ore records as I think is likely here, you now have a many to many relationship.
Many to many relationships are implemented in almost all cases with a Join table.
Here's a download link to a demo file (Click the blue download button): http://www.4shared.com/file/PLhjErzu/Contracts_to_Companies.html
It links "contracts" to "companies" so you'll need to think of Companies as "ores" and Contracts as "Minerals", but it illustrates how to do this in FileMaker.
many thanks for your reply and for the link, I greatly appreciate your input.
this post to let you know that I found a solution for my requirement; it makes use of two more appearances of the 'Minerals' table in the graph that shows the table relationships. It's probably not an efficient way of resolving the matter but it works for me.
I need to work on the 'Join Table' concept as I seem to have a bit of a mental block with that atm; I seem to be a bit slow on the uptake these days with concepts that are new to me - old dogs and new tricks, how true.