Extract a specific strong from a column

Hi,

this seems like a really straight forward task but I can't find a solution

I have a table of expenses, and I need to exclude the expenses that are mileage from my data.

Unfortunately the only data I have to go off for this is an inconsistent "description" column, with values that might look like this:

All I want to do is create a column that extracts each instance of "mileage" from the "description" column, which I will then use to filter out the results I do not want. All of the default extract options are no good as the data is too inconsistent.