Willis (asker) Dec 3, 2013:

In the end, and reading the references, I decided to go with "Minijob Agency"; "Minijob Centre" is too British and less easily understood by the Cdn recipients of the translation.
The reference to the handelswissen.net website provided by Jochen König was very helpful. It also indicates that the employer makes a number of contributions to the Agency on behalf of the employee and can make a slight deduction for income tax. Because "Knappschaft Geringverdienst" is in the heading of the document and not in the list of deductions or payments, and because there is no obligation to make deductions even for tax, that is why I decided against mentioning "deductions", although I had favoured it earlier.

Thank you everyone!

Jochen König Dec 3, 2013:

insignificant employment deduction This is in fact a deduction made by the employer to the federal Knappschaft-Bahn-See insurance for low-wage employees with a wage up to €400/month. http://www.handelswissen.net/data/handelslexikon/buchstabe_g... So I agree with Willis that in this context anything about "mining" is not going to work.

Willis (asker) Dec 2, 2013:

I agree that "Knappschaft" is normally a miners' guild or association, but in this context which is so far removed from mining, I cannot think it will work here. On the other hand, the suggestion of "deduction" is a step in the right direction; it is just a question now of fitting it together with "Geringverdienst" (rather than Geringverdiener), particularly as a piece of information on the pay slip makes clear that he was not a low-wage-earner. This is part of the puzzle which perhaps I should have added earlier.