Yes, if you borrowed the item(s) from the General Library of UMinho (BGUM), the UMinho Library on the Azurém Campus (BPG), the Library on the Couros Campus (BCC), the Education Sciences Library (BCE), the Law Library (BD), the Prof. Joaquim Pinto Machado Library (BMP), or the Nuno Portas Library (BNP) of the University of Minho. You can send the publication(s) to the library's address.
Consult the addresses for each library here.
The Documentation and Library Services Unit considers the effective return date to be the date on the postmark and recommends that you send the item(s) by registered mail and/or with return receipt requested.
I returned the publication(s) I had borrowed by mail (CTT). How do I know if the publication(s) arrived at the library?