  Scholarly Open Access repositories contain lots of treasures including rare
or otherwise unpublished materials and articles that scholars self-archive,
often as part of their institution's mandate. But it can be hard to discover
this material unless users know exactly where to look. Since the very
beginning, libraries have played a major role in supporting the OA movement.
Next to all services they can provide to support the deposit of research output
in the repositories, they can make Open Access materials widely discoverable by
their patrons through general search engines (Google, Bing...), specialized
search engines (like Google Scholar) and library discovery tools, thus
expanding their collection to include materials that they would not necessarily
pay for. In this paper, we intend to focus on two aspects regarding Open Access
and Primo discovery tool. In early 2013, Ex Libris Group started to add
institutional repositories to Primo Central Index (PCI), their mega-aggregation
of hundreds of millions of scholarly e-resources. After 2 years, it may be
interesting to take stock of the current situation of PCI regarding Open Access
institutional repositories. On basis of a survey to carry out among the Primo
community, the paper also shows how libraries using Primo discovery tool
integrate Green Open Access contents in their catalog. Two major ways are
possible for them: Firstly, they can directly harvest, index and manage any
repository in their Primo and display those free contents next to the more
traditional library collections; Secondly, if they are PCI subscribers, they
can quickly and easily activate any, if not all, of the Open Access
repositories contained PCI, making thus the contents of those directly
discoverable to their end users.
