Google gets 7 hits (not including this question!) for the search: 1913 Portland free speech fight "Mary Schwab", including Portland Radical History Tour. This site says: "This is for you to take to the library or the Historical Society or to the City Archives and spend hours finding details...". The links specifically to Mary Schwab (www.fresnoalliance.com/IWW/analysis.htm) and the 1913 Free Speech Fight (www.fresnoalliance.com/IWW/analysis.htm) are broken, but their names, places and dates can give you hints for more searches. IWW portland "free speech fight" site:edu gets 36; IWW portland "free speech fight" 1913 gets 240, etc.
Pursuing those "Historical Society" and "City Archives" leads, the Oregon Historical Society gets no hits for: mary schwab in its catalog, and their links to other sources such as Northwest Digital Archives also get no hits for Mary Schwab as a phrase. The Portland City Archives may be a bit of a project to access - see Using the City of Portland’s Archives (Historical Collection) for some not very detailed information.
But the Oregon Historical Society's page makes it clear that much of their archival material still must be searched onsite in card files. Northwest Digital Archives What are Finding Aids? page explains the limitations of what it has online; "In most cases, reproductions of the collections themselves are not online, although in some cases the finding aids in NWDA will contain links to digital material." In its database search, iww free speech gets 6 hits, and you can click on "view search terms" to see where in the database record they appear. Possibly, Mary Schwab documents could be buried deep in a collection and there would only be general information in the database record, such as "free speech movements", etc. But the search: "portland free speech" 1913 gets zero hits. The 37 for portland free speech 1913 are probably from the words all being in the long database records (finding aids), but VERY far apart and totally unrelated.
If you are near a large academic library, you can also try these searches in big commercial databases such as America History and Life, JSTOR, Project Muse, and even Proquest Dissertations. The phrase: Mary Schwab gets zero hits in America History & Life, but iww and free speech gets 11 (searching "TX all text", which means titles, abstracts and subjects). In Proquest Dissertations, mary schwab also gets zero hits. Portland and free speech only gets "Elizabeth Gurley Flynn: A portrait" by Cole, Stephen Charles, Ph.D., Indiana University, 1991, 211 pages; AAT 9203430, and judging from the abstract, it does not seem to say anything about the 1913 Portland fight. Even the very broad search: iww and free speech picks up just one more dissertation: RUNNING THE GAUNTLET: CULTURAL SOURCES OF VIOLENCE AGAINST THE I.W.W. (VOLUMES I AND II) by TOWNSEND, JOHN CLENDENIN, Ph.D., University of Minnesota, 1980, 427 pages; AAT 8109518. Its long abstract mentions San Diego 1912, and I suspect even its lengthy references list would be a VERY long shot. JSTOR gets 12 hits for the search: "mary schwab", but it appears to me that they are contemporary authors, and not he person from 1913.
In short, this appears to be a major piece of research. Quite possibly her papers never made it into any archives, but it might take dozens of hours to make a conclusive guess that in fact they didn't (as in looking for quotations, it's very hard to "prove a negative")