When we can't find a person in a collection of historical records, or don't have enough information to know if it is our ancestor or not, it helps to widen the search -- and the same is true for finding material that will give you historical context about your question.
If you haven't done so already, write out a short biographical sketch of your ancestor and create a timeline of the events in his life that you know about so far. Make a list of all the source material you've looked at with notes about where you found them. This needn't be as formal as a report that a professional genealogist or an academic historian might create (although you can have that as a goal as you want). The purpose of this exercise is to collect all the information you know in one place so you can review and examine it as a whole, instead of just looking at isolated bits and pieces. You'll mine these sources for clues, and use your biographical sketch to evaluate whether any new record belongs to your ancestor, or someone else with the same name.
Next you might consider narrowing down the scope of your search by thinking of a more precise research question such as Did my ancestor make a Mining Claim? For a good starter on that topic see the post California Mining Claims on the blog The Educated Genealogist and the post Mining the 1872 Act records by The Legal Genealogist for a discussion of federal records. Both of these posts are crammed with references you can use for further research, including a link to a 1851 Poll Tax List of Miners Along the Yuba River on RootsWeb.
To look at the Gold Rush from the perspective of scholars who do population studies, see Migrating to Riches?: Evidence from the California Gold Rush by Karen Clay and Randall Jones (both at Carnegie Mellon University).
For other overviews on the Gold Rush, see the Ancestry Wiki article California Gold Rush (originally written by Dwight A. Radford, Thelma Berkey Walsmith, and Nell Sachse Woodard for Red Book: American State, County, and Town Sources.); for a case study, see the FamilySearch blog post History Mystery: Breaking All the Rules. Look for blog posts or articles in genealogy publications from researchers who are also studying Yuba County, and see what sources they found and what search techniques they use. See PERSI (the PERiodical Source Index) to search for topics that may be of interest to you -- if you find an article that interests you, you can request a copy from the Allen County Public Library (link in the Other resources section below).
When you visit the websites of State Archives or State Libraries, see if they have finding aids or research guides. Some examples:
When starting research on any new topic or area, you can also collect material from other sites like Wikipedia, like this article on the Yuba Goldfields. Reading the bibliography or source lists for articles and guides is the key for getting ideas for further research.
Don't neglect historical newspapers such as those found in the
California Digital Newspaper Collection, or letters and diaries, which can be found via ArchiveGrid, NUCMC, or the Digital Public Library of America.