1955 is probably best known to readers of this blog as the year that Disneyland opened. Knott's Berry Farm had been around for many years at that point, and luckily for us, it did not whither and die when its flashy new neighbor moved in - in fact, it thrived!
I don't recall seeing photos of the "Lucky Cuss" mine before. This apparatus apparently hoisted up buckets full of ore-laden rock and dirt and dumped it into that wagon. The dirt was then panned by Knott's visitors nearby. I think that might be the ticket booth for the gold panning visible behind the wagon and through the timbers.
And there's Old Betsy! You can still see her at Knott's today.