Well before the gold rushes, Australia was a continent in the South Pacific inhabited by Indigenous/Aboriginal peoples. Numerous Asian, Ocieanic, and European traders had visited the continent, but it wasn't 1770 that it was claimed for Britain by Captain Cook. Australia was used as a British penal colony starting in 1788. There were willing immigrants/settlers as well. Any discussion of Australia prior to the gold rushes would need to discuss the three group (Aboriginals, prisoners, and settlers) and what life was like for them.
Sometimes when I look for reliable sites, I'll search out .gov (is the Australian equivalent .au?) and .org endings. Here are a few on Australian history:
postcolonialweb.org/australia/colonialov.html
gutenberg.net.au/aust-history.html
australianhistory.org
Of course I haven't vetted the information contained in any of the sites.
Eric Noto