Australia : Miners on shipping registers.

I have found a potential relative (surname/age/occupation)on an 1885 shipping register for the vessel SS Liguria, that routed Melbourne+Sydney to London.

He is recorded as J ENGLAND aged 27 years single and described as a miner.

Which, to a certain extent could be the John ENGLAND b 1859 in Buniniyong, Victoria that I am seeking details about ( who may be my GGF ).

Within this one document, reviewed, there are quite a few miners listed as passengers, which surprised me. One or two, might suggest just travelling, but upwards of thirty named, is it a migration for commercial reasons.

Not having much, if any, knowledge of the then mining industry, might someone have an / any idea why so many miners might have been travelling to London (with no specific port of landing named )at this period in time.

To me it looks as though it may have been opportunistic travel.
Was there (in todays parlance ) recruitment for miners.

Might someone be able to advise or have come across a similar finding ?

Any information greatly appreciated.

Thanks Brian E