They are gold-mining.
"They have found gold here, and gold in abundance, and hither have come, by ship and steamship, all the unfortunate of the earth.

The English factory labourer and the farmer-ridden peasant; the Irish pauper; the starved Scotch Highlander.

I hear a grand swelling chorus rising above the murmur of the evening breeze; that is sung by German peasants revelling in such plenty as they never knew before, yet still regretting fatherland, and then I hear a burst of Italian melody replying.

Hungarians are not wanting, for all the oppressed of the earth have taken refuge here, glorying to live under the free government of Britain; for she, warned by American experience, has granted to all her colonies such rights as the British boast of possessing." I did not understand him then.

But, since I have seen the living wonder of Ballarat, I understand him well enough.
He ceased.