Who is Chilean miners from The Voyage of the Beagle and what is their importance?

Darwin observes two distinctive kinds of Chilean miners. The first works very hard for three weeks straight, and then receives two days off to spend with their families. The second kind works hard as well but spends all their money during the time off on clothes and drink. By today's standards, the miners are terribly exploited, but Darwin reports the men like the work better than farm work.