alien nation - What were the slaves doing on the spaceship?

From the intro to the 1989 Alien Nation TV show:

That was the scene in California's Mohabi desert five years ago. Our historic first view of the newcomer ship. Theirs was a slave ship, carrying a quarter of a million beings, bred to adapt and labour in any environment. But they've washed ashore on Earth, with no way to get back to where they came from. And in the last five years the Newcomers have become the latest addition to the population of Los Angeles.

I've watched the whole series but didn't manage to catch an explanation of what the slaves were actually doing aboard the spaceship before it crashed. The Overseers were obviously controlling the Newcomers to extract some sort of forced labour from them (they're slaves, after all). However, what specifically were the Newcomers doing during their enslavement?

Answer

The ship Gruza appears to be a transport, taking slaves from a place that they're no longer needed to a place where they're needed more. Although the Tenctonese seem to form a general underclass, at least some were used as slave labour for mining

This tracking device is very much like what the overseers used on us at mining camps.

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On board the ship itself, most of the aliens seem to have been in hibernation with a skeleton crew of a few hundred kept awake to run and service the ship and its crew.

CAL-TECH PROFESSOR: From the time mankind first gazed up at the stars there had been speculation about a visit by people from "out there." How ironic that when that first contact was made, the two hundred and sixty thousand occupants aboard the craft were as surprised as we were about their arrival. That they awakened from frozen hibernation to find their malfunctioning autopilot had landed them here by mistake.

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