As for his sister, she might have been removed, like Winston himself, to one of the colonies for homeless children (Reclamation Centres, they were called) which had grown up as a result of the civil war, or she might have been sent to the labour camp along with his mother, or simply left somewhere or other to die.
There are no more uses of "reclamation" in the book.
Show samples from other sources
The Bureau of Reclamation is trying to put all waste water to a second use.
...any place there was mining before the 1970s, there’s a real need for reclamation.