Newcastle United duo Alex Gilliead and Macaulay Gillesphey will remain on loan to Carlisle United for the remainder of the League Two season.
Gillesphey and Gilliead, both 19, have played five games apiece in all competitions, including September's 1-1 League Cup draw at Liverpool.
"You can tell both lads have got ability," Curle told the club website.
"They weren't brought in as projects, they were brought in because they added something to the squad we didn't have."
He added: "They've joined a football club in ourselves which has one eye on youth development."