Has anyone heard of Blackmine Mills or know where it is/was? I'm assuming it was near Framwellgate which was given as the father's abode at the time of Thomas Ayre's 1816 baptism, but a search of websites covering local mills doesn't throw up any possibilities. The family were papermakers so it does sound likely...
It's given as the place of birth for Thomas Ayre on what I think is the only likely 1851 census return:
https://www.ancestry.co.uk/interactive/8860/DURHO107_2391_2391-0624/14583047- however he, his wife and their son are all 10 years older than they should be! They're at 46 Long Row, Coxhoe, and he's a blacksmith, as he was in 1841 (in Aycliffe). But his wife's name and birthplace (Martha and Billingham) are unusual enough in this area to make me think there's a strange transcription error.
In 1861 their ages are correct, and he's now a coal miner at 56 Long Row (again, added 10 on, unless he actually did just move up the road!) but he has given his birth place as Hett - where the family moved round about 1820ish. It seems he died in 1867, certainly before 1871 anyway, so can't get any more info... But I do hate having missing census info, so would be glad to put this one to bed...
BTW, there are other returns for another Thomas Ayre, slightly older and born in Hett, who also married a Martha (Robinson, from Yorkshire) but as I've seen the actual marriage record to Martha Kingston, am discounting those.