Ultimately distant, newborn chick — mine closer? (8)
I believe the answer is:
thatcher
'mine closer?' is the definition.
(Margaret Thatcher's government closed many mines)
'ultimately distant newborn chick' is the wordplay.
'ultimately' says to take the final letters.
'newborn chick' becomes 'hatcher' (chick that has just hatched).
The last letter of 'distant' is 't'.
't'+'hatcher'='THATCHER'
(Other definitions for thatcher that I've seen before include "Margaret, ex-prime minister, or a traditional roofer" , "Stateswoman" , "Baroness --, former PM" , "who created Boris's hairstyle?" , "Worker on ladder" .)