My miners were later than yours and they moved for better wages and conditions; Newcastle definitely paid more than Scottish mine owners.
I found this information:-
There are extensive records of bonded coal miners in Scotland and, to a lesser extent, in Newcastle (North East England), although the nature of the bondage was fundamentally different in each region.
Scotland: Legal Serfdom (1606–1799)
In Scotland, colliers and salters were, by law, bonded to their masters, effectively a form of hereditary serfdom.
The Law: The Colliers and Salters (Scotland) Act 1606 made miners "thirled" (bound) to the pit. If a colliery was sold, the miners and their families were sold with it. A 1641 Act broadened this to include other laborers.
Records:
Estate and Colliery Papers: Detailed records exist in family archives (e.g., Rothes MSS, Wemyss papers) including "Lists of Coal Hewers and Bearers". These list names, who they belonged to, their wives/children (who worked as bearers), and their movements.
Sale of Labourers: Documentation exists regarding the sale of collieries where 40 "good colliers" with their families were valued at £4,000 in 1771.
Baptismal Records: Children were "arled" (formally bound to the master) at their christening, a custom noted in parish records.
Legal Cases: Many records exist in the Court of Session regarding the chase and return of deserted colliers.
Emancipation: The bond was broken in stages by acts in 1775 and 1799, with final liberation in 1799.
Newcastle and Durham:
Yearly Bond (18th–19th Century)
In Newcastle and the Durham area, miners were not legally bonded for life, but were instead bound by a yearly contract known as the "Pitman's Bond".
The Bond: Miners signed an agreement to work for one coal owner for one year.
Records:
Pitmen's Bonds: The North of England Institute of Mining and Mechanical Engineers and Tyne & Wear Archives hold numerous original bonds. These are legal documents containing the names of the miners, the colliery, and the conditions.
Durham Mining Museum Records: Their database (Mining Durham's Hidden Depths) contains lists of workers and sample bonds from the 18th and 19th centuries.
Conditions: If they broke this bond (e.g., by striking or leaving), they could be imprisoned. This practice was abolished in 1872.
Durham Mining Museum
Where to Find Records
National Records of Scotland (NRS): Holds extensive colliery and estate records, including wage books and lists of bound miners.
National Mining Museum Scotland: Provides research guides for family history.
Tyne & Wear Archives / Durham Record Office: The main repositories for Newcastle/Durham pitmen's bonds.
Mining Institute (Mining Institute of the North East): Holds 18th-century colliery papers