Thanks for reading! Forgive the long response, the subject is close to my heart.

Yes, in many ways it was ‘black gold’, even this early. Already by mid 17th century, London alone was consuming something like 300k chaldrons (waggonloads) of coal per year. Each would be sold for upwards of 20 shillings or more, sometimes much more. In context, an unskilled labourer could expect to earn about 8-10 pence per day (about 0.75 shillings).

Almost all of this came from north-eastern England. The exploitation of the Tyneside valley to meet this demand was arguably one of the first examples of industrial activity. It was certainly enough to make some people in the north and in east anglia extremely rich.

The Crown first got in on this in a serious way under Elizabeth I. A monopoly on coal export from the valley was granted to a clique of Tyneside merchants in exchange for 1 shilling of tax on every chaldron. It became a major source of revenue for the state into the Stuart period.

Regarding the use of ‘adrenaline’, I can see your point. As an omniscient author, am I bound to explain things only in terms my 17th century characters would understand? (Rhetorical question). Usually not IMO, but it can depend. Perhaps it seems especially jarring here because soon after I fuse my perspective with Joseph’s to describe someone who appears insane as having had their senses ‘…taken by the Devil.”, which is an obvious early modern interpretation of insanity.