It's a great subject and unlike many cavers, the literature part of things is a massive part of what interests me. I remember seeing "Exploring Cornwall's Mines 1" in a shop and bought it and that got me out of poking around adits and tips in the tamar valley and ultimately caving and doing it really seriously, to the degree that I find myself out on multiple sites every week. It is a fantastic subject with almost limitless amounts of information to get into, before you do your poking around.
If you can sit there and say "Yes, I am really keen on this and I want to know more" it's a good idea to get a handle on the information available.
As others have mentioned. A copy of Dines (Moorebooks) is essential. It tells you what is where and allows you to make more sense of the 6" maps (of which the hamilton jenkin variety are the most common in circulation). This puts you in the right ballpark. With this and Acton/Brown's series, you would be pretty well set up.
Bradford Barton always has some goodies and among them are "The History of Copper Mining in Cornwall and Devon" which is an utterly outstanding text and really brings it alive. You also have "Cornish Mining" by Bryan Earl, which is another good overview of your basic subject matter which you need in order to have a good handle on what was actually going on.
If minerals/geology are your thing, you need to get a copy of "The Mineralogy of Cornwall and Devon" by JH Collins. This is pretty much the bible of what stuff can be found on what tips. Again, combined with Dines and 6" maps, you're off in a major way. The old (1904-10) geological memoirs are exceedingly good. Including titles such as "The geology of the country around Falmouth and Truro, including the camborne mining district". That again draws from other rarer and classic texts like Henwood's Metalliferous Deposits 1843 (which is about £200, if you can find one).
I pretty much have a complete library (apart from the migration/social stuff) and the above are pretty damn essential...they are the spine of the subject....how could I forget...."Mines and Miners of Cornwall Vols 1-16" by Hamilton Jenkin. These are the fruit of his work which resulted in a lot of maps getting scribbled on. For obscure things and amusing anecdotes, these are essential. They are expensive, look to pay £15-20 at least. You can get them cheaper though. They are something to build up.
Then, use the CRO. I have managed to stay well away from the CRO (Cornwall Record Office) - Dines gives you a number of pieces of information...the 6" OS map number like 63NE and then whatever plans are included, like R92A. If you go into the record office, they have literally thousands of plans you can browse through. It is a total privilage to handle these amazing documents which are sometimes incredible. If you are interested in a place and want to make sense of it. Type CROCAT into Google and search their records. You email them
[email protected] and say "Do you have any appointments for the map table on such and such date" and they give you an answer. You confirm your time and say can I see so-and-so 5 documents and when you roll in there, they give you some cotton gloves and you can knock yourself out.
The records are utterly incredible.
In my estimation, half of the joy is doing the prep before the practical. You look at Dines, the HJ maps and the plans and when you roll up, you can sometimes really appreciate what the place must have been like in a sublime manner.
Anyway, good luck, it's one hell of a subject/hobby/job.