Most later C19 and early C20 surveying textbooks have chapters on how to draw plans, with examples of what was at the various times considered good practice. These examples tend to be extracts and details rather than complete plans, though some books contain complete plans of limited areas (both surface and underground) as fold-out plates. Such books are readily available second-hand though prices can vary a fair bit between booksellers.
From the later C19 there were many books published on engineering drawing and, with the advent of affordable colour printing, they usually contain some pages of equisite colour shading. These books are usually very cheap second-hand.
There was always a degree of cross-over in drawing techniques between engineering and mine surveying.
Staffordshire China is, I'm sure, correct about the pervasive influence of NCB surveying techniques and plan drawing standards due to NCB-trained men swamping the sector in the UK. However, the radical chnage from ornate plans to simply laid-out plans, and from ornate letters and borders to very simple styles, was well underway in Edwardian times. When my wife's grandfather trained as an engineer in the 1920s, he was only taught lettering styles that look like modern DIN stencil lettering.
The students, plans mentioned up-thread would have been standard exercises, repeated year after year by classes of student surveyors and draughtsmen with little variation. I caught the tail-end of such practice when being taught survey in the early 1980s.
I've seen somewhere a paper on the early C20 revolution in plan presentation (i.e. from ornate to maximum legibility) - possibly in an American journal such as "Industrial Archaeology" or "Technology and Culture". It confirmed that practices were similar and changed at similar times both sides of the Atlantic.
All the drawing instruments are readily available second-hand: expensively if you fancy a large intact and matched set in a wooden case, but very cheaply if you don't mind mismatched instruments (which describes my older instruments!). If you become a real enthusiast you can start to look for esoteric instruments such as 3 foot tramel compasses (got one!) and sets of railway curves (only ever seen one set).
The best places to see plans from different periods from which you can copy details that take your eye is, of course, county record offices in mining regions. I xeroxed and traced cartouches, titles, north pointers, corner decorations and borders from various plans to create a set of features that became my standard repertoire - and I'm sure that draughtsmen of old did essentially the same - i.e. copied features and styles they liked the look of (unless a head draughtsman prescribed set styles).
Its all good harmless fun for the long winter evenings!