Here's top views and side views of an Arizona mine:

http://sharlot.org/archives/maps/map24.html

It is typical of hard-rock gold and silver mines (the McCabe-Gladstone mine produced gold, silver, copper, lead, zinc, and tin). It's about 1100' end to end (say 360 yards, or 183 hexes at 2 yards per hex). There are ten underground levels.

Workings include the McCabe shaft (900 feet deep) and the Gladstone shaft (1,100 feet deep), 800 feet apart, plus several miles of horizontal workings. Production was approximately $3,000,000 (period values). Ore assayed about 1.6 oz. gold per short ton & 10.2 oz. silver per short ton. Production included some 1,200,000 pounds of copper; 500,000 pounds of lead.

I'd suggest "compressing by two" -- leaving the mine components the same size, but reducing the horizontal spread on the map by about a power of two. That'd make the mine 60 hexes end-to-end, able to fit on a big battlemat.

There are three vertical shafts that reach to the surface (with elevator headframes over them), and one tunnel at the 100' level which runs out of the hillside (about 400' -- 66 hexes -- from the main vertical shaft, or 33 hexes on "compressed by two" size). Ore is mostly removed via the vertical shafts, since it's in the lifting buckets anyway -- no need to unload it at the 100' level.

A typical level is about 600' across. If you do the mine in "compressed by two", that's 50 hexes wide.

I've done simplified maps for the 500', 800' and 900' levels (using the "compressed by two" method). The wide vertical black line is a main "broadway" tunnel, found on pretty much every level; on the 100' level it's the one that leads to the outside.

Narrow gauge mine cars are used in the tunnels, which are 5' or 6' wide and 6' tall. They widen out at various spots where ore removal is taking place, or to allow mine cars to use passing tracks. The "broadway" tunnel is 10' wide, to accomodate two sets of rails for mining cars, and slightly taller (8' high). Large water pumps sit in the lower levels of many mines, keeping water out of the workings; they are usually alongside the shafts which bring steam, hydraulic power, or electricity from the surface. Broad roaring fans ventilate bad air, from underground gas pockets and blasting operations. Noisy bucket-chain lifts remove the ore from the mines to the headframes; caged elevators move the miners and their equipment up and down.

18" gauge cars are more common for hand-worked mines; 2' cars are more modern, and will be made up into trains pulled by electric or gasoline engines. 30", 36", and metre gauge cars are used on larger, modern mines only. Besides ore cars, there are timber carts (to carry wooden beams), latrine carts, etc.

A glossary of mining terms.

Here's the 500' deep level:

And here's the 800' deep level:

And the 900' deep level: