There isn't much information, but the bible of local mining "Dines" refers to Wheal Fursden in the area. This was also known as Wheal Peverall.
There is a plan in the Michell Archive at CRO code M-208 which is a copy of the 1880 ordnance survey 25" map with mining features added on. This includes 3 shafts and 4 lodes, all of which are to the NW of the mill. It is likely these structures run into New Wendron Consols to the east.
The Cornwall Interactive Mapping site is good for trivia. Find it on google, then select "historic" from the menu on the left, then "Event Record" from the sub menu. Then find your point on the map, click it and read any relevant PDF file. Cornwall archaeological unit provide some quality reports which hide in this location. Perhaps they have surveyed the area.
For general interest, seek out a book called "Wendron Tin" by AK Hamilton Jenkin.
http://crocat.cornwall.gov.uk/DServe/searchpage.htm The record office might have something, but you'll have to put all sorts of things into the search box to bring something up. The tithe maps may be worth a look, as may some of the relevant estate archives. For this, you type in a directory code and bring the whole lot up. It might take some trawling. If you want to look at maps, you'll need to book a slot at the map table in advance. The staff are very helpful in there and the place is mind boggling.
Good luck.