South Crofty Mine Level Plans: The information on this page has been written by my friend Dr Nick LeBoutillier and reproduced here with his permission.
Between 1993 and 1998 South Crofty Mine worked stopes between the 260 fathom level and the 445 fathom level. The main working levels were 400, 420 and 445, with their respective sublevels on a number of lodes. Some work was carried out below 260 fm (Tincroft South Lode), on and below 290 fm (Pryce’s Lode, Dolcoath South Lode), 315 fm (Dolcoath South Lode), 340 fm (Dolcoath South Lode, Prospect A Lode and NPZ (335 fm in Robinson’s section)), 360 fm (No:8 Lode, Pegmatite Zone, NPZ, Dolcoath North Lode) and 380 fm (No:4 Lode, NPZ); but the lower levels were the main focus of production. Below 400 fm, the main production lodes were the Roskear A, B (hangingwall) and D Lodes, No:4 Lode, No:8 Lode and Providence Lode.
There was a turn-out from the lower leg of the decline at 470 fm elevation (awaiting the development of that level), with the decline halting around 490 fm elevation (roughly 3000 feet below surface), equalling, or perhaps beating, the depth of Dolcoath Mine, the deepest in Cornwall. Unfortunately these lowermost sections of the mine were never utilised, although plans for the development of the 470 fm level were fairly advanced before the mine closed in 1998.
Level plans, for geological mapping, forward development planning and exploration, etc, are an essential part of any mining operation. During the 1980’s and early 1990’s South Crofty had the services of a number of talented draughtsmen (most notably the late Nick Talbott who became a free-lance artist after leaving South Crofty, widely known for his stunningly detailed mining and railway drawings & paintings) who transferred survey and geological data onto film sheets. The standard scale used by the Geology Department was 1:500 and these sheets, covering the whole mine on all levels 180 fm level, were almost works of art, beautifully draughted and lettered. By the mid-1990’s surveying had become computerised, with survey information stored within the theodolite (total station) and transferred directly to a PC. This allowed computer-generated plans to be rapidly produced and these largely superceded the earlier film plans. A programme of plan digitisation by the Survey Department (Robin Boon, Andy Staples, Allan Reynolds and Andy Seager) eventually saw the main levels and later sublevels of the whole mine, from 310/315 fm downwards, available in digital format.
The mine grid was aligned along the main lode strike (roughly 067 degrees) with the main datum point at Robinson’s Shaft (Mine Grid 0m (E/W), 10000m N). Elevations were based on a datum level some 2000m below Deep Adit Level. This system was used for all of the mine with the exception of the North Pool Zones (NPZ), a complex area of en-echelon lodes, pegmatites and replacement bodies, that had a markedly different strike and their own localised grid.