WN Wheal Norris
EC East Caradon
CM Craddock Moor
MV Marke Valley
NP North Phoenix
SP South Phoenix
SC South Caradon
WC West Caradon
WM Wheal Mary Ann
This diagram displays to scale, the depth of mine workings shown on Brenton Symons’ 1863 map of the Liskeard area, in Cornwall. The units are in fathoms (6 feet). The table at the bottom of the blog lists the mines in order of descending depth.
The two deepest workings on the map are Wheal Mary Ann and Phoenix United, both at 230 fathoms (1380 feet, 420 meters), almost a third of a mile deep. For comparison, the Caradon Hill radio mast only stands 130 fathoms above the summit.
All the dividend paying mines had a depth of between 90 and 250 fathoms, the shallowest being East Caradon Mine. The average depth of the progressive mines was 77 fathoms with the shallowest mine in production being Wheal Norris, at only 52 fathoms.
A large number of progressive mines exist around the 50 fathom depth, all being new mines or re-workings started since 1858. Wheal Norris (WN) is the shallowest mine in production, but it exploited shallow tin reserves to offset the cost of sinking shafts to reach the copper.
90 fathoms was the depth of the first of the dividend paying mines, East Caradon (EC), which was also paying the largest dividends. Below this 90 fathom threshold half of the mines were making a profit, down to the 230 fathoms of Wheal Mary Ann (WM) and Phoenix. (PX).
Amidst the deep mines of the area, two stand out as symbols of investor’s optimism or gullibility. South Phoenix (SP) and West Sharptor both continued to demand high calls from its adventurers, and yet no sign of ore had yet been forthcoming.
In this table the dividend paying mines are green, and the operational non dividend paying are in blue.
The next post in this blog will explore the financial and production figures for the District in 1863.
Brenton Symons’ map is available on ‘The Liskeard Mining area in 1863′