Wheal Brothers icluded Wheal Duchy and Wheal Sisters. Wheal Sisters was developed on the same lode to the east.
1810 The mine was first opened under the name of Wheal Duchy. When prospecting for copper ore, silver ore was found probably associated with a north-south crosscourse. The lode is recorded as being upto 31cms wide, and the silver ore up to 15cms wide. The silver lode was found in the adit level, from there it extended to a depth of 55 mts, and for a length in the lode of 5.5mts. The silver deposit consisted of native silver, pyrargyrite, acanthite, galena, siderite. (records also record grey and black sulphides of silver and antimony).
1816 Wheal Duchy was closed
1833 reopend and called Wheal Brothers. When the 30 fathom level was investigated a quantity of silver ore was found standing in the stopes. The previous owners had apparently not recognised it as silver ore. And within three months nearly 6000 uk pounds worth of silver ore had been produced.
1874 The mine was being worked inconjuction with Silver Vally mine (which was at work in 1852 as well).
Wheal Duchy 200 tons of silver ore
East Cornwall Mines