| Year | Activity |
|---|---|
| 1830s | owned by Richard Garnons - proprietor of Dorothea Slate Quarry, > 4,000 tons of ore being produced. |
| c1850 | Worked by private company via two shafts. |
| 1863 | Workings down to 70 fathom level. |
| 1873 | New shaft sunk at western end. |
| 1877 | Work ceased. |
| 1880 | Caernarfon Copper Company. Winze at Golden Venture Shaft reveals good ore. |
| 1883 | Financial problems and poor ore returns. |
| 1884 | Sale of assets. |
| 1890 | John Thomas, auctioneer from Caernarfon listed as owner, few men employed for next 5 years. |
| 1900 | Nantlle Vale Copper Mining Company - return 74 tons ore. |
| 1907 | Talysarn Mining Company employs 12 men underground, 35 in 1909, turning good ore, but not enough for profit. |
| 1914 | Liquidator appointed. |
| 1917 | Mining Corporation of Great Britain worked together with Drwsycoed. |
Summary from Bick
Publications (7)
- (1925); BGS - Mineral Resources of GB (c1920s) Vol XXX - Copper Ores: Midlands, Lake District & N Wales; 102 pages
- (2004); Ogofa GCPC Journal No 6,; 11 pages
- BGS - Mine Plans (large, zoomable) - Simiddle,dylluan And Drwys-Y-Coed Copper Mines (slates); 1 pages
- Bick, D.E. (2003); Old Copper Mines of Snowdonia, The; pp. 53-57
- Colman, T.B.; NMRS (1990); British Mining No.41; Sediment - Hosted, Base-Metal, Vein Mineralisation at Drws y Coed and Cwm Pennant, Snowdonia, North Wales; pp. 41-5
- NMRS (1991); British Mining 41; Memoirs 1991; pp. 43
- NMRS (1991); British Mining 41; Memoirs 1991; pp. 46
