Geochemical investigations around Trewalder, near Camelford, Cornwall

Stream sediment geochemistry to the north of St. Teath revealed two zinc anomalies suggestive of-an apparently unexplored extension to the lead lode of Trewalder Mine. Although this mine was never more than a small affair, the prospect of zinc and argentiferous lead mineralisation in a location accustomed to extractive operations merited further limited geochemical investigation. More detailed stream sampling and geochemistry confirmed these early findings, with a significant length of the River Allen reporting anomalous zinc levels in both sediments and panned concentrates. The absolute contents in these media indicate that most of the anomaly is due to hydromorphic transportation of zinc. There is no correlation with either lead or silver, rendering the prospect of lead-silver-zinc lode somewhat less likely. a significant One hundred and fifty soil samples were collected from six lines sited to intersect at right angles the strike of the Trewalder Lode and its possible extensions to the north. A wide range of elements were determined on these samples. Log-probability plots failed to show any significant correlation between the distribution populations and the mapped Ethology and mineralisation. Traverse profiles for Pb, Zn and Ba, on the other hand, can be interpreted as showing both particulate and hydromorphic anomalies which suggest that there may be more than one mesothermal lode in the Trewalder area, north of that hamlet for some distance, and that to extending the north of the River Allen, near Helland, the lode may change in character to become essentially barite. Although there has been no work to evaluate the extended mineralisation, it appears from the relatively low tenor of the anomalies that the prospects of significant economic ore concentrations must be extremely small. Some previously unexplored Pb-Zn-Ba mineralisation seems to be indicated on the slopes to the west of the River Allen.