Ann: EVG Updates Results from San Gerardo Ecuador, page-6

re: Ann: EVG Updates Results from San Gerardo... Hi SeamFiend,
jsut quickly:
0.1-0.3% Cu in soils is very good: either the mineralized rock is essentially at current surface, or else of a high enough grade that leaching thru the soil still gives a solid reading.

second, the difference between coring and trenching is that coring is using a drill rig to "cut" a cylindrical sample of solid rock anywhere from 2m to 2000m depth and bring it to the surface to be examined, measured and sampled. core rigs are usually ap[plied to mature targets due to the high costs involved.

trenching is simply using a backhoe or excavator to cut a shallow (1-4m deep) trench through the soil profile and into weathered bedrock for a fast, inexpensive look at the geology. samples can also be taken (eg 1m intervals in a channel across the trench wall or floor)
trenching is handy early on in assessing young targets as it is cheap, fast