30 feet

[MatthewParis]

Hi! I'm a noob here and would benefit from your advice.

I reckon I know where some interesting artefacts can be found. These are gold, silver, other metals and a wide variety of other materials. I also think I know where they are: in a half-mile arc of farmland, at a depth of 30 feet. Subsoil is sea sand, then chalk and the artefacts will be sitting on the chalk.

Before spending (or raising) serious money (or even entering negotiations), it would be good to be able to confirm the locations. Which technologies and reputable kit would you recommend? Man-portable would be a bonus.

Thanks