I am not clear on if the land is public or not.
From "http://cashandtreasures.wikifoundry.com/page/Massachusetts", "General description: An old silver mine in
Newbury. A lot of galena, pyrite, and siderite can be found here. Minor
amounts of malachite and chalcopyrite have been found here. Many
minerals here will fluoresce under both shortwave and longwave UV
wavelengths.
Handy to bring along:
1. Shovel
2. Hammer and hand pick
3. Chisel & safety gear
Helpful notes to newcomers:If you ever go to this location, the
mine is currently behind houses on a place called Scotland Heights. To
find galena and pyrite, one will have to dig in the mine dumps. Bug
spray can be quite handy at this location."