Achanarras quarry is owned by Scottish Natural Heritage. This cache is straight forward, with the aid of the info board at the carpark close to the cache. (Marked as a waypoint.)
To open the cache you need the following information: Triassic period 2nd number, 2nd digit, Devonian period 1st number 3rd digit, Neogene 2nd number 2nd digit, Permian 1st number 3rd digit.