Need help with 900 silver drinking vessel - marked ATN

[rover]

I have looked everywhere I know to look and can't identify this mark. It came out of an estate where most of the silver was mexican, so I am assuming this is too. It has the initial ATN on either side of pick axes, all inside a shield cartouche. If anyone knows this mark, I will be eternally grateful for your help.

[lbglass]

I have ten desert plates with the same mark. I believe they are Columbian. Did you find anything out about it.

[buddy]

I have four wine goblets ...same mark if you find any more info on the mark please advise, mine were brought from Columbia S.A. by my Great Uncle around 1920.

[rusei]

no more idea where this mark comes from?

[2209patrick]

See: viewtopic.php?f=32&t=13150

and: viewtopic.php?f=32&t=17771