Help with PS hallmark on aprox 10 oz bar

[Agstacker]

I would like to find out the name and other info about the refinery whose hallmark is on this 10.17 troy oz bar. I spent hours looking through the silver mark encyclopedia but I couldn't find a match. Any help would be appreciated. I'm sorry I don't have an web image to link this post to but the bar is about 3"x2"x1" and the letters PS are located on the left side, the P is at the top and the S is nestled just under the round top part of the P. Each letter is about an inch high. There are no other serial type numbers and the only other info on the bar is .999 silver, 10.17 Troy oz.[/img]
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