Recipe is Titanium:Tungsten:Silver. A good ratio appears to be (N : N-1 : N-2) but (1 : >2/3 : >1/3) appears to work.
Tolerant of at least some impurities.
I used 8-9 stones for 11-14 cluster of titanium, then filled up with 10-13 tungsten and 9-12 silver. This gave me about 23-25 metal blue per smelt, or about 90 for a bit less than 2 hours work.
There is an amalgation furnace there, currently in a compound without cornerstone. (I put a cornerstone in the compound - Var-LeTha.) Until such a time that it can be moved to the main compound, please consider bringing a few straws, bricks, flax and boards to maintain it.
Write "/info emc" for details about this mine.