Likely flotation as a first step which will recover most of the...

Likely flotation as a first step which will recover most of the stibnite ( as it’s a sulphide) into the concentrate, along with the gold.
Removal of the stibnite from the concentrate is complicated , requiring oxidation first usually then there are a couple of possible process routes.
all are expensive.
For a small company like CAI it’s a no brainer, IMO
for the relatively low grades and tonnages likely, the oxidation step is just too expensive to be economically justified.
Sell the concentrate to an existing smelter or an POX plant and take the gold ( and possibly ) antimony credits.
Then all you need is a small flotation circuit tacked onto the existing CIL plant. Float cells, small thickener, filtration unit and a bag house for shipping.Maybe 20-30 $ million , ball park.
Thats my 2 cents worth.