Alex, I am vaguely familiar with the WEX / GPXM story. I looked at GPXM a while back, and I could not figure out if they would actually be profitable. The mine is very small, and they have a lot of overhead. They also took out a lot of big loans at loan shark rates. They never did a real feasibility study, so the only way to know is happening financially is to wait for quarterly reports.
WEX might be a better way to invest in the deal, but it does not have a U.S. tracking stock.