Western RookieThe case history you provided was from Australia, not the Canadian Shield. When was the last time Australia was covered by a sheet of ice?
You shouldn't really need to talk to anyone about SGH. I think common sense should prevail here. The vast majority of the Canadian Shield, including the Abitibi and Swazye areas, are covered by glacial drift/till. Depths can reach several hundred meters. There is no B horizon. Remember that glacial drift does not represent the composition of bedrock below.
Look at it this way. GLD has no idea how thick the glacial drift is in the area of their survey. Whatever the depth is what do you thing the results from the survey would represent? Do you think the sampling of the top 10 cm or so of the glacial material represents the 10's of meters of glacial material below, or do you think it somehow reflects bedrock?
Company's like GLD, which appears to be strictly promotional, will use SGH surveys as a promotional tool and to justify exploration and even drilling in areas that really should be just considered moose pasture. Remember there is pressure on juniors to spend the money they raise on exploration, and investors prefer that the money is spent on drilling.