|Picture by WotW|
Additionally, the article proposes "there is a fake icy-stone alley being constructed". Though the pics look intriguing, this unfortunately is not the case.
Some detective work via Google showed that there has not been any kind of special setup or preparation - this is what the site always looks like. Well, at least in the last few months.
It's a construction site at Búrfell Power Station which is being enhanced until 2018, and those walls look like this because they have been prepared during the excavation process (I'm not an engineer, but it seems to be kind of a shotcreting construction); but certainly not for GoT or another production. The following pics are official ones published by the constructing companies in July / August 2016:
You can even watch a nice aerial video of the whole area here (well, they obviously had drones there! ;-)):
That being said, the location could theoretically be used for GoT production anyway, but there simply is not the slightest clue hinting at it at the moment... besides that mysterious "local shopkeeper" of course ;-).
Well, I guess that "shopkeeper" (if he exists) is just having a very funny time, quietly giggling to himself. And we will have to continue looking for GoT locations in Iceland...