22 and change, after all, appears to be fairly long-term support for GDX , so I would look to add positions via naked short puts or short put verticals at the 21 strike or below (the Dec 16th 21 pays .80/contract). The alternative is to wait to see if /GC 1250 holds up here or gives up the ghost on the increased probability of a Dec rate hike or the currently increased likelihood that the US Presidential election result will be in Clinton's favor, which is generally viewed as market bullish/risk off.
* -- I'm currently in a GDX covered call with a per share cost basis around 24/share and really only want to add position if it dramatically improves that cost basis. Not sure whether being put shares at 21 would do that, so I may thumb twiddle to see if we get something around 17.50. You never know, really ... .