Article in the Australian this morning suggests PEM could seriously benefit if the A$ erodes further against US$, although they don't suggest trading on that basis alone.
According to UBS a US5c depreciation in the A$ could benefit PEM's earnings by 125% (based on sp of 16.5c)
http://www.theaustralian.com.au/business/opinion/unearth-a-fortune-with-these-dollar-dazzlers/story-e6frg9lo-1226642443977