I have held gold mining mutual funds for years.
They sort of reflect gold demand, but due to my technical mining process exposure to some of the majors, it seems they values more reflect their position in the market, their prospects for being able to produce at good economics and any proprietary technologies they may have to distinguish them from other miners.
I bought in when gold and the MF was pretty low. I stick with them, as playing Day Trading style is too subject to rapid and sometimes short lived big moves. Over the long haul they have appreciated much more than not.
My 2cents worth.
Just plain good sense. Know the sector, go fo the long investment. Good job.