I think there is some correlation, but this especially applies to producing mines. Junior mines are first of all, as you correctly say, often far away from producing. But if I look at recently produced annual results of mining stocks, it is quite common to see cash costs/oz go up as well, meaning that profits may not always improve when precious metals price rise.

If you are into technical analysis, you might want to check the gold/GDXJ-ratio, which gives you a good indication of when to put your money in junior mining stocks and when to prefer investing in gold. The GDXJ is the junior gold mining ETF. Right now would be a good time to buy the sector rather than gold itself. On http://jsmineset.com/2011/04/17/gdx-majors-versus-gdxj-juniors-ratio-chart/ there was a post about it - quite a good read.