I am a long-term holder of PNA (since 2003), and accumulated...

I am a long-term holder of PNA (since 2003), and accumulated over the past 5 years on what appears to be sound fundamentals and good management.
Now in 2008 PNA has:
1. become a producer;
2. already made 2 shipments ($100million);
3. significant upgrade of resources;
4. In budget and on time with development;
5. Alleviated much of the "wet season" problems.
Yet, SP keeps falling, more than 50% over past 8 months.
What is it I am missing?
Will continue to hold and am concerned.
Any clues, ideas, suggestions.
I feel the old appraoch of finding a company with good prospects and sound development of fundamentals, then buying and holding is no longer a relevant investment strategy in this climate.
thanks Jahar