Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Centerra Gold (CGAU 0.99%) jumped as much as 13% briefly today after updating its reserves.

So what: Management said that indicated resources increased by 406,000 ounces at its Oksut project in Turkey, to 1.1 million ounces. Probable reserves increased by 114,000 at the Gatsuurt project in Mongolia. 

Now what: Those were the positives, but gold reserves fell by 53,000 overall this year after accounting for 912,000 processed ounces. The other challenge is that the company's year-end reserves were estimated using a gold price of $1,300 per ounce, down from $1,350 a year ago, but still above today's price of $1,258. That's the core problem for gold miners, who have less economically viable gold as the price falls, which I think it will continue to do in 2014. For that reason, I'm not buying into the pop today.