What: Shares of gold explorer Eldorado Gold (NYSE:EGO) were off 12.3% at 10:45 a.m. ET on Monday after its preliminary 2015 results and guidance disappointed Wall Street.

So what: Eldorado shares have slumped sharply over the past year on concerns surrounding the development of its Skouries mine in Greece, and today's preliminary results -- management expects to record an impairment charge of up to $1.6 billion related to its Greece operations -- coupled with downbeat guidance only reinforce those worries. So while gold production and all-in sustaining cash costs for 2015 -- 723,532 ounces and $841 an ounce, respectively -- managed to top estimates, the threat of continued opposition from Greece's ruling Syriza party to the Skouries mine is forcing analysts to quickly recalibrate their growth estimates going forward. 

Now what: For 2016, management now expects production to drop to 565,000-630,000 ounces and its all-in sustaining cash cost to rise to $940-$980 an ounce. "Looking at Eldorado's long-term plan, the Company remains committed to its portfolio of Greek assets and the realizable benefits to all of the stakeholders involved," said President and CEO Paul Wright. "Our operations in Turkey and China remain on track and on budget to continue operating for years to come." When you couple Eldorado's exposure to volatile gold prices with its regulatory troubles in Greece, however, conservative Fools might want to just stay on the sidelines.