Toronto-based Aurico Gold (TSX:AUQ,NYSE:AUQ) reported a fourth-quarter loss of $134.4 million after taking a $127 million impairment charge related to stripping costs at its El Chanate mine in Mexico. The loss compares to net income of $23 million during the fourth quarter of 2011.Polyus Gold (LSE:POLG), Russia's largest gold miner, saw its share price drop this week after it announced delays to its Natalka project. Reuters reported that the large gold mine in the Russian Far East will begin operations in summer 2014, not by the end of this year as was previously planned. Junior company news GoldQuest Mining (TSXV:GQC) spiked 30.9 percent on Wednesday after the company announced discovery of a new trend about two kilometers west of its Romero project in Dominican Republic. Samples taken from the kilometer-long trend returned grades over 1 percent copper, with five samples over 10 percent and 13 samples grading between 5 and 10 percent. GoldQuest had a spectacular run last year, with the stock price gaining an eye-popping 726 percent, earning it the top spot among Gold Investing News' Top 10 Gold Juniors of 2012. Northern Vertex Mining (TSXV:NEE), exploring for gold and silver in Arizona, has demonstrated positive economics for its Moss Mine project. The Moss Mine shows a net present value of $110 million based on a 5-percent discount rate, and would yield investors a 117.9-percent (pre-tax) internal rate of return on a quick payback of 15 months, according to its preliminary economic assessment (PEA) released Thursday. Premium Exploration (TSXV:PEM) announced the signing of an Option and Joint Venture Agreement with Logan Resources Ltd. (TSXV:LGR) Under the terms of the agreement, Logan has an option to acquire a 75-percent interest in the Idaho Gold property. Colombian Mines (TSXV:CMJ) announced that reconnaissance work identified additional high grade mineralization up to 2.3 grams of gold per tonne, 203 grams silver per tonne and 10.1-percent copper in grab samples from outcropping mineralization in a new area in the Mercedes property.