The ratings of 30 Metals and Mining stocks are down this week, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Allied Nevada Gold (AMEX:ANV) earns an F (“strong sell”) this week, moving down from last week’s grade of D (“sell”). Allied Nevada Gold engages in the evaluation, acquisition, exploration, and advancement of gold exploration and development projects. In Portfolio Grader’s specific subcategories of Earnings Momentum, Earnings Revisions, and Earnings Surprise, ANV also gets an F. The stock’s trailing PE Ratio is 42.60. For more information, get Portfolio Grader’s complete analysis of ANV stock.

Aurizon Mines’ (AMEX:AZK) rating falls to a D (“sell”) this week, down from C (“hold”) the week prior. Aurizon Mines engages in the acquisition, exploration, development, and production of gold properties in North America. In Earnings Momentum, Earnings Revisions, Earnings Surprise, and Sales Growth the stock gets F’s. To get an in-depth look at AZK, get Portfolio Grader’s complete analysis of AZK stock.

The rating of Banro Corp. (AMEX:BAA) declines this week from a D to an F. Banro Corporation is engaged in the exploration and development of four gold properties, which are known as Twangiza, Namoya, Lugushwa and Kamituga. The stock gets F’s in Earnings Revisions and Cash Flow. For a full analysis of BAA stock, visit Portfolio Grader.

First Majestic Silver’s (NYSE:AG) rating weakens this week, dropping to a D versus last week’s C. First Majestic Silver is a silver producing mining company. The stock price has fallen 9.7% over the past month, worse than the 5.9% increase the S&P 500 has seen over the same period of time. For more information, get Portfolio Grader’s complete analysis of AG stock.

This week, General Moly’s (AMEX:GMO) rating worsens to a D from the company’s C rating a week ago. General Moly develops, explores, and mines molybdenum minerals in the United States. The stock also gets an F in Equity. For a full analysis of GMO stock, visit Portfolio Grader.

Slipping from C to a D rating, Golden Star Resources (AMEX:GSS) takes a hit this week. Golden Star Resources is a mid-tier gold mining company. The stock also gets an F in Earnings Revisions. To get an in-depth look at GSS, get Portfolio Grader’s complete analysis of GSS stock.

Vista Gold (AMEX:VGZ) is having a tough week. The company’s rating falls from a D to an F. Vista Gold is engaged in the evaluation, acquisition, exploration and advancement of gold exploration and potential development projects. The stock gets F’s in Equity and Cash Flow. For more information, get Portfolio Grader’s complete analysis of VGZ stock.

The rating of Nevsun Resources (AMEX:NSU) slips from C to a D. Nevsun Resources is a gold producer and base metal developer. The stock gets F’s in Earnings Momentum and Sales Growth. To get an in-depth look at NSU, get Portfolio Grader’s complete analysis of NSU stock.

North American Palladium (AMEX:PAL) earns an F this week, moving down from last week’s grade of D. North American Palladium is a mineral exploration and production company. The stock gets F’s in Earnings Revisions, Equity, and Cash Flow. For a full analysis of PAL stock, visit Portfolio Grader.

Silver Wheaton (NYSE:SLW) earns a D this week, falling from last week’s grade of C. Silver Wheaton is a global silver streaming company. The stock gets F’s in Earnings Surprise and Sales Growth. For more information, get Portfolio Grader’s complete analysis of SLW stock.

AuRico Gold (NYSE:AUQ) gets weaker ratings this week as last week’s C drops to a D. AuRico Gold engages in the exploration, development, and production of gold and silver projects and properties in Canada, Mexico, and Australia. The stock also rates an F in Cash Flow. Share prices fell 6.2% over the past month. For a full analysis of AUQ stock, visit Portfolio Grader.

This is a rough week for Hecla Mining (NYSE:HL). The company’s rating falls to D from the previous week’s C. Hecla Mining explores, develops, and mines precious metals, gold, and silver. The stock gets F’s in Earnings Growth, Earnings Momentum, and Earnings Revisions. Earnings Surprise, Margin Growth, and Sales Growth also get F’s. Investors seem to agree with the downgrade and have pushed down the share price 5.4% over the past month. The trailing PE Ratio for the stock is 48.30. To get an in-depth look at HL, get Portfolio Grader’s complete analysis of HL stock.

Compania de Minas Buenaventura (NYSE:BVN) experiences a ratings drop this week, going from last week’s D to an F. Buenaventura Mining is a precious metals company engaged in the exploration, mining, and processing of gold, silver and, to a lesser extent, other metals. Wall Street appears to agree with the stock downgrade, with share prices dropping 10.8% over the past month. For more information, get Portfolio Grader’s complete analysis of BVN stock.

Gold Fields (NYSE:GFI) earns an F this week, falling from last week’s grade of D. Gold Fields is engaged in the mining, exploration, extraction, processing, and smelting of gold. The stock also gets an F in Sales Growth. To get an in-depth look at GFI, get Portfolio Grader’s complete analysis of GFI stock.

The rating of Harmony Gold Mining (NYSE:HMY) declines this week from a D to an F. Harmony Gold Mining is a mining company which produces gold from its operations in the district of Virginia, Orange Free State. The stock also gets an F in Earnings Momentum. The stock price has fallen 16.4% over the past month. For a full analysis of HMY stock, visit Portfolio Grader.

IAMGOLD Corp. (NYSE:IAG) earns an F this week, moving down from last week’s grade of D. Iamgold is involved in the exploration for, and development and production of mineral resource properties throughout the world. The stock gets F’s in Earnings Surprise and Sales Growth. Share prices fell 21.4% over the past month. To get an in-depth look at IAG, get Portfolio Grader’s complete analysis of IAG stock.

POSCO (NYSE:PKX) is having a tough week. The company’s rating falls from a D to an F. POSCO produces hot rolled steel, cold rolled steel, stainless steel, and other forms of steel. For more information, get Portfolio Grader’s complete analysis of PKX stock.

This week, McEwen Mining’s (NYSE:MUX) rating worsens to an F from the company’s D rating a week ago. McEwen Mining explores for, develops, and produces mineral properties. The stock gets F’s in Earnings Revisions, Equity, and Cash Flow. Wall Street appears to agree with the stock downgrade, with share prices dropping 10.1% over the past month. For a full analysis of MUX stock, visit Portfolio Grader.

AMCOL (NYSE:ACO) gets weaker ratings this week as last week’s C drops to a D. AMCOL International is a specialty minerals company that offers various industrial and consumer product lines. The stock also gets an F in Earnings Surprise. To get an in-depth look at ACO, get Portfolio Grader’s complete analysis of ACO stock.

Slipping from a D to an F rating, Aluminum Corp. of China (NYSE:ACH) takes a hit this week. Aluminum Corporation of China is a producer of aluminium, with operations in bauxite mining, alumina refining, primary aluminium smelting, and aluminium fabrication. It also provides ancillary products and services. The stock rates an F in Earnings Growth, Earnings Momentum, and Equity. Cash Flow, Margin Growth, and Sales Growth also get F’s. For more information, get Portfolio Grader’s complete analysis of ACH stock.

New Gold Inc.’s (AMEX:NGD) rating weakens this week, dropping to a D versus last week’s C. New Gold acquires, explores, and develops gold properties. The stock also rates an F in Earnings Surprise. As of Jan. 28, 2013, 11.5% of outstanding New Gold Inc. shares were held short. The stock has a trailing PE Ratio of 42.80. For a full analysis of NGD stock, visit Portfolio Grader.

NovaGold Resources (AMEX:NG) experiences a ratings drop this week, going from last week’s D to an F. NovaGold Resources explores and develops mineral properties in North America. The stock gets F’s in Equity and Sales Growth. The stock currently has a trailing PE Ratio of 197.70. To get an in-depth look at NG, get Portfolio Grader’s complete analysis of NG stock.

This is a rough week for Paramount Gold & Silver (AMEX:PZG). The company’s rating falls to D from the previous week’s C. Paramount Gold & Silver explores for precious metals in Mexico. The stock gets F’s in Earnings Growth and Equity. For more information, get Portfolio Grader’s complete analysis of PZG stock.

The rating of Exeter Resource (AMEX:XRA) slips from a D to an F. Exeter Resource explores for, evaluates, and develops mineral deposits in South America. The stock gets F’s in Earnings Revisions, Equity, and Cash Flow. For a full analysis of XRA stock, visit Portfolio Grader.

This week, Endeavour Silver (NYSE:EXK) drops from a D to an F rating. Endeavor Silver is a small-cap silver mining company focused on the growth of its silver production, reserves and resources in Mexico. The stock gets F’s in Earnings Growth, Earnings Revisions, and Earnings Surprise. The stock has a trailing PE Ratio of 27.20. For more information, get Portfolio Grader’s complete analysis of EXK stock.

Coeur d’Alene Mines (NYSE:CDE) earns an F this week, falling from last week’s grade of D. Coeur d’Alene Mines engages in the ownership, operation, exploration, and development of silver and gold mining properties primarily located in the United States, Mexico, Bolivia, Argentina, and Australia. The stock receives F’s in Earnings Growth, Earnings Momentum, and Earnings Revisions. Earnings Surprise, Margin Growth, and Sales Growth also get F’s. Investors seem to agree with the downgrade and have pushed down the share price 5.7% over the past month. The stock’s trailing PE Ratio is 91.30. For a full analysis of CDE stock, visit Portfolio Grader.

Compass Minerals (NYSE:CMP) gets weaker ratings this week as last week’s C drops to a D. Compass Minerals produces and markets inorganic mineral products. The stock gets F’s in Earnings Growth and Sales Growth. The stock price has fallen 5.2% over the past month. To get an in-depth look at CMP, get Portfolio Grader’s complete analysis of CMP stock.

Silvercorp Metals (NYSE:SVM) earns an F this week, moving down from last week’s grade of D. Silvercorp Metals is involved with the acquisition, exploration and development of silver-related mineral properties in China. The stock gets F’s in Earnings Surprise and Sales Growth. Investors seem to agree with the downgrade and have pushed down the share price 17.1% over the past month. For more information, get Portfolio Grader’s complete analysis of SVM stock.

This week, Eldorado Gold’s (NYSE:EGO) rating worsens to an F from the company’s D rating a week ago. Eldorado Gold acquires, explores, and develops mineral properties. The stock gets F’s in Earnings Momentum, Earnings Surprise, and Sales Growth. The trailing PE Ratio for the stock is 25.50. For a full analysis of EGO stock, visit Portfolio Grader.

The rating of Stillwater Minin (NYSE:SWC) slips from C to a D. Stillwater Mining is engaged in the development, extraction, processing, refining and marketing of palladium, platinum and associated metals from a geological formation in south central Montana known as the J-M Reef and from the recycling of spent catalytic converters. The stock gets F’s in Earnings Growth, Earnings Momentum, Margin Growth, and Sales Growth. As of Jan. 28, 2013, 14.5% of outstanding Stillwater Minin shares were held short. The stock currently has a trailing PE Ratio of 28.00. To get an in-depth look at SWC, get Portfolio Grader’s complete analysis of SWC stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.