Editor's Note: TheStreet ratings do not represent the views of TheStreet's staff or its contributors. Ratings are established by computer based on metrics for performance (which includes growth, stock performance, efficiency and valuation) and risk (volatility and solvency). Companies with poor cash flow or high debt levels tend to earn lower ratings in our model Two out of the three major indices are trading up today with the Dow Jones Industrial Average ( ^DJI) trading up 4 points (0.0%) at 14,823 as of Tuesday, April 30, 2013, 12:55 PM ET. The NYSE advances/declines ratio sits at 1,672 issues advancing vs. 1,218 declining with 158 unchanged. The Basic Materials sector currently sits down 0.27 versus the S&P 500, which is unchanged. On the negative front, top decliners within the sector include Marathon Petroleum ( MPC), down 5.67, Valero Energy Corporation ( VLO), down 2.09, Imperial Oil ( IMO), down 1.49, LyondellBasell Industries ( LYB), down 1.27 and Petroleo Brasileiro SA Petrobras ( PBR.A), down 0.98. Top gainers within the sector include Suncor Energy ( SU), up 5.1%, BP ( BP), up 2.1%, Halliburton Company ( HAL), up 1.6%, Occidental Petroleum Corporation ( OXY), up 1.4% and Total ( TOT), up 1.2%. TheStreet Ratings group would like to highlight 3 stocks pushing the sector lower today: 3. Buenaventura Mining Company ( BVN) is one of the companies pushing the Basic Materials sector lower today. As of noon trading, Buenaventura Mining Company is down $1.54 (-7.2%) to $19.68 on average volume Thus far, 1.1 million shares of Buenaventura Mining Company exchanged hands as compared to its average daily volume of 1.5 million shares. The stock has ranged in price between $19.42-$20.33 after having opened the day at $20.25 as compared to the previous trading day's close of $21.22. Compa ia de Minas Buenaventura S.A.A., a precious metals company, engages in the exploration, mining, and processing of gold and silver in Peru. It also explores for other metals, including zinc, lead, and copper. Buenaventura Mining Company has a market cap of $5.5 billion and is part of the metals & mining industry. The company has a P/E ratio of 7.0, below the S&P 500 P/E ratio of 17.7. Shares are down 41.9% year to date as of the close of trading on Monday. TheStreet Ratings rates Buenaventura Mining Company as a hold. The company's strengths can be seen in multiple areas, such as its revenue growth, largely solid financial position with reasonable debt levels by most measures and expanding profit margins. However, as a counter to these strengths, we also find weaknesses including weak operating cash flow, a generally disappointing performance in the stock itself and feeble growth in the company's earnings per share. Get the full Buenaventura Mining Company Ratings Report now. Exclusive Offer: Jim Cramer's 'go-to' small/mid-cap guru Bryan Ashenberg only buys stocks he thinks could return 50-100%. See his top picks for 14-days FREE.