Mining stocks are doing well with giant Rio Tinto among the risers after it revealed record full-year profits yesterday, as well as a $5bn share buy-back and a 20% increase in the dividend.Today, the stock was given a lift by comments by Credit Suisse, which said that the buy-back is a good sign that the company is willing to increase cash returns alongside a capital expenditure-intensive growth strategy, estimating that it will be 2-3% earnings per share-accretive once complete. General retail sector is being led lower by struggling sportswear group JJB Sports, after it warned it could go bust unless landlords agree to cut rents on 95 stores it has earmarked for possible closure. JJB's plan comes just two years after it did a similar deal, called a company voluntary agreement or CVA, on 140 stores.Top performing sectors so far todayAlternative Energy 3,471.91 +2.46%Mining 27,829.62 +2.20%Gas, Water & Multiutilities 4,614.31 +1.87%Technology Hardware & Equipment 798.93 +1.63%Beverages 9,335.99 +1.50%Bottom performing sectors so far todayPersonal Goods 20,070.25 -1.27%General Retailers 1,681.37 -1.08%Food & Drug Retailers 4,708.75 -0.41%Automobiles & Parts 4,945.01 -0.33%Mobile Telecommunications 4,127.40 -0.30%