Mining stocks have come off slightly after some good gains recently as commodity prices retreat following a strong performance. Vedanta is one of the worst hit. The Indian miner is to raise $1bn through an issue of convertible bonds, but major shareholder Volcan has declined to take part in the issue.In other mining news South African metal recycler SA Metals has recommended its shareholders approve a takeover offer from platinum producer Sylvania Resources. Sylvania is down 5% though.Defensively-oriented pharmaceutical stocks are in demand. Sector giants AstraZeneca and GlaxoSmithKline are both higher.Top performing sectors so far todayAutomobiles & Parts 2,201.36 +4.89%Fixed Line Telecommunications 1,507.37 +4.06%Pharmaceuticals & Biotechnology 7,555.45 +3.60%Technology Hardware & Equipment 249.47 +1.68%Mobile Telecommunications 2,689.12 +1.63%Bottom performing sectors so far todayMining 15,477.24 -2.38%Forestry & Paper 2,404.71 -2.08%Industrial Engineering 2,611.14 -1.71%Life Insurance 3,054.95 -1.64%General Retailers 1,426.02 -1.40%