The miners were the best performers on Friday afternoon, with stocks averaging gains of nearly 2% by 13:50.Leading the charge was copper giant Kazakhmys after a $1.5bn loan facility signed for the Aktogay copper project in East Kazakhstan meant that it has now secured funding for all of its development projects. Shares jumped nearly 4% to head the FTSE 100.Evolution Securities reiterated its add rating on Kazakhmys following the announcement, saying that it recommends the stock over its copper peers. The broker thinks that the stock is "markedly undervalued" in relation to the wider mining sector, trading at just four times prospective earnings, compared to Antofagasta which trades at an earnings multiple of eleven. Nevertheless, Antofagasta was the next best riser on the Footsie, gaining 3.36%. Xstrata, Fresnillo, Rio Tinto and ENRC were also in demand.Meanwhile, electricity stocks were falling with heavyweight constituents Drax and SSE in the red. Nomura reiterated its 'reduce' rating on coal-fired power station operator Drax today, saying that while the shares are pricing in an optimistic scenario from the firm's proposed biomass conversion, "key near-term share price drivers are likely to disappoint".AIM-listed Greenko, a clean energy generator and supplier to the mainstream Indian energy market, was a heavy faller losing over 14% following yesterday's first half results. The firm said on Thursday that turnover fell from €25.8m to 19.8m in the six months ended 30 September, while cash balances and deposits decreased from €73.3m to €49.75m.Top performing sectors so far todayMining 19,403.52 +1.98%Banks 3,293.31 +1.31%Mobile Telecommunications 4,089.06 +1.20%Fixed Line Telecommunications 2,187.41 +1.10%Chemicals 6,431.57 +1.06%Bottom performing sectors so far todayReal Estate Investment & Services 1,471.73 -2.10%Industrial Transportation 2,181.27 -1.67%Electricity 7,945.42 -1.39%Software & Computer Services 703.46 -0.80%Real Estate Investment Trusts 1,710.52 -0.68%