The miners were the worst performers of the day on Tuesday on fears over the economic outlook for China. Ian Ashby, President of BHP Billiton's iron ore division, told reporters in Australia that "the (Chinese) economy is shifting, it's changing. Steel growth rates will flatten and they have flattened." Similarly, Rio Tinto's Managing Director of expansion projects David Joyce also said that the "rate of GDP growth in China is more immediately slowing". Nevertheless, he assured that the company remains confidence of a soft landing for the economy.Meanwhile, falling house prices and rising fuel costs are also feared to be limiting economic expansion. Both BHP Billiton and Rio Tinto were heavy fallers, joined by sector peers Fresnillo, Vedanta, Antofagasta, ENRC, Kazakhmys, Randgold and Anglo American.Energy firm National Grid was one of the few risers of the day after being hailed as the top pick of the UK utilities sector by Nomura. The broker said it offers "growth opportunity in UK transmission and screens well on relative value." FTSE 100 - RisersVodafone Group (VOD) 169.65p +1.37%Tesco (TSCO) 332.80p +0.54%Sainsbury (J) (SBRY) 306.00p +0.46%Whitbread (WTB) 1,725.00p +0.23%National Grid (NG.) 632.50p +0.08%FTSE 100 - FallersFresnillo (FRES) 1,684.00p -5.18%Vedanta Resources (VED) 1,348.00p -4.94%Rio Tinto (RIO) 3,452.00p -4.50%Antofagasta (ANTO) 1,195.00p -4.09%BHP Billiton (BLT) 1,965.50p -4.03%Anglo American (AAL) 2,507.50p -4.02%Eurasian Natural Resources Corp. (ENRC) 660.50p -3.93%GKN (GKN) 207.00p -3.90%Randgold Resources Ltd. (RRS) 6,315.00p -3.73%IMI (IMI) 967.00p -3.69%BC