BUZZ-Antofagasta: bottom of FTSE on GS downgrade
** Antofagasta (Other OTC: ANFGF - news) falls 3 pct as Goldman downgrades stock on valuation grounds
** Top faller on FTSE 100 in early trade, also one of most traded by average volume
** Stock up 4 pct since GS (KSE: 078935.KS - news) added to buy list on Oct. 17, compared to fall of 12 pct for mining sector
** 5.5x EV/EBITDA ratio at top of co's historical valuation range
** Co has also benefited from depreciation of Chilean peso , down 15 pct v US dollar in 2014 and a further 4 pct YTD
(RM (LSE: RM.L - news) : alasdair.pal.thomsonreuters.com@reuters.net)