** Indian miner Hindustan Zinc HZNC.NS gains 4.8% to 439.25 rupees; set for best day in nearly 3 months
** Spot silver XAG= rose 2% to $40.44 per ounce, the highest since September 2011 GOL/
** Silver metal operations contributed ~19% to HZNC's June-quarter revenue
** Stock top pct gainer on Nifty metal index .NIFTYMET, which is up 1.2%
** About 5.8 million shares traded, 3.2x the 30-day avg
** YTD, stock down ~1%
(Reporting by Manvi Pant in Bengaluru)
((Manvi.Pant@thomsonreuters.com; +918447554364;))