** Hindustan Zinc stock HZNC.NS down 6% to 457 rupees, biggest intra-day pct drop since April 4
** Parent Vedanta Ltd VDAN.NS selling 1.6% stake in miner HZNC via $350 million block deal at floor price of 452.50, IFR reports
** VDAN currently holds a little over 63% stake in HZNC
** Floor price at a 7% discount to last close
** Vedanta did not immediately respond to Reuters' request for comment
** HZNC is top loser on Nifty mid-cap index .NIFMDCP100, which is mostly unchanged; VDAN shares up 0.5%
** About 108 mln shares change hands
** YTD - HZNC up 3.3%; Nifty mid-cap index up 2%
(Reporting by Sethuraman NR in Bengaluru)
((Sethuraman.NR@thomsonreuters.com; (+91 9945291420); Reuters Messaging: nallur.sethuraman.thomsonreuters.com@reuters.net ))