** Shares of Spain-based Atalaya Mining Copper SA ATYM.L rise as much as 7.4% to 848p - among biggest gainers on FTSE midcaps .FTMC index
** Co sees FY2026 copper production within previously guided 50,000-54,000 tonnes; silver output seen at 0.9-1.1 mln ounces
** CEO Alberto Lavandeira says firm is "increasingly confident" about both business outlook and copper market
** "In our view, the shares offer longer-term value of over 1,600p," Peel Hunt analysts say
** YTD, stock is down ~3%
(Reporting by Neeshita Beura in Bengaluru)
((Neeshita.Beura@thomsonreuters.com))