BUZZ-Australia's Viento Group rises on contract win
** Civil and mining contractor Viento Group Ltd rises as much as 28.6 pct
** Says wins contract from Rio Tinto Ltd (Xetra: 855018 - news) for construction of tailings storage facility (http://bit.ly/1I8iuTt)
** Adds A$7.3 mln contract (excluding GST (Taiwan OTC: 5262.TWO - news) ) is due to start in June and expected to run for 5 months
** Viento Group shares have lost 12.24 pct this year, amid a slump in iron ore and other commodity prices (Reuters Messaging: shounak.dasgupta.thomsonreuters.com@reuters.net)