** Shares of Calix CXL.AX rise as much as 30.1% to A$0.605, hitting their highest level since July 31
** Stock logs its biggest intraday pct gain since September 15
** Environmental technology firm executes deal with mining giant Rio Tinto RIO.AX for over A$35 million ($22.86 million)of cash and in-kind support for demonstration of co's Zero Emissions Steel Technology (ZestyTM) in Kwinana, Western Australia
** Stock down nearly 20% this year, including the day's move
($1 = 1.5314 Australian dollars)
(Reporting by Rajasik Mukherjee in Bengaluru)
((Rajasik.Mukherjee@thomsonreuters.com))