** Godolphin Resources GRL.AX jumps as much as 20% to A$0.012; marks biggest intraday pct gain since March 18
** Stock hits highest since March 28
** Diversified miner inks earn-in and joint venture agreement with Canadian mineral explorer Great Plains Metals GPS.V
** Says GPS will earn up to 51% stake in co's copper gold projects
** Godolphin Resources's managing director says deal will reduce co's expenditure commitments
** GRL last up 10%, trims YTD losses to 31%
(Reporting by Rajasik Mukherjee in Bengaluru)
((Rajasik.Mukherjee@thomsonreuters.com))