Australian player Rumford had started the day three shots clear but while he could only muster an outward half of level-par 36, Ryder Cup player Jiminez carded three birdies to turn in 33 and share the lead.
The pair are two clear of a group of seven players which includes Wales’ Rhys Davies, United States’ Dustin Johnson, Swedish pair Rickard Karlberg and Alex Noren, Dane Soren Kjeldsen, India’s Shiv Kapur and South Korean Dae-hyun Kim.
World number one Lee Westwood needs to finish no worse than fifth this week to keep top spot and was 2-under par through 12 holes to reach 6-under par overall, but had pulled his tee-shot at the par-3 13th hole well to the left and atop a steep bank seconds before the warning claxon was sounded to bring play to a halt.
Westwood shares 6-under and T11 with Ireland’s Shane Lowry who was 4-under par with one to play.
Westwood’s fellow tipster pick, Dutchman Robert Jan-Derksen was also making progress through the field and was 2-under par through 16 holes to move into a share of 14th place on 4-under; while Thongchai Jaidee was struggling, reaching the turn in 2-over par 38 to drop to 3-over par overall through nine holes.