298 PH/s is about 0.028% of the network's current 1.06 ZH/s. At today's difficulty one block costs roughly 637 ZH of hash work, so that peak rate buys an expected block every 25 days of continuous hashing. A six hour run is a one percent shot, and no block today is the arithmetic rather than bad luck. Tomorrow with 162 PH ready the expectation stretches to 45 days per block.