I compiled a CPU miner used it for about 4-5 hours, but then the Pi becomes unresponsive and I can no longer SSH in, and the mining stops.

I'm using the official power supply so I can't see how it would be a power issue. Would overheating cause the Pi to just lock up like that? The official Raspbian distribution seems to work just fine indefinitely running.

Could you maybe suggest where I could find some logs as to what's happening?

Thanks.