Edit: not just freshly-generated coins that weren't mined by any pool that blockchain.info is aware of, but ones that were mined with a very unusual 47.5 BTC / 2.5 BTC split in the coinbase payout, which means custom software.
Edit 2: and yep, that entire payment comes from coinbase transactions paid to http://blockchain.info/address/1PSf86KnLuzM7Ris5kDhTEZwooR3p2iyfV - which represents 5+% percent of the total Bitcoin hashpower right now at a quick estimate. I have a bad feeling about this.
For me it looks like he bought this coins directly from a large miner, which makes sense to me.
It's GPUMAX. There was a thread about this some time ago, when GPUMAX hashing power was being directed to a private pool, with 47.5BTC going to some other address for every block. At the time, Pirate said that this private pool would be "part of the business model" of GPUMAX.
Asides from GPUMAX being a coin laundry I don't really see what use it'd be when mining to a pool under your control...