The 266th solo block was mined by a solo miner with a hashrate of 60 TH/s and earned approximately 6.27102221 BTC ($243,000) in the process. The miner was solo mining on ckpool similar to previous solo miners who earned a block reward on their own.
Dr. Con Kolivas, administrator of ckpool Tweeted to confirm that the miner in question joined ckpool about a month ago and has successfully received the reward.
Based on the current Bitcoin network difficulty, the odds of this particular miner with 60TH has a less than 1 in ~20,000 chance of solving a block per day while solo mining. The miner had a miniscule 0.000024% of the total network’s hashrate.
The miner earned 6.27102221 BTC consisting of the 6.25 BTC block reward, plus the transaction fees of all the transactions included in that block, minus the 2% ckpool fee.
A tweet in response to a similar event by bitcoin mining pool Slush Pool explained that it is technically not possible to solo mine given the way the bitcoin network operates. From a technical standpoint, miners must interface with the network via a pool implementation. Solo miners are able to earn an entire block reward with ckpool because they reward the individual miner in their pool that solves any given block. This method for rewards is unique to how most mining pools operate.
The majority of mining pools split each reward found between all the miners in proportion to the hashrate they provide to the pool. The ckpool method essentially means that miners are going for lower frequency of higher rewards (potentially taking years or decades to solve a block, depending on their hashrate) while miners using traditional pools will get a higher frequency of lower rewards.
Over a long enough time period the rewards earned by a miner in either scenario average out to be the same but the variance in frequency and size of each reward is different.