A single Bitcoin (BTC) miner from the Solo CK mining pool has defied the odds after successfully adding a new block on the Bitcoin blockchain, taking home 6.25 BTC ($266,000) for their efforts.

The lucky miner, who may have been mining on just one or two machines, solved a block with their modest hash rate capacity of 126 terahashes per second (TH/s). According to a Tuesday tweet from Solo admin Con Kolivas, it’s equivalent to about 0.000072% of the total Bitcoin network hash rate, which is 175,000,000 TH/s.

Bitcoin mining expert and member of the Bitcoin Mining Council Hass McCook told Cointelegraph that he has never heard of anything like it, adding, “To say this is very rare is an understatement.”

“Usually, having 0.000072% of the hash rate means that, on average, Solo CK will win 0.000072% of the blocks, or about 1 in 1,400,000,” he explained.

“Everything in Bitcoin is probabilistic, even transaction settlement. The more confirmations you have on your tx, the less likely it will be reversed.”

Related: How to mine Bitcoin: A beginners guide to mine BTC

According to McCook, the miner could’ve been using a single machine. “The Antminer S19 is a 110TH/s machine, so Solo CK could have even been mining with just one overclocked rig. More likely, it was five or six Antminer S9 units. Either way, it could very easily be a home miner,” he said.

A machine’s hash rate refers to how many hashes, or mathematical equations, it can solve per second. On average, a new Bitcoin block is mined every 10 minutes. Kolivas estimated the chances weren’t quite so high, with a one in 10,000 chance of finding a block per day with that hash rate, but added the miner probably wouldn’t repeat the feat.

“For the miner involved, it’s a once-in-a-lifetime chance,” Kolivas wrote.

“It’s usually larger miners that solve blocks statistically, but there is no reason even the smallest miner can’t solve one.”

He noted a small miner in his pool had solved a block about one year ago.