A 49 TH/s Solo Miner Found a Bitcoin Block at Record Difficulty

A participant mining through Solo CKpool found Bitcoin block 907,283 on July 26, 2025 with an attributed hashrate of only 49 terahashes per second. The valid block created a gross reward of 3.15407105 BTC: the protocol’s 3.125 BTC block subsidy plus 0.02907105 BTC in transaction fees.

The event mattered because the miner succeeded while Bitcoin’s difficulty stood at a then-record 127.62 trillion. Industrial mining companies and conventional pools operated vastly larger fleets, but proof of work did not assign blocks according to market share or company size. Every valid hash attempt remained a probabilistic entry in the same competition.

The result did not show that small-scale solo mining was predictably profitable. It showed something narrower and verifiable: a relatively small participant could still produce a winning hash, although the timing of any such success was uncertain.

What the block record establishes

Blockchain explorers identify the block by hash `000000000000000000012b46e1a7ce322e850afde12422c440ee19d9c1b6d74a`. Its header timestamp was 14:15:56 UTC on July 26, equivalent to 7:15:56 a.m. Pacific daylight time. The block encoded difficulty of approximately 127,620,086,886,392 and included 4,038 transactions.

Its coinbase data contained the Solo CKpool identifier. Later on July 26, CKpool operator Con Kolivas attributed the block to a participant identified in abbreviated form as `35Wu~yPhF` and reported 49 TH/s of hashrate. Hashrate is not encoded in the block header, so that figure is an attributable pool-operator observation rather than a measurement independently recoverable from the blockchain.

The 3.15407105 BTC figure is the block’s gross subsidy-and-fee total, not a verified net payment after any pool charge, operating expense, tax or equipment cost. No dollar conversion is used because Bitcoin trades continuously across multiple venues and the chain itself records BTC amounts, not a contemporaneous exchange rate.

Why the result was unusual

Solo CKpool provides mining infrastructure without distributing every block across participants in the manner of a conventional proportional pool. A participant searches independently for a qualifying hash and receives the economic benefit when that participant finds one, subject to the service’s applicable terms.

Expected block production is proportional to a miner’s share of total active hashpower, but actual discoveries are random. A miner can run for far longer than the statistical expectation without finding a block, or succeed much sooner. One winning block therefore cannot establish a sustainable revenue rate for a 49 TH/s operation.

The network context made the disparity especially stark. At block 907,200, Bitcoin had raised difficulty from approximately 126.27 trillion to 127.62 trillion, an increase of about 1.07%. That retarget carried a timestamp of 01:16:29 UTC on July 26, or 6:16:29 p.m. Pacific on July 25. Block 907,283 arrived 83 blocks into the new, more difficult epoch.

What the event did not prove

Difficulty is a dimensionless comparison with Bitcoin’s easiest proof-of-work target; it is not a direct count of machines or electricity consumption. Network hashrate also cannot be observed through a complete machine census. It is estimated from block production, which varies because of mining luck.

The block did not demonstrate decentralization across the mining industry as a whole, identify the participant’s hardware, establish electricity consumption or prove profitability. It supplied a cleaner lesson about protocol design: Bitcoin accepted the valid proof of work without regard to whether its producer was a public company, a dominant pool or a comparatively small solo participant.