A few known Bitcoin mining farms

[Note: the following overview on known Bitcoin mining farms was originally included in a new paper but needed to be removed for space and flow considerations]

Several validators on the Bitcoin network, as well as many watermarked token issuers, are identifiable and known.1 What does this mean?  Many Bitcoin validators are drifting usage outside the pseudonymous context of the original network due to their use of specialty equipment that creates a paper trail.  In other words, pseudonymity has given way to real world identity.  Soon issuers of color will likely follow because they too have strong ties to the physical, off-chain world.

For instance, on August 4, 2015, block 368396 was mined by P2Pool. This is notable for two reasons.

The first is that the block included a transaction sent from Symbiont.io, a NYC-based startup building “middleware” that enables organizations and financial institutions to create and use ‘smart securities’ off-chain between multiple parties and have the resulting transaction hashed onto a blockchain, in this case, the Bitcoin blockchain.2

Several weeks later, Symbiont announced that it would begin using their “stack” to provide similar functionality on a permissioned ledger.3 This follows a similar move by T0.com – a wholly owned subsidiary of Overstock.com – which initially used Open Assets to issue a $5 million “cryptobond” onto the Bitcoin blockchain, but have subsequently switched to using a “blockchain-inspired” system designed by Peernova.456

The second reason this was notable is that the block above, 368396, included at least one transaction from Symbiont which was mined by a small pool called P2Pool.7 Unlike other pools discussed in this paper, P2Pool is not continually operated in a specific region or city.

It is decentralized in that all participants (hashers) must run their own full Bitcoin nodes which stand in contrast with pools such as F2Pool, KnC mining pool and BTCC (formerly called BTC China), where the pool operator alone runs the validating node and the labor force (hashers) simply search for a mid-state that fulfills the target difficulty.8

Due to this resource intensive requirement (running a full node requires more bandwidth and disk space than merely hashing itself), P2Pool is infrequently used and consequently comprises less than 1% of the current network hashrate.

P2Pool’s users are effectively pseudonymous. Due to the intended pseudonymity it is also unclear where the transaction fees and proceeds of hashing go. For instance, do the hashers comprising this pool benefit from the proceeds of illicit trade or reside in sanctioned countries or who to contact in the event there is a problem? And unlike in other pools, there is no customer service to call and find out.

Bitcoin’s – and P2Pool’s – lack of terms of service was intentionally done by design (i.e., caveat emptor). And in the event of a block reversal, censored transaction or a mere mistake by end-users, as noted above there is no contract, standard operating procedure or EULA that mining pools (validators) must adhere to. This is discussed in section 3.

This pseudonymous arrangement was the default method of mining in 2009 but has evolved over the years. For example, there are at least two known incidents in which a miner was contacted and returned fees upon request.

Launched in late summer of 2012 and during the era of transition from GPUs and FPGA mining, ASICMiner was one of the first publicly known companies to create its own independent ASIC mining hardware. Its team was led by “FriedCat,” a Chinese businessman, who custom designed and integrated ASIC chips called Block Eruptors, ASICMiner operated their own liquid immersion facility in Hong Kong.9

At its height, ASICMiner (which solo-mined similar to KnC and BitFury do today) reached over 10% of the network hashrate and its “shareholders” listed its stock on GLBSE (Global Bitcoin Stock Exchange), GLBSE is a now defunct virtual “stock market” that enabled bitcoin users to purchase, trade and acquire “shares” in a variety of listed companies.10 GLBSE is notable for having listed, among other projects, SatoshiDice which was later charged by the Securities and Exchange Commission (SEC) for offering unregistered securities to the public.1112

While unregistered stock exchanges catering to cryptocurrency users and China-based mining pools may be common sights today, on August 28, 2013, a bitcoin user sent a 200 bitcoin fee that was processed by ASICMiner.13 Based on then-market rates, this was approximately worth $23,518.14 The next day, for reasons that are unknown, ASICMiner allegedly sent the errant fee back to the original user.15 At the time, one theory proposed by Greg Maxwell (a Bitcoin Core developer) was that this fee was accidentally sent due to a bug with CoinJoin, a coin-mixing service.16

Liquid Bitcoin

Liquid cooled hashing equipment at ASICMiner in 2013. Source: Xiaogang Cao

The second notable incident involved BitGo, a multisig-as-a-service startup based in Palo Alto and AntPool, a large China-based pool (which currently represents about 15% of the network hashrate) operated by Bitmain which also manufacturers Antminer hardware that can be acquired directly from the company (in contrast to many manufacturers which no longer sell to the public-at-large). On April 25, 2015 a BitGo user, due to a software glitch, accidentally sent 85 bitcoins as a mining fee to AntPool. Based on then-market rates, this was worth approximately $19,197.17

The glitch occurred in BitGo’s legacy recovery tool which used an older version of a library that causes a 32-bit truncation of values and results in a truncation of outputs on the recovery transaction.18 To resolve this problem, the user “rtsn” spent several days publicly conversing with tech support (and the community) on Reddit.19

Eventually the glitch was fixed and Bitmain – to be viewed as a “good member of the community” yet defeating the purpose of a one-way-only, pseudonymous blockchain – sent the user back 85 bitcoins.

May Bitcoin Fee

Fee to Bitmain (Antpool) highlighted in red on Total Transaction Fee chart.  Source: Blockchain.info

On September 11, 2015 another user accidentally sent 4.6 bitcoins (worth $1,113) as a fee to a mining pool, which in this instance was AntPool.20 Bitmain, the parent company, once again returned the fee to the user.

Do we know about other farms?21

HaoBTC is a newly constructed medium-sized hashing farm located in Kangding, western Sichuan, near the Eastern border with Tibet.22 It currently costs around 1.5 million RMB per petahash (PH) – or $242,000 – to operate per year. This includes the infrastructure and miner equipment costs. It does not include the operating costs which consists of: electricity, labor, rent and taxes (the latter two are relatively negligible).

The facility itself cost between $600,000 – $700,000 to build (slightly less than the $1 million facility BitFury built in 2014 in the Republic of Georgia) and its electrical rate of 0.2 RMB per kWh comes from a nearby hydroelectric dam which has a 25,000 kW output (and cost around $10 million to construct).23

In dollar terms this is equivalent to around $0.03 / kWh (during the “wet” or “summer” season). For perspective, their electric bill in August 2015 came in at 1.4 million RMB (roughly $219,000); thus electricity is by far the largest operating cost component.

When all the other costs are accounted for, the average rises to approximately $0.045 per kWh. The electricity rate is slightly more expensive (0.4 RMB or $0.06) during winter due to less water from the mountains. The summer rate is roughly the same price as the Washington State-based hashing facilities which is the cheapest in the US (note: it bears mentioning that Washington State partly subsidizes hydroelectricity).


HaoBTC staff installing hashing equipment. Source: Eric Mu

At this price per joule it would cost around $105 million to reproduce “work” generated by the 450 petahash Bitcoin blockchain. Due to a recent purchase of second-hand ASICMiner Tubes, HaoBTC currently generates just over 10 PH and they are looking to expand to 12 PH by the end of the year.24 The key figure that most miners are interested in is that at the current difficulty level it costs around $161 for HaoBTC’s farm to create a bitcoin, giving them a nearly 100% margin relative to the current market price.

The ASIC machines they – and the rest of the industry uses – are single use; this hashing equipment cannot run Excel or Google services, or even bitcoind. Thus common comparisons with university supercomputers is not an apples-to-apples comparison as ASIC hashing cannot do general purpose computing; ASIC hashing equipment can perform just one function.25

There is also a second-hand market for it. For instance, hashing facilities such as HaoBTC actively look to capitalize off their unique geographical advantages by using older, used hardware. And there is a niche group of individuals, wanting to remain anonymous, that will also purchase older equipment.26

Although individual buyers of new hashing equipment such as Bob, do typically have to identify themselves to some level, both Bob can also resell the hardware on the second-hand market without any documentation. Thus, some buyers wanting to buy hashing equipment anonymously can do so for a relative premium and typically through middlemen.2728

While Bitbank’s BW mining farm and pool have been in the news recently29, perhaps the most well-known live visual of mining facilities is the Motherboard story on a large Bitcoin mining farm in Dalian, Liaoning:30

Incidentally, while Motherboard actually looked at just one farm, the foreigner helping to translate for the film crew independently visited another farm in Inner Mongolia which during the past year Bitbank apparently acquired.31

Are there any other known facilities outside of China?32

Genesis Mining

Source: Business Insider / Genesis Mining

Genesis Mining is a cloudhashing service provider that purportedly has several facilities in Iceland.33 According to a recent news story the company is one of the largest users of energy on the island and ignoring all the other costs of production (aside from electricity), it costs about $60 to produce a bitcoin.34 However, when other costs are included (such as hardware and staffing) the margin declines to — according to the company — about 20% relative to the current bitcoin price. At the time of the story, the market price of a bitcoin was around $231.

The four illustrations above are among a couple dozen farms that generate the majority of the remaining hashrate.

What does this have to do with colored coins?

The network was originally designed in such a way that validators (block makers) were pseudonymous and identification by outside participants was unintended and difficult to do.  If users can now contact validators, known actors in scenic Sichuan, frigid Iceland or rustic Georgia, why not just use a distributed ledger system that already identifies validators from the get go?  What use is proof-of-work at all? Why bother with the rhetoric and marginal costs of pseudonymity?

The social pressure type of altruism noted above (e.g,. Bitmain and BitGo returning fees) actually could set a nebulous precedent: once block rewards are reduced and fees begin to represent a larger percentage of miner revenue, it will no longer be an “easy” decision to refund the user in the event there is a mistake.35 If Bitmain did not send a refund, this backup wallet error would serve as a powerful warning to future users to try and not make mistakes.

While there have been proposals to re-decentralize the hashing process, such as a consumer-device effort led by 21inc which amounts to creating a large corporate operated botnet, one trend that has remained constant is the continued centralization of mining (block making) itself.3637 The motivation for centralizing block making has and continues to be about one factor: variance in payouts.38 Investors in hashing prefer stable payouts over less stable payouts and the best way to do that with the current Poisson process is to pool capital (much like pooling capital in capital markets to reduce risk).

Whether or not these trends stay the same in the future are unknown, however it is likely that the ability to contact (or not contact) certain pools and farms will be an area of continued research.

Similarly one other potential drawback of piggy backing on top of a public blockchain that could be modeled in the future is the introduction of a fat tail risk due to the boundlessness of the price of the native token.39 In the case of price spikes even if for short time can create price distortions or liquidity problem on the off-chain asset introducing a correlation between the token and the asset that theoretically was not supposed to be there.

  1. For instance, the staff of Let’s Talk Bitcoin issues LTBCoin on a regular basis to listeners, content creators and commenters. []
  2. Wall Street, Meet Block 368396, the Future of Finance from Bloomberg []
  3. On August 20, 2015, Symbiont announced it is also building a permissioned ledger product. See also the second half of Bitcoin’s Noisy Size Debate Reaches a Hard Fork from The Wall Street Journal, Why Symbiont Believes Blockchain Securities Are Wall Street’s Future from CoinDesk and Why Symbiont Believes Blockchain securities are Wall Street’s Future []
  4. The CoinPrism page for the specific token that Overstock.com initially used for the “cryptobond” can be viewed here; similarly the file on the T0 domain that verifies its authenticity can be seen here. See also: World’s First Corporate “Cryptobond” was issued using Open Assets []
  5. Overstock CEO Uses Bitcoin Tech to Spill Wall Street Secret from Wired and Overstock.com and FNY Capital Conclude $5 Million Cryptobond Deal from Nasdaq []
  6. One reviewer likened the Overstock “cryptobond” proof of concept as a large wash trade: ”Basically it’s a cashless swap of paper and thus no currency settlement. And the paper has no covenants and thus very easy to digitally code. Basically Overstock is paying FNY a spread of 4% for doing this deal. And if the bond and loan are called simultaneously, say in the next month, that means that Overstock paid FNY about $16,667.00 to do this trade. And since there was no cash exchanged, I am presuming, then this is smoke and mirrors. But they actually did it. However, I don’t see much of a business model where the issuer of a bond has to simultaneously fund the investor with a loan to buy the bond and pay him 33 basis points to boot!” []
  7. P2Pool wiki and P2Pool github []
  8. See Target, How Bitcoin Hashing Works and On Mining by Vitalik Buterin []
  9. ASICMINER: Entering the Future of ASIC Mining by Inventing It from Bitcoin Talk, Mystery in Bitcoinland…. the disappearance of FriedCat from Bitcoin Reporter; Chinese Mining mogul FriedCat has stolen more than a million in AM hash SCAM from Bitcoin Talk and Visit of ASICMINER’s Immersion Cooling Mining Facility from Bitcoin Talk []
  10. See 12.2 Pool and network miner hashrate distributions from Organ of Corti and Bitcoin “Stock Markets” – It’s Time To Have A Chat from Bitcoin Money []
  11. See SEC Charges Bitcoin Entrepreneur With Offering Unregistered Securities from SEC and the Administrative Proceeding order []
  12. In (Rosenfeld 2012) the author noted that one of the risks for running an “alternative to traditional markets” – such as GLBSE – were the regulatory compliance hurdles. Overview of Colored Coins by Meni Rosenfeld, p. 4. []
  13. Block 254642 and Some poor person just paid a 200BTC transaction fee to ASICminer. []
  14. According to the Coindesk Bitcoin Price Index, the market price of a bitcoin on August 28, 2013 was approximately $117.59. []
  15. Included in block 254769 []
  16. A thread discussed this theory: Re: CoinJoin: Bitcoin privacy for the real world (someday!) []
  17. According to the Coindesk Bitcoin Price Index, the market price of a bitcoin on April 25, 2015 was approximately $225.85. []
  18. The user “vytah” debugged this issue in a reddit thread: Holy Satoshi! Butter pays 85Btc transaction fees for a 16Btc transaction. Is this the largest fee ever paid? []
  19. Help! Losing Over 85 BTC Because of BitGo’s Flawed Recovery Process! on Reddit []
  20. To AntMiner, miner of block #374082. I did an accidental 4.6 BTC fee. on Reddit []
  21. Readers may be interested in a little more history regarding self-identification by miners: Slush, the first known pool, began publicly operating at the end of November 2010 and was the first to publicly claim a block (97838).   Eligius was announced on April 27, 2011 and two months later signed the first coinbase transaction (130635).   DeepBit publicly launched on February 26, 2011 and at one point was the most popular pool, reaching for a short period in May 2011, more than 50% of the network hashrate. See Deepbit pool owner pulls in $112* an hour, controls 50% of network and DeepBit pool temporarily reaches critical 50% threshold from Bitcoin Miner and What has been the reaction to permissioned distributed ledgers? []
  22. This information comes from personal correspondence with Eric Mu, July 7, 2015 as well as two other public sources: Inside a Tibetan Bitcoin Mine: The Race for Cheap Energy from CoinTelegraph and Three months living in a multi-petahash BTC mine in Kangding, Sichuan, China from Bitcoin Talk []
  23. Last summer BitFury quickly built a relatively cheap data center in Georgia partly due to assistance from the national government. See BitFury Reveals New Details About $100 Million Bitcoin Mine from CoinDesk []
  24. Personal correspondence with Eric Mu, August 10, 2015 []
  25. One common talking point by some Bitcoin enthusiasts including venture capitalists is that Google’s computers, if repurposed for mining Bitcoin, would generate only 1-2% of the network hashrate – that the Bitcoin network is “faster” than all of Google’s data centers combined. This is misleading because these Bitcoin hashing machines cannot provide the same general purpose utility that Google’s systems can. In point of fact, the sole task that ASIC hashing equipment itself does is compute two SHA256 multiplications repeatedly. []
  26. Some academic literature refers to miners on the Bitcoin network as “anonymous participants.” In theory, Bitcoin mining can be anonymous however by default mining was originally a pseudonymous activity. Participants can attempt to remain relatively anonymous by using a variety of operational security methods or they can choose to identify (“doxx”) themselves as well. See The Bitcoin Backbone Protocol: Analysis and Applications by Garay et al. []
  27. Thanks to Anton Bolotinsky for this insight. []
  28. This is similar to the “second-hand” market for bitcoins too: bitcoins originally acquired via KYC’ed gateways sometimes end up on sites like LocalBitcoins.com (akin to “Uber for bitcoins”) – where the virtual currency is sold at a premium to those wanting to buy anonymously. []
  29. The Unknown Giant: A First Look Inside BW, One of China’s Oldest and Largest Miners from Bitcoin Magazine []
  30. Inside the Chinese Bitcoin Mine That’s Grossing $1.5M a Month from Motherboard []
  31. Jake Smith, the translator, also wrote a short story on it: Inside one of the World’s Largest Bitcoin Mines at The Coinsman []
  32. While it is beyond the scope of this paper, there are a couple of general reasons why medium-sized farms such as HaoBTC have been erected in China. Based upon conversations with professional miners in China one primary reason is that both the labor and land near energy generating facilities is relatively cheap compared with other parts of the world. Furthermore, energy itself is not necessarily cheaper, unless farms managers and operators have guanxi with local officials and power plant owners.   And even though it is common to assume that due to the capital controls imposed at a national level – citizens are limited to the equivalent of $50,000 in foreign exchange per year – there have been no public studies as to how much capital is converted for these specific purposes. There are other ways to avoid capital controls in China including art auctions and pawn shops on the border with Macau and Hong Kong. See also How China’s official bank card is used to smuggle money from Reuters and What Drives the Chinese Art Market? The Case of Elegant Bribery by Jia Guo See On Getting Paid From China. Is There Really A $50,000 Yearly Limit? from China Law Blog and Bitcoins: Made in China []
  33. Look inside the surreal world of an Icelandic bitcoin mine, where they literally make digital money from Business Insider []
  34. It is unclear how much hashrate they actually operate or control, a challenge that plagues the entire cloudhashing industry leading to accusations of fraud. []
  35. And this is also a fundamental problem with public goods, there are few mechanisms besides social pressure and arbitrary decision making to ration resources. As described in (Evans 2014), since miners are the sole labor force, they create the economic outputs (bitcoins) and security, it is unclear why they are under any expectation to return fees in a network purposefully designed to reduce direct interactions between participants. See Economic Aspects of Bitcoin and Other Decentralized Public-Ledger Currency Platforms by David Evans []
  36. See 21 Inc Confirms Plans for Mass Bitcoin Miner Distribution from CoinDesk and What impact have various investment pools had on Bitcoinland? []
  37. In 2014 the state of New Jersey sued a MIT student, Jeremy Rubin, for creating a web-based project that effectively does the same thing as the silicon-based version proposed by 21inc. See Case Against Controversial Student Bitcoin Project Comes to Close from CoinDesk. In addition, the FTC, in its case against Butterfly Labs also looked at BFL not informing customers properly regarding difficulty rating changes. According to the FTC’s new release on this case: “A company representative [BFL] said that the passage of time rendered some of their machines as effective as a “room heater.” The FTC charged that this cost the consumers potentially large sums of money, on top of the amount they had paid to purchase the computers, due to the nature of how Bitcoins are made available to the public.” []
  38. This issue was cited in the CryptoNote whitepaper as one motivation for creating a new network. On p. 2: “This permits us to conjecture the properties that must be satisfied by the proof-of-work pricing function. Such function must not enable a network participant to have a significant advantage over another participant; it requires a parity between common hardware and high cost of custom devices. From recent examples [8], we can see that the SHA-256 function used in the Bitcoin architecture does not possess this property as mining becomes more efficient on GPUs and ASIC devices when compared to high-end CPUs. Therefore, Bitcoin creates favourable conditions for a large gap between the voting power of participants as it violates the “one-CPU-one-vote” principle since GPU and ASIC owners possess a much larger voting power when compared with CPU owners. It is a classical example of the Pareto principle where 20% of a system’s participants control more than 80% of the votes.” []
  39. I would like to thank Ayoub Naciri for providing this example. []
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