The mining map aims to track the geographic distribution of Bitcoin’s total hashrate over time. Available in monthly intervals starting from September 2019, it extrapolates from a representative sample of geolocational mining facility data. This sample is based on the aggregation of individual pool distributions that are periodically collected from several Bitcoin mining pools through a dedicated API.

We have partnered with several Bitcoin mining pools to collect geolocational mining facility data in a non-obtrusive and privacy-preserving manner. This geolocational data is based on IP addresses of mining facility operators (‘hashers’) that connect to the servers of mining pools.

There are various methods available to approximate Bitcoin’s geographical hashrate distribution, each having their own set of trade-offs and limitations. We opted for the top-down mining pool approach because it provides the right balance between data availability and robustness on one hand, as well as data granularity and confidentiality on the other hand.

Maintaining a bottom-up list of individual mining facilities is cumbersome, prone to error and/or omission, requires constant monitoring and updating, relies on a combination of different data sources that tend to be difficult to verify, and exposes individual facility operators to potential privacy risks. In contrast, the top-down pool approach eliminates much of the overhead associated with data collection (by significantly reducing the amount of data that needs to be collected), uses a single, consistent methodology throughout the process (thereby reducing the risk of incompatible or otherwise conflicting data points), and protects the privacy of both individual mining facility and pool operators (thanks to the double aggregation performed by different parties).

Our dataset empirically recorded for the first time the seasonal hashrate migration within mainland China which was previously only anecdotally observed. As can be seen in the chart below, miners within China were staying mostly in the more stable coal-fired regions like Xinjiang in late autumn, winter and spring (’dry season’), and migrated to regions with significant temporary overcapacities in low-cost hydropower, like Sichuan, between May and October during the ‘wet season’. Since the government crackdown on the mining industry in June 2021, no data has been available – and the migrations have likely become a phenomenon of the past.