Mining is the process by which new blocks are added to a proof-of-work blockchain, and simultaneously the process by which new coins are issued. A miner collects pending transactions from the mempool, assembles them into a candidate block along with the hash of the previous block, and then starts trying different nonce values in the block header, hashing each resulting header and checking whether the result is below the current difficulty target. Because hash functions produce effectively random outputs, there is no shortcut — the miner just has to try values until one works. When a valid nonce is found, the miner broadcasts the block to the network and collects the block reward (currently 3.125 BTC on Bitcoin, plus transaction fees from the block).
This process takes the entire Bitcoin network about 10 minutes on average for each block, by design — the difficulty target is automatically adjusted every 2,016 blocks (roughly two weeks) to keep the block time near that target regardless of how much hashing power is on the network. If total hashrate rises, difficulty goes up. If hashrate falls, difficulty comes back down. This self-regulating mechanism is what keeps Bitcoin’s issuance schedule on track even as mining technology evolves by many orders of magnitude.
The Industrial Reality
Mining in the early years was a hobbyist activity done on personal computers, then on gaming GPUs. It stopped being anything a hobbyist could profitably do around 2013, when ASICs — chips designed specifically to do SHA-256 hashing and nothing else — took over the network. Today, Bitcoin mining is a capital-intensive industrial operation run by public companies (Marathon Digital, Riot Blockchain, CleanSpark, Core Scientific, TeraWulf) and private operators, with facilities ranging from small warehouses to purpose-built data centres sited near cheap power sources.
The economics are straightforward: miners make money when the value of the block reward plus transaction fees exceeds their cost of electricity and the amortised cost of their hardware. Electricity is usually the biggest recurring cost, which is why miners locate wherever power is cheap — historically in inner Mongolia and Sichuan (until China’s 2021 ban), currently in West Texas, Kazakhstan, Paraguay, Russia, Ethiopia, and anywhere else where sub-five-cent-per-kWh power is available. Many operations colocate with stranded renewable generation (flared natural gas, curtailed wind, hydro in wet seasons) to use power that would otherwise be wasted.
The capital cycle is brutal. When Bitcoin’s price rises, miner margins fatten, new equipment gets ordered, and hashrate surges as new capacity comes online. When the price falls or a halving cuts the reward, the least efficient miners become unprofitable and have to shut down or upgrade. Public miners sometimes survive the down phase by selling equity or borrowing; private miners sometimes do not, and you see bankruptcies and asset sales at the bottom of every cycle. Core Scientific famously went through Chapter 11 in 2022 and emerged the following year; Compute North did not make it out.
What Mining Is Actually Producing
A persistent criticism of Bitcoin mining is that it consumes large amounts of electricity — hundreds of terawatt-hours per year at current scale, comparable to a mid-sized country — to produce, in a narrow technical sense, just a bunch of hash outputs. Defenders argue that what the power is producing is not hashes but security: the cumulative energy spent making the chain is also the cumulative energy that would be needed to rewrite it, and that is the economic barrier that prevents 51 percent attacks.
Whether you find that argument compelling depends partly on how much you value Bitcoin’s security properties in the first place. Critics point out that the same security could in principle be had with proof-of-stake at a fraction of the energy cost — Ethereum’s transition to PoS in September 2022 reduced its energy consumption by roughly 99.95 percent. Supporters argue that PoW has a track record that PoS does not yet have, that the energy used is mostly coming from stranded or renewable sources, and that the external consequences of PoW mining are less severe than they first appear. The debate is unresolved and probably will not be settled by argument.
Pool Mining
Because the probability of any individual miner finding the next block is tiny at current hashrate, almost all miners participate in pools — cooperative arrangements where many miners contribute hash power to a shared search and split the rewards proportionally to their contribution. This gives individual miners predictable daily income instead of waiting years for a lucky block. The largest pools — Foundry USA, AntPool, F2Pool, Viabtc — each account for significant fractions of network hashrate, and the concentration of mining power in a small number of pools has been a periodic concern for decentralisation. A pool with 51 percent of the hashrate could in principle attack the network, and while no pool has done so, the potential is one of the arguments for keeping pool market share diffuse.