Mining is how transactions are checked, recorded, and added to a blockchain that uses proof of work. Miners use computers to compete in solving a tough math problem. Whoever solves it first adds a new block of transactions and earns a reward in the network’s coin, plus any fees from the block.
Mining has two main jobs in proof-of-work blockchains. It organizes and confirms transactions so everyone’s copy of the ledger matches. It also creates new coins by giving block rewards to miners. These roles let a blockchain work without a central authority.
When someone sends cryptocurrency, the transfer is shared with the network and waits in a group of unconfirmed transactions called the mempool. Miners choose transactions from this group and put them into a candidate block. Each miner tries to find a special number, called a hash, that meets the network’s rules. The first miner to find a valid hash shares the block, and other nodes check and accept it. In Bitcoin, this process happens about every ten minutes.
Proof of work is a set of rules that makes miners do a lot of computing before they can add a block. This work makes it expensive to change past blocks, since an attacker would have to redo the computing for that block and all the ones after it. The network also changes how hard the hashing problem is, so blocks are added at a steady rate.
People or groups who run mining computers are called miners or mining nodes. They can mine on their own or join mining pools for more regular payouts. Rewards come from new coins and transaction fees in the block. Pools split rewards among members based on how much work each person did.
Mining first used regular CPUs, then switched to graphics cards, and later to special machines built for fast hashing. As mining grew, people looked for cheaper electricity and stronger equipment to keep up. These changes have made mining more industrial and concentrated in some areas.
Since miners use real resources to add blocks, mining helps protect the blockchain from spam and from people trying to take over the ledger. Having many independent miners and making it hard to change old blocks makes proof-of-work networks strong.
Mining uses a lot of energy, which has led to concerns about its impact on the environment. Some projects and miners try to use cleaner energy or move to places with extra renewable power. Other blockchains avoid heavy computing by using different ways to reach agreement.
Not every blockchain uses mining. Proof-of-stake is a popular alternative where validators keep the network safe by locking up tokens instead of doing lots of computing. This method removes the need for mining but still keeps the ledger distributed.
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