A 51% attack is a serious threat to the security of the blockchain network, and it can be particularly devastating for miners who are relying on their investments in cryptocurrency. In this type of attack, an attacker gains control over more than 50% of the network's computing power, which allows them to manipulate transactions and potentially double-spend coins.

If a miner is facing a 51% attack, there are several steps they can take to protect themselves and prevent further damage:

1. They should immediately stop mining until they have resolved the issue.

2. They should notify other nodes on the network about the potential breach so that other miners can also take action to secure their systems.

3. They should work with other miners on the network to increase computational power in order to counteract any attempts by attackers to gain control over more than half of it.

4. They should also consider implementing additional security measures such as two-factor authentication (2FA), multi-signature wallets or cold storage options like hardware wallets.

It's important for all members of cryptocurrency networks including miners, developers and users alike- remain vigilant against possible attacks in order maintain system integrity and protect valuable assets from being compromised by malicious actors seeking personal gain at your expense!