Is my mining address a private key?

[JamesPiechota]

Your mining address is not a private key - it is a public address. But it is paired with a private key (stored in your wallets directory with a name like arweave_keyfile_MININGADDRESS.json) which you will need to sign any blocks you mine. When mining, only nodes that will sign blocks need to have a private key / wallet.json stored locally