Generally, a mining node is a full node with the mining option enabled. However, they can also be lightweight nodes participating in a mining pool, with the pool server maintaining the full node.
The mining node constructs blocks and fills them with a properly ordered set of transactions from the pool of open transactions called the mempool (short for memory pool).
Next, it typically uses purpose-built mining hardware called ASICs (or other mining hardware) to find a number (the nonce), which, when combined with the block header, results in the block header’s hash value below the current threshold given by the previous difficulty adjustment. This process is called mining or hashing (we will cover this more in future education articles). If it finds a valid combination, it broadcasts the block along with the number it found so that other nodes can verify the validity of the claim. Thus, mining nodes compete to create Bitcoin blocks. Once a block is successfully mined, it is added to the blockchain, and the process repeats for the next block.