Odaily News According to mempool data, miners mined an empty block (i.e., the block only contains one transaction, Coinbase, the block reward) at Bitcoin height 866508, which is only 36 seconds away from the previous block height. Miners pack empty blocks for economic reasons, which is the wisest choice for miners. In order to make full use of this time for mining and avoid conflicts with transactions packed in the parent block, miners cannot fill transactions into the block, which means that miners can only try to mine empty blocks.