Miners haven't sold yet, even though mining costs have gone up" meaning, Bitcoin miners (miners) haven't sold the Bitcoin they get from mining, even though the cost of mining Bitcoin (mining costs) has gone up. This may be caused by factors such as market conditions, regulations, and profits derived from Bitcoin mining.

"Mining costs" in the context of the Bitcoin halving refers to the costs incurred by Bitcoin miners (miners) to mine Bitcoin. This includes the costs of providing the power, equipment, and other costs required to mine Bitcoin.