Is Bitcoin mining halal?

Mining means contributing real computing work to secure a network, in return for newly-issued coins and fees. Because there is genuine effort and a real service rendered, many scholars view mining itself more favourably than mere speculation.

The remaining questions are practical: the lawfulness of the coin being mined, the source of the electricity and capital (avoiding interest-based loans), and honest dealing. Mining a coin tied to gambling or interest would inherit those problems.

As always, the underlying coin matters — check its assessment first.