Mining decarbonization is conventionally measured through emissions intensity, a metric that can improve steadily while the underlying extract-process-use-discard system remains as linear as ever. This essay distinguishes carbon performance from circularity and separates circularity itself into four loops: internal operational circularity, resource circularity, industrial circularity, and lifecycle circularity, each of which can stagnate independently of falling carbon numbers. It cautions that circularity is not automatically safer than storage, reprocessing legacy tailings can reintroduce geotechnical instability, and recovered secondary materials can carry contamination into new settings, risks that deserve evaluation on their own terms rather than assumption of improvement. Its central contribution is governance circularity: the claim that responsibility for a material's consequences must circulate along with the material itself rather than lapsing at the boundary of a transaction, extending this series' earlier arguments about closure as a handoff and residual risk as an inherited obligation into the circular economy context.