Across the industrialized world, coal mining leaves behind vast accumulations of mineral waste—material long regarded as an environmental burden to be contained rather than a resource to be understood. A new scientific review proposes that coal gangue, rich in silica, iron, and trace metals, carries within its own structure the chemical potential to break down water pollutants when properly awakened through heat, grinding, and chemical treatment. The insight reframes a familiar human dilemma: what we discard may hold the means to repair what we have damaged.