Of course; if that was the original design intent. Screw capacity is a volumetric consideration. Lump size must be the same. Limestone is denser than coal so a machine properly designed for coal should trip out when fed with limestone, whereas a limestone machine would run light with coal. To run both materials effectively the screw speed should be variable.

If anybody comes along howling about extra wear just consider; do you want to use 1 screw or have an interchangeable pair of screw spouts.

As is often the case it depends on how much life is, or would be, left in the existing machine & how much money you can spend. ■