Actually links mineral sprites with their new location (#37564)

Fixes sprites being broken

code/game/objects/items/stacks/sheets/mineral.dm

@@ -19,9 +19,6 @@ Mineral Sheets
 		- Abductor
 */
 
-/obj/item/stack/sheet/mineral
-	icon = 'icons/obj/mining.dmi'
-
 /obj/item/stack/sheet/mineral/Initialize(mapload)
 	pixel_x = rand(-4, 4)
 	pixel_y = rand(-4, 4)
@@ -63,7 +60,6 @@ GLOBAL_LIST_INIT(sandstone_recipes, list ( \
 
 /obj/item/stack/sheet/mineral/sandbags
 	name = "sandbags"
-	icon = 'icons/obj/stack_objects.dmi'
 	icon_state = "sandbags"
 	singular_name = "sandbag"
 	layer = LOW_ITEM_LAYER