Rhiwgreiddyn slate quarry, Ceinws/ Esgairgeiliog. In the large open chamber inside the entrance to the mid level workings, in the far left corner, is a flooded shaft down to the bottom level, below the council road. Rising directly up from this shaft is a near verticle incline, which climbs straight up the back of the open chamber to a winding house at the top, level with the upper tramway and workings of the quarry.