The dyke of the 9th reservoir is also constructed from fly ash. Alkaline liquor is ponding on top of the decanted red mud. The 9th storage reservoir is also overfilled. Now that the mud amount stored in the 10th reservoir became less the statical safety of the 9th reservoir is insecure. Because of overloading, part of the water will be emptied.
Final closure of the storage reservoirs is done usually by removal or evaporating of the ponding liquor. It is followed by covering by soil layer or other composites then planting of vegetation.
Left to the 9th storage reservoir is the power plant wherefrom the flyash originates. Between the power plant and the 9th reservoir one can see the vegetated surfaces of previous red mud storage reservoir.
This is the cheapest red mud storage method. It requires neither drying, nor neutralisation. Water removal is neither spontaneous nor accelerated. The used cover material can be usually waste soil, sewage sludge or other wastes. These reservoirs can be reopened any time and the stored material used in the future.