ice movement at the same time that the flooded ice layer 34 is being built and cooled blocks of ice are mined from the natural ice sheet the cut ice blocks are cured by placing them such that air can circulate on all sides to cool them to approach ambient temperature this can be done by placing the blocks on slats so that the cold air can surround and contact most of the exterior surface of the ice block this ice island will probably be constructed when the ambient temperature is 25 u00b0 c or colder by cutting blocks small enough e g 2 u00d7 4 u00d7 6 feet they can be cooled rather quickly by decreasing the ice block temperature we increase the ice strength and the blocks also lose concentrated brine which otherwise might later cause ice deterioration when the ice blocks have reached approximately the ambient temperature throughout and have lost their excess brine they may be called 34 cured 34 ice blocks the cured ice blocks are also more easily frozen together after the flooded ice has cured or reached its desired temperature layers of the cured ice blocks are placed on the flooded ice layer 34 and frozen together with sea water to construct the upper layer 40 unlike the technique described in connection with fig3 an insulation layer is not required over the lower flooded or constructed ice layer 34 this is because the ice blocks are colder than the underlying ice and acts as a heat sink in addition to not needing an insulation layer the build up rate for the ice block method only depends on the amount of equipment on site and is not limited by the weather conditions another advantage is that no impervious layer is needed beneath.