PODED-G General, Guideline for Drilling and Blasting Coral Reef for Armor Stone at Enewetok Atoll, M.I. 5. To recover armor stone sized rock it is necessary that controlled blasting merely fracture the reef crust to just the extent necessary that proper excavation equipment can break off the required size of stone. Consequently a carefully planned excavation technique must be developed together with the blasting procedure. 6. Powder to rock ratios will range from less than one pound to more than two pounds per cubic yard. Where the hard reef crust layers are less than four to five feet thick excess energy (more than one pound per cubic yard) is either absorbed in the more porus underlayers or is vented (wasted) at the reef surface. Excess energy occuring where hard reef crust layers exceed five feet will cause crumbling or shattering and must be avoided in blasting for armor stone. 7. For coral reef blasting, contractors have used a five minute delay train with two detonating cord trunk lines and a non-electric fuse lighter. 8. Shot holes should be sounded with a calibrated blasting stick to insure no caving has occurred prior to loading. Shot holes should be loaded immediately after drilling. Rising tides can carry sand into open holes unless the top of holes are closed (stoppers). 9. Drilling and loading will be done under increasing depths of water within the drill hole. All loaded shot holes will be detonated the same day of loading. 10. Team work and close coordination is necessary to efficiently use the short daylight work period. D. INVESTIGATIONS 1. Investigations are to outline and define the thickest and hardest reef crust layers for mining 1500 to 3000 pound armor stones. 2. Select widest reef area on ocean side for a quarry site. 3. Within the widest reef area select the highest elevated reef crust 4. Sand and rock rubble may cover portions of the selected reef area. for inital investigations. Clearing exploration paths through the rubble is required to expose the reef surface and for keeping test shot holes open.