b'C H A P T E R 2T H E N A V A L P R O V I N G G R O U N Dtry converged at the test site to observe Although technicians tried to collectand take measurements. The public unexploded ordnance after each test,found perches on East and Middle they often failed to find it all.buttes and along the highway. At Boise, Occasionally a projectile was initiatedtwo hundred miles away, a small group by desert heat, as someone wrote inclustered atop Table Rock Mesa east of 1949. It is possible that some [unex-the city to watch and listen. None were ploded projectiles] may be lying loosedisappointed. The blast produced a pur- in the area. To the cairns and dry irri-ple-gray cloud a mile wide and more gation canals already in the landscape,than a mile high. It left a crater fifteen the years of explosives experimenta-feet deep. The group on Table Rock tion added huge craters, piles of shat- U.S. Army Corps of Engineers, Rock Island DistrictMesa heard the report fifteen minutes tered concrete and twisted metal, and One of ten craters in Mass Detonation Area, whereafter the blast. None of the other igloos bomb shells. 21 an igloo-type magazine containing up to 500,000constructed as close as two hundred pounds of TNT was detonated in October 1946.feet away ignited, but the windows After the American victory over Japan,blew out of a test barracks erected a naval vessels were quickly decommis-half mile away. 19 sioned. Coastal bases started shippingto Pocatello one trainload after anotherOther experiments tested the perfor- of guns, armor plate, gun housings, andmance of different kinds of projectiles, miscellaneous materials for storage.fuzes, and explosive loads. The engi- Much of this materialnets, floats,neers and chemists tested smokeless anchors, mooring rings, buoyswentpowder and amitol charges, and tested to the Naval Proving Ground to awaitfor fragmentation of projectiles. They sandblasting and repainting.sought ways to store large quantities of Experiments continued into 1947 andprojectilesor redesign the projec- 1948, but at a slower pace than before INEEL Cultural Resources 4A-18tilesto prevent all of them from det- and no longer in association with the The Atomic Energy Commission adapted one of theonating at once in case of an accident Pocatello gun plant, which curtailed its Navys ordnance storage bunkers as a laboratory foraboard a ship or other place where operations in late 1949. 22 calibrating dosimetry equipment.they had to be stored in intimate con-tact with each other. Test by test, they Some of the later tests were classified.refined their understanding of how Project Elsie is thought to have testedexplosives might safely be stored and the performance of sixteen-inch shellsa n s p o r t e d .tr 20made with depleted uranium. The pur-pose of Project Marsh is still generallyunknown. In 1947, the Naval ProvingGround was designated a depot forstockpiling surplus manganese for theUnited States Treasurystarting withnearly twenty-five tons. In 1948 there U.S. Army Corps of Engineers, Rock Island Districtwere tests of influence fuzes and coun- This 500-pound semi-armor-piercing bomb wastermeasures for guided missiles. 23 found near the Experimental Dairy Farm during theordnance cleanup of the 1990s.1 5'