UNITED STATES
DEPARTMENT OF LABOR

Abstract: At approximately 11:34 a.m. on December 22, 2000, Employee #1, #2 and #3 had initiated a metal casting process in the casting pit when molten metal erupted from the pit. The process was a semi-continuous direct chill casting process. An electric arc casting furnace was used to melt copper raw material. The copper was poured from the furnace into a launder (pouring tundish) and then into three copper molds which were 11 in. in diameter and 19.44 in. long. The final product was copper logs that were approximately 22.6 in. in length and 11 in. in diameter. The explosion involving the casting of the molten copper process occurred in the East Casting Machine in Mold Number 6. The blast forced the pivoted point of the launder upward and discharged most of the copper from the mold. Prior to the explosion, the three employees were having problems maintaining the proper flow rate into Mold Number 6 because of the spout became clogged with debris. One of the employees used a lance rod to clear the spout. While attempting to clear the spout and regulate the molten copper flow into the mold, the explosion occurred and sprayed molten metal upon the workers. They all received severe burns and were hospitalized. In the hospital, they were treated for multiple burns located on various body regions. From the inspection of the Casting Machine, the copper shell in the Mold Number 6 after the explosion had become lodged within the mold and separated from the mold cup. As for the log, it did not travel downwards with the mold cup but left a space between the log and the mold cup. The creation of a space between these two articles is likely due to water or condensation being introduced into the mold cup. As the molten copper or formed copper log contacted the moisture in the space, the heat caused the liquid to vaporize causing a rapid expansion of super-heated steam. This steam forced its way through a weak spot in the shell bottom and propelled the molten metal from the mold.