Traffic was allowed to continue through the area, although orange road-construction signs were placed on both sides of the wreck area to warn drivers. DENR spokeswoman Kim McIntosh said officials from cyanide-manufacturer Cyanco of Winnemucca were en route by plane to oversee handling of the truck and its chemical load. She said South Dakota does not require special permits for mines or its suppliers to transport cyanide. Black Hills gold mines have used cyanide to extract gold from crushed rock since the early 1900s. Development of open-pit gold and silver mining has increased area cyanide use since 1982, but McIntosh and Wharf general manager John Begeman said they did not know of another traffic incident involving a cyanide shipment in that time.
Sodium cyanide is a white, crystalline compound.
Begeman said the Wharf mine in 1989 switched from cyanide-briquette shipments because premixed solutions are considered safer to handle. The more than 5,000 gallons of solution contains about 15,000 pounds of cyanide, which will provide about a week's worth of processing for gold and silver, he said.