The mud started gushing from the ground nearly 10 months ago when a shaft probing for natural gas pierced a pressurized aquifer about 9,000 feet underground. Since then about 1 billion cubic feet of mud has spread across two square miles.

The mud has buried 12 villages and 20 factories, inundating roads and rice fields and displacing 15,000 people. It is still flowing, at more than 3.5 million cubic feet a day, and no one can say when it might stop.

“After two months, we realized that this was not stopping,” Mr. Bijaksana said, “so we started trying to figure a way to stop it.”

The idea is to jam the gullet of the geyser with 1,000 or more balls linked together like charm bracelets, in bunches of four, the biggest of them weighing about 175 pounds.
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Chief Sgt. Sumarono, a soldier stationed at the team’s media center, told The Jakarta Post that local soothsayers had said spirits who lived in the crater would be angry after being hit by the giant concrete balls.

“The mud explosion happened because the spirits in the crater are angry,” said Sergeant Sumarono, who like many Indonesians uses only one name.

“The insertion of the balls will only spark more anger. The soothsayers have already said there will be a new and much bigger burst. I believe this.”