By Heri Retnowati SIDOARJO, Indonesia, March 13 (Reuters) - A torrent of mud that has inundated villages on Indonesia's Java island shows no signs of abating despite efforts to plug it by dropping hundreds of concrete balls into its source, an official said on Tuesday. The mud has displaced about 15,000 people following an oil-drilling accident in May in Sidoarjo, an industrial suburb near Surabaya city in the east of Java island, and destroyed toll roads, railways tracks and submerged factories. In the latest move to brake the mudflow, scientists have dropped 296 clusters of concrete balls linked to steel cables into the mouth of the eruption. But scientists involved in the effort said it was too early to say whether the work was a success. "We are still evaluating. We are studying the volume of the flow, which has now increased from 125,000 cubic metres to 160,000 cubic metres a day," said Rudi Novrianto, a spokesman for the government team tasked with dealing with what scientists dub the "mud volcano". He said pebbles, sand and stones the size of tennis balls had now been found in the mud, in addition to clay. But Satria Bijaksana, a member of a separate team of scientists who initiated the concrete ball experiment, said mud pressure had eased after the balls were dropped. "We have noticed an increase in hydrogen sulphide, indicating that pressure is decreasing," Bijaksana told Reuters. He said fears of some other scientists that the balls would force the mud to erupt in other points due to built-up pressures had not materialised. Under the plan, 375 clusters will be lowered into the main hole from where the mud has been gushing, with each chained cluster consisting of four 20-40 cm (8-16 in) diameter balls. Bijaksana said the remaining 78 clusters of balls would be dropped in the next few days. Anger has been mounting in the area over the hot mud, with displaced residents frequently holding street rallies demanding cash compensation instead of resettlement. PT Lapindo Brantas, the operator of the well where the mud has erupted, had been told by the government to pay 3.8 trillion rupiah ($412.3 million) to victims and for efforts to plug the mud flow. But a team set up by the government said the cost would reach around 7.6 trillion rupiah. Lapindo and PT Energi Mega Persada Tbk, which indirectly controls it, dispute whether the mud flow was caused by the drilling and also whether Lapindo alone should shoulder the cost. Energi is owned by the Bakrie Group, controlled by the family of Indonesia's chief social welfare minister, Aburizal Bakrie. Lapindo holds a 50-percent stake in the Brantas block from where the mud is gushing. Energi International Tbk holds 32 percent and Australia-based Santos Ltd the remaining 18 percent. ($1 = 9,215.92 rupiah) (Additional reporting by Ahmad Pathoni)
