BEIJING - ConocoPhillips China, the operator of two leaking oil platforms in Northeast China's Bohai Bay, said on Wednesday that it had discovered more oil-based drilling mud near a leaking platform - a discovery that may push up the volume of its oil spill to a new high.

A man points to oil on the beach in Laoting county, Hebei province, on July 26. The oil is suspected to have come from the oilfield spill in Bohai Bay. [Photo/ China Daily]

The news came just a day after the State Oceanic Administration (SOA) criticized the Houston-based energy company for failing to stop the leak and clean up the contamination quickly enough.

The company said it is still estimating the amount of the new discovery. "We're hoping to get the amount in the next day or two," ConocoPhillips spokesman John McLemore told China Daily via telephone on Wednesday.

"We anticipate that it will push the total amount of oil and oil-based drilling mud released to pass the previous estimate of 1,500 barrels. The discovery has been reported to the relevant authorities," the company said in a statement on its website.

Liu Fenglin, director of the press office in the North China Sea Branch of the SOA, confirmed with China Daily on Wednesday that ConocoPhillips had sent a report on the freshly detected oily mud on the seabed but questioned the timing.

McLemore told China Daily the oily mud was not easy to spot due to the muddy water on the seabed, and it was not discovered until Wednesday.

Liu, however, argued that the company has been cleaning up the leak for more than a month and there is no reason not to have detected the mud. "Did they suspend all the operations in the two platforms? How many people and machines have been devoted to the cleanup?" Liu questioned.

A conference was held by experts in the North China Sea Branch to discuss the progress of the company's cleanup on Wednesday.

Maritime authorities earlier this week urged ConocoPhillips China to clean up the oil-polluted seabed by Sunday and to submit a report on its cleanup work by next Wednesday.

The new discovery will cause more oil sheen to be seen on the surface, and may affect its cleanup process to meet the deadlines set by the SOA, McLemore said.

"We're striving to meet the deadline, but it will depend on the sea currents and weather conditions. We don't want to put our divers at risk," he said.

The North China Sea Branch of the SOA issued a notice on Monday ordering the company to appropriately dispose of contaminants to avoid further pollution from the oil spill, which started on June 4 near Platform B of the Penglai 19-3 oilfield.

China National Offshore Oil Corp, the nation's biggest maritime oil producer, is ConocoPhillips' partner in the oilfield.

"Full-field side sonar imaging is being conducted to assess geological conditions of the seabed," ConocoPhillips said, adding that the team has imaged 279 kilometers and has now finished 97 percent of the survey.

However, environmentalists have concerns over the impact of the spill.

Zhong Yu, a senior action coordinator of international environmental organization Greenpeace, told China Daily that a 100-percent cleanup in oil spills is impossible and the environmental impact will last for decades.

"ConocoPhillips and the State Oceanic Administration should release the reason for the incident and the latest information to the public as soon as possible to avoid potential leaks and impact," Zhong said.