Climate protestors demonstrate outside the UK headquarters of British oil giant BP in central London, on September 1, 2009. The protestors, who earlier targeted the head office of a leading bank, said they were demonstrating against the bank's investments in fossil fuel projects, especially funding for the coal industry and tar sands extraction in Canada. (Leon Neal/AFP/Getty Images)
Shell said it has let the Greenpeace protesters continue their action, which is aimed at spreading the message that development of Canada's oil sands worsens climate change.
The peaceful demonstration was timed to coincide with Canadian Prime Minster Stephen Harper's visit with U.S. President Barack Obama in Washington Wednesday, a meeting Greenpeace said had not produced the results it had hoped for.
"We haven't seen nearly enough concrete commitments from the Harper-Obama meeting that they will move quickly to help the world avert catastrophic climate change," Greenpeace spokesman Mike Hudema said in a statement.
About 25 activists entered the mine on Tuesday and locked down a massive dump truck and mining shovel. The company temporarily suspended production at the 155,000 barrel a day site, but resumed operations late in the day.
Hudema said there was a "cordial atmosphere" between demonstrators and Shell staff at the mine, and both sides stressed they were taking care to ensure the safety of everyone.
"Our offer to discuss their concerns about oil sands developments and their vision for the energy future still stands. Greenpeace has not yet responded," the oil major said in a statement.
The company said it is working hard to improve its environmental performance, by developing a carbon capture and storage project for its oil sands operations, and advocating a Canadian and international carbon cap and trade policy.
The Muskeg River mine's other owners are Chevron Corp and Marathon Oil Corp, with 20 percent each. It is one of four major oil sands mining operations near Fort McMurray, Alberta.
