A spokeswoman for the subsidiary, Flint Hills Resources, said the company "may consider additional support". The Kochs' company has estimated annual revenues of $100 billion, owns refineries in Alaska, Texas and Minnesota, and controls about 4,000 miles of oil pipelines.
An additive to fluids used in oil drilling, developed with a subsidiary of the resource company Schlumberger, promised to make drilling more efficient and to leave less waste in the ground; instead, barrels of the stuff decomposed before they could be used.
On Thursday, Arizona's Department of Environmental Quality granted Rosemont Copper, a subsidiary of Augusta Resource of Vancouver, a crucial air quality permit, saying emissions from the proposed mine would not violate federal standards for carbon monoxide, nitrogen and sulfur dioxide, or fine and large particles.
But Antofagasta added 33.5p to 883p, and Vedanta Resources rose 23p to £11.83 as it recruited former Rio Tinto chief executive Tom Albanese as chairman of its resources subsidiary.
Eurasian Natural Resources Corporation is 3.3p lower at 216.7p but Vedanta Resources has risen 28p to £11.88 as it recruited former Rio Tinto chief executive Tom Albanese as chairman of its resources subsidiary.
Fiduciary Trust, a subsidiary of Franklin Resources, which manages money for wealthy clients, had its headquarters at 2 World Trade Center, and executives there say they remain deeply concerned about the employees who are still missing.
The miner, which is developing a copper and gold project in the Gobi desert, confirmed that its Mongolian subsidiary, Turquoise Hill Resources, had received an "information request" from the Mongolian Anti-Corruption ACAhority (ACA).
Michael Lissack, who was an investment banker at Smith Barney in the late 1980s, worked with Mr. Sokol when he ran Ogden Projects, the resource recovery subsidiary of the Ogden Corporation.
The mine's operator, Genwal Resources, a subsidiary of the Murray Energy Corporation, has insisted that an earthquake caused the collapse.
