bankrupt

In its list of the 30 largest unsecured claims, Blackjewel says it owes over $60 million in royalties to the U.S. Department of the Interior.

A Feb. 4 hearing is scheduled in the matter in U.S. Bankruptcy Court in Texas.

Cambridge Analytica says it has been "vilified" for actions it says are both legal and widely accepted as part of online advertising.

In the papers filed in court in Houston, the company lists $1.3-billion in assets and $3.9-billion in debt.

New energy technology and tightening environmental regulations have throttled the industry and led to a wave of mine closures and jobs cuts.