So, just how "liberal" is the 9th U.S. Circuit Court of Appeals, you ask?  Or, maybe you didn't ask, but as that relates to what their decision will be regarding the Thacker Pass case appeal I would imagine that their liberal vs conservative bend is going to be pertinent to how they will rule the Thacker Pass case presently before them for review.

“So the predominance of conservative dissenters has distorted people’s view [of the court as liberal],” 

In a new study in the William & Mary Bill of Rights Journal, University of Pittsburgh law professor Arthur Hellman the question of liberal vs conservative as it applies to the 9th U.S. Circuit Court of Appeals is addressed and it is linked below:

How Liberal Is the 9th Circuit? New Study Takes Deep Dive | National Law Journal

Let's hope that Professor Hellman's bottom line statement, quoted above, is truly correct regarding a "distorted people's view (of the court as liberal)".  It is a complicated question and I have no background in law to help me through the maze to deciper the question: Liberal vs Conseervative.  Does it really matter, since the Court might take a Liberal stance on one question before it and a Conservative, or at least a more Conservative, stance on another case?

They certainly have had their share of reversals in the recent past by the U.S. Supreme Court as exampled by:

9th Circuit has another year of reversals at Supreme Court - Los Angeles Times (latimes.com)

Republican Conservatives have long held that the 9th US Circuit Court of Appeals is the "most Liberal Court in America".  President Trump and Conservative pundits have used the 9th Circuit Court of Appeals for target practice for many years and there exists a plethora of articles that support that line of attack from the Right.

I couldn't find anything quickly, at least, that would review the history of decisions by the 9th U.S. Circuit Court of Appeals regarding mining and environmental issues.  Perhaps one of the more in the know members of our tiny band will share his or her knowledge in that more eurdite nether region of decisions made at the 9th Hole.

I look forward to elucidation on this subject by any of our illustrious members.  Thanks!

Okiedo