Thomas

facts. For the second time, see Thomas v. CalPortland Co. (Thomas I), 993 F.3d

1204 (9th Cir. 2021), and because the Commission misapplied the substantial

evidence standard, we grant Thomas’s petition and vacate and remand.

1. Standard of Review. The Mine Act instructs that “[t]he findings of the

Commission with respect to questions of fact, if supported by substantial evidence

on the record considered as a whole, shall be conclusive.” 30 U.S.C. § 816(a)(1); see

also Miller Min. Co. v. Fed. Mine Safety & Health Rev. Comm’n, 713 F.2d 487, 490

(9th Cir. 1983) (“This court will uphold the factual findings of the administrative

law judge if there is substantial evidence to support them.”). It also defines the

Commission’s review authority over the decisions of its administrative law judges

(ALJ). 30 U.S.C. § 823(d). As relevant here, the Commission may only review an

ALJ’s factual findings for substantial evidence, id. § 823(d)(2)(A)(ii)(I),

(d)(2)(A)(iii), and it commits legal error if it does not apply this standard. Thomas I,

993 F.3d at 1211 n.4; accord, e.g., Donovan ex rel. Chacon v. Phelps Dodge Corp.,

709 F.2d 86, 91–92 (D.C. Cir. 1983); Sec’y of Lab. v.…