Rockwood Cas. Ins. Co. v. Dir., Office of Workers' Comp. Programs, 917 F.3d 1198

Claimant Tony Kourianos worked ~27 years as a coal miner and filed a Black Lung Benefits Act (BLBA) claim; OWCP identified Hidden Splendor as the responsible operator and Rockwood is Hidden Splendor’s insurer.
Hidden Splendor initially contested liability but later accepted the responsible-operator designation before the district director and reiterated that concession before the ALJ; Rockwood sought to withdraw that stipulation at the ALJ hearing.
Medical record: normal X-rays and pulmonary function tests; arterial blood gas tests (at Price, UT, ~5,566 ft) produced an exercise PO2 of 59 (PCO2 33) which qualifies as “impairing” under Appendix C for the 3,000–5,999 ft band.
Three physicians: Dr. Gagon (examined claimant) diagnosed chronic bronchitis, found exertional hypoxemia and concluded claimant cannot perform his usual (fire-boss) work; Drs. Zaldivar and Selby (record reviewers) attributed findings largely to smoking/altitude and disputed disability.
ALJ found claimant totally disabled, applied the 15‑year presumption (claimant worked >15 years), and held Hidden Splendor liable; BRB affirmed. Rockwood petitioned for review challenging (1) denial of withdrawal of the responsible-operator stipulation and (2) the disability/entitlement finding.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether ALJ abused discretion by denying Hidden Splendor/Rockwood leave to withdraw its stipulation that Hidden Splendor was the responsible operator	Kourianos (and Director): Employer conceded before district director; withdrawal denied properly because employer failed to timely raise the issue	Rockwood: Stipulation should be withdrawable because evidence (job duties) showed claimant didn’t work as a miner for a year; issue was newly revealed at ALJ hearing	Denial affirmed — employer’s liability was reasonably ascertainable earlier and it waived challenge by not timely contesting before the district director; ALJ properly applied 20 C.F.R. § 725.463(b)
Whether substantial evidence supports ALJ’s finding of total respiratory disability and application of 15‑year presumption	Kourianos: Exercise arterial blood gas produced a qualifying PO2 under Appendix C; Dr. Gagon’s exam/opinion ties impairment to coal-dust exposure and inability to perform usual work	Rockwood: PO2 was normal for Price altitude and physicians who reviewed records tied impairment to smoking/altitude, so no disability caused by pneumoconiosis	Affirmed — ALJ properly relied on qualifying Appendix C blood-gas result and credited Dr. Gagon’s opinion over record-reviewers; substantial evidence supports total disability and therefore application of the 15‑year presumption; employer failed to rebut disease, causation, or disability-causation presumptions

Antelope Coal Co. v. Goodin, 743 F.3d 1331 (10th Cir. 2014) (BLBA framework and presumption discussion)
Energy West Mining Co. v. Estate of Blackburn, 857 F.3d 817 (10th Cir. 2017) (elements to obtain BLBA benefits and burden-shifting under presumptions)
Consolidation Coal Co. v. Dir., OWCP, 864 F.3d 1142 (10th Cir. 2017) (application of 15‑year presumption and legal/clinical pneumoconiosis)
Andersen v. Dir., OWCP, 455 F.3d 1102 (10th Cir. 2006) (legal pneumoconiosis concept)
Erie Boulevard Hydropower, LP v. FERC, 878 F.3d 258 (D.C. Cir. 2017) (agency bound by its own regulations)
Hansen v. Dir., OWCP, 984 F.2d 364 (10th Cir. 1993) (substantial-evidence review of ALJ medical credibility determinations)
Killman v. Dir., OWCP, 415 F.3d 716 (7th Cir. 2005) (weight to physician who addressed claimant’s actual work duties)
Consolidation Coal Co. v. Dir., OWCP (Burris), 732 F.3d 723 (7th Cir. 2013) (stipulations bind parties on responsible-operator issues)