Clinchfield Coal Co. v. DOWCP: Deference to ALJ Medical-Credibility Findings and Use of the Regulatory Preamble in Mixed-Cause Black Lung Claims

I. Introduction

This unpublished Fourth Circuit decision, Clinchfield Coal Company v. Director, Office of Workers' Compensation Programs & Johnny L. Wallace, No. 24‑1875 (4th Cir. Dec. 23, 2025), arises under the Black Lung Benefits Act (BLBA), 30 U.S.C. §§ 901–944. The case concerns a miner, Johnny Wallace, who filed a subsequent claim for federal black lung benefits after his initial claim was denied. An Administrative Law Judge (ALJ) awarded benefits; the Benefits Review Board (BRB or Board) affirmed; and Clinchfield Coal Company petitioned the Fourth Circuit for review.

Although unpublished and therefore not binding precedent in the Fourth Circuit, this opinion is a detailed application of recent BLBA case law, especially Island Creek Coal Co. v. Blankenship, 123 F.4th 684 (4th Cir. 2024), American Energy, LLC v. Director, OWCP, 106 F.4th 319 (4th Cir. 2024), and Extra Energy, Inc. v. Lawson, 140 F.4th 138 (4th Cir. 2025). It reinforces several important principles:

The strong deference owed to an ALJ’s weighing of conflicting medical evidence in black lung claims, particularly in "battle of the experts" situations involving both coal dust exposure and long-term smoking.
The permissibility and scope of using the Department of Labor’s Preamble to the black lung regulations as scientific context when assessing medical opinions.
The doctrine of abandonment of issues based on inadequate briefing in the court of appeals and failure to raise arguments before the BRB.
How proof of legal pneumoconiosis can effectively satisfy multiple elements of entitlement, including disease, disease arising out of coal mine employment, and disability causation.

The Fourth Circuit ultimately denied Clinchfield’s petition for review, leaving intact the award of black lung benefits to Wallace.

II. Summary of the Opinion

The court’s disposition and principal holdings can be summarized as follows:

The Fourth Circuit reviews the BRB’s legal conclusions de novo but defers to the ALJ’s factual findings if supported by substantial evidence, consistent with Island Creek.
Under Fed. R. App. P. 28(a)(8)(A), Clinchfield abandoned its challenge to the ALJ’s finding of total disability by offering only a bare, conclusory assertion without developed argument or record citations.
Clinchfield likewise abandoned any challenge to the ALJ’s credibility findings regarding its own experts (Drs. Sargent and McSharry) by not properly raising that challenge before the BRB.
The ALJ’s finding that Wallace suffers from legal pneumoconiosis (COPD/emphysema/chronic bronchitis significantly related to coal dust exposure) is supported by substantial evidence, particularly the opinion of Dr. Habre, which was based on corrected and accurate coal mine and smoking histories.
The ALJ permissibly gave reduced weight to Dr. Mabe’s opinion because it relied on inaccurate exposure and smoking histories, and permissibly rejected key aspects of Drs. Sargent’s and McSharry’s opinions because they dismissed a valid, qualifying pulmonary function test (PFT) and over-relied on negative x-rays.
The ALJ properly relied on the regulatory Preamble as one factor in evaluating Dr. McSharry’s failure to address the additive effects of coal dust and smoking, consistent with American Energy and Extra Energy; the ALJ did not shift the burden of proof to Clinchfield.
Because "legal pneumoconiosis" by definition "arises out of coal mine employment," establishing legal pneumoconiosis satisfied both the first (existence of pneumoconiosis) and second (arising out of coal mine employment) entitlement elements.
The ALJ’s finding that Wallace’s pneumoconiosis was a substantially contributing cause of his total disability is supported by substantial evidence, especially in light of American Energy and Toler v. Eastern Assoc. Coal Co., 43 F.3d 109 (4th Cir. 1995).
Because the BRB affirmed based on legal pneumoconiosis alone and did not rely on the ALJ’s clinical pneumoconiosis finding, the Fourth Circuit did not address Clinchfield’s x‑ray-based arguments; its review is limited to the grounds used by the BRB (Extra Energy).

III. Detailed Analysis

A. Factual and Procedural Background

Johnny Wallace originally filed a black lung claim in 2010. That claim was denied because he failed to prove:

that he had pneumoconiosis,
that he was totally disabled by a pulmonary or respiratory impairment, and
that any pneumoconiosis was caused by his coal mine work.

In July 2019, Wallace filed a subsequent claim. Under 20 C.F.R. § 725.309(c), a subsequent claim can be considered only if the miner proves a "change in an applicable condition of entitlement"—meaning that at least one element of entitlement that was previously decided against the claimant is now proven. Here, Wallace’s later success in establishing total disability satisfied this threshold.

The ALJ made several key factual findings:

Wallace had 13.44 years of qualifying coal mine employment.
His usual coal mine work (roof bolter doing "face work" underground) required medium to heavy exertion and involved substantial coal dust exposure.
He had a smoking history of at least 30 pack‑years and was still smoking about one‑quarter pack per day.

The medical evidence came from four physicians:

Dr. Donovan Mabe (DOL-sponsored exam, Dec. 2019): diagnosed both clinical and legal pneumoconiosis; found total disability from pulmonary/respiratory impairment; attributed disability substantially to coal dust exposure.
Dr. Antoine Habre (claimant’s expert, two exams in Dec. 2021): likewise diagnosed clinical and legal pneumoconiosis; found total disability; and opined that coal dust exposure substantially contributed to the impairment, particularly by worsening emphysema and chronic bronchitis.
Dr. Jeffrey Sargent (employer’s expert, May 2020) and Dr. Roger McSharry (employer’s expert, Oct. 2021): both concluded that Wallace did not have clinical or legal pneumoconiosis, was not totally disabled by any significant pulmonary impairment, and that any impairment was attributable solely to cigarette smoking.

After hearing and weighing this evidence, the ALJ:

Found a valid and qualifying PFT (Dec. 14, 2021) supporting total respiratory disability.
Credited Drs. Habre and, to a lesser extent, Mabe on the existence of legal pneumoconiosis and causation.
Discounted key aspects of Drs. Sargent’s and McSharry’s opinions, particularly their rejection of the qualifying PFT and their failure to adequately consider coal dust as a causal or aggravating factor.
Found that Wallace had both clinical and legal pneumoconiosis and was totally disabled, with pneumoconiosis substantially contributing to that disability.

The BRB affirmed the ALJ’s findings on:

total disability,
legal pneumoconiosis, and
disability causation as to legal pneumoconiosis.

Crucially, the BRB did not reach or rely on the ALJ’s finding of clinical pneumoconiosis. Clinchfield then petitioned the Fourth Circuit for review.

B. Standard of Review and Administrative Law Framework

The court applied the standard articulated in Island Creek Coal Co. v. Blankenship, 123 F.4th 684 (4th Cir. 2024):

It reviews the BRB’s legal conclusions de novo.
It defers to the ALJ’s factual findings if supported by substantial evidence—that is, "more than a mere scintilla" and "such relevant evidence that a reasonable mind might accept as adequate to support a conclusion."

The court also stressed that the ALJ must:

analyze all relevant evidence; and
adequately explain the rationale for crediting or discrediting evidence.

At the same time, consistent with Island Creek, the ALJ’s "duty of explanation is not intended to be a mandate for administrative verbosity." The explanation is adequate if the reviewing court can understand what the ALJ did and why.

This framework is critical: it underscores that appellate courts, especially in BLBA cases, are not fact-finders. Their role is to ensure that the ALJ’s decision is both legally correct and supported by substantial evidence—not to re‑weigh competing medical opinions.

C. Precedents and Authorities Cited

The opinion relies heavily on the following authorities:

Island Creek Coal Co. v. Blankenship, 123 F.4th 684 (4th Cir. 2024)

Provides the standard of review in black lung appeals, emphasizing substantial evidence review of ALJ fact‑finding and the sufficiency of a clear, but not excessively verbose, explanation of reasoning.
Extra Energy, Inc. v. Lawson, 140 F.4th 138 (4th Cir. 2025)

Discusses the BLBA’s purpose ("to provide benefits to coal miners who are totally disabled due to pneumoconiosis"); elaborates on review of causation in the presence of smoking; underscores that appellate courts must not substitute their judgment for the ALJ’s in "battle of the experts" situations; and clarifies the permissible use of the Preamble to the black lung regulations.

Also important for the principle that the Fourth Circuit’s review is limited to the grounds relied upon by the BRB.
American Energy, LLC v. Director, OWCP, 106 F.4th 319 (4th Cir. 2024)

Sets out the four elements a miner must prove by a preponderance of the evidence:
1. Existence of pneumoconiosis (clinical or legal);
2. That the pneumoconiosis arose out of coal mine employment;
3. Total disability due to a pulmonary or respiratory impairment; and
4. Pneumoconiosis is a substantially contributing cause of total disability.
It also explains:
- The distinction between clinical and legal pneumoconiosis;
- The inclusion of COPD (chronic bronchitis, emphysema, asthma) in "legal" pneumoconiosis;
- That once "legal pneumoconiosis" is shown, the "arising out of coal mine employment" element is automatically satisfied; and
- That in some cases, establishing legal pneumoconiosis may effectively satisfy the causation element as well when the same condition causes the disability.
Edwards v. City of Goldsboro, 178 F.3d 231 (4th Cir. 1999)

Interprets Fed. R. App. P. 28(a)(8)(A) and holds that failure to develop an argument with reasons and supporting citations in an opening brief results in abandonment of that claim on appeal.
Toler v. Eastern Assoc. Coal Co., 43 F.3d 109 (4th Cir. 1995)

Holds that once an ALJ has found that a claimant has pneumoconiosis and is totally disabled, the ALJ generally may not credit a doctor’s opinion that pneumoconiosis did not cause the disability if that opinion rests on the premise that the miner does not have pneumoconiosis or is not disabled. To credit such an opinion, the ALJ must find "specific and persuasive reasons" showing the doctor’s causation analysis is independent of those erroneous premises.
Regulatory provisions
- 20 C.F.R. § 725.309(c): Defines what constitutes a "change in an applicable condition of entitlement" for subsequent claims.
- 20 C.F.R. § 718.201(a)(2), (b), (c): Defines "legal pneumoconiosis" as any chronic lung disease or impairment "significantly related to, or substantially aggravated by," coal dust exposure, and recognizes pneumoconiosis as a latent and progressive disease that may first become detectable after coal dust exposure ceases.
- 20 C.F.R. § 718.204(b)(1)–(2), (c)(1): Defines "total disability" and sets out methods of proof (including qualifying PFTs and medical opinions) and when pneumoconiosis is a "substantially contributing cause" of disability.
Preamble to the Regulations Implementing the Federal Coal Mine Health and Safety Act of 1969, 65 Fed. Reg. 79920, 79941 (Dec. 20, 2000)

The Preamble summarizes the medical and scientific evidence underlying the regulations, including:
- That coal dust exposure can cause COPD, even in the absence of radiographic evidence of clinical pneumoconiosis.
- That the effects of coal dust and cigarette smoking on lung function are often additive or synergistic.
Fourth Circuit precedent permits ALJs to consult the Preamble as scientific context when evaluating medical opinions.

D. The Court’s Legal Reasoning

1. Total Disability: Abandonment Through Inadequate Briefing

The ALJ found total disability based on:

A valid, qualifying PFT performed on December 14, 2021 during Dr. Habre’s evaluation; and
Medical opinion evidence (Drs. Mabe and Habre) concluding Wallace could not perform his usual coal mine work or similar employment given his respiratory limitations.

Under 20 C.F.R. § 718.204(b)(2)(i)-(iv), total disability can be established through:

Qualifying PFTs,
Qualifying arterial blood gas studies,
Evidence of cor pulmonale with right‑sided congestive heart failure, or
Reasoned medical opinions.

Both Drs. Sargent and McSharry acknowledged that the Dec. 14, 2021 PFT was numerically "qualifying" but insisted it was invalid due to poor effort and that Wallace’s lung function was "normal or close to normal." The ALJ rejected that characterization and credited Dr. Habre’s view that the PFT was valid.

On appeal, Clinchfield offered only "a single, conclusory statement" that the ALJ’s total disability finding was erroneous, without any supporting argument. Citing Fed. R. App. P. 28(a)(8)(A) and Edwards, the court held that this failure to provide developed argument triggered abandonment:

"Failure to comply with the specific dictates of this rule with respect to a particular claim triggers abandonment of that claim on appeal."

Thus, the total disability finding became effectively unchallenged and binding for purposes of the court’s review. This is significant: employers (and claimants) must fully brief any issue they wish to preserve.

2. Legal vs. Clinical Pneumoconiosis and Mixed Etiology

The court restated the distinction between:

Clinical pneumoconiosis: recognized medical conditions such as coal workers’ pneumoconiosis, usually shown by x‑ray or pathology, involving the deposition of coal dust particles and fibrotic reaction in the lungs.
Legal pneumoconiosis: a broader regulatory category that covers any chronic lung disease or impairment and its sequela "significantly related to, or substantially aggravated by" coal dust exposure. This expressly includes COPD, chronic bronchitis, emphysema, and asthma.

Critically:

Coal dust need not be the exclusive cause of the impairment.
A miner may have a long and substantial smoking history and still establish legal pneumoconiosis if coal dust exposure is a significant contributor or aggravator of the disease.
It can be difficult—even for experts—to precisely differentiate between the effects of smoking and the effects of coal dust, but that difficulty does not defeat a legal pneumoconiosis finding.

The Fourth Circuit emphasized (following Extra Energy) that this area of law has generated repeated litigation, but the court has "never deviated" from its standard of review: the ALJ is the one who resolves the "battle of the experts." The appellate court defers to the ALJ’s weight-of-the-evidence determinations if properly reasoned and supported.

3. Crediting the Claimant’s Expert (Dr. Habre) on Legal Pneumoconiosis

Clinchfield’s principal attack on the legal pneumoconiosis finding was that the ALJ allegedly failed to recognize that Drs. Mabe and Habre used:

an overstated coal mine employment history, and
a minimized smoking history.

The court rejected this characterization. It carefully tracked the ALJ’s handling of each physician:

Dr. Mabe:
- Believed Wallace had 16 years of coal mine work and only 5 pack‑years of smoking, both inaccurate.
- The ALJ recognized this error and gave his opinions reduced weight on that basis.
- Importantly, the ALJ did not rely primarily on Mabe’s opinion to establish legal pneumoconiosis.
Dr. Habre:
- Initially recorded 16 years of coal mine employment and no smoking history in early reports, but was "always aware" of ongoing smoking based on arterial blood gas (ABG) findings.
- Before rendering his final opinions, he was explicitly informed that:
  - the agency had calculated 13 years of qualifying coal mine employment; and
  - Wallace had a smoking history exceeding 30 pack‑years.
- Dr. Habre then adjusted his analysis and expressly acknowledged both:
  - the significant smoking history; and
  - substantial coal dust exposure, including intensive "face" work as a roof bolter with high dust levels.
- He diagnosed emphysema and chronic bronchitis, recognized smoking as a contributor, but concluded that coal dust exposure played a substantial role in the decline of lung function and the disabling impairment.
- He reasoned that coal dust worsened Wallace’s emphysema and aggravated his symptoms, in line with the known synergistic impact of coal dust and smoking.
- He grounded his conclusions in:
  - accurate occupational and smoking histories,
  - chest x‑ray findings,
  - PFT results (including the qualifying 2021 PFT),
  - chronic bronchitis and clinical symptom profile, and
  - accepted medical understanding of combined exposures.

On that basis, the ALJ gave probative and dispositive weight to Dr. Habre’s final, corrected opinion and found that Wallace established legal pneumoconiosis. The Fourth Circuit held that this reasoning was both:

accurately grounded in the record; and
adequately explained.

Thus, the court affirmed the ALJ’s choice to rely on Dr. Habre over Clinchfield’s experts regarding the existence of legal pneumoconiosis.

4. Discounting Employer’s Experts and the Role of the Preamble

Clinchfield argued the ALJ improperly discredited Drs. Sargent and McSharry and shifted the burden of proof to the employer to disprove legal pneumoconiosis.

Procedural abandonment at the BRB stage. The court first noted a procedural bar:

Clinchfield did not directly challenge the ALJ’s reasons for discrediting these experts before the BRB.
The BRB therefore affirmed the ALJ’s credibility findings on that basis.
On appeal, Clinchfield did not contend that it had properly raised this issue to the BRB or that the BRB erred in its approach.
Consequently, any challenge to the ALJ’s weighing of these experts was abandoned.

Substantive review (even if preserved). The court went on to hold that even if the issue were preserved, the ALJ’s treatment of employer’s experts was legally proper:

Drs. Sargent and McSharry:
- Concluded Wallace had no significant pulmonary impairment and no legal pneumoconiosis;
- Based this in part on their belief that there were no valid PFTs or ABGs showing significant lung disease;
- Dismissed the Dec. 14, 2021 PFT as invalid, contrary to the ALJ’s now unchallenged finding that it was both valid and qualifying for total disability purposes;
- Relied, at least partly, on the absence of positive x‑ray evidence; but negative x‑rays cannot rule out legal pneumoconiosis because legal pneumoconiosis does not depend on radiographic findings.

The ALJ’s decision to give limited weight to opinions that:

contradicted the ALJ’s own well-supported finding of a valid, qualifying PFT; and
placed undue weight on x‑rays in the context of legal pneumoconiosis

was fully consistent with substantial-evidence review and prior case law.

Use of the Preamble. Clinchfield further argued that the ALJ improperly relied on the Preamble, particularly in criticizing Dr. McSharry for not addressing whether coal dust played any role in Wallace’s pulmonary impairment.

The Fourth Circuit reaffirmed its holdings in American Energy and Extra Energy:

ALJs are permitted to consult the Preamble when evaluating the credibility of medical opinions on both:
- the existence of pneumoconiosis; and
- the cause of the miner’s disabling impairment.
ALJs may note "tensions" or inconsistencies between a physician’s reasoning and the medical-scientific principles reflected in the Preamble.
However, they may not mechanically discredit an opinion solely because it conflicts with the Preamble without proper explanation.

The court found that the ALJ’s use of the Preamble here was proper:

The ALJ did not discredit Dr. McSharry solely because he failed to consider coal dust or because his conclusions conflicted with the Preamble.
Instead, the ALJ:
- identified several independent reasons for discounting his opinion (rejection of the valid PFT, overreliance on x‑rays, etc.); and
- used the Preamble only as one additional factor to highlight his failure to consider the additive effects of coal dust and smoking.
Consistent with Extra Energy, this context-sensitive use of the Preamble was entirely permissible.

The court also rejected Clinchfield’s argument that the ALJ erred in crediting Habre over its experts based on the time gap between Wallace’s coal mine employment and the first abnormal PFT. Citing 20 C.F.R. § 718.201(c), the court reminded that pneumoconiosis is a latent and progressive disease and may become detectable only after coal dust exposure has ceased. The ALJ was entitled to prefer the experts who accepted this premise over those who did not.

5. Satisfying Multiple Elements Through Legal Pneumoconiosis

The Fourth Circuit underscored a doctrinally important point drawn from American Energy:

Once a miner proves legal pneumoconiosis—i.e., that his chronic lung disease is significantly related to or substantially aggravated by coal dust exposure—he automatically satisfies the requirement that the disease arose out of coal mine employment.

As the court put it:

"A miner who satisfies the first element of his claim by establishing legal pneumoconiosis necessarily satisfies [the] second element [because,] by definition, legal pneumoconiosis arises out of coal mine employment."

Moreover, in some circumstances, such as where COPD itself both constitutes legal pneumoconiosis and is the cause of total disability, establishing legal pneumoconiosis may effectively satisfy the causation element as well.

6. Disability Causation and the Toler Constraint

The final element Wallace had to prove was that pneumoconiosis was a "substantially contributing cause" of his total disability, under 20 C.F.R. § 718.204(c)(1). This is satisfied if pneumoconiosis either:

has a material adverse effect on the miner’s respiratory or pulmonary condition; or
materially worsens a totally disabling respiratory or pulmonary impairment caused by another condition (e.g., smoking).

The ALJ found:

Wallace’s total disability resulted from COPD and emphysema.
Those conditions were made significantly worse by coal dust exposure—i.e., they constituted legal pneumoconiosis.
Dr. Habre’s opinion (and, to a lesser extent, Dr. Mabe’s) credibly linked coal dust exposure to the disabling impairment.

This reasoning "dovetailed" with the earlier legal pneumoconiosis finding. As American Energy notes, in such cases, proof of legal pneumoconiosis may essentially resolve the causation element: the same disease (COPD/emphysema) both qualifies as legal pneumoconiosis and causes the disabling respiratory limitations.

The ALJ then applied Toler:

Drs. Sargent and McSharry opined that pneumoconiosis played no role in Wallace’s disability—but their opinions were premised on the absence of legal pneumoconiosis and, in effect, on the absence of any significant pulmonary impairment.
Having found that Wallace does have legal pneumoconiosis and is totally disabled, the ALJ could credit those causation opinions only if she found "specific and persuasive reasons" showing that their no‑causation views did not rest on those erroneous premises.
The ALJ found no such reasons; instead, the record suggested that their causation analysis was inextricably tied to their rejection of pneumoconiosis itself.

The Fourth Circuit agreed that the ALJ properly applied Toler and that her causation finding was supported by substantial evidence.

7. Limited Scope of Review: Legal vs. Clinical Pneumoconiosis

Clinchfield also attempted to attack the ALJ’s finding that x‑rays showed simple (clinical) pneumoconiosis. However:

The BRB did not rely on that clinical pneumoconiosis finding; it affirmed solely on the basis of legal pneumoconiosis and its contribution to disability.
Under Extra Energy, the Fourth Circuit’s review is limited to the grounds actually relied upon by the BRB.

Therefore, the court declined to reach the clinical pneumoconiosis/x‑ray issue and found no reason to remand. The Board’s decision, grounded in legal pneumoconiosis and causation, was adequately supported by the ALJ’s record-based findings.

E. Impact and Practical Implications

1. For Claimants

This decision reinforces that miners with mixed etiologies (smoking plus coal dust) can still prevail if they show coal dust significantly contributed to or aggravated COPD/emphysema.
Independent medical opinions that:
- use accurate exposure and smoking histories,
- engage all objective testing (including PFTs and ABGs), and
- explicitly address additive effects of coal dust and smoking
will carry significant weight with ALJs and withstand appellate review.
The decision shows that a prior denial is not the end: a miner who later demonstrates total disability can meet the "change in an applicable condition of entitlement" standard for a subsequent claim.

2. For Employers and Insurers

Experts must be prepared to:
- engage with the Preamble’s medical principles (especially coal dust–related COPD and additive effects with smoking); and
- offer a reasoned, scientifically grounded explanation when attributing disease solely to smoking in a miner with substantial coal dust exposure.
Attempts to discredit PFTs as invalid must be robustly supported; if the ALJ finds the test valid and qualifying, opinions premised on "no valid PFT" will be vulnerable to being discounted.
It is crucial to preserve issues:
- Arguments not properly raised before the BRB may be treated as waived in the court of appeals.
- Arguments that are presented in only skeletal form in the Fourth Circuit brief will be deemed abandoned.

3. For ALJs and the BRB

The case validates ALJs’ use of the Preamble as scientific guidance, provided they:
- do not rely on it mechanistically; and
- explain how tensions between a physician’s reasoning and the Preamble bear on credibility.
It confirms that ALJs may:
- discount medical opinions based on inaccurate coal mine and smoking histories; but
- credit opinions where the physician corrects those histories and updates their conclusions accordingly.
ALJs are reminded to:
- give clear, organized explanations of why certain medical opinions are credited or discredited;
- explicitly tie factual findings (e.g., validity of tests, years of exposure, smoking history) to their evaluation of expert opinions.
The BRB’s practice of declining to review arguments that were not adequately raised below is reinforced, as is the principle that appellate review is limited to the grounds on which the BRB relied.

F. Clarifying Key Legal and Medical Concepts

1. Clinical vs. Legal Pneumoconiosis

Clinical pneumoconiosis:
- The traditional medical disease recognized as coal workers’ pneumoconiosis.
- Usually diagnosed via chest x‑ray or pathology showing coal dust particles and fibrotic nodules.
Legal pneumoconiosis:
- A regulatory concept encompassing any chronic lung disease or impairment "significantly related to, or substantially aggravated by" coal dust exposure.
- Includes chronic bronchitis, emphysema, COPD, asthma, etc., when linked to coal dust.
- Does not require x‑ray or pathological proof of classic "coal workers’ pneumoconiosis."

2. Substantial Evidence

"Substantial evidence" is:

More than a "mere scintilla" of evidence; and
That which a reasonable mind might accept as adequate to support a conclusion—even if another decision-maker might weigh the evidence differently.

This standard gives substantial deference to the ALJ’s factual findings, especially in technical, expert-heavy cases like BLBA claims.

3. Abandonment of Issues on Appeal

Under Fed. R. App. P. 28(a)(8)(A), an appellant’s brief must include:
- contentions,
- reasons, and
- citations to authorities and parts of the record.
Failure to develop an argument with reasoning and support—such as offering only a conclusory sentence—results in abandonment of that issue in the appellate court.
Similarly, issues not raised (or insufficiently raised) before the BRB cannot ordinarily be raised for the first time in the court of appeals.

4. Qualifying Pulmonary Function Tests (PFTs)

Under the BLBA regulations, PFT results are compared to regulatory tables that set threshold values (based on age, height, sex) to determine whether the test is "qualifying" for total disability. A test is:

Qualifying if the FEV₁ and other relevant measures meet or fall below the table values, indicating significant impairment.
Valid if it meets technical and procedural quality standards (proper effort, cooperation, reproducibility, etc.).

An ALJ may accept one physician’s assessment of validity over another’s, provided the choice is reasoned and explained.

5. Latent and Progressive Nature of Pneumoconiosis

20 C.F.R. § 718.201(c) recognizes that pneumoconiosis:

may be latent (not clinically evident immediately); and
may be progressive (worsening over time),

such that it may first become detectable only after coal dust exposure has ended. Thus, a significant lapse of time between cessation of coal mine work and observed pulmonary impairment does not, by itself, refute pneumoconiosis.

6. "Substantially Contributing Cause" in BLBA Causation

Pneumoconiosis substantially contributes to disability if it:

has a material adverse effect on the respiratory condition; or
materially worsens an existing totally disabling impairment from other causes (like smoking).

This is a less demanding standard than sole causation or "but-for" causation. Coal dust need not be the only cause, but it must be a real, significant contributing factor.

IV. Conclusion

Clinchfield Coal Co. v. DOWCP (Wallace) does not break new doctrinal ground, but it powerfully illustrates how the Fourth Circuit’s recent BLBA jurisprudence operates in practice. It:

Reinforces that ALJs are the primary arbiters of complex expert evidence in black lung cases, and that their findings will be upheld if supported by substantial evidence and adequately explained.
Confirms the legitimacy of using the regulatory Preamble as scientific context when evaluating medical opinions, particularly on the interplay between coal dust and smoking.
Highlights the importance of accurate exposure and smoking histories in medical opinions, and validates ALJs’ decisions to discount opinions rooted in serious factual errors.
Shows how establishing legal pneumoconiosis (especially COPD/emphysema tied to coal dust) can simultaneously satisfy multiple elements of BLBA entitlement, including origin and causation.
Emphasizes strict enforcement of procedural rules on issue preservation and briefing: undeveloped arguments in the court of appeals and issues not adequately raised before the BRB will be treated as abandoned or waived.

In combination with Island Creek, American Energy, and Extra Energy, this case further consolidates a coherent, claimant-accessible framework for adjudicating black lung claims in the Fourth Circuit, particularly where coal dust exposure and heavy smoking coexist. Although unpublished, it will likely serve as a persuasive example for future litigants and adjudicators navigating similar battles over medical causation and the weight of expert testimony under the Black Lung Benefits Act.