                             PUBLISHED

UNITED STATES COURT OF APPEALS
                 FOR THE FOURTH CIRCUIT


ELM GROVE COAL COMPANY,                  
                     Petitioner,
                  v.
DIRECTOR, OFFICE OF WORKERS’
COMPENSATION PROGRAMS, UNITED                      No. 05-1108
STATES DEPARTMENT OF LABOR;
VELMA BLAKE, Widow of Ivan
Randall Blake,
                      Respondents.
                                         
          On Petition for Review of a Decision and Order
                   of the Benefits Review Board.
                           (04-186-BLA)

                       Argued: February 3, 2006

                       Decided: March 7, 2007

      Before NIEMEYER, MOTZ,1 and KING, Circuit Judges.




Petition for review granted in part; Decision and Order vacated and
remanded by published opinion. Judge King wrote the opinion, in
which Judge Niemeyer joined.

  1
   Judge Motz participated in oral argument in this case, but recused her-
self prior to it being decided. This decision is thus rendered by a quorum
of the panel.
2               ELM GROVE COAL v. DIRECTOR, OWCP
                             COUNSEL

ARGUED: Douglas Allan Smoot, JACKSON & KELLY, P.L.L.C.,
Charleston, West Virginia, for Petitioner. Barry H. Joyner, UNITED
STATES DEPARTMENT OF LABOR, Office of the Solicitor,
Washington, D.C.; Anne Megan Davis, JOHNSON, JONES, SNELL-
ING, GILBERT & DAVIS, P.C., Chicago, Illinois, for Respondents.
ON BRIEF: Kathy L. Snyder, JACKSON & KELLY, P.L.L.C., Mor-
gantown, West Virginia, for Petitioner. Howard M. Radzely, Solicitor
of Labor, Donald S. Shire, Associate Solicitor, Christian P. Barber,
Counsel for Appellate Litigation, Rita A. Roppolo, UNITED
STATES DEPARTMENT OF LABOR, Office of the Solicitor,
Washington, D.C., for Respondent Director, Office of Workers’ Com-
pensation Programs. Thomas E. Johnson, JOHNSON, JONES,
SNELLING, GILBERT & DAVIS, P.C., Chicago, Illinois, for
Respondent Velma Blake, Widow of Ivan Randall Blake.


                              OPINION

KING, Circuit Judge:

   Elm Grove Coal Company petitions for review of the December
2004 Decision and Order of the Benefits Review Board (the "BRB")
affirming the award of benefits made by an Administrative Law Judge
("ALJ") to retired coal miner Ivan R. Blake under the Black Lung
Benefits Act, 30 U.S.C. §§ 901-945 (the "Black Lung Act" or the
"Act").2 Elm Grove raises multiple contentions of error, including, of
most significance: (1) a claim that recently amended regulations limit-
ing the admissible medical evidence in Black Lung Act proceedings
are invalid; (2) alternatively, that the new evidence-limiting rules, if
valid, were nonetheless misapplied by the ALJ in excluding certain
evidence submitted by Elm Grove; and (3) that the ALJ erroneously
barred Elm Grove’s discovery of draft reports and communications
    2
   The Director of the Office of Workers’ Compensation Programs (the
"Respondent Director" or the "Director") and Velma Blake, widow of
Ivan R. Blake (the "Respondent Blake" or simply "Blake") are the two
respondents in this proceeding.
                ELM GROVE COAL v. DIRECTOR, OWCP                       3
between Blake’s lawyers and their expert witnesses. As explained
below, we reject the first of these three contentions, but agree with
Elm Grove on its second and third contentions. We thus grant Elm
Grove’s petition for review in part, vacate the 2004 Decision and
Order of the BRB, and remand for such further proceedings as may
be appropriate.3

                                   I.

                                   A.

                                   1.

   Enacted on December 30, 1969, the Black Lung Act is intended to
provide benefits to coal miners who have been totally disabled by
pneumoconiosis, as well as to the surviving dependents of miners
whose deaths were due to such disease. See 30 U.S.C. § 901.4 Under
Part B of the Act, see id. §§ 921-925, claims filed on or before
December 31, 1973, are to be adjudicated by the Secretary of Health
and Human Services and paid by the United States. Pursuant to Part
C of the Act, see id. §§ 930-944, claims filed after December 31,
1973, are to be adjudicated by the Secretary of Labor (the "Secre-
tary") and, in the absence of an approved state workers’ compensation
law, paid by the responsible mine operator.

  The Black Lung Act incorporates various other statutory provisions
— including provisions pertaining to administrative rule-making and
adjudication of claims — by both internal cross-reference and refer-
  3
     Elm Grove also contends that the ALJ’s findings of pneumoconiosis
and of totally disabling pulmonary or respiratory impairment due to
pneumoconiosis are irrational, not supported by substantial evidence, and
contrary to law. We need not reach these contentions because we vacate
the Decision and Order of the BRB on other grounds and remand for fur-
ther proceedings.
   4
     It is recognized that "[c]oal workers’ pneumoconiosis — black lung
disease — affects a high percentage of American coal miners with
severe, and frequently crippling, chronic respiratory impairment." Usery
v. Turner Elkhorn Mining Co., 428 U.S. 1, 6 (1976). "The disease is
caused by long-term inhalation of coal dust." Id.
4               ELM GROVE COAL v. DIRECTOR, OWCP
ence to other statutes. For instance, its Part C incorporates, "to the
extent appropriate," the provisions of Part B. 30 U.S.C. § 940. Part B,
in turn, incorporates a number of provisions from Title II of the Social
Security Act. Id. § 923(b). One such incorporated provision from the
Social Security Act is 42 U.S.C. § 405(a), which endows the Com-
missioner of Social Security with the "full power and authority to
make rules and regulations and to establish procedures, not inconsis-
tent with the provisions of this subchapter, which are necessary or
appropriate to carry out such provisions," and to "adopt reasonable
and proper rules and regulations to regulate and provide for the nature
and extent of the proofs and evidence and the method of taking and
furnishing the same in order to establish the right to benefits hereun-
der."

  Significantly, Part B of the Black Lung Act mandates that, "[i]n
determining the validity of claims under this part, all relevant evi-
dence shall be considered." 30 U.S.C. § 923(b) (emphasis added) (the
"All Relevant Evidence Provision" or the "Provision"). The All Rele-
vant Evidence Provision was added to the Act in 1972, in the context
of prohibiting the denial of benefits based only on the results of a
chest roentgenogram. See id. In fuller part, the Provision reads as fol-
lows:

    No claim for benefits under this part shall be denied solely
    on the basis of the results of a chest roentgenogram. In
    determining the validity of claims under this part, all rele-
    vant evidence shall be considered, including, where relevant,
    medical tests such as blood gas studies, X-ray examination,
    electrocardiogram, pulmonary function studies, or physical
    performance tests, and any medical history, evidence sub-
    mitted by the claimant’s physician, or his wife’s affidavits,
    and in the case of a deceased miner, other appropriate affi-
    davits of persons with knowledge of the miner’s physical
    condition, and other supportive materials.

Id. (emphasis added).

   Finally, Part C of the Black Lung Act incorporates certain provi-
sions of the Longshore and Harbor Workers’ Compensation Act,
including 33 U.S.C. § 919(d), which in turn incorporates provisions
                  ELM GROVE COAL v. DIRECTOR, OWCP                         5
of the Administrative Procedure Act (the "APA"), by reference to 5
U.S.C. § 554. See 30 U.S.C. § 932(a). The APA provides, as relevant
here, that "[a]ny oral or documentary evidence may be received, but
the agency as a matter of policy shall provide for the exclusion of
irrelevant, immaterial, or unduly repetitious evidence." 5 U.S.C.
§ 556(d) (the "Irrelevant Evidence Exclusion").

                                     2.

   On December 20, 2000, after several years of consideration, the
Secretary issued sweeping revisions to the rules governing the adjudi-
cation of miners’ claims under Part C of the Black Lung Act, effec-
tive January 19, 2001.5 See Regulations Implementing the Federal
Coal Mine Health and Safety Act of 1969, as Amended, 65 Fed. Reg.
79,920 (Dec. 20, 2000) (to be codified at 20 C.F.R. pts. 718, 722,
725-727) (the "Amended Regulations"). The Amended Regulations
include limitations on the amount of medical evidence that each party
may submit (the "Evidence-Limiting Rules"). The Secretary proposed
the Evidence-Limiting Rules "in order to ensure that eligibility deter-
minations are based on the best quality evidence submitted rather than
on the quantity of evidence submitted by each side." Regulations
Implementing the Federal Coal Mine Health and Safety Act of 1969,
as Amended, 62 Fed. Reg. 3338, 3338 (proposed Jan. 22, 1997) (to
be codified at 20 C.F.R. pts. 718, 722, 725-727). In explaining, the
Secretary observed that,

      [c]urrently, in establishing their eligibility to benefits, claim-
      ants must confront the vastly superior economic resources of
  5
    Under the Act, a miner or his survivor seeking benefits under Part C
of the Act must first file a claim with the District Director in the Depart-
ment of Labor’s Office of Workers’ Compensation Programs. The Dis-
trict Director then determines, in relevant part, whether the claimant is
entitled to benefits and which mine operator is responsible for paying
them. If a party is dissatisfied with the District Director’s determination,
that party may appeal by requesting a formal hearing before an ALJ. The
ALJ’s ruling may subsequently be appealed to the BRB, and the BRB’s
decision may be appealed to the court of appeals in the appropriate cir-
cuit. See National Mining Ass’n v. Dept. of Labor, 292 F.3d 849, 854
(D.C. Cir. 2002).
6                  ELM GROVE COAL v. DIRECTOR, OWCP
        their adversaries: coal mine operators and their insurance
        carriers. Often, these parties generate medical evidence in
        such volume that it overwhelms the evidence supporting
        entitlement that claimants can procure. The proposed
        changes limiting evidentiary development attempt to make
        more equitable the adjudication of black lung claims and
        reduce the costs associated with these cases.

Id.; see also Regulations Implementing the Federal Coal Mine Health
and Safety Act of 1969, as Amended, 65 Fed. Reg. at 79,989-95
(describing development of Evidence-Limiting Rules and reasons for
them).

   The Evidence-Limiting Rules, as promulgated, are found in the
Code of Federal Regulations, in various subparts of 20 C.F.R. § 725.
Pursuant thereto, a claimant and the responsible operator are each
entitled to submit, in support of their respective affirmative cases, "no
more than two chest X-ray interpretations, the results of no more than
two pulmonary function tests, the results of no more than two arterial
blood gas studies, no more than one report of an autopsy, no more
than one report of each biopsy, and no more than two medical
reports." 20 C.F.R. § 725.414(a)(2)(i), (3)(i).6 They further provide
that "[a]ny chest X-ray interpretations, pulmonary function test
results, blood gas studies, autopsy report, biopsy report, and physi-
cians’ opinions that appear in a medical report must each be admissi-
ble under" either paragraph (a)(2)(i), paragraph (a)(3)(i), or paragraph
(a)(4) (allowing "any record of a miner’s hospitalization for a respira-
tory or pulmonary or related disease, or medical treatment for a respi-
ratory or pulmonary or related disease, [to] be received into
evidence"). § 725.414(a)(2)(i), (3)(i).
    6
    The Evidence-Limiting Rules define a "medical report" as "a physi-
cian’s written assessment of the miner’s respiratory or pulmonary condi-
tion." 20 C.F.R. § 725.414(a)(1). Such a "report may be prepared by a
physician who examined the miner and/or reviewed the available admis-
sible evidence." Id. The Evidence-Limiting Rules exclude from the
"medical report" definition "[a] physician’s written assessment of a sin-
gle objective test, such as a chest X-ray or a pulmonary function test."
Id.
                 ELM GROVE COAL v. DIRECTOR, OWCP                       7
   To rebut evidence submitted in support of an opposing party’s
affirmative case, the claimant and the responsible operator each may
submit, inter alia, "no more than one physician’s interpretation of
each chest X-ray, pulmonary function test, arterial blood gas study,
autopsy or biopsy" submitted by the opposing party.
§ 725.414(a)(2)(ii), (3)(ii).7 Finally, in response to rebuttal evidence
with respect to medical testing, the Evidence-Limiting Rules autho-
rize a party to "submit an additional statement from the physician who
originally interpreted the chest X-ray or administered the objective
testing." Id. And, in the event that "rebuttal evidence tends to under-
mine the conclusion of a physician who prepared a medical report,"
a party may "submit an additional statement from the physician who
prepared the medical report explaining his conclusion in light of the
rebuttal evidence." Id.

   The limitations on the introduction of medical evidence imposed
by the Evidence-Limiting Rules also apply to the testimony of physi-
cians, either in person or by deposition. See 20 C.F.R. § 725.457(d)
(providing that "[a] physician whose testimony is permitted under this
section may testify as to any other medical evidence of record, but
shall not be permitted to testify as to any medical evidence relevant
to the miner’s condition that is not admissible"); 20 C.F.R. § 725.458
(requiring that "[t]he testimony of any physician which is taken by
deposition shall be subject to the limitations on the scope of the testi-
mony contained in § 725.457(d)").

   Significantly, the Evidence-Limiting Rules also spell out that medi-
cal evidence in excess of the limitations contained therein may be
admitted into the hearing record in a Black Lung Act proceedings for
  7
    The Evidence-Limiting Rules further allow each party to submit addi-
tional evidence to rebut the results of any other testing submitted by the
opposing party under 20 C.F.R. § 718.107 (authorizing party to submit
"[t]he results of any medically acceptable test or procedure reported by
a physician and not addressed in this subpart, which tends to demonstrate
the presence or absence of pneumoconiosis, the sequelae of pneumoconi-
osis or a respiratory or pulmonary impairment"). Where the results of
such other testing have been submitted, the opposing party may "submit
one physician’s assessment of each piece of such evidence in rebuttal."
20 C.F.R. § 725.414(a)(2)(ii), (3)(ii).
8                ELM GROVE COAL v. DIRECTOR, OWCP
"good cause." See 20 C.F.R. § 725.456(b)(1) ("Medical evidence in
excess of the limitations contained in § 725.414 shall not be admitted
into the hearing record in the absence of good cause.").

                                    3.

   By its June 2002 decision in National Mining Ass’n v. Department
of Labor, the District of Columbia Circuit (the first and only other cir-
cuit to consider the validity of the Evidence-Limiting Rules), upheld
the Evidence-Limiting Rules against a challenge brought by mine
operators, insurance companies, and the National Mining Association
(collectively, "National Mining"). See 292 F.3d 849, 873-74 (D.C.
Cir. 2002).8 National Mining contended that the Evidence-Limiting
Rules ran afoul of the APA’s authorization for "each party to submit
whatever evidence that party thinks is needed to prove its case or
defense." Id. at 873 (internal quotation marks omitted). The D.C. Cir-
cuit disagreed, however, concluding that National Mining’s theory
that the APA "permits introduction of unlimited amounts of evidence
is flatly contradicted by the statute itself, which," under the Irrelevant
Evidence Exclusion, "empowers agencies to ‘exclu[de] . . . irrelevant,
immaterial, or unduly repetitious evidence’ as ‘a matter of policy.’"
Id. at 873-74 (quoting 5 U.S.C. § 556(d)) (alteration in original). The
court of appeals further observed that the Black Lung Act "authorizes
the Secretary to issue regulations ‘provid[ing] for the nature and
extent of the proofs and evidence and the method of taking and fur-
nishing the same in order to establish the rights to benefits.’" Id. at
874 (citing 30 U.S.C. § 923(b) (incorporating 42 U.S.C. § 405(a)))
(alteration in original).

   In upholding the Evidence-Limiting Rules, the D.C. Circuit
rejected National Mining’s assertion that the rules established "inflex-
ible limits." National Mining, 292 F.3d at 874. The court recognized
and emphasized that, "[o]n the contrary, the rules give ALJs discre-
tion to hear additional evidence for ‘good cause.’" Id. (citing 20
C.F.R. § 725.456(b)(1)). Furthermore, the court of appeals discredited
National Mining’s contention that the Evidence-Limiting Rules are
    8
   The National Mining appellants also challenged (with some success)
various other aspects of the Amended Regulations that are not at issue
in this proceeding. See 292 F.3d at 867-75.
                 ELM GROVE COAL v. DIRECTOR, OWCP                          9
"arbitrary and capricious because they are unsupported by medical
evidence." Id. The court cited record evidence indicating that the new
evidentiary limits, rather than being "artificial," were devised to "en-
able ALJs to focus their attention on the quality of the medical evi-
dence in the record before them." Id. (internal quotation marks and
alteration omitted). The court also observed that the record reflected
"the need for evidence limitations," because, "in their absence, law-
yers often waste ALJs’ time and resources with excessive evidence."
Id. (noting example where "mine operator’s lawyer submitted eighty-
nine separate X-ray re-readings from fourteen different experts").
Finally, the D.C. Circuit emphasized National Mining’s concession at
oral argument "that ALJs have always had discretion to exclude evi-
dence in precisely the manner outlined by the new evidence-limiting
rules." Id. The court of appeals thus reasoned that "it would be strange
indeed to conclude that the Secretary acted arbitrarily and capri-
ciously by codifying evidentiary limits that ALJs have always had the
discretion to impose." Id.

                                     B.

   Ivan Blake filed the application for benefits at issue in this pro-
ceeding on April 4, 2001 (following the January 19, 2001 effective
date of the Evidence-Limiting Rules).9 On March 6, 2002, the District
Director awarded benefits to Blake. At Elm Grove’s request, the mat-
ter was subsequently forwarded to an ALJ (the "first ALJ") for a for-
mal hearing.

   By Order of November 26, 2002, the first ALJ addressed several
pre-hearing issues raised by the parties. See J.A. 657-60.10 First, he
denied a motion by Elm Grove to compel Blake to produce draft
reports and communications sent by his counsel to their physician-
experts. In so ruling, the first ALJ concluded that the communications
sought by Elm Grove were "protected by the work product doctrine,
and thus, not discoverable." Id. at 659. Next, he ruled, noting Elm
   9
     Blake’s April 4, 2001 application for benefits was his second such
application. He had filed his first application in 1986, which the Director
denied.
   10
      Our citations to "J.A. ___" refer to the contents of the Joint Appendix
filed by the parties in this appeal.
10              ELM GROVE COAL v. DIRECTOR, OWCP
Grove’s objection to the validity of the Evidence-Limiting Rules, that
he was constrained under the D.C. Circuit’s National Mining decision
to apply those Rules. Finally, the first ALJ denied a motion by Blake
to exclude evidence submitted by Elm Grove in excess of that permit-
ted under the Evidence-Limiting Rules, but informed the parties that
he would entertain a renewal of the motion at the hearing on Blake’s
claim.

   On June 4, 2003, the hearing on Blake’s claim was held in Whee-
ling, West Virginia, before a different ALJ (the "second ALJ") than
the one who had handled the pre-hearing motions (the "ALJ hear-
ing"). See J.A. 720-802. At the outset of the ALJ hearing, the second
ALJ observed that "this case is under the new regulations [including
the Evidence-Limiting Rules] as it was filed after January 19, 2001,"
and that, "therefore, the evidentiary limitations which are in effect in
those new regulations apply, except for showing of good cause." Id.
at 724. Consistent with his reading of 20 C.F.R. § 725.414(a)(3)(ii),
the second ALJ limited Elm Grove to introducing one physician’s
interpretation of an X-ray to rebut two interpretations of that same X-
ray being submitted by Blake in his affirmative case. In so ruling, the
second ALJ rejected Elm Grove’s contention that it should be allowed
to rebut Blake’s two interpretations of the X-ray with two interpreta-
tions of its own.

   During the ALJ hearing, Elm Grove noted its intention to contest
the validity of the Evidence-Limiting Rules, and reiterated its position
that it was entitled to documents provided to Blake’s experts by his
counsel. The second ALJ responded that he was inclined "to abide by
the prior ruling in the case," excluding discovery of the attorney-
expert communications under the work product doctrine. J.A. 751.
Elm Grove then discussed the evidence that it wished to submit in
excess of the restrictions set forth in the Evidence-Limiting Rules.
When the second ALJ asked for Elm Grove’s "good cause argument,"
Elm Grove replied that "[o]ur good cause argument in this case would
be that under the Fourth Circuit’s Decision in the Underwood case,
they have deemed that all relevant evidence should be considered and,
therefore, the Underwood case in this position would triumph over the
regulation. Our contention is essentially the regulation is invalid." Id.
at 765; see Underwood v. Elkay Mining, Inc., 105 F.3d 946 (4th Cir.
1997) (examining interplay between Irrelevant Evidence Exclusion
                ELM GROVE COAL v. DIRECTOR, OWCP                      11
and All Relevant Evidence Provision and concluding that ALJ had not
erred in admitting cumulative evidence). The second ALJ rejected
Elm Grove’s contention, observing that Underwood "was decided
under the old regulations." J.A. 765. He further rejected Elm Grove’s
assertion that the D.C. Circuit’s decision in National Mining was not
binding precedent, explaining that "it’s binding unless there’s prece-
dent to the contrary in the Fourth Circuit. And there isn’t." Id. at 766.

   On October 16, 2003, the second ALJ issued his Decision and
Order awarding benefits to Blake (the "ALJ Decision"). See J.A. 803-
20. In relevant part, the second ALJ concluded that his previous rul-
ings on evidentiary issues "shall stand." Id. at 805 n.4. Elm Grove
appealed the ALJ Decision to the BRB, which affirmed the award of
benefits to Blake by its Decision and Order of December 28, 2004
(the "BRB Decision"). See J.A. 821-38.11 In relevant part, the BRB
Decision rejected Elm Grove’s challenge to the validity of the
Evidence-Limiting Rules, including its contentions that the Rules
were in conflict with the All Relevant Evidence Provision and our
decision in Underwood. The BRB concluded that the Secretary had
properly promulgated the Evidence-Limiting Rules pursuant to the
Black Lung Act’s authorization to regulate "the nature and extent of
proofs and evidence and the method of taking and furnishing the same
in order to establish the right to benefits," 30 U.S.C. § 923(b) (incor-
porating 42 U.S.C. § 405(a)), and the APA’s empowerment of agen-
cies to "provide for the exclusion of irrelevant, immaterial, or unduly
repetitious evidence" as "a matter of policy," 5 U.S.C. § 556(d).

   The BRB Decision affirmed the exclusion of evidence submitted
by Elm Grove in excess of that permitted under the Evidence-
Limiting Rules without a showing of "good cause." J.A. 825. With
respect to Elm Grove’s X-ray interpretation rebuttal evidence, the
BRB Decision upheld the second ALJ’s ruling limiting Elm Grove to
one interpretation to rebut the two interpretations submitted by Blake.
Id. Finally, the BRB Decision rejected Elm Grove’s assertion that it
was entitled to copies of draft reports and communications from
  11
   In rendering the BRB Decision of December 28, 2004, one of three
members of the Board dissented on one merits issue, which he would
have remanded for further consideration. See J.A. 838. That issue is not
implicated in this proceeding.
12              ELM GROVE COAL v. DIRECTOR, OWCP
Blake’s lawyers to their experts; in so doing, the BRB determined that
the ALJs did not abuse their discretion in applying the work product
doctrine. Id. at 826-27.

  Elm Grove has timely filed its petition for review in this Court, and
we possess jurisdiction pursuant to 33 U.S.C. § 921(c).

                                  II.

   Elm Grove presents three primary contentions in this appeal.12 First
and foremost, it challenges the validity of the Evidence-Limiting
Rules (the "Evidence-Limiting Rules issue"). That is, Elm Grove con-
tends that the Evidence-Limiting Rules conflict with controlling pre-
cedent and provisions of the Black Lung Act, and that they arbitrarily
and capriciously limit the evidence that each party can submit in pro-
ceedings under the Act. We review the Evidence-Limiting Rules issue
de novo, pursuant to the two-step process enunciated by the Supreme
Court in Chevron, U.S.A., Inc. v. Natural Resources Defense Council,
467 U.S. 837, 842-43 (1984). In so doing, we first examine Elm
Grove’s contention that our 1997 decision in Underwood v. Elkay
Mining, Inc., 105 F.3d 946 (4th Cir. 1997) constitutes controlling pre-
cedent. We then turn to our Chevron analysis, assessing whether Con-
gress has spoken directly and conclusively on the Evidence-Limiting
Rules issue. Id. at 842. Because no such congressional intent is identi-
fied, we must assess whether the Evidence-Limiting Rules, as pro-
mulgated by the Secretary, are based on a permissible construction of
the Black Lung Act. Id. at 843.

   Although the Evidence-Limiting Rules issue presents a close ques-
tion, we nevertheless must reject Elm Grove’s contention that the
Rules are invalid. Accordingly, we examine two other contentions
made by Elm Grove in its petition: (1) that the second ALJ improp-
  12
     Other than Elm Grove’s primary contentions, as spelled out above,
certain additional assertions are addressed and disposed of in our foot-
notes. See notes 3, 14, & 18. Two final contentions, that the ALJ erred
in finding that Blake had shown good cause to submit late evidence, and
that the ALJ failed to consider certain X-ray classifications by two of
Elm Grove’s experts, have also been carefully considered, do not merit
further discussion, and are rejected.
                 ELM GROVE COAL v. DIRECTOR, OWCP                       13
erly excluded certain rebuttal evidence from the ALJ hearing ("the
Rebuttal Evidence issue"); and (2) that the ALJs and the BRB erred
in failing to compel discovery of certain draft reports and attorney-
expert communications between Blake’s lawyers and their experts
(the "Work Product issue"). As to the Rebuttal Evidence issue, we
review de novo any legal issue on the proper standard to be applied
for the "admission of evidence in hearings before the ALJ under the
Black Lung Benefits Act," and we review for abuse of discretion any
"question about the proper application of that standard." Underwood,
105 F.3d at 948-49. On the Work Product issue, we review de novo
the legal conclusions made by the ALJs and the BRB, and we assess
for abuse of discretion their application of that standard. See Consol.
Coal. Co. v. Williams, 453 F.3d 609, 614 (4th Cir. 2006); Underwood,
105 F.3d at 948-49.

                                   III.

   Elm Grove’s contention on the Evidence-Limiting Rules issue war-
rants our analysis of two separate but related assertions.13 First, Elm
Grove maintains that our 1997 decision in Underwood v. Elkay Min-
ing, Inc., 105 F.3d 946 (4th Cir. 1997) is "still the law in the Fourth
Circuit" and that the Evidence-Limiting Rules impermissibly conflict
with that decision’s interpretation of the All Relevant Evidence Provi-
sion. Petr.’s Br. 21-22. Second, Elm Grove contends that the
Evidence-Limiting Rules "fail both prongs of the Chevron test,"
asserting that the Rules are inconsistent with the plain language of the
Provision and are not premised on any reasonable construction of the
Act. Id. at 19.14
  13
      On the Evidence-Limiting Rules issue, Blake adopts the position of
the Director.
   14
      In its opening brief, Elm Grove summarily asserts that the Evidence-
Limiting Rules violate its "procedural and substantive due process rights
by denying the parties a full and fair hearing." Petr.’s Br. 15. Elm Grove
does not explain the basis for this contention, does not reference any rel-
evant case law or portions of the record, and does not otherwise explain
its contention. Accordingly, we deem this contention abandoned. See
Fed. R. App. P. 28(a)(9)(A) (noting that appellant’s brief must contain
"appellant’s contentions and the reasons for them, with citations to the
authorities and parts of the record on which the appellant relies"); see
14               ELM GROVE COAL v. DIRECTOR, OWCP
   The Respondent Director, on the other hand, contends that the
Evidence-Limiting Rules are entitled to Chevron deference, that they
are based on a permissible and reasonable construction of the Black
Lung Act, and that they were adopted pursuant to the Secretary’s "ex-
press statutory authority to adopt rules regulating the extent of the
proofs and evidence." Fed. Resp’t’s Br. 5.15 The Director further
asserts that Underwood is not controlling precedent in this proceed-
ing, maintaining that it addressed a different issue than that presented
here, and that it was rendered well before the Secretary’s promulga-
tion of the Evidence-Limiting Rules. Accordingly, the Director urges
us to uphold the validity of the Evidence-Limiting Rules, as did the
D.C. Circuit in 2002 with its National Mining decision.

                                   A.

   We begin our analysis with Elm Grove’s contention that the
Evidence-Limiting Rules conflict with Underwood. There, we were
called upon to consider the interplay between the Act’s All Relevant
Evidence Provision and the APA’s Irrelevant Evidence Exclusion.
Retired coal miner Elmer Underwood contended that an ALJ had
committed reversible error in denying him black lung benefits, by
admitting cumulative evidence offered against his claim by his former
employer, Elkay Mining. Underwood, 105 F.3d at 948. In support of

also Edwards v. City of Goldsboro, 178 F.3d 231, 241 (4th Cir. 1999)
(concluding that failure to comply with specific dictates of Rule
28(a)(9)(A) with respect to particular claim triggers abandonment of that
claim on appeal).
   15
      The Director also maintains in this proceeding that the All Relevant
Evidence Provision is not binding on claims filed after 1973. See Fed.
Resp’t’s Br. 11. He asserts that this Provision was included in the 1972
amendments to Part B of the Act (pertaining to claims filed with Social
Security Administration before December 31, 1973), and that Part C of
the Act (pertaining to claims filed with Department of Labor after
December 31, 1973) incorporates the 1972 amendments only "to the
extent appropriate." 30 U.S.C. § 940. We need not reach the merits of the
Director’s contention in this respect. Because the Evidence-Limiting
Rules are valid and not inconsistent with the Provision, we accept the
point that the Provision was incorporated into Part C of the Act for the
purposes of this proceeding.
                ELM GROVE COAL v. DIRECTOR, OWCP                      15
the ALJ’s ruling, Elkay Mining maintained "that ALJ’s are required
to admit all evidence, subject to objection, giving it weight where
appropriate." Id. at 949. In support of this proposition, Elkay Mining
relied on the Provision, as well as the BRB’s earlier ruling in Cochran
v. Consolidation Coal Co., 12 BLR (CCH) 1-136, 1-138 (Ben. Rev.
Bd. 1989). In Cochran, the BRB concluded that ALJs are "required,
subject to the objection by any party, to admit into the record all evi-
dence that has been timely developed and exchanged in accordance
with" applicable procedures. Id. at 1-138. Underwood countered that
the Irrelevant Evidence Exclusion "nevertheless requires the exclu-
sion of irrelevant, immaterial, or unduly repetitious evidence." Under-
wood, 105 F.3d at 949 (internal quotation marks omitted). In
resolving this dispute, Judge Niemeyer explained that the parties’
contentions "appear[ed], at first blush, to be in conflict," but that "a
closer look demonstrate[d] that they [were] not entirely inconsistent."
Id.

   We began our analysis in Underwood "with the statutory com-
mand" of the All Relevant Evidence Provision, coupled "with the rec-
ognition that black lung benefits proceedings are nonjury trials
conducted before ALJs who are charged with both conducting the
hearing and making findings of fact." 105 F.3d at 949. In so recogniz-
ing, we observed that,

    [i]n ruling on evidence, an ALJ sees both excludable and
    nonexcludable evidence, but in making a decision, he con-
    siders only admitted evidence. Because the ALJ is presum-
    ably competent to disregard that evidence which should be
    excluded or to discount that evidence which has lesser pro-
    bative value, it makes little sense, as a practical matter, for
    a judge in that position to apply strict exclusionary evidenti-
    ary rules.

Id. Substantiating the conclusion that strict exclusionary rules would
make little sense in Black Lung Act proceedings, we invoked our
decision in Multi-Medical Convalescent & Nursing Center of Towson
v. NLRB, 550 F.2d 974 (4th Cir. 1977), where we had discussed the
long-settled principle that an appellate court will rarely reverse a
judgment in a nonjury case because of the admission of incompetent
evidence. See Underwood, 105 F.3d at 949-50 (citing Multi-Med., 550
16               ELM GROVE COAL v. DIRECTOR, OWCP
F.2d at 977). And we repeated the advice given to administrative
agencies in Multi-Medical: "‘if in doubt, let it in.’" Id. at 950 (quoting
Multi-Med., 550 F.2d at 978). Indeed, we observed that the BRB had
applied our Multi-Medical decision in Cochran to "reach[ ] what
might appear to be an almost absolute rule that the ALJ is required
to admit all evidence that is timely developed and exchanged."
Underwood, 105 F.3d at 950. As we observed, although the BRB had
recognized in Cochran "the statutory limitations of relevancy," it had
also instructed "that where relevance is ‘questionable,’ the trier of fact
would be better advised to admit the evidence." Id. (citing Cochran,
12 BLR (CCH) at 1-138).

  Against this backdrop, we then examined the Irrelevant Evidence
Exclusion, observing that the exclusion of "irrelevant," "immaterial,"
and "unduly repetitious" evidence need not conflict with the All Rele-
vant Evidence Provision and the BRB’s Cochran decision. Under-
wood, 105 F.3d at 950. Focusing on unduly repetitious evidence, we
explained that such evidence "has little or no probative value and does
not fall within the statutory mandate to consider all ‘relevant’ evi-
dence." Id. We concluded that the Irrelevant Evidence Exclusion

     grants ALJ’s broad discretion to exclude excessive evidence
     which lacks significant probative value and, by implication,
     to limit examinations, evaluations, and consultations by
     experts when such events will, in the ALJ’s judgment,
     merely give rise to evidence so unduly repetitious as to be
     lacking in probative value.

Id. Underwood specifically warned, however, that we did "not mean
to authorize the ALJ to exclude merely repetitious or cumulative evi-
dence so long as such evidence retains nontrivial probative value." Id.
Rather, we carefully explained that, if evidence is to be excluded:

     [The ALJ] must conclude that the evidence serves little use-
     ful value other than to expand the record, impose additional
     cost, or repeat that which is already well established in the
     record. Two independent and qualified expert opinions that
     agree on a disputed point may be substantively more proba-
     tive than one. And while four similar opinions also may be
     more probative than two, it does not follow that four are
                  ELM GROVE COAL v. DIRECTOR, OWCP                     17
       twice as probative as two. There is a point of diminishing
       returns and a point at which additional evidence provides
       almost no value. Such determinations are matters for consid-
       eration by the ALJ based on the extent and nature of the dis-
       pute on the issue, the closeness of the question, and the
       nature of the opinions and qualifications of the experts giv-
       ing them.

Id. Finally, we admonished ALJs adjudicating Black Lung Act claims
to "recognize that they must consider all relevant evidence, erring on
the side of inclusion, but [to] exclude evidence that becomes unduly
repetitious in the sense that the evidence provides little or no addi-
tional probative value." Id. at 951.16

   In its petition for review, Elm Grove contends that Underwood is
controlling in this proceeding, and that it is inconsistent with the
Evidence-Limiting Rules. To the contrary, although Underwood’s
reasoning is persuasive, it is not directly on point and does not consti-
tute precedent on the Evidence-Limiting Rules issue. Underwood was
decided in 1997, well before the Secretary, in 2001, promulgated the
Evidence-Limiting Rules. Accordingly, the Underwood panel had no
reason to consider whether regulations limiting the amount of evi-
dence admissible in black lung proceedings might conflict with the
Black Lung Act. Instead, Underwood only assessed the interplay
between the All Relevant Evidence Provision and the Irrelevant Evi-
dence Exclusion — in the absence of the Evidence-Limiting Rules —
and decided that the ALJ had not erred in failing to exclude certain
evidence.

   As Elm Grove emphasizes, Underwood characterized the All Rele-
vant Evidence Provision as a "statutory command" and treated it as
requiring the admission of all proffered relevant evidence. Under-
wood, 105 F.3d at 949. We did so, however, without the benefit of
the Secretary’s Evidence-Limiting Rules. As Chevron and its prodigy
  16
     In Underwood, we concluded that the ALJ did not abuse his discre-
tion in admitting the cumulative evidence submitted by Elkay Mining.
See Underwood, 105 F.3d at 951 ("The fact that the evidence was cumu-
lative does not render it, ipso facto, ‘unduly repetitious’ as the term is
used in the Administrative Procedure Act . . . .").
18               ELM GROVE COAL v. DIRECTOR, OWCP
mandate, we cannot impose our own statutory construction, "as would
be necessary in the absence of an administrative interpretation," in
evaluating the views of the administrative agency entrusted with a
statutory scheme. Chevron, 467 U.S. at 843. Instead, we must accord
the Evidence-Limiting Rules the deference owed to an "executive
department’s construction of a statutory scheme it is entrusted to
administer." Id. at 844.

   The Supreme Court’s recent decision in National Cable & Televi-
sion Ass’n v. Brand X Internet Services, 545 U.S. 967 (2005),
explained the proper interplay between a prior judicial decision and
an agency construction of the same statutory provision. In Brand X,
the Court concluded that a "court’s prior judicial construction of a
statute trumps an agency construction otherwise entitled to Chevron
deference only if the prior court decision holds that its construction
follows the unambiguous terms of the statute and thus leaves no room
for agency discretion." Id. at 982. Observing that this "principle fol-
lows from Chevron itself," the Court determined that "[o]nly a judi-
cial precedent holding that the statute unambiguously forecloses the
agency’s interpretation, and therefore contains no gap for the agency
to fill, displaces a conflicting agency construction." Id. at 982-83.
Unfortunately for Elm Grove, Underwood did not hold that the All
Relevant Evidence Provision unambiguously forecloses an agency
interpretation and leaves no room for agency discretion. Accordingly,
to the extent that Underwood may conflict with the Evidence-
Limiting Rules, it does not trump those Rules, which constitute the
Secretary’s interpretation of the All Relevant Evidence Provision. As
a result, we are obliged to accord proper deference to the Secretary,
as "Chevron requires a federal court to accept the agency’s construc-
tion of the statute, even if the agency’s reading differs from what the
court believes is the best statutory interpretation." Id. at 980 (citations
omitted).

                                    B.

                                    1.

   We turn next to an assessment of Elm Grove’s contention that the
Evidence-Limiting Rules are invalid because they impermissibly con-
flict with the All Relevant Evidence Provision of the Black Lung Act
                ELM GROVE COAL v. DIRECTOR, OWCP                      19
and, in so doing, apply the framework established by the Supreme
Court in Chevron. See Chevron, 467 U.S. at 842-43. In applying
Chevron, we first ask "whether Congress has directly spoken to the
precise question at issue." Id. at 842. Our Chevron analysis would end
at that point if the intent of Congress is clear, "for the court, as well
as the agency, must give effect to the unambiguously expressed intent
of Congress." Id. at 842-43. If, however, "Congress has not directly
addressed the precise question at issue," we may not substitute our
own construction of the statute. Id. at 843. "Rather, if the statute is
silent or ambiguous with respect to the specific issue, the question for
the court is whether the agency’s answer is based on a permissible
construction of the statute." Id. In that regard, the courts have "long
recognized that considerable weight should be accorded to an execu-
tive department’s construction of a statutory scheme it is entrusted to
administer." Id. at 844.

                                   2.

   Before we can accord Chevron deference to the Evidence-Limiting
Rules, however, we must decide whether Congress delegated the nec-
essary rule-making authority to the Secretary of Labor. See United
States v. Mead Corp., 533 U.S. 218, 226-27 (2001) (holding that "ad-
ministrative implementation of a particular statutory provision quali-
fies for Chevron deference when it appears that Congress delegated
authority to the agency generally to make rules carrying the force of
law, and that the agency interpretation claiming deference was pro-
mulgated in the exercise of that authority"); see also A. T. Massey
Coal Co. v. Barnhart, 472 F.3d 148, 166 (4th Cir. 2006) (limiting
Chevron deference to circumstances where Congress has given an
agency authority to make rules and "the agency’s interpretation is ren-
dered in the exercise of that authority"). As the Supreme Court has
explained, the requisite congressional delegation of authority "may be
shown in a variety of ways, as by an agency’s power to engage in
adjudication or notice-and-comment rulemaking, or by some other
indication of a comparable congressional intent." Mead Corp., 533
U.S. at 227.

   In this situation, we can readily ascertain that Congress delegated
the necessary rule-making authority to the Secretary of Labor. Section
936 of the Black Lung Act authorizes the Secretary to issue regula-
20              ELM GROVE COAL v. DIRECTOR, OWCP
tions "appropriate to carry out the provisions of this subchapter," and
specifically provides that such regulations are to be promulgated in
conformity with the notice-and-comment rule-making provisions of
the APA. See 30 U.S.C. § 936 (providing that "[s]uch regulations
shall be issued in conformity with section 553 of Title 5, notwith-
standing subsection (a) thereof."). By way of incorporation from the
Social Security Act, the Act instructs the Secretary to "adopt reason-
able and proper rules and regulations to regulate and provide for the
nature and extent of the proofs and evidence and the method of taking
and furnishing the same in order to establish the right to benefits here-
under." See 30 U.S.C. § 923(b) (incorporating 42 U.S.C. § 405(a)).

   In addition, the applicable provisions of the APA instruct that
"[a]ny oral or documentary evidence may be received, but the agency
as a matter of policy shall provide for the exclusion of irrelevant,
immaterial, or unduly repetitious evidence." 5 U.S.C. § 556(d). As we
noted in 1999 in United States Steel Mining Co. v. Director, Office
of Workers Compensation, the APA provides for such evidentiary
exclusions "[b]ecause the wholesale admission of all evidence would
unnecessarily prolong and burden the process." 187 F.3d 384, 388
(4th Cir. 1999).

   By way of § 936, and Congress having incorporated § 405(a) of the
Social Security Act and § 556(d) of the APA into the Black Lung Act,
the Secretary has been vested with broad authority to implement the
mandate of the Black Lung Act. Pursuant thereto, the Secretary is
authorized to adopt reasonable regulations on the nature and extent of
the proofs and evidence in order to establish rights to benefits under
the Act, and to exclude evidence that is irrelevant, immaterial or
unduly repetitious as a matter of policy. Accordingly, the Evidence-
Limiting Rules, as promulgated by the Secretary, "qualif[y] for Chev-
ron deference." Mead Corp., 533 U.S. at 226. Because Congress has
expressly delegated authority to the Secretary to "elucidate a specific
provision of the statute by regulation," we are obliged to accord the
Evidence-Limiting Rules "controlling weight unless they are arbi-
trary, capricious, or manifestly contrary to the statute." Chevron, 467
U.S. at 844.
                ELM GROVE COAL v. DIRECTOR, OWCP                      21
                                   C.

                                   1.

   In applying Chevron, we must first assess Elm Grove’s contention
that the All Relevant Evidence Provision represents the clear and
unambiguous intention of Congress to preclude any limitations on
admissible evidence in Black Lung Act proceedings. See Chevron,
467 U.S. at 842. Elm Grove would have us rule that the Provision
requires the admission of all proffered evidence, without regard to
any exclusionary principle other than relevance. As the Director
points out, however, the terms of the Provision, and the statutory pro-
visions incorporated therein, conflict with Elm Grove’s contention.

   In undertaking the task of statutory construction, we "must not be
guided by a single sentence or member of a sentence," but instead
must "look to the provisions of the whole law, and to its object and
policy." U. S. Nat’l Bank of Or. v. Indep. Ins. Agents of Am., Inc., 508
U.S. 439, 455 (1993) (internal citations omitted). As we have hereto-
fore concluded, "the traditional rules of statutory construction to be
used in ascertaining congressional intent include: the overall statutory
scheme, legislative history, the history of evolving congressional reg-
ulation in the area, and a consideration of other relevant statutes."
Brown & Williamson Tobacco Corp. v. FDA, 153 F.3d 155, 162 (4th
Cir. 1998) (internal quotation marks and citations omitted). With
these principles in mind, we turn to Elm Grove’s contention on the
Provision.

                                   2.

   First of all, it is essential that the All Relevant Evidence Provision
be read and assessed in its entirety. Notably, the "all relevant evi-
dence" language follows the portion of the Provision that provides, in
relevant part, that "[n]o claim for benefits under this part shall be
denied solely on the basis of the results of a chest roentgenogram."
30 U.S.C. § 923(b). Instead of relying merely on a chest roentgeno-
gram, or chest X-ray, the All Relevant Evidence Provision instructs
the Secretary to consider "all relevant evidence" in determining the
validity of benefits claims pursued under the Black Lung Act. Rather
than constituting a prohibition against the promulgation of regulations
22                  ELM GROVE COAL v. DIRECTOR, OWCP
that might limit the quantity of evidence, the "all relevant evidence"
language, read and assessed in the context of the sentence immedi-
ately preceding it, precludes the Secretary from relying on only one
type of evidence, that is, a chest roentgenogram, in assessing claims
for benefits under the Act. These sentences are more appropriately
read in conjunction with one another — as both were added as a sin-
gle amendment in 1972. See Federal Coal Mine and Safety Act
Amendments, Pub. L. No. 92-303, 86 Stat. 150, 154 (1972).17

   Similarly, we are unable to divorce the "all relevant evidence" lan-
guage from the balance of the All Relevant Evidence Provision. After
instructing that "all relevant evidence shall be considered," the Provi-
sion goes on to list various types of relevant medical evidence con-
templated by its mandate, including, inter alia, blood gas studies,
electrocardiograms, pulmonary function studies, and physical perfor-
mance tests. Assessing the Provision in context, we are unable to dis-
cern any clear intention on the part of Congress to preclude the
Secretary from limiting the quantity of relevant evidence admissible
in Black Lung Act proceedings. It seems clear, however, that Con-
gress intended that the ALJs should not rely on a single type of medi-
cal evidence — the chest X-ray — in assessing black lung claims.

   It is also clear that the 1972 amendments — in addition to adding
the Provision to § 923(b) — incorporated the broad rule-making
  17
    The 1972 amendments instruct, in relevant part, that the "first sen-
tence of section 413(b) of such Act [codified as 30 U.S.C. § 923(b)] is
amended by inserting before the period at the end thereof the following:
       but no claim for benefits under this part shall be denied solely
       on the basis of the results of a chest roentgenogram. In determin-
       ing the validity of claims under this part, all relevant evidence
       shall be considered, including, where relevant, medical tests such
       as blood gas studies, X-ray examination, electrocardiogram, pul-
       monary function studies, or physical performance tests, and any
       medical history, evidence submitted by the claimant’s physician,
       or his wife’s affidavits, and in the case of a deceased miner,
       other appropriate affidavits of persons with knowledge of the
       miner’s physical condition, and other supportive materials."
See Federal Coal Mine and Safety Act Amendments, Pub. L. No. 92-303,
86 Stat. 150, 154 (1972).
                ELM GROVE COAL v. DIRECTOR, OWCP                      23
authority of the Secretary provided for in 42 U.S.C. § 405(a). See
Federal Coal Mine and Safety Act Amendments, Pub. L. No. 92-303,
86 Stat. 150, 152 (1972). Section 405(a), as part of the Social Security
Act, provides the Secretary with "full power and authority to make
rules and regulations and to establish procedures, not inconsistent
with the provisions of this subchapter, which are necessary or appro-
priate to carry out such provisions," as well as authority to regulate
"the nature and extent of the proofs and evidence and the method of
taking and furnishing the same." 42 U.S.C. § 405(a). Our reading of
the Provision in context, including the provisions of § 405(a), as
incorporated into § 923, strongly mitigates against Elm Grove’s con-
tention here. The congressional grant of broad authority to the Secre-
tary — to regulate the extent of proofs and evidence in Black Lung
Act proceedings — is simply inconsistent with Elm Grove’s conten-
tion that all relevant evidence can be submitted, without exception, in
such proceedings. As the Director points out in his appellate papers,
the Provision "has never been construed to prohibit reasonable regula-
tions that, when applied, resulted in the exclusion of relevant evidence
from the record." Fed. Resp’t’s Br. 13-15. By way of example, 20
C.F.R. § 725.457(a) precludes relevant expert witness testimony
unless the proponent thereof has notified the other parties, at least ten
days before an ALJ hearing, and § 725.461(b) provides that the unex-
cused failure of a party to attend an ALJ hearing constitutes a waiver
of any right to submit evidence there. In these circumstances, the All
Relevant Evidence Provision, assessed in the context of the relevant
statutory scheme, does not preclude the promulgation of appropriate
regulatory limits on evidence in Black Lung Act proceedings.

                                   D.

                                   1.

   Finally, in order to complete our Chevron analysis, we must assess
Chevron’s step two, asking whether the Evidence-Limiting Rules are
"based on a permissible construction" of the Black Lung Act and its
relevant incorporated statutory provisions. Chevron, 467 U.S. at 843.
In this analysis, we look to the legislative history of § 923(b), as well
as the other relevant provisions of the Black Lung Act, which together
spell out the authority of the Secretary to regulate the admission of
evidence in Black Lung Act proceedings.
24              ELM GROVE COAL v. DIRECTOR, OWCP
   As we have explained, the Secretary has construed the Provision in
a manner that does not conflict with the Evidence-Limiting Rules.
That is to say, the Secretary has concluded that the Provision is not
meant to require the admission of every piece of relevant evidence,
but rather that the "all relevant evidence" language is part of a larger
statutory mandate to consider all types of relevant medical evidence.
To determine whether her construction of this portion of the Act is a
permissible one, we look to the legislative history of the 1972 amend-
ments to § 923(b).

   In its Summary of Major Provisions of those amendments, the Sen-
ate Committee on Labor and Public Welfare described the purpose of
the amendments to § 923(b). See S. Rep. No. 92-743 (1972) as
reprinted in 1972 U.S.C.C.A.N. 2305, 2311. After acknowledging
that a chest roentgenogram (or chest X-ray) is an imperfect means of
diagnosing pneumoconiosis in coal miners, and observing that reli-
ance on chest X-rays alone has likely resulted in the denial of valid
black lung claims, the Committee described the relevant amendments
to § 923(b) as requiring the Social Security Administration to "use
tests other than the X-ray to establish the basis for a judgment that a
miner is or is not totally disabled due to pneumoconiosis." Id. at 2315.
Accordingly, as the Committee indicated, the Provision was not
intended to require that any particular quantity of relevant evidence
be submitted, but instead that the ALJ receive different types of medi-
cal evidence:

     The art of medical diagnosis of coal miners’ respiratory
     impairments is not so precise that a miner’s benefit should
     stand or fall on the basis of a single test. Every available
     medical tool should be used to assist a miner in successfully
     pursuing his claim for benefits. This provision seeks to
     expand the number of medical tools available for that pur-
     pose.

Id. at 2319 (emphasis added).

   Our analysis of the All Relevant Evidence Provision and its legisla-
tive history is thus consistent with the Secretary’s construction of it.
Congress intended the Provision to require the Secretary to consider
medical evidence outside the historical reliance on chest roentgeno-
                ELM GROVE COAL v. DIRECTOR, OWCP                     25
grams, and the Provision was not intended as a prohibition on regula-
tions that might limit the admissibility of certain other evidence in
Black Lung Act proceedings. Accordingly, we agree with the Secre-
tary’s conclusion that

    the historical context of the language demonstrates that it is
    a statutory exhortion for the agency to explore every avenue
    which may prove the claimant’s entitlement. Given the pol-
    icy behind the provision, its apparent breadth should not act
    as a guarantor for the admission of any quantity of evidence
    an operator might obtain which refutes a claimant’s entitle-
    ment.

Regulations Implementing the Federal Coal Mine Health and Safety
Act of 1969, as Amended, 62 Fed. Reg. at 3358-59.

                                   2.

   We next turn to an analysis of whether the Evidence-Limiting
Rules were premised on a permissible construction of the Black Lung
Act. In this regard, the Secretary has enumerated several reasons for
having promulgated the Evidence-Limiting Rules, including the fol-
lowing: (1) to "reduce the costs associated with [black lung claims]";
(2) "to make more equitable the adjudication of black lung claims";
and (3) "to ensure that eligibility determinations are based on the best
quality evidence submitted rather than on the quantity of evidence
submitted by each side." Regulations Implementing the Federal Coal
Mine Health and Safety Act of 1969, as Amended, 62 Fed. Reg. at
3338. And, the Secretary has concluded that the Evidence-Limiting
Rules will ensure the "fair, efficient and expeditious adjudication of
claims." Id. As we have noted, ALJs have always possessed discre-
tion, under the Act, to exclude cumulative evidence from Black Lung
Act proceedings, and they are instructed to exclude, as a matter of
policy, "irrelevant, immaterial, or unduly repetitious evidence." 5
U.S.C. § 556(d). The Evidence-Limiting Rules simply codify an
ALJ’s broad discretion in this regard, in light of the important consid-
erations identified by the Secretary, based on "more than 20 years of
experience in processing and adjudicating black lung benefits claims,
and more than thirteen years of experience in adjudicating claims
under the current program regulations." Regulations Implementing
26                ELM GROVE COAL v. DIRECTOR, OWCP
the Federal Coal Mine Health and Safety Act of 1969, as Amended,
62 Fed. Reg. at 3356. As the Supreme Court recognized in Chevron,

       the principle of deference to administrative interpretations
       has been consistently followed by this Court whenever the
       decision as to the meaning or reach of a statute has involved
       reconciling conflicting policies, and a full understanding of
       the force of the statutory policy in the given situation has
       depended upon more than ordinary knowledge respecting
       the matters subjected to agency regulation.

Chevron, 467 U.S. at 844. (internal citations and quotation marks
omitted).

   Finally, the Evidence-Limiting Rules do not arbitrarily or imper-
missibly limit the admission of medical evidence above the pro-
scribed limits. It is important that, to the contrary, they specifically
provide ALJs with the broad discretion to hear and admit additional
evidence for "good cause." 20 C.F.R. § 725.456(b)(1). This good
cause exception is vital to our analysis here, as it allows an ALJ to
retain and exercise discretion to admit relevant evidence beyond the
limits spelled out in the Evidence-Limiting Rules. See National Min-
ing, 292 F.3d at 874 (concluding that the Evidence-Limiting Rules do
not set "inflexible limits" but instead give ALJs discretion to hear
additional evidence for good cause).

   Accordingly, Elm Grove’s challenge to the Evidence-Limiting
Rules must be rejected. The Rules are a reasonable and valid exercise
of the Secretary’s authority to regulate evidentiary development in
Black Lung Act proceedings, they are based on a permissible con-
struction of the Act, and they are neither "arbitrary, capricious, [nor]
manifestly contrary to the statute." Chevron, 467 U.S. at 844.18
  18
    Elm Grove further contends that the second ALJ erred by failing to
find its additional exhibits admissible under the "good cause" exception
to the Evidence-Limiting Rules. See 20 C.F.R. § 725.456(b)(1). Elm
Grove raised the good cause exception at the hearing and argued that
"[o]ur good cause argument in this case would be that under the Fourth
Circuit’s Decision in the Underwood case, they have deemed that all rel-
                 ELM GROVE COAL v. DIRECTOR, OWCP                        27
                                    IV.

                                    A.

   Although we reject Elm Grove’s challenge to the validity of the
Evidence-Limiting Rules, we agree with its contention, on the Rebut-
tal Evidence issue, that the second ALJ misapplied one of those
Rules, 20 C.F.R. § 725.414(a)(3)(ii), in rejecting part of Elm Grove’s
rebuttal evidence at Blake’s ALJ hearing.19 As noted earlier, we
review de novo "a legal question about the proper standard for the
admission of evidence in hearings before the ALJ under the Black
Lung Benefits Act," and we review for abuse of discretion "a question

evant evidence should be considered and, therefore, the Underwood case
in this position would triumph over the regulation. Our contention is
essentially the regulation is invalid." J.A. 765. This argument was
rejected by both the second ALJ and the BRB. Elm Grove restates this
contention in its brief on appeal, asserting that the "ALJ also erred in his
failure to consider the relevant evidence by essentially determining ‘rele-
vancy’ fails to meet the good cause standard." Petr.’s Br. 60. If Elm
Grove’s contention is correct, good cause exists to permit all evidence
that is relevant, and the good cause exception found in § 725.456 would
render the Evidence-Limiting Rules of § 725.414 meaningless. Deeming
the Evidence-Limiting Rules valid, we reject Elm Grove’s position on
this point. Elm Grove’s assertions simply do not demonstrate any partic-
ularized showing of good cause, beyond its contention that the Evidence-
Limiting Rules are invalid.
   Elm Grove also contends that the second ALJ should have examined
the additional evidence that it sought to introduce in order to determine
if there was good cause and to decide whether it should have been
included the evidence in the record for appeal. We are unpersuaded by
these contentions. Elm Grove’s "good cause" argument was simply a
restatement of its contention that it should be allowed to submit all rele-
vant evidence at the hearing.
   19
      In order to rebut evidence submitted in support of an opposing
party’s affirmative case, a claimant and the responsible operator each
may submit, inter alia, "no more than one physician’s interpretation of
each chest X-ray, pulmonary function test, arterial blood gas study,
autopsy or biopsy" submitted by the opposing party. § 725.414(a)(2)(ii),
(3)(ii)
28              ELM GROVE COAL v. DIRECTOR, OWCP
about the proper application of that standard." Underwood, 105 F.3d
at 948-49.

   In their affirmative submissions at the ALJ hearing, Blake and Elm
Grove each submitted two X-ray interpretations: Blake submitted two
interpretations of the same X-ray (taken in October 2002), and Elm
Grove submitted one interpretation each of two different X-rays
(taken in September 2001 and November 2001). In seeking to rebut
Elm Grove’s X-ray interpretations, Blake submitted two additional
interpretations — one reading of the September 2001 X-ray and one
of the November 2001 X-ray. Elm Grove then sought to submit two
interpretations in rebuttal, i.e., since Blake had submitted two inter-
pretations of the October 2002 X-ray as affirmative evidence, Elm
Grove sought to submit two interpretations of that X-ray in response.
See J.A. 732-34. In ruling on this issue, the second ALJ interpreted
§ 725.414(a)(3)(ii) of the Evidence-Limiting Rules to mean that,
when a party submits two interpretations of the same X-ray as affir-
mative evidence (as Blake did here), only one interpretation of that
X-ray can be submitted on rebuttal. Id. at 735-36. The second ALJ
thus authorized Elm Grove to submit only one of its two proposed
rebuttal interpretations. Id.

   The Director defended the second ALJ’s ruling before the BRB,
but he has now reversed course and abandoned the BRB, conceding
in this proceeding that the ALJ erred. Fed. Resp’t’s Br. 5 (noting that
"[w]e agree with Employer, however, that the ALJ’s misunderstand-
ing of a provision of the regulation resulted in the erroneous exclusion
of one of Employer’s X-ray interpretations"). Respondent Blake, on
the other hand, maintains that the ruling of the second ALJ on the
Rebuttal Evidence issue was proper, and that it was consistent with
the Evidence-Limiting Rules. He contends that § 725.414(a)(3)(ii) of
those Rules limits the rebuttal evidence in this circumstance to a sin-
gle X-ray interpretation, based on the language that "[t]he responsible
operator shall be entitled to submit, in rebuttal . . . no more than one
physician’s interpretation of each chest X-ray." 20 C.F.R.
§ 725.414(a)(3)(ii).

   Having fully considered this contention, we conclude that
§ 725.414(a)(3)(ii) of the Evidence-Limiting Rules, and the identical
language found in § 725.414(a)(2)(ii) thereof, authorize the submis-
                ELM GROVE COAL v. DIRECTOR, OWCP                      29
sion of one piece of evidence on rebuttal for each piece of affirmative
evidence submitted by the other party. See Regulations Implementing
the Federal Coal Mine Health and Safety Act of 1969, as Amended,
65 Fed. Reg. at 79922 ("Each party may submit one piece of evidence
in rebuttal of each piece of evidence submitted by the opposing
party."). As the Director now concedes, "the clear tenor of the rebuttal
provision is that a party may submit one piece of rebuttal evidence for
each piece of affirmative evidence submitted by the opposing party."
Fed. Resp’t’s Br. 22. Section 725.414(a)(3)(ii) of the Evidence-
Limiting Rules, and the corresponding language found in
§ 725.414(a)(2)(ii) thereof, create a piece-for-piece opportunity for
rebuttal, as demonstrated by the phrase "one physician’s interpretation
of each . . . ." As the Director correctly points out, "the regulation’s
catch-all provision — dealing with evidence not captured by name —
is phrased in terms of a piece-for-piece match: the opposing party
‘shall be entitled to submit one physician’s assessment of each piece
of such evidence in rebuttal.’" Fed. Resp’t’s Br. 22-23 (quoting 20
C.F.R. § 725.414(a)(2)(ii), (a)(3)(ii)).

   The BRB has recently interpreted the rebuttal language from
§§ 725.414(a)(2)(ii) and (a)(3)(ii) of the Evidence-Limiting Rules to
authorize each party to submit one piece of evidence for each affirma-
tive piece of evidence submitted by the opposing party. See Ward v.
Consolidation Coal Co., BRB No. 05-0595 BLA (Ben. Rev. Bd. Mar.
28, 2006). Thus, the BRB in Ward has, contrary to its position in
Blake’s case, agreed with the "Director’s reasonable interpretation of
the regulation," and concluded that:

     Each party submits "chest X-ray interpretations" in its affir-
     mative case. 20 C.F.R. §§ 725.414(a)(2)(i), (a)(3)(i). Conse-
     quently, "chest X-ray interpretations" are what each party
     may rebut under 20 C.F.R. § 725.414(a)(2)(ii), (a)(3)(ii).
     Therefore, in the case at bar, since claimant submitted two
     interpretations of the March 5, 2002 X-ray in support of his
     affirmative case, employer was entitled to submit two inter-
     pretations in rebuttal under 20 C.F.R. § 725.414(a)(3)(ii).

Id. at 5.

  We view the present position of the Director as persuasive and
agree with Elm Grove that the second ALJ, at the hearing of June 4,
30               ELM GROVE COAL v. DIRECTOR, OWCP
2003, misapplied § 725.414(a)(3)(ii) of the Evidence-Limiting Rules
when he excluded Elm Grove’s second interpretation of the October
2002 X-ray. Accordingly, we grant Elm Grove’s petition for review
and vacate the BRB Decision and Order on this point.

                                    B.

   Finally, we examine and dispose of Elm Grove’s contention on the
Work Product issue, that is, that the ALJs and the BRB erred in ruling
that draft reports and attorney-expert communications between
Blake’s lawyers and their physician-experts were protected under the
work product doctrine and thus not discoverable.20 We apply a de
novo review to the legal conclusions made by the ALJs and the BRB
in this regard. See Consol. Coal Co. v. Williams, 453 F.3d 609, 614
(4th Cir. 2006). We assess for abuse of discretion their application of
the legal standard. Underwood, 105 F.3d at 948-49.

   Respondent Blake submitted medical reports of Drs. Lenkey and
Cohen for consideration in connection with this claim. When asked
about the content of his report during a pre-hearing deposition, Dr.
Lenkey admitted that he had not written "every word" of his report
and that Blake’s attorneys had provided him with certain documents.
J.A. 312. Dr. Cohen also testified by deposition that Blake’s counsel
had provided him with relevant documents and summaries. In pursu-
ing its contention here, Elm Grove asserts that materials provided by
counsel to a testifying expert witness concerning the relevant facts
and an expert’s opinions and reports are discoverable, and that the
ALJs and the BRB erred in denying its motion to compel production
of draft reports and attorney-expert communications between Blake’s
counsel and their experts. This is so, Elm Grove contends, because
"[w]hen an attorney interjects him or herself into the process by
which a testifying expert forms the opinions to be testified to at hear-
ing, that action affects the weight which the expert’s testimony
  20
    We choose to address this discovery issue because it is likely to arise
on remand. See Gordon v. Schweiker, 725 F.2d 231, 236 (4th Cir. 1984)
(noting, in an appeal from a denial of Social Security disability benefits,
that "[s]ince the case must be reconsidered by the Secretary, we do pro-
vide some guidance as to a matter very likely to arise at the hearing
which will occur").
                    ELM GROVE COAL v. DIRECTOR, OWCP                        31
deserves." Petr.’s Br. 26. In contrast, Blake maintains that the draft
reports and attorney-expert communications sought by Elm Grove
contain his counsel’s theories and mental impressions and are thus
protected by the work product doctrine.

   In his November 26, 2002 Order denying Elm Grove’s motion to
compel discovery, the first ALJ ruled that draft reports and attorney-
expert communications were not discoverable under the work product
doctrine, as articulated in the Rules of Practice and Procedure for
Administrative Hearings Before the Office of Administrative Law
Judges (the "ALJ Rules of Procedure"). See J.A. 657-59. With respect
to work product, the ALJ Rules of Procedure provide, in part, that

       [i]n ordering discovery . . . the administrative law judge
       shall protect against disclosure of the mental impressions,
       conclusions, opinions, or legal theories of an attorney or
       other representative of a party concerning the proceeding.

29 C.F.R. § 18.14(c). This rule of procedure is essentially identical to
the work product doctrine set forth in Rule 26(b)(3) of the Federal
Rules of Civil Procedure (the "Federal Rules"). Rule 26 was amended
in 1993, however, to mandate, inter alia, the disclosure of certain
information (even when provided by counsel) considered by testifying
experts in forming their opinions. See, e.g., Fed. R. Civ. P.
26(a)(2)(B) (mandating that testifying expert shall provide written
report to opposing party which includes "complete statement of all
opinions to be expressed and the basis and reasons therefor" as well
as "the data or other information considered by the witness in forming
the opinions").21 On the other hand, no corresponding revisions have
  21
    According to the Advisory Committee notes to the 1993 amendments
to Rule 26:
       The [expert] report is to disclose the data and other information
       considered by the expert and any exhibits or charts that summa-
       rize or support the expert’s opinions. Given this obligation of
       disclosure, litigants should no longer be able to argue that mate-
       rials furnished to their experts to be used in forming their opin-
       ions — whether or not ultimately relied upon by the expert —
       are privileged or otherwise protected from disclosure when such
       persons are testifying or being deposed.
Fed. R. Civ. P. 26 advisory committee’s note.
32                  ELM GROVE COAL v. DIRECTOR, OWCP
been made to the ALJ Rules of Procedure.22

   After ascertaining that 29 C.F.R. § 18.14(c) of the ALJ Rules of
Procedure incorporated the work product protections of the Federal
Rules, the first ALJ examined the analogous work product discovery
decisions under Rule 26 and observed that "the case law in this area
is far from clear." J.A. 658. Accordingly, he believed that "this mate-
rial could be treated as either discoverable, or protected work prod-
uct." Id. Ultimately, however, the first ALJ was "more persuaded by
the decisions that protect the communication between a party’s attor-
ney and its expert," concluding that the discovery sought would
undermine the honest and open communications between lawyers and
expert witnesses. See J.A. 659. The second ALJ, who conducted the
formal hearing on Blake’s claim, declined to disturb the first ALJ’s
ruling on this issue, and the BRB affirmed. See J.A. 755, 826-27.
There is no indication in the record that either of the ALJs or the BRB
made a specific review of the individual documents sought by Elm
Grove.
  22
    As a general proposition, an ALJ is bound by the ALJ Rules of Pro-
cedure. See 29 C.F.R. § 18.1. Section 18.1 thereof defines the scope of
those Rules, and provides, inter alia, that:
       These rules of practice are generally applicable to adjudicatory
       proceedings before the . . . Department of Labor . . . . To the
       extent that these rules may be inconsistent with a rule of special
       application as provided by statute, executive order, or regulation,
       the latter is controlling. The Rules of Civil Procedure for the Dis-
       trict Courts of the United States shall be applied in any situation
       not provided for or controlled by these rules, or by any statute,
       executive order or regulation.
Id. Although the work product protections in § 18.14(c) apply here, the
standard set forth therein is nearly identical to that found in Rule 26(b)(3)
of the Federal Rules. Because no BRB decision controls the work prod-
uct protections that § 18.14(c) affords to draft expert reports or attorney-
expert communications, we must assess the relevant case law on the
analogous work product protections of Rule 26. Cf. Johnson v. Royal
Coal Co., 326 F.3d 421, 427 (4th Cir. 2003) (utilizing decision interpret-
ing "analogous Fed. R. Civ. P. 36" to interpret 29 C.F.R. § 18.20, per-
taining to pre-hearing admissions).
                 ELM GROVE COAL v. DIRECTOR, OWCP                        33
   As explained below, we are unable, in these circumstances, to
agree that Blake’s expert witnesses could be properly and fully cross-
examined in the absence of the draft reports and attorney-expert com-
munications sought by Elm Grove. As the Supreme Court has cau-
tioned, "[e]xpert evidence can be both powerful and quite misleading
because of the difficulty in evaluating it." Daubert v. Merrell Dow
Pharm., Inc., 509 U.S. 579, 595 (1993) (citations omitted). And, as
several courts have observed, it is important to the proper cross-
examination of an expert witness that the adverse party be aware of
the facts underlying the expert’s opinions, including whether the
expert made an independent evaluation of those facts, or whether he
instead adopted the opinions of the lawyers that retained him.23 See,
e.g., Musselman v. Phillips, 176 F.R.D. 194, 200 (D. Md. 1997) ("It
cannot seriously be denied that the fact that an attorney has interjected
him or herself into the process by which a testifying expert forms the
opinions to be testified to at trial affects the weight which the expert’s
testimony deserves."); Karn v. Rand, 168 F.R.D. 633, 639 (N.D. Ind.
1996) ("[T]he impact of expert witnesses on modern-day litigation
cannot be overstated; yet, to some, they are nothing more than willing
musical instruments upon which manipulative counsel can play what-
ever tune desired. . . . Thus, full, effective cross examination is critical
to the integrity of the truth-finding process." (citations omitted));
Occulto v. Adamar of New Jersey, Inc., 125 F.R.D. 611, 615-16
(D.N.J. 1989) (noting that the "weight accorded to an expert’s opinion
must vary in accordance with the expert’s competence and knowl-
edge; an expert who can be shown to have adopted the attorney’s
opinion as his own stands less tall . . . than an expert who has engaged
in painstaking inquiry and analysis before arriving at an opinion").
  23
    The fact that a lawyer has participated in the preparation of his testi-
fying expert’s report does not bar the use of the expert’s opinion, or nec-
essarily even impeach the expert’s reliability. Such participation does,
however, potentially impact on the weight to be accorded such opinion
evidence. For example, the lawyer could have participated merely as the
expert’s scrivener, assisting in the report preparation process only, and
not directing the witness to emphasize any specific facts or reach any
particular opinions. The interplay between testifying experts and the law-
yers who retained them should, however, be fair game for cross-
examination.
34              ELM GROVE COAL v. DIRECTOR, OWCP
   Although our Court has not definitively addressed this precise
issue, other courts, under both pre- and post-amendment Rule 26,
have mandated the production of similar draft reports and attorney-
expert communications with respect to testifying experts. See, e.g., In
re Pioneer Hi-Bred Int’l, Inc., 238 F.3d 1370, 1375-76 (Fed. Cir.
2001) (concluding that documents and information provided to testi-
fying expert in connection with opinions and testimony are discover-
able by opposing party, whether or not expert relies on the documents
in preparing expert report); Intermedics, Inc. v. Ventritex, Inc., 139
F.R.D. 384, 387-88 (N.D. Cal. 1991) (holding that absent extraordi-
nary showing of unfairness beyond interests generally protected by
work product doctrine, communications from lawyer to expert related
to subject of expert’s testimony are discoverable, even if otherwise
considered opinion work product); Occulto, 125 F.R.D. at 616-17
(concluding, where evidence indicated that plaintiffs’s counsel had
drafted expert report, that draft reports and correspondence between
counsel and testifying expert were discoverable, and noting that it
"does not serve the truth-finding process to preclude meaningful
inquiry" into the derivation of expert’s opinion); Boring v. Keller, 97
F.R.D. 404, 407 (D. Colo. 1983) (concluding that "the opinion work
product rule is no exception to discovery under circumstances where
documents which contain mental impressions are examined and
reviewed by expert witnesses before their expert opinions are
formed").24
  24
     We recognize that certain courts, both before and after the 1993
amendments to Rule 26, have determined that draft reports provided to
testifying experts and attorney-expert communications are entitled to
varying degrees of work product protection. See, e.g., Bogosian v. Gulf
Oil Corp., 738 F.2d 587 (3d Cir. 1984) (discussing, prior to Rule 26
amendments, relationship between paragraphs (3) and (4) of Rule
26(b)and concluding opinion work product is entitled to protection even
when it has been disclosed to testifying expert); Nexxus Products Co. v.
CVS New York, Inc., 188 F.R.D. 7, 10-11 (D. Mass. 1999) (stating that
continued protection of core work product allows unconstrained commu-
nications between expert and attorney and better serves ultimate truth-
seeking function of trial process). We are unpersuaded by this line of
decisions and, as discussed herein, believe that the vastly superior view
is, consistent with the 1993 amendments to Rule 26, that such attorney-
expert communications are not entitled to protection under the work
product doctrine.
                 ELM GROVE COAL v. DIRECTOR, OWCP                      35
   The first ALJ properly observed, in ruling on this issue, that, "as
the trier of fact, seeking the truth is a vital function." J.A. 659. Here,
Drs. Lenkey and Cohen both acknowledge that Blake’s lawyer pro-
vided them with factual summaries and documents, and that he may
have contributed to the substance of their expert reports. Accordingly,
the disclosure to Elm Grove of the pertinent draft reports and
attorney-expert communications was potentially important to a full
and fair cross-examination and to the truth-seeking process. It is also
apparent that the discovery of such materials by Elm Grove will not
undermine any settled policies underlying the work product doctrine.
Attorney work product, and especially opinion work product, is still
protected from discovery, in order that a party may not advance its
case on "wits borrowed from the adversary." Hickman v. Taylor, 329
U.S. 495, 516 (1947) (Jackson, J., concurring). We have recognized
that the work product doctrine ensures that lawyers do not lose their
"incentive to do thorough research, relying instead on the opposing
party’s effort." In re Allen, 106 F.3d 582, 607 (4th Cir. 1997). Attor-
ney work product also enjoys protected status so as to allow the par-
ties to litigation "privacy in the development of legal theories,
opinions and strategies for the client." National Union Fire Ins. Co.
v. Murray Sheet Metal Co., 967 F.2d 980, 983 (4th Cir. 1992). As the
Musselman decision of the District of Maryland observed, however,
"this interest is hardly served when the attorney discloses [his legal
theories and opinions] to a retained expert in order to shape opinion
testimony to be offered at trial." Musselman, 176 F.R.D. at 201. Here,
Elm Grove sought discovery of draft reports and attorney-expert com-
munications in seeking to determine which portions of the expert
reports, if any, had been prepared by counsel, or with the assistance
of counsel, and to assess and ascertain which portions thereof resulted
from the experts’ independent efforts. Rather than seeking to benefit
from its opposing counsel’s work product, Elm Grove was seeking
these materials for an entirely legitimate purpose — to fully explore
the trustworthiness and reliability of Drs. Lenkey and Cohen. In sum,
draft expert reports prepared by counsel and provided to testifying
experts, and attorney-expert communications that explain the lawyer’s
concept of the underlying facts, or his view of the opinions expected
from such experts, are not entitled to protection under the work prod-
uct doctrine.25 See In re Pioneer Hi-Bred Int’l, Inc., 238 F.3d at 1375-
  25
    We observe that, in connection with discovery issues such as those
presented here, it is important to distinguish between testifying experts,
36              ELM GROVE COAL v. DIRECTOR, OWCP
76 (concluding that "because any disclosure to a testifying expert in
connection with his testimony assumes that privileged or protected
material will be made public, there is a waiver to the same extent as
with any other disclosure." (citations omitted)).

   In the context of the foregoing principles, the ALJs and the BRB
thus abused their discretion in categorically denying Elm Grove’s
motion to compel on the mistaken belief that the documents were pro-
tected work product, and in failing to specifically examine and assess
the documents being sought by Elm Grove. As a result, we also
vacate the BRB Decision and Order on the Work Product issue and
remand for the ALJ to appropriately examine and rule on the docu-
ments sought by Elm Grove, in light of the principles discussed
herein.

                                  V.

   Pursuant to the foregoing, we deny Elm Grove’s petition for review
on the Evidence-Limiting Rules issue. We grant its petition on the
Rebuttal Evidence and Work Product issues, vacate the BRB Decision
and Order, and remand for such further proceedings as may be appro-
priate.

                  PETITION FOR REVIEW GRANTED IN PART;
            DECISION AND ORDER VACATED AND REMANDED

on the one hand, and non-testifying or consulting experts, on the other.
Any such draft reports or attorney communications made or provided to
non-testifying or consulting experts should be entitled to protection
under the work product doctrine.
