                            PUBLISHED

UNITED STATES COURT OF APPEALS
                FOR THE FOURTH CIRCUIT


THE DANIELS COMPANY,                     
INCORPORATED,
                           Petitioner,
                 v.
FREDA MITCHELL, Surviving spouse                 No. 06-1137
of James Mitchell; DIRECTOR,
OFFICE OF WORKERS’ COMPENSATION
PROGRAMS,
                       Respondents.
                                         
              On Petition for Review of an Order of
                  the Benefits Review Board.
                         (05-0132-BLA)

                      Argued: November 29, 2006

                       Decided: March 15, 2007

          Before WILKINS, Chief Judge, and TRAXLER
                 and GREGORY, Circuit Judges.



Reversed in part, vacated in part, and remanded by published opinion.
Judge Traxler wrote the opinion, in which Chief Judge Wilkins and
Judge Gregory joined.


                             COUNSEL

ARGUED: Kathy Lynn Snyder, JACKSON KELLY, P.L.L.C., Mor-
gantown, West Virginia, for Petitioner. Joseph E. Wolfe, WOLFE,
2               THE DANIELS COMPANY, INC. v. MITCHELL
WILLIAMS & RUTHERFORD, Norton, Virginia; Rita A. Roppolo,
UNITED STATES DEPARTMENT OF LABOR, Office of the Solic-
itor, Washington, D.C., for Respondents. ON BRIEF: Douglas A.
Smoot, JACKSON KELLY, P.L.L.C., Morgantown, West Virginia,
for Petitioner. Howard M. Radzely, Solicitor of Labor, Patricia M.
Nece, Counsel for Appellate Litigation, UNITED STATES
DEPARTMENT OF LABOR, Office of the Solicitor, Washington,
D.C., for Respondent Director, Office of Workers’ Compensation
Programs.


                               OPINION

TRAXLER, Circuit Judge:

   In this claim for benefits under the Black Lung Benefits Act (the
"Act"), 30 U.S.C.A. §§ 901-945 (West 1986 & Supp. 2006), Daniels
Company, Inc. ("Daniels") seeks review of the Benefits Review
Board’s determinations that it is the coal mine operator responsible
for any award of benefits to claimant James Mitchell ("Mitchell") and
that Mitchell is entitled to benefits under the Act.1 For the reasons that
follow, we grant Daniels’ petition for review, vacate the challenged
decisions of the Board, and remand for further proceedings consistent
with this opinion.

                                    I.

   Mitchell worked for Daniels from September 1974 until February
1988, with the exception of a lay-off period from mid-January 1983
through November 1983. During this time, Daniels operated a fabri-
cating shop in Bluefield, West Virginia, engaged in the business of
building material-handling systems for various coal processing plants,
including design, procurement, project management, construction,
commissioning, and start-up of the systems. However, Daniels did not
    1
    Just prior to issuance of the final Board decision below, the Board
was notified that James Mitchell had died. His surviving spouse, Freda
Mitchell, was substituted as the claimant/respondent under the Act and
filed the petition for review to this court.
               THE DANIELS COMPANY, INC. v. MITCHELL                   3
                                     2
operate a coal mine or coal tipple, or provide services or perform
work at or near any such facility. All on-site construction related to
its business was performed by subcontractors. In June 1978, Daniels
Group, Inc., which owns Daniels, purchased Mesa Engineering
("Mesa"). Mesa provided maintenance and repair services on tipple
machinery, but all work was performed when the mines and tipples
were shut down.

   Although Mitchell never worked at coal tipples in his capacity as
a Daniels employee, Mitchell was at times offered the opportunity to
work for Mesa maintaining and repairing equipment at the tipples.
The work generally fell on weekends and holidays, providing Mitch-
ell an opportunity to earn wages at time-and-a-half and double-time
rates. In addition, Daniels was unionized under the United Steelwork-
ers Union, whereas Mesa was governed by the United Mine Workers
Union. Hence, Mitchell was paid a higher base "tipple-wage" rate of
pay for his Mesa work. According to Daniels, Mesa "exist[ed] for the
purpose of employing and paying Daniels Company’s shop’s employ-
ees on all jobs in which shop workers travel to and work at a client’s
work site." J.A. 407-08. It was necessary for Mesa to employ the
workers so that they could be paid "the United Mine Workers’ wage
rate and be compatible with other UMW workers at the client’s site."
J.A. 414. In sum, it is clear that all work performed by Mitchell at the
tipples was paid by Mesa and that Mitchell’s exposure to coal dust
was limited to the time that he performed such work as a Mesa
employee.

   The primary dispute in this case involves the amount of time that
Mitchell worked at the coal tipples and, in particular, the method by
which that time should be computed for the purpose of determining
whether Mitchell is entitled to black lung benefits and whether Dan-
iels can be held liable for such benefits under the Act. Mitchell con-
tends that he should be credited under the regulations with twelve
years of coal mine employment, which represents the entire time he
worked for Daniels. Daniels contends that Mitchell should only be
  2
   Generally, the coal tipple is the structure where the screening of the
coal occurs and the final product is prepared for transport in the stream
of commerce. See Dir., OWCP v. Consolidation Coal Co., 923 F.2d 38,
42 (4th Cir. 1991).
4               THE DANIELS COMPANY, INC. v. MITCHELL
credited with the time he actually worked at the coal tipples as a Mesa
employee.

   According to Mitchell’s Social Security records, Mitchell first
worked for Mesa in 1966 and 1967, a time frame which substantially
predates his employment with Daniels and Daniels Group’s acquisi-
tion of Mesa. It was, in any event, a brief and sporadic period of
employment; Mitchell earned only $916.70 in the last two quarters of
1966 and $124.88 in the first quarter of 1967.3 From 1967 through
1975, Mitchell earned no wages from Mesa, and the Social Security
records and Mitchell’s testimony confirm that he was employed
exclusively in non-coal-related employment during this eight-year
period.

   Mitchell began working for Daniels in September 1974. During the
years 1975 to 1978, which also pre-date Daniels Group’s acquisition
of Mesa, Mitchell was again paid a small amount of wages by Mesa,
earning $117.00 in 1975, $49.92 in 1976, $352.08 in 1977, and
$72.80 in 1978. Beginning in 1979, and coinciding with Daniels
Group’s purchase of Mesa, Mitchell earned the following wages from
Mesa: $554.99 in 1979; $1461.17 in 1980; $1244.41 in 1981;
    3
   Mitchell testified that he worked for Daniels at the tipples in 1966 and
1967. Daniels asserts that this was not possible because Mitchell did not
work for Daniels until 1974 and Mesa was not in existence before 1978.
This conflict was not discussed below, but is not significant as the
amount of time involved would be too small to affect the outcome. In
any event, the Social Security records document that Mitchell worked for
HJD Company during all four quarters of 1966 and the first quarter of
1967 and that he did not begin employment with Daniels until the last
quarter of 1974. There is, however, evidence that prior to Daniels
Group’s acquisition of Mesa in 1978, Peters Construction Company,
which was also a signatory to the UMW labor contract and owned by
Daniels Group, sometimes performed maintenance work at Daniels’ cus-
tomer sites. Peters Construction Company merged with Mesa in February
1979 and the name was changed to Mesa, which maintained the federal
employee identification number of the former entity. Accordingly,
Mitchell’s testimony may not be inconsistent with Daniels’ account.
Mitchell could have performed a small amount of tipple work for Peters
Construction in connection with a Daniels job.
               THE DANIELS COMPANY, INC. v. MITCHELL                   5
$8085.15 in 1982; $3523.93 in 1983; $1691.28 in 1984; $244.08 in
1985; $240.48 in 1986; and $654.64 in 1987.

   Employment records from Mesa were also introduced. Initially,
they indicated that Mitchell had worked a total of 680 hours for Mesa
while also an employee of Daniels. Additional records were later
found that raised that figure to 832.5 hours. According to Daniels,
Mitchell worked for Mesa for four days in 1979, eight days in 1980,
five days in 1981, twenty-six days in 1982, eleven days in 1983, five
days in 1984, one day in 1985, and one day in 1986. J.A. 409.

   Mitchell’s testimony was largely consistent with the documentary
evidence. He was unable to estimate the percentage of time he worked
at the tipples during his employment with Daniels, but confirmed that
he was not "at coal mining sites on a regular bas[is] during [ ]his four-
teen year period" of employment with Daniels. J.A. 193. He testified
that he only worked at the tipples when work there was offered and
that Mesa paid him for the work at tipple wages. He also confirmed
that coal was not being processed during his work, but testified that
coal dust present in the machines was often disturbed during the job.

   In February 1988, Mitchell suffered an unrelated on-the-job injury
when a hammer fell three stories and struck his head, ending his
employment. Shortly thereafter, Mitchell began experiencing persis-
tent fevers, fatigue and headaches. He underwent several hospitaliza-
tions and was diagnosed variously with meningitis, sarcoidosis, and
possible tuberculosis. Although his skin test for tuberculosis was neg-
ative, medical evidence indicated that active tuberculosis could exist
despite a negative reading. In June 1988, Mitchell was treated with
anti-tuberculosis medications and responded favorably. He never
returned to work at Daniels.

   In January 1997, nearly nine years later, Mitchell filed a claim for
black lung benefits under the Act. Mitchell alleged that he had
worked for Daniels from September 1974 to February 1988, in the
repair and maintenance of coal tipple equipment, and requested an
examination by Dr. Rhett Jabour. The Department of Labor desig-
nated Daniels as the responsible coal mine operator liable for the pay-
ment of any black lung benefits which may be due under the Act.
Daniels responded and denied liability, asserting that it was "an engi-
6              THE DANIELS COMPANY, INC. v. MITCHELL
neering/design company with a fabricating shop for spare parts and
construction of proprietary equipment" and "not an operator of a
mine or other covered facility." J.A. 117.

   In connection with his claim, Mitchell received the requested phys-
ical examination by Dr. Jabour, as well as x-rays, a CT scan of his
chest, pulmonary function studies, and arterial blood gas studies. Dr.
Jabour, who appears to have been provided with a twelve year history
of coal mine work, diagnosed Mitchell with complicated pneumoco-
niosis. Several x-ray readings by other physicians confirmed the pres-
ence of radiological evidence consistent with pneumoconiosis.

   On July 18, 1997, following an initial determination denying bene-
fits, an informal conference was held at Mitchell’s request before the
district director. For reasons not apparent from the record, Daniels did
not appear. However, the district director subsequently issued a Mem-
orandum of Conference finding that "[a]ll parties agreed that Mr.
Mitchell was a coal miner within the meaning of the Act and Regula-
tions," "agreed to 12 years of employment as a coal miner," and
"agreed that The Daniels Company meets all requirements for desig-
nation as responsible operator." J.A. 135. The district director also
found that Mitchell had established the existence of pneumoconiosis
and that, based upon the ten-year employment presumption contained
in the regulations, the pneumoconiosis arose from coal mine employ-
ment. See 20 C.F.R. § 718.302 (2006) ("If a miner who is suffering
or suffered from pneumoconiosis was employed for ten years or more
in one or more coal mines, there shall be a rebuttable presumption
that the pneumoconiosis arose out of such employment. (See
§ 718.203)."). However, benefits were denied because Mitchell had
failed to establish total disability. See 20 C.F.R. § 718.204 (2006).

   Pursuant to Mitchell’s request, a hearing was held on October 7,
1998, before Administrative Law Judge ("ALJ") Stuart Levin. Dan-
iels’ personnel director and a shop foreman appeared at the hearing
without legal representation. Although ALJ Levin initially questioned
the propriety of holding the hearing without legal representation pres-
ent for Daniels, he ultimately proceeded and allowed the Daniels
employees to testify regarding Mitchell’s employment history with
Daniels and Mesa and the extent of Mitchell’s actual exposure to coal
dust during his employment.
               THE DANIELS COMPANY, INC. v. MITCHELL                   7
   On May 18, 1999, ALJ Levin awarded benefits to Mitchell. The
ALJ found that "Daniels Company and Mesa Engineering were one
and the same employer," and that Daniels had previously stipulated
to its status as the responsible operator and to Mitchell’s history of
twelve years of coal mine employment. J.A. 251. The ALJ also found
that Mitchell had established complicated pneumoconiosis by radio-
graphic evidence, entitling him to an irrebuttable presumption of total
disability due to pneumoconiosis. See 20 C.F.R. §§ 718.204(b)(1),
718.304 (2006).

   Daniels obtained legal counsel and filed a petition for review with
the Board, challenging the propriety of the hearing being conducted
without its being specifically informed of the right to legal counsel,
as well as the determination that it was the responsible operator and
that Mitchell was entitled to benefits. On June 28, 2000, the Board
rejected the attorney representation claim and affirmed the responsi-
ble operator designation because Daniels had not timely objected to
the finding and, alternatively, because it was supported by substantial
evidence. However, the Board vacated and remanded the award of
benefits because the ALJ had failed to weigh conflicting medical evi-
dence on the issue of complicated pneumoconiosis. On remand, ALJ
Levin rejected Daniels’ assertion that the medical reports failed to
take into account Mitchell’s history of tuberculosis and found that
Mitchell had established complicated pneumoconiosis entitling him to
benefits.

   Daniels filed a petition for review, but shortly thereafter filed a
petition for modification and moved to remand the claim to the dis-
trict director for modification proceedings. See 20 C.F.R.
§ 725.310(a) (2006) (providing that "[u]pon his or her own initiative,
or upon the request of any party on grounds of a change in conditions
or because of a mistake in a determination of fact, the district director
may, at any time before one year from the date of the last payment
of benefits, or at any time before one year after the denial of a claim,
reconsider the terms of an award or denial of benefits"). Conse-
quently, the Board dismissed the petition for review subject to rein-
statement, and remanded the matter to the district director.

   In modification proceedings, Daniels submitted additional informa-
tion regarding the structure of Daniels and its relationship to Mesa,
8              THE DANIELS COMPANY, INC. v. MITCHELL
as well as more comprehensive records and testimony detailing
Mitchell’s work history at the tipples. Daniels also submitted medical
reports from Drs. Zaldivar, Meyer, Fino, Branscomb, Wiot, and Spitz,
who, by way of summary, collectively opined that Mitchell’s pulmo-
nary impairments were the result of his history of tuberculosis, sarcoi-
dosis, and cigarette smoking, and could not be the result of coal
workers’ pneumoconiosis given his limited actual exposure to coal
dust. The details of the medical opinions, as well as those submitted
in support of Mitchell, are exhaustively discussed in the underlying
decisions. For our purposes, it is sufficient to note that the parties
agree that Mitchell’s x-rays and CT scan show significant abnormali-
ties in his lungs, including opacities greater than one centimeter, but
disagree as to the cause of the abnormalities. Mitchell claims they are
the result of complicated pneumoconiosis caused by coal dust expo-
sure. Daniels asserts they are the result of sarcoidosis and tuberculo-
sis, and that Mitchell’s coal dust exposure was insufficient to have
resulted in simple, much less complicated, coal workers’ pneumoco-
niosis. The district director denied Daniels’ request for modification
without explanation.

   A hearing was thereafter held before ALJ Linda Chapman. With
regard to Daniels’ challenge to its designation as the responsible oper-
ator, ALJ Chapman found that ALJ Levin’s findings — that Mitchell
had worked as a miner for Daniels for twelve years and that Daniels
was properly designated the responsible operator — were "law of the
case" and could not be challenged in modification proceedings. With
regard to the entitlement claim, ALJ Chapman found no mistake of
fact in ALJ Levin’s determination that Mitchell had established com-
plicated pneumoconiosis by the x-ray evidence. In her ruling, how-
ever, ALJ Chapman refused to consider the additional medical reports
submitted by Daniels because she viewed them as having been based
solely on the assumption that Mitchell "had only 670 hours of coal
dust exposure, contrary to its earlier stipulation of 12 years, when in
fact [Daniels] has not established that there were no significant peri-
ods of coal dust exposure, and thus has not rebutted the regulatory
presumption that [Mitchell] was regularly and continuously exposed
to coal dust during the course of his employment with [Daniels]." J.A.
694. Given the stipulated history of twelve years of regular and con-
tinuous coal dust exposure, ALJ Chapman found "that the new medi-
cal opinion evidence does not affirmatively show that the opacities on
                THE DANIELS COMPANY, INC. v. MITCHELL                    9
[Mitchell’s] x-ray are not there, or are not what they seem to be, that
is, complicated pneumoconiosis." J.A. 694.

   Daniels thereafter sought Board review of ALJ Chapman’s deci-
sion, as well as reinstatement of its appeal of ALJ Levin’s decision.
The Board affirmed ALJ Levin’s decision and denied the claim that
ALJ Levin had erred in failing to notify Daniels of its right to counsel.
With regard to ALJ Chapman’s decision, the Board vacated the deter-
mination that ALJ Levin’s findings could not be challenged under the
"law of the case" doctrine and remanded for a determination of
"whether the stipulations were fairly entered into" at the informal con-
ference "and therefore binding upon the parties." J.A. 746. If so, the
parties could be bound on modification by them. If not, the ALJ was
directed to "render findings on whether [Daniels] meets the require-
ments of being named the responsible operator under the regulations
and the length of [Mitchell’s] coal mine employment." J.A. 746 (foot-
note omitted). With regard to ALJ Chapman’s finding that Mitchell
was entitled to benefits, the Board affirmed by a split decision.

   On remand, ALJ Chapman found that Daniels had fairly entered
into the stipulations and was bound by them. In the alternative, she
found that "the record supports the original findings of Judge Levin"
regarding those issues. J.A. 780.4 On review, the Board reversed ALJ
Chapman’s finding that Daniels had fairly entered into the stipula-
tions because Daniels was not present at the informal conference. See
Wellmore Coal Corp. v. Stiltner, 81 F.3d 490, 497 (4th Cir. 1996)
(noting that "the informal conference contemplated by the regulations
cannot take place without all parties present. Nor can a valid or mean-
ingful Memorandum of Conference be issued when the issues were
  4
    ALJ Chapman also sua sponte considered and held "that the interests
of justice have not been served by allowing [Daniels] to reopen these fac-
tual determinations by way of modification, and to attempt to make a
better showing, after its own failure to preserve those issues in accor-
dance with the procedural rules." J.A. 778. Nevertheless, she addressed
the issue of the fairness of the stipulations as directed by the Board and,
as noted by the Board, did not base her decision upon this initial determi-
nation regarding the propriety of allowing Daniels to reopen the issues
in modification proceedings. Accordingly, we also decline to address the
issue.
10             THE DANIELS COMPANY, INC. v. MITCHELL
not discussed by the parties and the deputy commissioner"). However,
the Board affirmed ALJ Chapman’s alternative finding that the record
sufficiently supported Daniels’ designation as the responsible opera-
tor. With regard to the entitlement issue, the Board believed it unnec-
essary to address whether ALJ Chapman’s finding that Mitchell had
twelve years of coal mine employment was supported by substantial
evidence because the ALJ’s finding that Mitchell had complicated
pneumoconiosis was not based upon a ten-year presumption of causa-
tion and, consequently, the award of benefits "[wa]s not tainted by
findings regarding the years of coal mine employment." J.A. 861.

                                   II.

   Daniels now seeks review of the Board’s decisions, challenging its
designation as the responsible operator, its determination that Mitch-
ell is entitled to black lung benefits, and its rejection of the attorney
representation challenge.

   On a petition for review of an order of the Board affirming an
ALJ’s decision, "we undertake an independent review of the record,
as in the place of the [Board]," see Dehue Coal Co. v. Ballard, 65
F.3d 1189, 1193 (4th Cir. 1995), to determine whether the decision
"is in accordance with the law and supported by substantial evidence,"
Collins v. Pond Creek Mining Co., 468 F.3d 213, 217 (4th Cir. 2006).
"In doing so, we confine our review to the grounds upon which the
[Board] based its decision." Id. We review the Board’s conclusions of
law de novo. See id.

                                  III.

   We begin with Daniels’ challenge to its designation as the respon-
sible coal mine operator liable for the payment of the black lung bene-
fits awarded to Mitchell under the Act.

                                   A.

  Under the Act, liability for the payment of black lung benefits is
imposed upon the coal industry. For claimants who worked as coal
miners on or after January 1, 1970, the Act places liability upon indi-
                THE DANIELS COMPANY, INC. v. MITCHELL                     11
vidual "responsible operator[s]." See Armco, Inc. v. Martin, 277 F.3d
468, 473 (4th Cir. 2002); see also 30 U.S.C.A. § 932 (West 1986 &
Supp. 2006); 20 C.F.R. § 725.490 (2000).

   The "responsible operator" is "the operator which is determined lia-
ble for the payment of benefits" under the regulations. 20 C.F.R.
§ 725.492(a) (2000). It is the Director’s burden to identify the respon-
sible operator, see 20 C.F.R. § 725.412 (2000), and to develop evi-
dence sufficient to support the conclusion that a potentially
responsible operator is liable for benefits. See Dir., OWCP v. Trace
Fork Coal Co., 67 F.3d 503, 507 (4th Cir. 1995) (holding that the
applicable regulations "give the Director, not [the designated respon-
sible operator], the power to develop evidence on [the responsible
operator] issue").5

   "For the purposes of determining whether an employer is or was
an operator or other employer covered by the Act which may be
found liable for the payment of benefits," there is a "presumption that
during the course of an individual’s employment, such individual was
regularly and continuously exposed to coal dust during the course of
employment." 20 C.F.R. § 725.492(c) (2000). This presumption "may
be rebutted by a showing that the employee was not exposed to coal
dust for significant periods during such employment." Id. In addition
to meeting other conditions specified in § 725.492,6 which are not at
issue here, the regulations also provide that "the operator or other
employer with which the miner had the most recent periods of cumu-
lative employment of not less than 1 year, as determined in accor-
dance with paragraph (b) [of section 725.493] shall be the
  5
     Under revisions to the regulations made effective to claims filed after
January 19, 2001, the burden now falls upon the designated responsible
operator to prove "[t]hat it is not the potentially liable operator that most
recently employed the miner." 20 C.F.R. § 725.495(c)(2)(2006).
   6
     "[T]he miner’s disability or death must have arisen, at least in part,
out of his employment with that operator; the operator must have oper-
ated a coal mine or other facility for any period after June 30, 1973; the
miner must have worked for the operator for at least one day after
December 31, 1969; and the operator must be capable of providing for
the payment of benefits." Armco, Inc. v. Martin, 277 F.3d 468, 473 n.1
(4th Cir. 2002).
12              THE DANIELS COMPANY, INC. v. MITCHELL
responsible operator." 20 C.F.R. §725.493(a)(1) (2000) (emphasis
added). Section 725.493(b), in turn, provides as follows:

      From the evidence presented, the identity of the operator or
      other employer with which the miner had the most recent
      periods of cumulative employment of not less than 1 year
      and, to the extent the evidence permits, the beginning and
      ending dates of such periods, shall be ascertained. For pur-
      poses of this section, a year of employment means a period
      of 1 year, or partial periods totalling 1 year, during which
      the miner was regularly employed in or around a coal mine
      by the operator or other employer. Regular employment
      may be established on the basis of any evidence presented,
      including the testimony of a claimant or other witnesses, and
      shall not be contingent upon a finding of a specific number
      of days of employment within a given period. However, if
      an operator or other employer proves that the miner was not
      employed by it for a period of at least 125 working days,
      such operator or other employer shall be determined to have
      established that the miner was not regularly employed for a
      cumulative year by such operator or employer for the pur-
      poses of paragraph (a) of this section. A "working day"
      means any day or part of a day for which a miner received
      pay for work as a miner (see § 725.202(a)).

20 C.F.R. § 725.493(b) (2000) (emphasis added).7 If the responsible
coal mine operator is "[in]capable of assuming its liability for the pay-
ment of continuing benefits," 20 C.F.R. § 725.492(a)(4) (2000), and
there is no "successor operator" liable for the payment of continuing
benefits, 20 C.F.R. § 725.493(a)(2) (2000), the next most recent
employer satisfying the definition of responsible operator will be con-
sidered the responsible operator, see 20 C.F.R. § 725.493(a)(4)
(2000). "[I]f no responsible operator can be identified, benefits are
  7
   Under § 725.202 of the regulations, the definition of a "miner"
includes persons who work in coal mine construction and transportation.
20 C.F.R. § 725.202(a) (2006). Such workers are considered miners "to
the extent [the] individual is or was exposed to coal mine dust as a result
of employment in or around a coal mine or coal preparation facility." 20
C.F.R. § 725.202(b) (2006).
               THE DANIELS COMPANY, INC. v. MITCHELL                 13
paid by the Black Lung Disability Trust Fund." 20 C.F.R. § 725.1(d)
(2000).

   In Armco, we interpreted the responsible operator provisions and
held that they provide for a distinct "two-step inquiry for determining
operator liability." Armco, 277 F.3d at 474. First, the "court must
determine whether a miner worked for an operator for ‘a period of
one year, or partial periods totaling one year.’" Id. (quoting 20 C.F.R.
§ 725.493(b) (1999)). Second, the court must determine "whether a
miner’s employment during that one year was ‘regular,’ i.e. whether,
during the one year, the miner ‘was regularly employed in or around
a coal mine.’" Id. (quoting 20 C.F.R. § 725.493(b)(1999)) (emphasis
added). The determination of whether the miner was "regularly
employed," in turn, is the subject of the remaining three sentences of
Section 725.493(b).

    The next sentence explains that "[r]egular employment may
    be established on the basis of any evidence presented,
    including the testimony of a claimant or other witnesses, and
    shall not be contingent upon a finding of a specific number
    of days of employment within a given period." The sentence
    thereafter establishes that if this evidence reveals that "the
    miner was not employed by [the operator] for a period of at
    least 125 working days, such operator or other employer
    shall be determined to have established that the miner was
    not regularly employed for a cumulative year." Finally, for
    establishing the 125 day minimum for regular employment,
    the subsection defines a working day to be "[all] or part of
    a day for which a miner received pay." All three sentences
    thus define "regular employment" and do not undermine the
    threshold requirement of one year of employment.

Id. at 474 (quoting 20 C.F.R. § 725.493(b) (1999) (internal citations
omitted). In summary, in order to establish that a particular operator
is properly designated the "responsible operator" under § 725.493(b),

    it must be shown that (1) a miner worked for the coal mine
    operator for one year or partial periods totalling one year
    and (2) the miner worked regularly during that one-year
    period. To fulfill the requirement of working "regularly," the
14              THE DANIELS COMPANY, INC. v. MITCHELL
      subsection imposes a minimum of 125 working days. Thus,
      the regulations provide that responsible operator liability
      does not arise unless an operator employed a miner for one
      calendar year during which the miner regularly worked for
      that operator, defining "regularly worked" to be a minimum
      of 125 work days.

Id. at 474-75 (emphasis added).

                                  B.

   In the proceedings below, ALJ Chapman found that Mitchell was
exposed to coal dust when he worked at the coal tipples for Daniels,
entitling him under § 725.492(c) to a presumption of regular and con-
tinuous exposure to coal dust during the course of his entire employ-
ment with Daniels. She rejected Daniels’ attempt to rebut the
presumption through its records of Mitchell’s actual coal dust expo-
sure because the "evidence supplied by [Daniels] indicated that
[Mitchell] worked a minimum 670 hours at the tipples from 1979 to
1986" and contradicted "the Social Security earnings records [which]
show that [Mitchell] began his employment in 1966, and ended in
1988." J.A. 781. Concluding that Daniels had failed to "establish that
Claimant had no significant periods of coal dust exposure," ALJ
Chapman ruled that Daniels had failed to "rebut[ ] the presumption set
forth in 20 C.F.R. § 725.492(c)." J.A. 781.8

   Having found that Mitchell was entitled to a presumption of
twelve-plus years of regular and continuous coal dust exposure during
his employment with Daniels under § 725.492, ALJ Chapman then
turned to § 725.493 and concluded that Daniels had been properly
designated the responsible operator because Mitchell had "worked at
least one cumulative year as a coal miner for Mesa." J.A. 782. The
ALJ arrived at this conclusion, however, by applying revised regula-
  8
   Because the Board reversed ALJ Chapman’s conclusion that the origi-
nal stipulations found by Judge Levin — that Mitchell had twelve years
of coal mine employment and that Daniels is the responsible operator —
were fairly entered into and binding on Daniels, we need only review
ALJ Chapman’s alternative finding that the stipulations were supported
by the record.
                THE DANIELS COMPANY, INC. v. MITCHELL                  15
tion 20 C.F.R. § 725.101(a)(32)(iii) (2006) and finding, based upon
Mitchell’s employment by Mesa in 1966-67, 1975-78, and 1979-87,
that Mitchell had "worked well over 200 days in or around the coal
mines" for Mesa. J.A. 783. Because Mitchell "met the minimum 125
days requirement" of § 725.493, ALJ Chapman held, Daniels "ha[d]
not established [Mitchell] was not regularly or continuously exposed
to coal dust." J.A. 783.9

  Daniels petitioned for review arguing, inter alia, that ALJ Chap-
man erred in applying revised regulation § 725.101(a)(32)(iii) to cal-
culate Mitchell’s working days for purposes of the responsible
operator inquiry and erred in finding it to be the responsible operator
under §§ 725.492 and .493 of the regulations.

                                   C.

   As correctly noted by Daniels, substantial revisions to the black
lung regulations were promulgated in 2000 and became effective on
January 19, 2001. With specified exceptions, including those provi-
sions which govern the responsible operator inquiry, the revised regu-
lations apply to all claims pending on that date. See 20 C.F.R.
§ 725.2(c) (2006). As a result, the revisions to the black lung regula-
tions govern the issue of whether Mitchell is entitled to black lung
benefits under the Act but not the issue of whether Daniels was prop-
erly designated the responsible operator liable for the payment of ben-
efits under the Act. See 20 C.F.R. § 725.2 (2006) (noting that the
revised regulations apply to the adjudication of claims pending on
January 19, 2001, with the exception of, among others, the responsi-
ble coal mine operator provisions set forth in §§ 725.491, 725.492,
725.493, 725.494).

   Under the revised regulations, "[a]n operator may be considered a
‘potentially liable operator’ with respect to a claim for benefits . . .
if," among other things, "[t]he miner was employed by the operator
  9
   ALJ Chapman also concluded, without explanation, that the "Social
Security earnings records clearly establish that [Mitchell] has sufficient
quarters of employment with Mesa to establish twelve years of coal mine
employment." J.A. 783. The Board did not affirm this finding nor is it
supported by substantial evidence.
16               THE DANIELS COMPANY, INC. v. MITCHELL
. . . for a cumulative period of not less than one year" as defined in
"§ 725.101(a)(32)." 20 C.F.R. § 725.494(c) (2006). Section
725.101(a), which provides general definitions for various terms used
in the regulations, now includes a definition at subsection (a)(32) for
a "year," as "a period of one calendar year (365 days, or 366 days if
one of the days is February 29), or partial periods totaling one year,
during which the miner worked in or around a coal mine or mines for
at least 125 ‘working days.’" 20 C.F.R. § 725.101(a)(32).10 Subsection
(iii) of Section 725.101(a)(32), upon which ALJ Chapman relied, pro-
vides that:

       If the evidence is insufficient to establish the beginning and
       ending dates of the miner’s coal mine employment, or the
       miner’s employment lasted less than a calendar year, then
       the adjudication officer may use the following formula:
       divide the miner’s yearly income from work as a miner by
       the coal mine industry’s average daily earnings for that year,
       as reported by the Bureau of Labor Statistics (BLS). A copy
       of the BLS table shall be made a part of the record if the
       adjudication officer uses this method to establish the length
       of the miner’s work history.

20 C.F.R. § 725.101(a)(32)(iii) (2006).11
  10
      A "‘working day’ means any day or part of a day for which a miner
received pay for work as a miner, but shall not include any day for which
the miner received pay while on an approved absence, such as vacation
or sick leave." 20 C.F.R. § 725.101(a)(32) (2006). However, "[i]n deter-
mining whether a miner worked for one year, any day for which the
miner received pay while on an approved absence, such as vacation or
sick leave, may be counted as part of the calendar year and as partial
periods totaling one year." Id.
   11
      According to the Judges’ Benchbook of the Black Lung Benefits Act,
the Bureau of Labor Statistics table referenced in § 725.101(a)(32) does
not exist. The Department has adopted for use a table set forth as Exhibit
610 of the Office of Workers’ Compensation Programs Coal Mine
(BLBA) Procedure Manual instead. See http://oalj.dol.gov/PUBLIC/
BLACK_LUNG/REFERENCES/REFERENCE_WORKS/BEN06.
HTM#_FTNREF4. For ease of reference, we continue to refer to it as the
BLS table.
               THE DANIELS COMPANY, INC. v. MITCHELL                17
   On review of the ALJ’s determination, the Board acknowledged
that § 725.101(a)(32)(iii) is inapplicable to the responsible operator
inquiry, but nevertheless affirmed. Specifically, the Board held that
use of the formula "as a guide" was permissible because § 725.493
provides no suggested method of calculation and the ALJ had the dis-
cretion to apply any reasonable method. The Board also rejected Dan-
iels’ assertion that remand was required due to the ALJ’s failure to
explain her calculation and provide a copy of the BLS average daily
earnings table as required by § 725.101(a)(32)(iii), because Daniels,
in the context of applying the same calculation to the entitlement
issue, had calculated 217.23 working days with Mesa. The Board then
affirmed the ALJ’s finding that Daniels had failed to "prove that the
miner was not employed by it for at least 125 working days pursuant
to Section 725.493(b)," and the "related finding that, based on a find-
ing of over 200 working days, employer did not rebut the presumption
of Section 725.492(c) . . . (requiring proof that the miner ‘was not
exposed to coal dust for significant periods during such employ-
ment’)." J.A. 863.

                                  D.

   We hold that the ALJ had insufficient evidence to sustain the des-
ignation of Daniels as the responsible operator liable for the payment
of black lung benefits to Mitchell under the Act and that the ALJ and
Board erred as a matter of law in its application of the regulations
governing the proper designation of the responsible operator.

   Daniels, which is unionized under the United Steelworkers Union,
does not operate a coal mine or coal tipple and does not perform coal
mine or coal tipple work. It was designated the responsible operator
under the Act by the director because Mitchell, in his original claim
filed in January 1997, asserted that he worked for Daniels repairing
and maintaining coal tipples from September 1974 to February 1988
(not 1966 to 1988 as found by the ALJ). The evidence, however, does
not support even the former assertion, nor has Mitchell maintained as
much in these proceedings. Mitchell was employed full-time by Dan-
iels from September 1974 to February 1988, but not as a miner. Thus,
standing alone, Daniels could not be designated a responsible operator
under the Act because it is not engaged in coal mine or coal tipple
work, nor did Mitchell technically perform any such work or receive
18             THE DANIELS COMPANY, INC. v. MITCHELL
wages for it from Daniels. Mitchell did, however, work sporadically
in the tipples from 1979 to 1986, while also employed by Daniels, on
a part-time and as-needed basis repairing and maintaining equipment
located at various tipple sites as an employee of Daniels’ sister com-
pany, Mesa, which is unionized under and subject to the United Mine
Workers Union.

   Notwithstanding this undisputed evidence of a much more limited
exposure to coal tipple work, the ALJ found that Mitchell was entitled
to a presumption of regular and continuous exposure to coal dust dur-
ing his entire tenure of employment with Daniels and that Daniels had
failed to rebut that presumption. This determination was based upon
the ALJ’s finding that Mitchell’s history of 670 hours of coal tipple
employment covered only the years 1979 to 1986, and did not account
for the fact that the Social Security records contained a work history
from 1966 to 1988.

   The ALJ’s finding that Mitchell was employed by Daniels from
1966 to 1988 is clearly unsupported by the evidence in the record.
Indeed, the evidence in this regard is uncontradicted. However, even
if one attributes Mitchell’s coal tipple work for Mesa to Daniels and
concludes that he was entitled to the presumption of regular and con-
tinuous exposure to coal dust during his actual years of employment
with Daniels (1974-1988), Daniels has rebutted the presumption of
regular and continuous coal dust exposure during those years through
the uncontradicted evidence that Mitchell’s actual exposure was lim-
ited to the relatively small amount of time he was technically working
for and paid by Mesa.

   The director has likewise failed to demonstrate that Daniels meets
the criteria for designation as the responsible operator under
§ 725.493. Although it is not entirely clear from the analysis, it
appears that the ALJ found that Mitchell had "worked at least one
cumulative year as a coal miner for Mesa" because he had worked for
Mesa in or around the coal tipples "for a period of at least 125 work-
ing days." J.A. 782 (emphasis added). And, the ALJ also arrived at
the finding of greater than 125 working days by applying
§ 725.101(a)(32)(iii) (2006). Hence, it appears that the ALJ may have
viewed Daniels to be a responsible operator based upon the general
                THE DANIELS COMPANY, INC. v. MITCHELL                  19
presumption of § 725.492, and viewed Mesa to be a responsible oper-
ator based upon the specific criteria of § 725.493.

   In any event, an employer’s liability as the responsible operator for
payment of any award of black lung benefits to a miner does not arise
unless the evidence establishes that the employer employed the miner
for one calendar year during which the miner regularly worked in or
around a coal mine (or tipple in this case), defining regularly worked
to be a minimum of 125 working days. See 20 C.F.R. § 725.493
(2000); Armco, 277 F.3d at 474-75. A "‘working day’" means any day
or part of a day for which a miner received pay for work as a miner."
20 C.F.R. § 725.493 (2000). It is a distinctive two-step inquiry. See
Armco, 277 F.3d at 474.

   If we view Mitchell as an employee of only Mesa when he was
working as a miner, the first step of the "responsible operator" inquiry
is not met. The ALJ found that Mitchell "worked at least one cumula-
tive year as a coal miner for Mesa," J.A. 782, based upon her finding,
under the revised regulation, that Mitchell "worked well over 200
days in or around the coal mines," J.A. 783. This finding, however,
conflates the two inquiries and relies upon an inapplicable regulation,
rendering it erroneous as a matter of law. It is also unsupported by
substantial evidence as no one claims that Mitchell worked for Mesa
for a period of one year or partial periods totaling one year.

   If we view Mitchell as an employee of Daniels and attribute his
time in the coal tipples as a Mesa employee to Daniels, as apparently
the Board did, then the evidence is sufficient to establish the first step
of the inquiry. Mitchell was employed by Daniels for the minimum
period of one year. The evidence is insufficient, however, to establish
the second step of the inquiry — that Mitchell "was regularly
employed in or around a coal mine by the operator or other employer"
during his employment. 20 C.F.R. § 725.493(b) (2000).

   The ALJ found that Mitchell worked "well over 200 days in or
around the coal mines" based upon a purported calculation of working
days under revised regulation 20 C.F.R. § 725.101(a)(32)(iii). The
Board acknowledged that the revised regulation was inapplicable, but
held that its use as a "guide" was permissible and affirmed the finding
20              THE DANIELS COMPANY, INC. v. MITCHELL
that Mitchell had more than 125 working days for purposes of
§ 725.493. This was error.

   First, even if it would be generally appropriate to use
§ 725.101(a)(32)(iii)’s formula as a "guide" to calculate "working
days" in cases which precede its effective date, it was not appropriate
to apply it as a guide in this case. By its terms, the regulation may be
used in situations where the miner’s employment lasted less than one
year or "the beginning and ending dates of the miner’s coal
mine employment" cannot be established. See 20 C.F.R.
§ 725.101(a)(32)(iii) (2006). Here, the record contains documentary
evidence of Mitchell’s employment by Mesa, including "payroll reg-
isters listing the specific dates on which the miner was dispatched to
the coal mine tipples, his hours, and his pay." J.A. 867. The formula’s
calculation is also to be based upon BLS average daily earnings for
the coal mine industry, and any calculation thereunder "shall" be
accompanied by a copy of the BLS table. Here, the ALJ did not attach
the table and did not explain her calculation. Nor does it appear that
she took into account the undisputed evidence that Mitchell, by virtue
of the character of his work for Mesa, was paid tipple wages at
inflated overtime rates. In short, § 725.101(a)(32)(iii) is not applicable
to the responsible operator inquiry in this case, nor would we affirm
its use as a "guide" given the multiple deficiencies present in its appli-
cation; its use as a "guide" in this case could not help but yield an
unreliable and unfair result.

   Second, even if we thought the calculation to be appropriate and
representative of Mitchell’s actual work days in the tipples, the find-
ing that Mitchell "worked well over 200 days in or around the coal
mines" (or 217 days as calculated by the Daniels in the entitlement
context) does not translate to a finding that Daniels has been properly
designated a responsible operator.12 In order for Daniels to be liable
  12
    Daniels does not dispute that it calculated 217 days under the regula-
tion’s formula in the context of addressing the entitlement issue. How-
ever, this was done for the purpose of demonstrating that the finding of
twelve years of coal mine employment — which impacts the determina-
tion of whether Mitchell had coal miner’s pneumoconiosis — would also
be unsupported by the calculation under the regulation. Daniels’ calcula-
tion does not undermine the actual evidence of Mitchell’s working days,
               THE DANIELS COMPANY, INC. v. MITCHELL                  21
as the "responsible operator" under § 725.493(b), the director was
required to show that Daniels employed Mitchell "for one calendar
year during which the miner regularly worked for [Daniels], defining
‘regularly worked’ to be a minimum of 125 work days." Armco, 277
F.3d at 475 (emphasis added). However, because Mitchell worked
approximately 200 days in coal tipples over the course of his entire
fourteen-year career as a Daniels employee, the Board held that he
was properly deemed to have worked regularly as a coal miner in coal
mine employment. Under the view of the Board and director, "regular
employment" under § 725.493(b) is established if an employee works
a total of 125 days over the course of his entire period of employment,
even if that employment lasts for a decade or more. So long as the
employee worked a total of at least 125 days in or around a coal mine
or tipple at any time during his employment, he will be deemed to
have been "regularly employed in or around a coal mine." Id. at 474
(internal quotation marks omitted). We have not interpreted § 725.493
in such a manner nor, as we noted in Armco, do the intervening
amendments to the regulations support such an interpretation:

    In 20 C.F.R. § 725.494(c)(2001), the Department of Labor
    states that an operator is a responsible operator only if the
    miner at issue "was employed by the operator . . . for a
    cumulative period of not less than one year." The section
    then references 20 C.F.R. § 725.101(a)(32) (2001), which
    defines a "year" as "a period of one calendar year (365 days,
    or 366 days if one of the days is February 29), or partial
    periods totaling one year, during which the miner worked in
    or around a coal mine or mines for at least 125 ‘working
    days.’" Although these later revisions do not bind our inter-

nor would any calculation under that regulation take into account that
Mitchell’s wages were substantially inflated because he was paid time-
and-a-half, double-time, and sometimes triple-time wages because his
work fell on holidays and weekends when the tipples were not in opera-
tion. Accordingly, the estimate produced by the formula would be
expected to substantially exceed the actual days worked. In short, it is
unfair to excuse the ALJ’s improper use of the regulation simply because
Daniels arrived at a similar figure when properly applying it on an unre-
lated issue.
22               THE DANIELS COMPANY, INC. v. MITCHELL
       pretation of the regulations as they stood at the time of the
       claim’s resolution, they do inform our analysis of what the
       earlier, less clearly written regulations were intended to
       mean.

Id. at 475 (emphasis added).

   To conclude, in order to designate Daniels as the responsible oper-
ator liable for the payment of any benefits due under the Act, it was
incumbent upon the director to show that Daniels employed Mitchell
"for one calendar year during which [Mitchell] regularly worked for
[Daniels], defining ‘regularly worked’ to be a minimum of 125 work
days." Id. at 475 (emphasis added). The director was not put to this
task and substantial evidence does not support the determination.
Accordingly, we grant Daniels’ petition for review of the decision of
the Benefits Review Board and reverse the Board’s decision affirming
Daniels’ designation as the responsible operator under the Act.13

                                   IV.

  We now turn to Daniels’ challenge to the ALJ’s determination that
Mitchell is entitled to black lung benefits under the Act.

   In order to establish an entitlement to black lung benefits, "a claim-
ant must prove that (1) he has pneumoconiosis; (2) the pneumoconio-
sis arose out of his coal mine employment; (3) he has a totally
disabling respiratory or pulmonary condition; and (4) pneumoconiosis
is a contributing cause to his total respiratory disability." See Milburn
Colliery Co. v. Hicks, 138 F.3d 524, 529 (4th Cir. 1998); 20 C.F.R.
§§ 718.201-.204 (2006).

   With regard to the second element, § 718.203 of the regulation
"sets forth two methods by which a claimant may establish that his
pneumoconiosis arose at least in part out of his coal mine employ-
  13
    Because we hold that Daniels was not properly designated to be the
responsible operator, it is unnecessary for us to address Daniels’ alterna-
tive argument that ALJ Levin erred in conducting the initial hearing in
this case without specifically advising Daniels of its right to representa-
tion by legal counsel.
                THE DANIELS COMPANY, INC. v. MITCHELL                  23
ment." Napier v. Dir., OWCP, 890 F.2d 669, 671 (4th Cir. 1989) (per
curiam). "If a miner who is suffering or suffered from pneumoconio-
sis was employed for ten years or more in one or more coal mines,
there shall be a rebuttable presumption that the pneumoconiosis arose
out of such employment." 20 C.F.R. § 718.203(b) (2006); see also 20
C.F.R. § 718.302 (2006) (same). But "[i]f a miner who is suffering or
suffered from pneumoconiosis was employed less than ten years in
the nation’s coal mines, it shall be determined that such pneumoconi-
osis arose out of that employment only if competent evidence estab-
lishes such a relationship." 20 C.F.R. § 718.203(c) (2006). The
presumption "appl[ies] only if a miner worked in one or more coal
mines for the number of years required to invoke the presumption,"
and "[t]he length of the miner’s coal mine work history must be com-
puted as provided by 20 C.F.R. § 725.101(a)(32)." 20 C.F.R.
§ 718.301 (2006).

   With regard to the element of total disability, § 718.304 of the reg-
ulation provides for "an irrebuttable presumption" of total disability
"due to pneumoconiosis if (A) an x-ray of the miner’s lungs shows
at least one opacity greater than one centimeter in diameter; (B) a
biopsy reveals ‘massive lesions’ in the lungs; or (C) a diagnosis by
other means reveals a result equivalent to (A) or (B)." E. Associated
Coal Corp. v. Dir., OWCP, 220 F.3d 250, 255 (4th Cir. 2000) (foot-
note omitted); 20 C.F.R. § 718.304 (2006). "The condition described
by these criteria is frequently referred to as ‘complicated pneumoco-
niosis,’ although that term does not appear in the statute." E. Associ-
ated Coal, 220 F.3d at 255.

   In this case, Mitchell’s x-rays and CT scan showed significant
abnormalities in his lungs, including opacities greater than one centi-
meter in diameter, which could be consistent with pneumoconiosis
and entitle him to the irrebuttable presumption of total disability. It
is not enough, however, for the miner to prove that he has radio-
graphic findings consistent with complicated pneumoconiosis and,
thereby, that he is entitled to the irrebuttable presumption of total dis-
ability. The presumption of § 718.304 only establishes the third requi-
site element of proving total disability. The miner must also
independently establish the second element — that his "pneumoconi-
osis arose at least in part out of coal mine employment." 20 C.F.R.
§ 718.203(a) (2006).
24             THE DANIELS COMPANY, INC. v. MITCHELL
   Early in these proceedings, the director found that the parties had
stipulated to "12 years of employment as a coal miner" at the informal
conference and that, based upon the 10-year employment presumption
contained in 20 C.F.R. § 718.302, Mitchell had established that the
pneumoconiosis arose from coal mine employment — stipulations
that were upheld by ALJ Levin and ALJ Chapman. In modification
proceedings, ALJ Chapman also refused to consider the expert opin-
ions of Drs. Zaldivar, Wiot, Banscomb, Fino, Meyer, and Spitz, who
concluded that the abnormalities were not the result of coal dust expo-
sure because the 670 hours of exposure upon which their opinions
were based was "contrary to [Daniels’] earlier stipulation of 12
years," J.A. 694, and did "not take into account the years 1966 to
1978, and 1987 and 1988, when [Mitchell’s] social security earnings
records reflect that he worked for [Daniels]." J.A. 693. Accordingly,
ALJ Chapman ruled that "the new medical opinion evidence does not
affirmatively show that the opacities on [Mitchell’s] x-ray are not
there, or are not what they seem to be, that is, complicated pneumoco-
niosis." J.A. 694.

   Albeit through a tortured procedural history, the Board ultimately
ruled that Daniels had not fairly entered into the stipulations at the
informal conference and were not bound by them, but affirmed the
ALJ’s alternative finding that Mitchell was entitled to benefits
because he had established the existence of complicated pneumoconi-
osis under 20 C.F.R. § 718.304 and because the new medical opinion
evidence regarding causation did not refute that finding. The Board
declined, however, to endorse the ALJ’s finding that Mitchell had
twelve years of coal mine employment:

     [R]eview of the administrative law judge’s decision reveals
     that the stipulation form reflecting twelve years of coal mine
     employment had no bearing on her decision; she relied upon
     the evidence in the record to find that the abnormalities
     shown on x-ray were complicated pneumoconiosis arising
     out of coal mine employment. . . .

     [T]he determination that claimant established the existence
     of complicated pneumoconiosis arising out of coal mine
     employment was made without benefit or application of the
     ten year presumption at Section 718.203(b). Accordingly,
               THE DANIELS COMPANY, INC. v. MITCHELL                  25
    we need not address whether the administrative law judge
    on remand erred in finding that the record supported a find-
    ing of twelve years of coal mine employment. In sum, since
    both [ALJs] analyzed the evidence of record to find that
    claimant established the existence of complicated pneumo-
    coniosis arising out of coal mine employment, the award of
    benefits is not tainted by findings regarding the years of coal
    mine employment.

J.A. 860-61. The dissenting judge disagreed. She would have
remanded the case to the ALJ for proper calculation of the years of
coal mine employment under § 725.101(a)(32) and reconsideration of
the medical evidence in light of this finding. As noted by the dissent-
ing judge:

    In this case, the length of the miner’s coal mine work history
    and the number of his working days are essentially the
    same, since the record documents that the miner’s coal mine
    employment occurred when he was sent to coal mine tipples
    to install equipment manufactured by his employer, not dur-
    ing the bulk of his time that he spent working in his employ-
    er’s fabrication shop building that equipment. The record
    contains payroll registers listing the specific dates on which
    the miner was dispatched to the coal mine tipples, his hours,
    and his pay. Thus, employer validly argues that the adminis-
    trative law judge should have determined the length of the
    miner’s coal mine employment by using the same formula
    from Section 725.101(a)(32) that she employed to calculate
    the miner’s working days.

    Using the formula in Section 725.101(a)(32)(iii), the admin-
    istrative law judge determined that the miner worked "well
    over 200 days in or around the coal mines." Yet when she
    determined the length of the miner’s coal mine employment
    [for purposes of the responsible operator inquiry], she
    merely referenced his Social Security earnings records to
    find twelve years of coal mine employment.

J.A. 866-67 (internal citations and footnote omitted).
26              THE DANIELS COMPANY, INC. v. MITCHELL
   On appeal, Mitchell acknowledges the ALJ’s failure to compute
Mitchell’s coal mine work history under § 725.101(a)(32) for pur-
poses of evaluating his entitlement to benefits under the Act, but he
asserts that we should affirm because (1) causation was not based
upon the ten year presumption found at 20 C.F.R. § 718.203; and (2)
the entitlement to benefits determination was based upon § 718.304’s
irrebuttable presumption of total disability, which flows from the
presence of opacities greater than one centimeter in diameter on the
x-ray and not from the establishment of a certain minimum number
of years of coal mine employment. We are unpersuaded.

   First, it is clear that Mitchell was originally awarded benefits based
upon the now-defunct stipulation of twelve years of coal mine
employment. After that stipulation was found non-binding, the ALJ
failed to properly calculate the number of work days, failed to evalu-
ate the medical evidence in light of the limited history of coal dust
exposure, and discredited numerous medical reports from competent
physicians who relied on a history of much less than twelve years of
coal mine employment in reaching their opinion that the x-ray opaci-
ties could not have resulted from coal dust exposure. To the extent
she considered the causation element separately, she appears to have
relied upon her determination that the record supported a finding that
Mitchell had twelve years of coal mine employment, but that finding
was not affirmed by the Board and is not supported by substantial evi-
dence.14
  14
     As noted above, the amendments to the regulations are applicable to
the entitlement issue, but not the responsible operator issue. The ALJ
purported to calculate Mitchell’s coal mine work history under
§ 725.101(a)(32) for purposes of evaluating whether Daniels was prop-
erly designated the responsible operator, and determined that Mitchell
worked "well in excess of 200 days," but did not reach a definite calcula-
tion, did not explain her calculation, and did not attach the required BLS
document. The ALJ did not utilize § 725.101(a)(32) in evaluating Mitch-
ell’s coal employment history when determining that he was entitled to
benefits. Had she done so, we must assume that she would have arrived
at the same approximation of 200 days and would not have calculated
Mitchell’s coal mine work history anywhere close to the requisite ten
years necessary to invoke the presumption of causation under § 718.302.
               THE DANIELS COMPANY, INC. v. MITCHELL                 27
   The Board’s conclusion that the finding of twelve years of coal
mine employment is irrelevant to the entitlement issue because the
irrebuttable presumption of § 718.304 was applied and subsumed the
causation element is also erroneous. Although true that the § 718.304
presumption of total disability is not dependent upon a finding of ten
or more years of coal mine employment, it is only an irrebuttable pre-
sumption of total disability. To prove entitlement to benefits, the
remaining elements must be satisfied. As noted by the dissenting
judge,

    with less than ten years of coal mine employment, the miner
    would have had to prove that his complicated pneumoconio-
    sis, if present, arose out of coal mine employment. See 20
    C.F.R. § 718.203(b), (c) . . . . In reviewing the various
    administrative law judges’ decisions over the course of the
    claim proceedings, I am not convinced that the miner was
    made to prove that his complicated pneumoconiosis arose
    out of coal mine employment.

J.A. 868. We agree. Because the ALJ erred in failing to calculate
Mitchell’s years of coal mine employment in accordance with the reg-
ulations and erred in failing to properly consider and weigh the medi-
cal evidence in light of an accurate history of coal dust exposure, we
vacate the award of black lung benefits and remand for further pro-
ceedings in accordance with this opinion.

                                  V.

   For the foregoing reasons, we grant Daniels’ petition for review
and reverse the decision and order finding Daniels to be the responsi-
ble coal mine operator liable for payment of black lung benefits to
Mitchell under the Act. Because Daniels is entitled to be dismissed,
further challenges to the award of black lung benefits now falls upon
the director. Accordingly, we vacate the decision awarding black lung
benefits and remand the remainder of this matter to the Board for a
determination of the director’s position on Mitchell’s continued enti-
tlement to benefits in the wake of our responsible operator ruling and,
if necessary, a proper calculation of the length of Mitchell’s coal mine
employment and evaluation of the medical evidence in light of that
finding.
28   THE DANIELS COMPANY, INC. v. MITCHELL
                                  REVERSED IN PART,
                                  VACATED IN PART,
                                    AND REMANDED
