Secretary of Labor v. KC Transport, Inc.

United States Court of Appeals
FOR THE DISTRICT OF COLUMBIA CIRCUIT

Argued December 15, 2022 Decided August 1, 2023

No. 22-1071

SECRETARY OF LABOR, MINE SAFETY AND HEALTH
ADMINISTRATION,
PETITIONER

v.

KC TRANSPORT, INC. AND FEDERAL MINE SAFETY AND
HEALTH REVIEW COMMISSION,
RESPONDENTS

On Petition for Review of a Decision of the
Federal Mine Safety and Health Review Commission

Susannah M. Maltz, Attorney, U.S. Department of Labor,
argued the cause for petitioner. With her on the briefs was
Emily Toler Scott, Counsel for Appellate Litigation.

James P. McHugh argued the cause for respondent KC
Transport, Inc. With him on the brief was Christopher D.
Pence. Thaddeus Jason Riley entered an appearance.

Before: WILKINS, WALKER, and PAN, Circuit Judges.
 2
Opinion for the Court filed by Circuit Judge WILKINS.

Dissenting opinion filed by Circuit Judge WALKER.

WILKINS, Circuit Judge: Congress affirmed the
importance of regulating effective health and safety standards
within the mining industry when it enacted the 1977 Federal
Mine Safety and Health Amendments Act (“Mine Act”), Pub.
L. No. 95-164, 91 Stat. 1290 (1977) (codified as amended at 30
U.S.C. § 801 et seq.). This dispute does not concern the
substance of the Mine Act’s safety standards, but rather the
jurisdictional boundaries to which they apply.

KC Transport is an independent trucking company that
provides various hauling services. Some of its clients include
mining companies, and KC Transport used a facility, located
over one mile from one of its client’s mining extraction sites,
as a maintenance area. A Mine Safety and Health
Administration (“MSHA”) inspector visited this area, after
having inspected the nearby mine, and observed two of KC
Transport’s trucks undergoing maintenance. Both trucks were
raised, unblocked from motion, and one truck had a person
standing underneath it. Because the trucks’ conditions violated
safety standard 30 C.F.R. § 77.404(c), the MSHA inspector
issued KC Transport two citations. KC Transport contested
MSHA’s jurisdiction to issue the citations, arguing that the
Mine Act does not apply. If the Mine Act does apply, however,
KC Transport concedes that its trucks violated safety standards
and the citations are thus valid.

The Mine Act governs the regulation of “coal or other
mine[s,]” 30 U.S.C. § 802(h)(1), as well as the activities of
those who “operate[], control[], or supervise[,]” or “perform[]
services or construction at such mine[s],” called “operator[s,]”
id. § 802(d). Its jurisdiction covers all “mines,” which are
 3
defined by statute as: (A) extraction sites; (B) the “private
ways and roads appurtenant” thereto; and (C) a list of items
“used in, or to be used in, or resulting from,” mining-related
activity. Id. § 802(h)(1).

In the proceeding on review challenging MSHA’s
jurisdiction, the Federal Mine Safety and Health Review
Commission (“Commission”) held that for the list of items, in
§ 802(h)(1)(C), to be considered a “mine,” the items had to be
located at an extraction site, id. § 802(h)(1)(A), or the roads
appurtenant thereto, id. § 802(h)(1)(B). Because neither the
trucks nor the facility, associated with the citations at issue,
were located on land covered under subsections (A)–(B), the
Commission found they failed to constitute a “mine” and
vacated the citations. The Commission also found that, as an
independent contractor not engaged in servicing a mine at the
time of citation, KC Transport failed to qualify as an “operator”
under § 802(d) of the Mine Act.

The Secretary of Labor (“the Secretary”), acting through
MSHA, appeals the Commission’s decision and asks us to
uphold the two citations as an appropriate exercise of the
Secretary’s jurisdiction under the Mine Act. In the Secretary’s
view, subsection (C) of the “mine” definition covers KC
Transport’s facility and trucks because they were “used in”
mining activity. See § 802(h)(1)(C).

Given the Mine Act’s language, context, and our binding
precedent, we find that the Commission erred in its
interpretation of the “mine” and “operator” definitions. And
we generally defer to the Secretary’s reasonable interpretation
of an ambiguous statute—even when the Commission
disagrees. See Martin v. Occupational Safety & Health Rev.
Comm’n, 499 U.S. 144, 158 (1991); Excel Mining, 334 F.3d at
6. But here, the Secretary’s position treats subsection (C) as
 4
unambiguous and makes no meaningful effort to address the
numerous practical concerns that would arise under such an
interpretation. Therefore, and in conformity with our
precedent, we vacate and remand the Commission’s decision,
allowing the Secretary to interpret the statute’s ambiguous
language. See Sec’y of Lab. v. Nat’l Cement Co. of Cal., Inc.
(“National Cement I”), 494 F.3d 1066, 1077 (D.C. Cir. 2007).

I.

A.

Congress enacted the Federal Coal Mine Health and Safety
Act (“Coal Act”) in 1969 with the purpose of “improv[ing]
mandatory health or safety standards to protect the health and
safety of the Nation’s coal miners[.]” Pub. L. No. 91-173,
§ 2(g), 83 Stat. 742, 743 (1969). As our nation’s use of mines
continued, so too did the occurrence of mining-related
incidents. For example, 226 miners tragically died from
unexpected mine explosions in West Virginia, Ohio, and
Pennsylvania in 1940 alone. See J. Davitt McAteer, The
Federal Mine Safety and Health Act of 1977: Preserving a Law
that Works, 98 W. Va. L. Rev. 1105, 1113 (1996). Additional
incidents also took the lives of 119 miners in Illinois in 1951;
78 miners in West Virginia in 1968; 91 miners in Idaho in
1972; and 26 miners in Kentucky in 1976. Id.

Because several forms of mine-related property were not
enumerated in the Coal Act’s mine definition, incidents like the
collapse of a retention dam left confusion as to whether the
Coal Act’s protections applied. This lack of clarity put the
Act’s jurisdictional bounds in question, prompting
congressional action. Indeed, upon enacting the more
comprehensive 1977 Mine Act, Congress cited the 1972
collapse of the West Virginia retention dam—“result[ing] in a
 5
large number of deaths, and untold hardship to downstream
residents[]”—as a reason to amend the “mine” definition.
S. REP. NO. 95–181, at 14 (1977) (explaining the need to clarify
the “mine” definition as “the Committee [was] greatly
concerned that at [the time of the 1972 dam incident], the scope
of the authority of the Bureau of Mines to regulate such
structures . . . was questioned [under the Coal Act]”).

The Mine Act established one regulatory scheme, covering
the mining of coal, metals, and non-metals. See Sec’y of Lab.
v. Excel Mining, LLC, 334 F.3d 1, 3 (D.C. Cir. 2003) (citing 30
U.S.C. § 961(a)). In doing so, Congress affirmed that “the first
priority and concern of all in the coal or other mining industry
must be the health and safety of its most precious resource—
the miner[.]” 30 U.S.C. § 801(a). It also aimed “to provide
more effective means and measures for improving the working
conditions” in American mines and “to prevent death[,] serious
physical harm, and . . . occupational diseases[.]” Id. § 801(c).
The Secretary is authorized to enforce this goal, and the Mine
Act “created within the Department of Labor a new agency,
[MSHA], to administer its provisions.” Am. Coal Co. v.
FMSHRC, 796 F.3d 18, 21 (D.C. Cir. 2015). Under this
structure, the Secretary “develop[s] and “promulgate[s]”
“improved mandatory health or safety standards for the
protection of life” in mines. 30 U.S.C. § 811(a). MSHA
enforces these standards by conducting regular inspections, see
§ 813(a); issuing safety orders, see § 813(k); and issuing
citations for violations, see §§ 813(a), 815(a); for the Secretary
to then assess and assign a corresponding penalty, see § 820(a).
Any resulting citations, orders, or penalties may be reviewed
by the Commission. In practice, mine operators may contest
citations before an administrative law judge (“ALJ”), and
either party may subsequently appeal the ALJ’s decision to the
Commission. Am. Coal Co., 796 F.3d at 21.
 6
Given the nature of this case, it is important to emphasize
that no part of this miner-safety-centered process applies absent
jurisdiction. Whether property is subject to the Mine Act’s
frequent inspections and other procedures is thus contingent
upon whether the property constitutes a “mine.” A “coal or
other mine” is defined under 30 U.S.C. § 802(h)(1) as:

(A) an area of land from which minerals are
extracted in nonliquid form or, if in liquid form,
are extracted with workers underground, (B)
private ways and roads appurtenant to such area,
and (C) lands, excavations, underground
passageways, shafts, slopes, tunnels and
workings, structures, facilities, equipment,
machines, tools, or other property including
impoundments, retention dams, and tailings
ponds, on the surface or underground, used in,
or to be used in, or resulting from, the work of
extracting such minerals from their natural
deposits in nonliquid form, or if in liquid form,
with workers underground, or used in, or to be
used in, the milling of such minerals, or the
work of preparing coal or other minerals, and
includes custom coal preparation facilities.

30 U.S.C. § 802(h) (emphases added). In sum, the statute’s
jurisdiction over “mines” covers: (1) extraction sites; (2) the
“private ways and roads appurtenant” thereto; and (3) a list of
items “used in, or to be used in,” mining-related activity. Id.

B.

The material facts are undisputed. See J.A. 4–13 (Joint
Stipulations). KC Transport is an independent trucking
company that operates truck maintenance and storage, and also
 7
provides hauling services to various businesses for different
materials (e.g., coal, earth, and gravel). The following events
took place at one of KC Transport’s locations—the Emmett
facility located in Emmett, West Virginia.

One of KC Transport’s clients is a coal mine operator
named Ramaco Resources (“Ramaco”) that maintains five
mines near the Emmett facility (“facility”). Ramaco’s
representatives informed KC Transport that it could use the
facility for maintenance, as Ramaco had no plans to operate a
coal mine there. KC Transport accepted and began using the
facility as its “maintenance area/shop.” J.A. 7. KC Transport
also obtained commercial insurance covering the facility.

At the time in question, the facility included only a parking
area and two maintenance shipping containers. The facility
was described as a “convenient centralized maintenance
facility . . . for KC Transport,” J.A. 7, and KC Transport used
it to operate about 35 trucks. Ramaco’s deep mines are about
four to five miles away, and its strip mines are about six miles
away. An estimated “60% of the [facility’s] services”
supported Ramaco’s five nearby mines, and the remaining 40%
of services aided other companies like “American Electric
Power [] and other coal operators.” J.A. 7. The types of trucks
at the facility are a mix of (1) off-road trucks, providing
haulage for Ramaco’s five nearby mines; and (2) on-road
trucks used in earth and gravel haulage for other customers, as
well as coal haulage services for non-Ramaco customers.

The facility is on Right Hand Fork Road located over one
mile from one of Ramaco’s coal plants, the Elk Creek
Preparation Plant. Right Hand Fork Road is a road off of the
haulage road that runs past Elk Creek Plant and dead ends on
the other side of the facility. The facility is about 1000 feet
from the haulage road, and while the road leading “into the KC
 8
Transport facility is not a coal haulage road[,] [it] does branch
off from a haulage road.” J.A. 6. The only way to access the
facility is by advancing through a gate entrance on Right Hand
Fork Road, and while part of the haul-road is public, everything
past the gate is reserved for authorized persons. During this
time, however, the gate was not operational.

On March 11, 2019, an MSHA coal mine inspector visited
Ramaco’s nearby Elk Creek Prep Plant. Although MSHA had
never inspected, or even attempted to inspect, KC Transport’s
trucks at the facility, MSHA regularly inspected KC
Transport’s trucks along the haulage road, as well as at the Elk
Creek Plant. Upon completing the Elk Creek Plant inspection,
the inspector went “looking for trucks” that MSHA had
previously cited and intended to terminate those citations. J.A.
5; see 30 U.S.C. § 814(e)(3). The inspector traveled over a mile
along the haulage road, turned off this road onto Right Hand
Fork Road, continued along this road for about 1000 feet, and
ultimately reached the facility.

Upon arriving at the facility, the inspector observed KC
Transport’s trucks undergoing maintenance. According to
MSHA safety regulations, “[r]epairs or maintenance shall not
be performed on machinery until the power is off and the
machinery is blocked against motion, except where machinery
motion is necessary to make adjustments.” 30 C.F.R.
§ 77.404(c). Two of KC Transport’s trucks, however, were
unblocked. Notably, because these particular trucks “were not
licensed to haul products over public roads[,]” they were “only
being operated on private land,” J.A. 10, and “regularly used to
haul coal from the five Ramaco mines to the Elk Creek prep
plant[,]” J.A. 8. At the time of inspection, the first truck was
“jacked up with the wheels and tires off both back axles[,]” and
“[w]ork [was] being performed on the brakes located on the
back axles of the truck.” J.A. 30–31. The second truck was
 9
raised and a miner was underneath it, “standing on the frame of
the truck[.]” J.A. 31; see J.A. 58. Because neither of the two
trucks were “blocked against motion,” the inspector found KC
Transport in violation of 30 C.F.R. § 77.404(c), and issued
Citations Nos. 9222038 and 9222040.

C.

The primary issues in this litigation concern jurisdiction:
(1) whether the facility or the two trucks constituted a “mine”
under 30 U.S.C. § 802(h)(1)(C) of the Mine Act, such that
MSHA had the authority to cite KC Transport for violating
safety regulation 30 C.F.R. § 77.404(c); and (2) whether an
independent contractor like KC Transport only qualifies as an
“operator” under 30 U.S.C. § 802(d) when actively working at
a mine site. If the Mine Act does apply, the parties agree both
citations should be upheld and KC Transport owes a penalty
fee of $3,908 regarding citation No. 9222038, and $4,343
regarding citation No. 9222040. See J.A. 12–13.

Once KC Transport contested the two citations, both the
Secretary and KC Transport filed cross-motions, requesting
summary decision of the jurisdictional issue. The ALJ rejected
the parties’ interpretations of subsection (C), but ultimately
ruled in MSHA’s favor and upheld the two citations as a proper
exercise of the Mine Act’s jurisdiction. In the ALJ’s view, the
facility and the mining-related equipment located therein were
too connected to the mining process to be excluded from the
Mine Act’s jurisdiction. Thus, the ALJ found the facility
constituted a “mine” under the subsection (C)’s plain meaning,
“and because the trucks were used in mining and parked at the
facility,” they qualified as “equipment” under subsection (C).
J.A. 84.
 10
On appeal, a divided Commission reversed the ALJ’s
finding of jurisdiction and vacated the two contested citations.
According to the majority, 30 U.S.C. § 802(h)(1)
unambiguously limits the “mine” definition to extraction sites
and lands appurtenant thereto. Thus, the Commission held
“that an independent repair, maintenance, or parking facility
not located on or appurtenant to a mine site and not engaged in
any extraction, milling, preparation, or other activities within
the scope of subsection 3(h)(1)(A) is not a mine within the
meaning of section 3(h) of the Mine Act.” J.A. 168. In a
secondary holding, the Commission also found that KC
Transport did not qualify as an “operator” under the Mine Act,
because “[a]s an independent contractor, KC Transport is an
operator subject to MSHA jurisdiction [only] while performing
work at a mine site.” J.A. 165. One commissioner dissented,
taking an even broader view than the ALJ, and argued that
regardless of the facility, trucks constitute mines as they were
“used in” mining and are “integral” to that process. J.A. 176.
The Secretary filed a petition for review of the Commission’s
decision.

II.

We review the Commission’s legal findings de novo. See
Am. Coal Co., 796 F.3d at 23. “Under the Mine Act, the
Secretary’s interpretation of the law must ‘be given weight by
both the Commission and the courts.’” Excel Mining, 334 F.3d
at 5–6 (quoting Sec’y of Lab. v. Cannelton Indus., Inc., 867
F.2d 1432, 1435 (D.C. Cir. 1989) (quoting S. REP. NO. 95–181,
at 49)). Should the Secretary and the Commission advance
differing interpretations, “it is . . . the Secretary rather than the
Commission who is entitled to the deference described in
Chevron U.S.A. Inc. v. Natural Resources Defense Council,
Inc., 467 U.S. 837 (1984).” Excel Mining, 334 F.3d at 6
(cleaned up); see also Am. Coal, 796 F.3d at 23–24. But if the
 11
Secretary incorrectly treats the statute as unambiguous, such
that deference is not appropriate, we have previously remanded
the case to the Commission, instructing the Secretary to
interpret the statute in recognition of its ambiguities. See Sec’y
of Lab. v. Nat’l Cement Co. of Cal., Inc. (“National Cement
II”), 573 F.3d 788, 791 (D.C. Cir. 2009).

A.

“Under these circumstances, the Secretary’s litigating
position before the Commission is as much an exercise of
delegated lawmaking powers as is the Secretary’s
promulgation of a workplace health and safety standard.”
Martin, 499 U.S. at 157. Accordingly, we turn to the
Secretary’s argument, maintaining that the trucks at issue fell
under the Mine Act’s jurisdiction under a plain reading of
subsection (C). The Secretary maintains this Court should
uphold the contested citations because 30 U.S.C.
§ 802(h)(1)(C) unambiguously grants MSHA jurisdiction over
both the trucks and the maintenance facility. Under this
interpretation, subsection (C) unambiguously extends the Mine
Act’s jurisdiction to cover each of the enumerated types of
items if “used in, or to be used in” mining. Because the trucks
are “equipment,” and because both the trucks and the facility
were “used in” mining activity, the Secretary argues they
satisfy the “mine” definition.

Although advancing an opposing interpretation, the
Secretary, like KC Transport in defending the Commission’s
decision, asserts that the Act’s “mine” definition is
unambiguous. As such, the Secretary urges us to uphold the
citations as a proper exercise of MSHA’s jurisdiction under a
plain reading of the statute.
 12
This was the case in National Cement I, 494 F.3d at 1066.
The central issue there was whether “a road National Cement
use[d] to access its cement processing plant [] pursuant to a
nonexclusive right-of-way grant” constituted a “mine” under
30 U.S.C. § 802(h)(1). Id. at 1068. The Secretary defended its
jurisdiction over the private road, arguing that because the road
led to a cement processing plant, it unambiguously constituted
a “private way[] and road[] appurtenant to” an extraction area
under a plain reading of subsection (B), 30
U.S.C. § 802(h)(1)(B). Finding subsection (B) ambiguous, we
declined to “accord the Secretary’s litigating position Chevron
deference because she incorrectly treated the statute as
unambiguous and interpreted it accordingly.” Nat’l Cement I,
494 F.3d at 1073 (citing Peter Pan Bus Lines, Inc. v. Fed.
Motor Carrier Safety Admin., 471 F.3d 1350, 1354 (D.C. Cir.
2006) (“[D]eference to an agency’s interpretation of a statute
is not appropriate when the agency wrongly believes that
interpretation is compelled by Congress.” (internal quotation
marks omitted))).

As we explained, the statute’s use of the term “private”
could encompass either a “group or class of persons,” or “a
particular person[,]”—and similarly, “appurtenant” could
mean a road either “subject to a transferable right of way
benefitting the mine lessee,” or “dedicated exclusively to the
use of the mine.” Nat’l Cement I, 494 F.3d at 1074. Thus, we
vacated and remanded the Commission’s decision for the
Secretary to interpret the ambiguous provision. On remand, the
Secretary relied on two subsections and argued that subsection
(B) extended over the road itself, while subsection (C) covered
the mine-related vehicles traveling on the road. See 573 F.3d
at 794. Satisfied that this interpretation reasonably accounted
for the statute’s ambiguities, the National Cement II Court
found “the Secretary’s interpretation of subsection (B)” was
“entitled” to deference. Id. at 793.
 13

Such an approach was not unique to National Cement I, as
we took a similar path in Akzo Nobel Salt, Inc. v. Federal Mine
Safety and Health Review Commission, 212 F.3d 1301, 1304–
05 (D.C. Cir. 2000). There, the Secretary asserted that a
regulation unambiguously applied to and covered the citation
at issue. We disagreed and found the regulation’s language
ambiguous. The Secretary, however, “never grappled with”
the “regulation’s clear ambiguity[,]” and because the Secretary
had taken inconsistent positions, we vacated and remanded the
Commission’s decision. Id. at 1305 (instructing the
Commission to secure the Secretary’s regulatory interpretation,
“and to resolve the case applying standard deference principles
to that interpretation”).

To be clear, it is the Secretary’s litigating position
resulting from a citation—not the Commission’s position—
that is ordinarily owed deference. See Excel Mining, LLC, 334
F.3d at 6 (citing Martin, 499 U.S. at 157). We cannot defer,
however, when the Secretary’s position mistakenly advances
an interpretation compelled by Congress when the statute is in
fact ambiguous. And as our case law shows, we have
previously addressed such a mistake by remanding the case for
the Secretary to account for the identified ambiguity.

As we discuss below, here again, we are faced with a
situation where the Secretary incorrectly asserts that the
relevant text—30 U.S.C. § 802(h)(1)(C)—is unambiguous.
Thus, we remand the case, allowing the Secretary to address
§ 802(h)(1)(C)’s ambiguities.

Beginning with the statutory text, recall that § 802(h)(1)
defines a “mine” as: (1) the physical extraction site, under
subsection (A); (2) any “private ways and roads appurtenant”
to that extraction site, under subsection (B); and (3) the items
 14
“used in, or to be used in, or resulting from” mining activity,
under subsection (C). Congress’s inclusion of subsection (C)
clarifies that the Mine Act extends beyond the land and roads
covered in subsections (A)–(B). The Secretary argues the
“mine” definition must be read so broadly that it incorporates
each of subsection (C)’s items as an individual “mine.” Put
differently, the Secretary advances a view under which all
“machines, tools,” and even singular pieces of “equipment,”
could constitute a “mine”—no matter their location—so long
as they either were, or will be, “used in” mining activity. But
certain “equipment[]”—like a truck—is mobile, and without a
clear locational limit, it is impossible to ensure MSHA could
monitor the equipment’s location and complete the statutorily
mandated inspection requirements.

As indicated by its context, structure, and Congress’s use
of the phrase “coal or other mine” throughout Chapter 22 of
Title 30—location is central to the Mine Act. Consider the
process through which MSHA ensures compliance with the
Mine Act’s safety regulations. To start, Congress instructs that
“[e]ach operator of a coal or other mine subject to this chapter
shall file with the Secretary the name and address of such
mine[.]” 30 U.S.C. § 819(d) (emphases added). In addition to
recording the mine’s location, Congress also instructed that
each “coal or other mine” “shall” be inspected yearly, four
times a year for “each underground coal or other mine[,]” and
twice a year for “each surface coal or other mine.” Id. § 813(a).

The statute delineates the limited circumstances under
which the Secretary “may give advance notice of
inspections[,]” and provides that authorized representatives
“shall have a right of entry to, upon, or through any coal or
other mine.” Id. (emphasis added). No discretion is accorded
once the inspection is underway, and the Mine Act requires
inspectors to issue a citation upon belief “that an operator of a
 15
coal or other mine” violated “any mandatory health or safety
standard, rule, order, regulation, or order[.]” Id. § 814(a)).

In addition to requiring a physical address for inspection
purposes, the Mine Act also mandates that each “coal or other
mine” operator “designate a responsible official” “in charge of
health and safety” for each identified mine. Id. § 819(d). The
Mine Act even outlines certain design requirements for every
identified mine. “At each coal or other mine there shall be
maintained an office with a conspicuous sign designating it as
the office of such mine.” Id. § 819(a). This office must also
include “a bulletin board” near the entrance such that “orders,
citations, notices and decisions required by law or regulation .
. . may be posted[.]” Id. It is, thus, clear that no operator could
comply with these provisions without first identifying a
physical address for each of its mines.

The Commission’s interpretation fares no better than the
Secretary’s, because treating subsection (C) as inherently
connected to subsections (A)–(B) cannot be harmonized with
the statutory structure under which there are three separate and
independent subsections. See id. § 802(h)(1)(A)–(C). If a
“mine” is so clearly defined under subsections (A)–(B), what
then to make of subsection (C)? Because the Commission finds
it “clear that neither the purpose nor the language of the Act
indicate a further geographical extension of jurisdiction under
subsection (C)[,]” it reasons that subsection (C) must be read
as “catalog[ing] various mining-related places . . . and objects”
that are used in mining activity at physical extraction sites
described in subsection (A), or the roads appurtenant thereto,
described in subsection (B). J.A. 163–64; see Maxxim Rebuild
Co. v. FMSHRC, 848 F.3d 737, 740 (6th Cir. 2017) (explaining
that subsection (C) reads as though “the author went to a mine
and wrote down everything he saw in, around, under, above,
and next to the mine” and limiting the definition “only to
 16
everything that one would see in or around a working mine”
itself). Not so.

One need only look to Congress’s concerns—cited when
explaining its decision to revise the Coal Act’s “mine”
definition—to conclude that subsection (C) was incorporated
to specify that non-extraction site property may also constitute
a “mine” when it (1) is “used in,” (2) will “be used in,” or (3)
“result[s] from” the work of extracting or preparing minerals.
30 U.S.C. § 802(h)(1)(C). As briefly mentioned in relation to
the deadly mining-related incidents, subsection (C) was
necessary—at least in part—to ensure the Mine Act’s
jurisdiction extended to physical manifestations like dams that
may be distant from the actual extraction site. Limiting
jurisdiction to the land in subsections (A)–(B) would
effectively omit subsection (C) and could exclude the very
property Congress intended to cover.

The Commission’s decision cannot stand for another
fundamental reason: such a narrow view of 30 U.S.C.
§ 802(h)(1) conflicts with this Circuit’s precedent under which
we have clarified that the Mine Act extends beyond structures
on extraction sites. In Donovan v. Carolina Stalite Co., we
explained that the Mine Act “does not require that those
structures or facilities [listed in subsection (C)] . . . be located
on property where such extraction occurs.” 734 F.2d 1547,
1548, 1552 (D.C. Cir. 1984) (finding that a “slate gravel
processing facility” placed on “property immediately adjacent
to a quarry” fell under the Mine Act’s jurisdiction).
Importantly, we also endorsed the view that MSHA’s
“jurisdictional bases were expanded accordingly [in the 1977
Mine Act] to reach not only the ‘areas . . . from which minerals
are extracted,’ but also the ‘structures . . . which are used or are
to be used in . . . the preparation of the extracted minerals.’”
Id. at 1554 (quoting S. REP. NO. 95–181). This conclusion
 17
applies equally to all property listed in subsection (C) which,
as relevant here, includes both “structures” and “equipment.”

Although the Secretary nominally recognized that the
statute could be ambiguous, and advanced an alternative
argument seeking our deference, at no point during this
litigation did the Secretary grapple with the conflicting,
practical implications of the advanced interpretation. See
Sec’y Br. 38–42; Sec’y Reply Br. 5, 14–17; Sec’y Supp. Br.
11–13. Nor did the Secretary acknowledge the statute’s
ambiguity as demonstrated by its historical background. For
instance, when passing the 1977 Mine Act, Congress explained
it would “enlarge[] the definition of ‘mine’ in [30
U.S.C. § 802(h)] to include those mines previously covered by
the [1966] Federal Metal and Non-Metallic, Mine Safety Act
[‘Metal Act’].” S. REP. NO. 95–181, at 59; see Pub. L. No. 89-
577, 80 Stat. 772 (1966) (repealed 1977). The Metal Act fell
under the Department of Interior, and the Mining Enforcement
and Safety Administration (“MESA”) exercised the agency
enforcement role like the one MSHA occupies today. When
referring to the Metal Act’s jurisdiction, a 1974 MESA-OSHA
Memorandum of Understanding (“MOU”) explained that a
“mine,” under this predecessor to the Mine Act, included
“mineral extraction (mining) operations” as well as “milling
and preparation facilities and other surface facilities used in
mining or milling.” 39 Fed. Reg. 27,382, 27,383 (July 26,
1974) (summarizing 30 U.S.C. § 721(b)). From this, MESA
“interpret[ed] its authority to include the prescription and
enforcement of standards regarding” a variety of operations,
locations, and “transportation.” Id. But nowhere in the later
1979 MSHA-OSHA MOU, pertaining to the 1977 Mine Act, is
there any mention of MSHA’s authority as covering
transportation. 44 Fed. Reg. 22,827, 22,827 (Apr. 17, 1979).
What this might, or might not, signify—in relation to
subsection (C)’s scope today—remains a mystery as the
 18
Secretary’s briefs failed to discuss it. This lack of analysis
further indicates the need to remand for the Secretary to engage
with subsection (C)’s ambiguity.

In the Secretary’s view, however, any risk of incorrectly
broadening subsection (C) is mitigated by a functional analysis
that officials conduct in determining whether certain facilities
or equipment constitute a “mine.” Framed as a limitation, the
Secretary argues that whether facilities or equipment constitute
a “mine” depends only on a fact-based inquiry under which one
must evaluate how closely related the relevant facility or
equipment was to mining activity. Location is but one factor
that may be relevant to this “use-in-mining” analysis. Oral Arg.
Tr. at 10:3; see id. at 9–17; Sec’y Supp. Br. 13, 21. But such a
fact-based inquiry does nothing to explain how MSHA might
locate mobile equipment, such as the trucks at issue here, and
fulfill its mandatory obligations to “make frequent
inspections.” 30 U.S.C. § 813(a). Indeed, without an
identifiable address, how will inspectors know where to find all
equipment that has, or will be, “used in” mining? And how
long after equipment is “used in” mining does it still qualify as
a “mine” if no longer located on mine-related property? The
Secretary’s broad and categorical view, although temptingly
clear in theory, ultimately creates many more questions in
practice. These questions bespeak ambiguity, and the
Secretary’s litigation position must explain how they were
taken into account.

We note that all but three of the items enumerated in
subsection (C) constitute physical manifestations. The
physical manifestations—including, for example, “tunnels and
workings, structures, facilities, . . . [and] retention dams[]”—
are similar to the extraction sites and roads outlined in
subsections (A)–(B) because they are stationary and, thus,
associated with a particular location. 30 U.S.C. § 802(h)(1)(C).
 19
The three movable items—“equipment, machines, [and] tools,”
id.—stand alone as property subject to much broader, non-
mining related definitions. And as “[a] canon related to
noscitur a sociis, ejusdem generis, counsels: ‘Where general
words follow specific words in a statutory enumeration, the
general words are usually construed to embrace only objects
similar in nature to those objects enumerated by the preceding
specific words.’” Yates v. United States, 574 U.S. 528, 545
(2015) (cleaned up). One way of interpreting subsection (C) is
therefore to view the three movable items included in the
middle of the list in relation, and as connected, to the preceding
physical manifestations.

As applied here, there is at least a question of whether
“equipment, machines, [and] tools,” when read within the
wider Chapter 22 context, constitute “coal or other mine[s]”
only when there is an established connection to the fixed
physical manifestations listed before and after them. 30 U.S.C.
§ 802(h)(1)(C). It is unclear, however, whether such an
established connection impacts the circumstances under which
the three movable types of property remain “mines” when not
physically connected to the manifestations listed in subsections
(A)–(C). At a minimum, the statutory language, broader
context, and numerous practical concerns render subsection
(C)’s meaning ambiguous.

Our dissenting colleague contends that “an item listed in
subsection (C) must be located at an extraction site or a
processing plant to count as a ‘mine’ under the Act.”
Dissenting Op. 8. This restrictive construction of the statute
countermands our observation in Donovan that the Act
included a “sweeping definition of a mine[,]” 734 F.2d at 1554
(internal quotation marks omitted), as well as our ruling in
National Cement II that the “broad statutory definition of
‘mine[]’ . . . extends the protections of the Mine Act beyond
 20
the actual site where mining takes place.” 573 F.3d at 795. The
dissent’s interpretation also contradicts our recognition in
National Cement I that, as a procedural matter, the Secretary
should “confront” the breadth and ambiguity of the Act in the
first instance. 494 F.3d at 430. In that case, we held that
because the definitional terms of “mine” in subsection (B) of
the Mine Act “are ambiguous and the Secretary instead
interpreted them as having a plain, unambiguous meaning, we
vacate the Commission’s decision and remand for it to obtain
from the Secretary a Chevron step 2 interpretation[.]” Id.; see
also Akzo Nobel Salt, Inc., 212 F.3d at 1304–05 (explaining
that while the Secretary asserted that a Mine Act regulation
unambiguously applied, we found the regulation’s language
ambiguous and remanded for the Secretary to “grappl[e] with”
the “regulation’s clear ambiguity”). We are of course bound
by our precedent. LaShawn A. v. Barry, 87 F.3d 1389, 1393
(D.C. Cir. 1996). The dissent’s oversimplification also elides
the interpretive difficulty that arises when a truck is cited while
located on an extraction or processing site, but MSHA later
goes looking for the truck outside the extraction or processing
area to determine whether the cited violations have been
abated—which is exactly how the present dispute began. See
supra at 8; J.A. 5. Does the statute unambiguously provide that
MSHA loses jurisdiction over a truck once it leaves the
extraction or processing area? Apparently so, under the
dissent’s view. But that reading of the statute renders
enforcement of the Mine Act unworkable, frustrating
Congress’s intent.

B.

The Commission’s secondary ruling, concerning the Mine
Act’s “operator” definition, faces a similar fate as its first. An
“operator” is defined under § 802(d) as “any owner, lessee, or
other person who operates, controls, or supervises a coal or
 21
other mine or any independent contractor performing services
or construction at such mine[.]” 30 U.S.C. § 802(d) (emphasis
added). To further confirm that the Secretary lacked
jurisdiction to issue the citations, the Commission held that KC
Transport failed to qualify as an “operator” under the Mine Act.
It reasoned that “[a]s an independent contractor,” KC Transport
only qualifies as “an operator subject to MSHA jurisdiction
while performing work at a mine site[,]” and “[w]hen the
citations were issued” here, “KC Transport was not performing
services in a mine.” J.A. 165. Because the trucks were parked
and off the mine site, “KC Transport was not performing
services in a mine[]” when the two citations were issued and,
therefore, was not an “operator.” Id.

The Secretary asks us to vacate the ruling, not only
because the Commission incorrectly narrowed the
circumstances under which an independent contractor qualifies
as an “operator” under the Mine Act, but also because it
exceeded its jurisdiction by deciding an unraised issue in the
first instance. We find it especially telling that KC Transport
chooses not to defend the Commission’s “operator” ruling on
the merits. Instead, KC Transport insists this is a non-issue,
because rather than a secondary holding, the Commission
merely quoted statutory language discussing “operators” to
further support its “mine” definition ruling. This argument is
clearly rebutted by the record, revealing the Commission found
KC Transport “was not an operator under section 3(d)” because
it “was not performing services in a mine[.]” J.A. 165. We
therefore review the Commission’s secondary “operator”
holding and find it lacked jurisdiction to make such a ruling.

The Commission’s jurisdiction is limited to questions that
were reviewed by the ALJ, and then included in the petition for
discretionary relief on appeal. See 30 U.S.C. § 823(d)(2).
However, the record shows that the ALJ never considered KC
 22
Transport’s “operator” status. As the parties’ joint stipulations
confirm, KC Transport conceded that its trucks’ conditions
violated 30 C.F.R. § 77.404(c) “should the [ALJ] find that
MSHA did have jurisdiction over the trucks[.]” J.A. 12
(emphasis added). KC Transport then repeated this concession
in its briefs before the ALJ, and both parties advanced
arguments that focused exclusively on the Mine Act’s
jurisdiction concerning the trucks and, or, the facility. Neither
party so much cited 30 U.S.C. § 802(d)’s “operator” definition,
and there is no trace of such a discussion in the ALJ’s decision.
See J.A. 75 (“The parties have stipulated that should this Court
find that MSHA had jurisdiction over the trucks and location,
the cited conditions would constitute violations of 30 C.F.R.
§ 77.404(c)[.]”). And the parties maintained the same focus on
30 U.S.C. § 802(h)(1)’s “mine” definition before the
Commission. Thus, KC Transport’s “operator” status was not
questioned until the Commission issued its majority decision.

Because the Commission resolved this unraised issue on
its own without the benefit of briefing—and in the first
instance—it failed to abide by its jurisdictional boundaries
under 30 U.S.C. § 823(d)(2). And although there is a process
through which the Commission may exercise its discretion to
reach additional issues, see id. § 823(d)(2)(B), nothing in the
record shows it followed that procedure here.

***

To be sure, the Mine Act is intentionally broad, and this
characteristic helps enable the government to protect and
promote miner safety. Am. Coal Co., 796 F.3d at 25. We
reiterate, however, that broad authority does not equate
limitless jurisdiction. Nat’l Cement I, 494 F.3d at 1077. It is
the courts’ role to ensure this broad authority is exercised
within its jurisdictional bounds, and we use a variety of tools
 23
to do so. Ensuring that the Secretary adopts a reasonable
interpretation of its jurisdiction by grappling with the questions
and challenges posed by an ambiguous statute is one of the
devices in our toolkit. But without such an interpretation here,
there is nothing to which we may defer. Id. at 1075. Heeding
the lessons of National Cement I & II, we vacate the
Commission’s decision and remand for the Secretary to
reconsider its position pursuant to a revised interpretation of
subsection (C), after recognizing its ambiguity and addressing
the questions outlined in this opinion. See id. at 1077.

So ordered.
WALKER, Circuit Judge, dissenting:

KC Transport is a small trucking company. It occasionally
uses its trucks to haul coal for nearby mines. When those trucks
break down, KC repairs them at its truck-repair shop — some
four miles away from the nearest mine.

Because KC’s shop repairs mining trucks, the Secretary of
Labor says the shop is a “mine.” In his view, any “facilit[y]”
“used in . . . the work of extracting [coal]” is a “mine” under
the Mine Act. 30 U.S.C. § 802(h)(1). And that puts KC’s
truck-repair shop within the Mine Safety and Health Admin-
istration’s jurisdiction.

I disagree. To count as a “mine,” a “facility” like KC’s
shop must be located at an extraction site or a processing plant.
KC’s shop is not. So the Administration lacks jurisdiction over
it.

I would thus deny the Secretary’s petition for review.

I. Background

A. Mine Safety and Health Administration’s Jurisdiction

The Mine Act tasks the Secretary of Labor with setting
health-and-safety standards for mines. 30 U.S.C. § 811. To
enforce those standards, the Mine Safety and Health Admin-
istration must “make frequent inspections and investigations”
of “mines.” Id. § 813(a); see 29 U.S.C. § 557a. If a mine op-
erator fails to meet the agency’s safety standards, it may issue
a citation. 30 U.S.C. §§ 813, 802(d) (a mine “operator” “oper-
ates, controls, or supervises a . . . mine”).

Because the Administration may inspect and cite only
“mines,” its jurisdiction depends on the Mine Act’s definition
of “coal and other mines”:
 2

(A) an area of land from which minerals are ex-
tracted in nonliquid form or, if in liquid form,
are extracted with workers underground,
(B) private ways and roads appurtenant to such area,
and
(C) lands, excavations, underground passageways,
shafts, slopes, tunnels and workings, structures,
facilities, equipment, machines, tools, or other
property including impoundments, retention
dams, and tailings ponds, on the surface or un-
derground, used in, or to be used in, or result-
ing from, the work of extracting such minerals
from their natural deposits in nonliquid form,
or if in liquid form, with workers under-
ground, or used in, or to be used in, the milling
of such minerals, or the work of preparing
coal or other minerals, and includes custom
coal preparation facilities.

Id. § 802(h)(1) (emphases added).

Here, we must decide if a truck-repair shop that occasion-
ally fixes mining trucks is a “mine” within the Administration’s
jurisdiction.

B. KC Transport’s Citations

KC Transport has a contract to haul coal at Ramaco Re-
sources’ mines near Emmett, West Virginia. To help KC with
the job, Ramaco lets KC use a patch of land off a private road
near the mines to maintain its trucks. KC built a parking lot on
the land and installed two shipping containers to use as a
maintenance shop.
 3
KC’s shop is about a mile away from Ramaco’s coal-pro-
cessing plant and more than four miles away from Ramaco’s
nearest extraction site. In addition to its arrangement with Ra-
maco, KC uses trucks from the shop to serve customers that
don’t mine coal (or anything else). For instance, it has a “large
earth moving project” for a different company. JA 7.

In 2019, a mine-safety inspector visited KC’s repair shop.
He noticed that KC was servicing two dump trucks, but had not
taken sufficient precautions to prevent the truck beds from
moving during maintenance. That, the inspector decided, was
a violation of the Administration’s regulations. 30 C.F.R.
§ 77.404(c). So he issued KC two citations, one for each truck.

Rather than pay the citations, KC challenged them before
the Mine Safety Commission. It argued that the Administration
lacked jurisdiction to issue the citations. The agency may issue
citations only to “an operator of a coal or other mine,” and, KC
pointed out, its repair shop is not a “mine.” 30 U.S.C. § 814(a).

An administrative law judge rejected KC’s challenge,
holding that its shop is a “mine” under the Act. Because re-
pairing mining trucks is “essential to the coal hauling and prep-
aration process,” JA 91, the ALJ reasoned that the shop is a
“facilit[y]” that is “used in . . . the work of extracting . . . min-
erals.” 30 U.S.C. § 802(h)(1)).

On appeal, the Commission reversed. It held that the
ALJ’s reading of the statute divorced select words in the defi-
nition of “mine” from their context. The full defini-
tion — quoted above — is filled with geographic language
suggesting that a facility must be close to an extraction site to
count as a mine. Id.§ 802(h)(1). Because KC’s shop is “distant
from a mine site, owned by an independent company, and used
 4
for parking and repairing its vehicles,” it did not count as a
“mine.” JA 164. So the agency lacked jurisdiction over it.

Unhappy with the Commission’s decision, the Secretary
petitioned this court for review, challenging the Commission’s
interpretation of the Mine Act. I would deny the Secretary’s
petition. 1

II. KC’s Shop Is Not A “Mine”

KC’s truck-repair shop is not a “mine” under the Mine Act
because it is not located at an extraction site or at a processing
plant (where minerals like coal are milled or prepared, turning
them from ore into usable products).

A. The Act’s Definition of “Mine” Has Geographic Limits

Though the Mine Act’s definition of “mine” has no ex-
press geographic limit, the statute’s “carefully calibrated
scheme” confirms that there is one. Turkiye Halk Bankasi A.S.
v. United States, 143 S. Ct. 940, 947 (2023) (looking to the
statutory scheme to cabin the reach of a seemingly broad stat-
utory provision); Antonin Scalia, A Matter of Interpretation 24
(1997) (“the good textualist is not a literalist”).

1
“[A] constitutional quandary [is] raised by a federal court resolving
a lawsuit,” like this one, “between two Executive Branch agencies.”
United States Postal Service v. Postal Regulatory Commission, 963
F.3d 137, 143 (D.C. Cir. 2020) (Rao, J, concurring). “[S]uch dis-
putes do not appear to constitute a case or controversy for purposes
of Article III,” because “agencies involved in intra-Executive Branch
disputes are not adverse to one another (rather, they are both subor-
dinate parts of a single organization headed by one CEO).” SEC v.
FLRA, 568 F.3d 990, 997 (D.C. Cir. 2009) (Kavanaugh, J., concur-
ring). Our precedents, however, allow such suits to proceed.
 5
Recall that the Act defines “mine” in three subsections. 30
U.S.C. § 802(h)(1). To count as a mine, a facility must meet
the criteria in one of those subsections. Secretary of Labor v.
National Cement Co. of California, Inc., 573 F.3d 788, 795
(D.C. Cir. 2009) (each subsection independently defines
“mine”).

Two subsections have express geographic limits: Subsec-
tion (A) extends only to excavation sites, covering “area[s] of
land from which minerals are extracted,” and subsection (B)
includes “roads appurtenant to such area[s].” 30 U.S.C.
§ 802(h)(1).

That leaves us with subsection (C). It’s a catch-all list of
additional things that may count as mines if they are “used in”
“extracting,” “preparing,” or “milling.” Id. § 802(h)(1)(C).
That list breaks down into three categories:
• Structures found at excavation sites: “excavations, un-
derground passageways, shafts, slopes, tunnels and
workings.”
• Generic items: “lands, . . . structures, facilities, equip-
ment, machines, tools.”
• Structures found at preparation plants: “impound-
ments, retention dams, and tailings ponds.” 2

2
“Tailings” are a waste product generated by coal processing. They
are a “residue separated in the preparation of various products (such
as grain or ores).” Tailing (def. 1), Merriam-Webster (2023).
“[I]mpoundments, retention dams, and tailings ponds” are all struc-
tures used to store tailings. 30 U.S.C. § 802(h). An “impoundment”
is a generic term for a structure used to “retain tailings.” Technical
Report: Design and Evaluation of Tailings Dams, EPA, at 5 (Aug.
1994), https://perma.cc/68LA-UJRF. A “retention dam” is a method
of storing tailings in which the “dam[ ] [is] constructed at full height
 6

Because words “are known by their companions,” it makes
sense to read the generic items in light of the two other catego-
ries in the list. Gutierrez v. Ada, 528 U.S. 250, 255 (2000).
Doing so suggests that lands, structures, facilities, and equip-
ment must either be at an excavation site or at a processing
plant to count as “mines” under the Act. Cf. Donovan v. Car-
olina Stalite Co., 734 F.2d 1547, 1548, 1552 (D.C. Cir. 1984)
(subsection (C) “does not require” that processing facilities “be
located on property where . . . extraction occurs,” so a pro-
cessing facility “immediately adjacent to a quarry” was a
“mine”).

Reading the Act that way reveals a geographic limit that
neatly mirrors the Act’s express functional limit. Under the
Act’s functional limit, no item on the list in subsection (C)
counts as a “mine” unless it is “used in, or to be used in, or
resulting from, the work of extracting . . . minerals . . . or . . .
the milling of such minerals, or . . . preparing coal or other min-
erals.” 30 U.S.C. § 802(h)(1)(C). 3 Because milling is a type
of coal preparation, the Act’s functional test boils down to ask-
ing whether an item on the list is used in extracting or

at the beginning of the disposal” (in other retention designs the height
of the embankment is increased as tailings are added). Id. at 6. And
a tailings “pond” is a body of wastewater held in by a dam or im-
poundment. See id. at 30.
3
Milling involves grinding coal into smaller chunks so that it is com-
mercially usable. See Peter T. Luckie & Leonard G. Austin, Coal
Grinding Technology, Dept. Energy (1980), https://perma.cc/EW37-
MDVA (describing how several types of coal mills operate). Coal
preparation involves extracting coal from the raw material extracted
at a mine site. See 30 U.S.C. § 802(i) (defining the “work of prepar-
ing the coal” as covering the gamut of coal processing: “breaking,
crushing, sizing, cleaning, washing, drying, mixing, storing, and
loading”).
 7
processing coal. Similarly, the Act’s geographic limit asks
whether an item is at an extraction site or a processing plant.

Now consider the Secretary’s literal reading of the statute.
The Secretary contends that the Administration’s jurisdiction
depends only on function, not location. Pet. Br. 16. In the Sec-
retary’s view, any “piece of equipment” or “facility” can be a
mine, no matter where it is located. Id.

The rest of the statute shows why that reading doesn’t
work. Many of the Act’s provisions assume that a “mine” has
a readily identifiable location. Thus, mine “operator[s]” must
“file with the Secretary” their mine’s “name and address.” 30
U.S.C. § 819(d). And at “each . . . mine” there must be “an
office with a conspicuous sign designating it as the office of
such mine.” Id. § 819(a). Similarly, the Mine Safety and
Health Administration must annually inspect each “coal or
other mine.” Id. § 813(a).

Those requirements would make no sense if a mine’s lo-
cation was unfixed.

Take an example. An independent contractor uses his
truck for a mining job each Wednesday. The rest of the week
he drives his truck 200 miles away for use on a construction
site. Even when it’s 200 miles away, that truck is a “mine” on
a literal reading of the statute: It is a “machine[ ]” that is “used
in, or to be used in, . . . the work of extracting . . . minerals.”
Id. § 802(h)(1). Yet that result clashes with the Act’s com-
mands to install “an office with a conspicuous sign” and to file
a mine’s “name and address.” Id. § 819(a), (d); see also
Maxxim Rebuild Co., LLC v. Federal Mine Safety & Health
Review Commission, 848 F.3d 737, 742 (6th Cir. 2017) (noting
that “other definitions in the Mine Act portray a mine as a
place”).
 8

The literal reading’s problems only deepen from there.
The Act covers “independent contractor[s]” when they are
“performing services or construction at [a] mine.” 30 U.S.C.
§ 802(d). But if the Act has no geographic limit, the agency
could inspect contractors anywhere they go — including at
their homes. That’s because a contractor’s tools and machinery
are “used in, or to be used in” extraction wherever they are. Id.
§ 802(h)(1)(C).

Such absurd results are not required by the Act’s text.
Reading the definition of “mine” in context shows that an item
listed in subsection (C) must be located at an extraction site or
a processing plant to count as a “mine” under the Act.

B. Processing Plants Fall Within the Geographic Limits

The Commission and the Sixth Circuit both held, as I
would, that the Act has a geographic limit. But they interpreted
that limit to cover only extraction sites. I part company with
them there. Textual clues suggest that the Act covers both ex-
traction sites (where ore is dug out of the ground) and pro-
cessing plants (where ore is made into a usable product).

In Maxxim Rebuild, the Sixth Circuit held that “facilities
and equipment” count as “mines” under the Act only “if they
are in or adjacent to — in essence part of” an extraction site.
848 F.3d at 740. The court reasoned that the list in subsec-
tion(C) reads as if the “author went to a mine and wrote down
everything he saw in, around, under, above, and next to the
mine.” Id. The Commission adopted the Sixth Circuit’s inter-
pretation in its decision in this case.

But subsection (C)’s list reads more like the “author went
to a mine [and a processing plant] and wrote down everything
 9
he saw.” Id. That’s because three items on the list — “im-
poundments, retention dams, and tailings ponds” — are asso-
ciated with coal processing, not coal extraction. 30 U.S.C.
§ 802(h)(1)(C); see supra note 2.

The rest of § 802(h)(1)(C) confirms that processing plants
are included in the Act’s geographic sweep. Any item in the
list counts as a “mine” if it is “used in, or to be used in . . . the
work of preparing coal.” 30 U.S.C. § 802(h)(1)(C) (emphasis
added). And the list ends by expressly stating that a “mine”
“includes custom coal preparation facilities.” Id.

Plus, because many preparation plants are not located at
extraction sites, the Sixth Circuit’s reading would produce an
odd regulatory checkerboard. Some processing plants would
be covered and others not, depending on how close they are to
an extraction site. See Standards of Performance for Coal
Preparation and Processing Plants, 74 Fed. Reg. 51,950,
51,961 (Oct. 8, 2009) (noting that coal-preparation plants may
be at “mine sites” or other “industrial sites”). That outcome is
hard to square with Congress’s express view that “coal prepa-
ration facilities” are covered by the Act. 30 U.S.C.
§ 802(h)(1)(C).

Finally, interpreting § 802(h)(1)(C) to cover processing
plants avoids surplusage. If subsection (C) were limited to
items at an extraction site, it would largely collapse into sub-
section (A), which covers “area[s] of land from which minerals
are extracted.” Id. But reading subsection (C) to include pro-
cessing plants gives it a distinct role in the statutory scheme. 4

4
My interpretation is consistent with precedent. Cf. Maj. Op. 19-20.
To repeat, I understand the items listed in § 801(h)(1)(C) to count as
“mines” if they are located either at an extraction site (where mining
 10

III. Remand to the Commission is Unwarranted

Though I read the Mine Act’s definition of “mine” more
narrowly than the Commission, I agree with its bottom-line
conclusion. KC’s truck repair shop is not a “mine” under the
Act because it is not at an extraction site or processing plant.
So I would deny the Secretary’s petition for review. See Cal-
cutt v. FDIC, 143 S. Ct. 1317, 1321 (2023) (we may affirm an
agency, despite disagreeing with its reasoning, if the agency
“was required to take [the] action” at issue (cleaned up)).

Today’s majority takes a different tack. It first decides that
the statute is ambiguous. Then, it remands to the agency to let
the Secretary have a crack at interpreting it. Presumably, once
the case comes back up on review, this court will defer under
Chevron to the Secretary’s interpretation of the now-ambigu-
ous statute — at least if it’s reasonable. See Chevron v. Natural
Resources Defense Council, 467 U.S. 837 (1984); Secretary of
Labor v. National Cement, 494 F.3d 1066, 1068 (D.C. Cir.
2007) (remanding to let the Secretary interpret an ambiguous
statute).

occurs) or at a processing plant (where ore is turned into a usable
product). So like National Cement II, I would not limit the Act’s
reach to “the actual site where mining occurs.” Secretary of Labor
v. National Cement Co. of California, Inc., 573 F.3d 788, 791 (D.C.
Cir. 2009). And like Donovan, I would consider a processing plant
“adjacent to a quarry” to be a “mine.” Donovan v. Carolina Stalite
Co., 734 F.2d 1547, 1552 (D.C. Cir. 1984). As for whether National
Cement I, 494 F.3d 1066, 1076 (D.C. Cir. 2007), means that “the
Secretary should ‘confront’ the breadth and ambiguity of the Act”
before a court may interpret it, Maj. Op. 20, “go take a look at the
decision,” Andy Warhol Foundation for the Visual Arts, Inc. v. Gold-
smith, 143 S. Ct. 1258, 1293 n.2 (2023) (Kagan, J., dissenting) (“I’ll
take my chances on readers’ good judgment”).
 11

But that approach too readily relinquishes this Court’s
duty to “decide all relevant questions of law” and to “inter-
pret . . . statutory provisions.” 5 U.S.C. § 706. Deference un-
der Chevron is appropriate only in those rare cases when “em-
ploying traditional tools of statutory construction” leaves a
court “unable to discern Congress’s meaning.” SAS Institute
Inc. v. Iancu, 138 S. Ct. 1348, 1358 (2018) (quoting Chevron,
467 U.S. at 843 n.9). And even then, a court must satisfy itself
that Congress meant to leave a “gap for the agency to fill” using
its expertise. Chevron, 467 U.S. at 843.

That is not this case. As the parties agree, the meaning of
the Mine Act depends on principles of statutory interpreta-
tion — not an exercise of policymaking discretion by the Sec-
retary. Thus, the Commission interpreted the Act using “the
traditional tools of statutory construction.” JA 161. And the
Secretary’s opening brief acknowledged that “[t]he text is all
that is necessary to divine the meaning of what constitutes a
mine.” Pet. Br. 17. At argument, the Secretary reiterated:
“[T]he statute is unambiguous. The Secretary is not asking this
Court for deference. The Secretary is simply asking that this
Court read the plain meaning of the statute, you know, as the
Secretary does.” Oral Arg. Tr. 39.

In those circumstances, deference is inappropriate. When
the “executive branch . . . ask[s] the court to do what courts
usually do in statutory interpretation disputes [and] supply its
best independent judgment about what the law means,” courts
should not “place[ ] an uninvited thumb on the scale in favor of
the government.” Guedes v. Bureau of Alcohol, Tobacco, Fire-
arms & Explosives, 140 S. Ct. 789, 790 (2020) (Gorsuch, J.,
concurring in denial of certiorari); see also HollyFrontier
Cheyenne Refining, LLC v. Renewable Fuels Association, 141
 12
S. Ct. 2172, 2180 (2021) (refusing to defer when “the govern-
ment [did] not invok[e] Chevron”).

Indeed, the Secretary’s shifting and self-serving interpre-
tations of the Mine Act show just how inappropriate remand is
here. When KC Transport first contested its citations before
the ALJ, the Secretary insisted that he had jurisdiction because
“each truck independently constituted a ‘mine’ ” under the Act.
JA 156. After the ALJ rejected that argument — in his view,
calling trucks “rolling mines” was “absurd” — the Secretary
tweaked his position, now contending that KC’s truck-repair
facility is a “mine.” Id.; Pet. Br. 17. Today’s remand gives the
Secretary a third bite at the apple.

What’s the upshot? A small trucking business is forced
once more to fight a moving target. “While it is true enough . . .
that one who deals with the Government may need to turn
square corners he need not turn them twice” — let alone three
times. United States v. Winstar Corp., 518 U.S. 839, 922
(1996) (Scalia, J., concurring) (cleaned up).

Because I agree with the parties that this case can be re-
solved using the traditional tools of statutory interpretation, I
would do just that.

* * *

To count as a “mine” under the Mine Act, a “facility” like
KC’s shop must be located at an extraction site or a processing
plant. KC’s shop is not. So the Administration lacks jurisdic-
tion over it.

Because the majority disagrees, I respectfully dissent.