United States Court of Appeals

FOR THE DISTRICT OF COLUMBIA CIRCUIT

Argued November 16, 2015 Decided July 5, 2016

No. 14-1285

ROSEBUD MINING COMPANY AND PARKWOOD RESOURCES,

INC.,

PETITIONERS

v.

MINE SAFETY AND HEALTH ADMINISTRATION AND 

JOSEPH A. MAIN, ASSISTANT SECRETARY OF LABOR FOR 

MINE SAFETY AND HEALTH,

RESPONDENTS

No. 14-1286

CANYON FUEL COMPANY, LLC, ET AL.,

PETITIONERS

v.

MINE SAFETY AND HEALTH ADMINISTRATION AND 

JOSEPH A. MAIN, ASSISTANT SECRETARY OF LABOR 

FOR MINE SAFETY AND HEALTH,

RESPONDENTS

On Petitions for Review of Decisions of the

Assistant Secretary of Labor for Mine Safety and Health 

Ralph Henry Moore II argued the cause for the 

petitioners. Patrick W. Dennison was with him on brief.
2

Lynne B. Dunbar, Attorney, United States Department 

of Labor, argued the cause for the respondents. W. Christian 

Schumann, Counsel, was with her on brief.

Before: HENDERSON, ROGERS and KAVANAUGH, 

Circuit Judges.

Opinion for the Court filed by Circuit Judge 

HENDERSON.

 KAREN LECRAFT HENDERSON, Circuit Judge: Several

coal mine operators—Rosebud Mining Company, Parkwood 

Resources, Inc., Canyon Fuel Company, LLC, Mountain Coal

Company, LLC, Bowie Resources, LLC and Peabody Sage 

Creek Mining, LLC (collectively, petitioners)—seek review 

of two orders of the United States Department of Labor 

(Labor)—per its Mine Safety and Health Administration 

(MSHA)—modifying the application of mandatory mine 

safety standards to their respective mines. The petitioners 

contend that the orders contain three conditions unnecessary 

to ensure adequate mine safety, thus making them arbitrary 

and capricious. For the reasons set forth below, we deny the 

petitions for review.

I. BACKGROUND

Under section 101(a) of the Federal Mine Safety and 

Health Act of 1977 (Mine Act), 30 U.S.C. §§ 801 et seq., the 

Labor Secretary must promulgate “mandatory health or safety 

standards for the protection of life and prevention of injuries 

in coal or other mines.” 30 U.S.C. § 811(a). The Assistant

Secretary of Labor for Mine Safety and Health (Assistant 

Secretary)1 may grant mine-specific modifications of the 

 

1

For MSHA matters, the Labor Secretary acts through the 

Assistant Secretary. 29 U.S.C. § 557a.
3

standards if he finds that “an alternative method of achieving

the result of such standard exists which will at all times 

guarantee no less than the same measure of protection 

afforded the miners of such mine by such standard, or that the 

application of such standard to such mine will result in a 

diminution of safety to the miners in such mine.” Id. 

§ 811(c). Thus, the statute permits modification if an equally 

effective alternative exists or if the standard itself negatively 

affects mine safety.2To satisfy either option, MSHA 

conducts a two-step inquiry which asks, first, whether the 

proposed alternative “promote[s] the same safety goals as the 

original standard with no less than the same degree of 

success” and, second, whether the “modification would 

achieve a net gain, or at least equivalence, in overall mine 

safety.” United Mine Workers of Am., Int’l Union v. MSHA, 

928 F.2d 1200, 1202 (D.C. Cir. 1991) (S. Ohio Coal Co.)

(emphasis added).3 At the second step, “both advantages and 

 

2

The latter scenario seems counter-intuitive—MSHA plainly 

does not intend to harm miners—but can be conceptualized as 

follows: assume arguendo that MSHA requires all elevator shafts 

to be manually operated, reasoning that elevators with electrical 

components could spark and start a mine fire. An operator with an 

especially deep shaft might argue that the requirement nonetheless 

results in a diminution in mine safety because a manual elevator is

relatively slow and, in a mine disaster, could prevent miners from 

surfacing quickly. For another example, see Int’l Union, United 

Mine Workers of Am. v. Fed. Mine Safety & Health Admin., 924 

F.2d 340 (D.C. Cir. 1991) (Quarto Mining). 

3 We have concluded that the “diminution of safety” clause 

requires only that the Assistant Secretary determine “whether 

application of a particular mandatory safety regulation would be 

unsafe” and that “the Assistant Secretary need not balance the 

efficacy of the existing rule against the net benefits produced by the 

proposed modification,” Quarto Mining, 924 F.2d at 343, basing 

our interpretation on the Assistant Secretary’s practice at the time. 
4

disadvantages of the alternative method” are weighed, 

including those that are unrelated to the original standard. Id. 

The party seeking modification has the burden of proof to 

establish that the proposed modification complies with 

section 811(c). 30 C.F.R. § 44.30(b). 

The modification process begins with an operator’s filing 

a petition for modification with MSHA. See id. § 44.10.

After an investigation, the MSHA Administrator issues a 

proposed order. Id. § 44.13. The operator may request a 

hearing before an administrative law judge (ALJ), id. 

§§ 44.14, 44.15, 44.20, who, after investigation/hearing,

issues his decision, id. § 44.32. Any party—including 

MSHA—may then appeal to the Assistant Secretary. Id. 

§ 44.33. The Assistant Secretary’s order may contain “special 

terms and conditions” which “shall have the same effect as a 

mandatory safety standard.” Id. § 44.4(c). “Only a decision 

by the Assistant Secretary [is] final agency action for 

purposes of judicial review.” Id. § 44.51. 

These six petitions for review involve MSHA’s 

“permissibility” requirements, which, in general, mandate that 

certain equipment located in certain mine areas be approved 

by MSHA (i.e., that they be permissible). The focus of the 

permissibility requirements is to “assure that [electrically 

operated] equipment will not cause a mine explosion or mine 

 

See id. at 344. The record reveals some confusion, however, about 

whether MSHA now applies the Southern Ohio Coal Co. test to

both statutory options or to the first only. Compare ALJ’s Decision 

and Order at 14, Rosebud Mining Co., Case Nos. 2010-MSA-1, 

2011-MSA-2, -11, -12 (Dep’t of Labor Apr. 11, 2013) (Rosebud 

ALJ Order I) with Assistant Secretary’s Decision and Order at 13, 

Case Nos. 2010-MSA-1, 2011-MSA-2, -11, -12 (Dep’t of Labor 

Nov. 14, 2013) (Rosebud Order I). Because the petitioners do not 

raise this issue, we do not reach it. 
5

fire . . . . ” 30 C.F.R. § 75.2; see also Administrator’s 

Proposed Decision and Order at 5, Canyon Fuel Co., Docket 

No. M-2009-025-C (Dep’t of Labor May 6, 2011) (“MSHA 

requirements for permissible . . . equipment are intended to 

prevent mine explosions from unpredicted methane 

accumulations, methane outbursts, or float coal dust in 

suspension by removing a possible ignition source.”). MSHA 

does not define “non-permissible” but its definition of 

“permissible” substantially illuminates the former. 

Permissible equipment includes, as relevant here, “completely 

assembled electrical machine[ry]” for which MSHA has 

issued “a formal approval.” 30 C.F.R. § 18.2. Thus,

electrical equipment without this approval is non-permissible 

and, accordingly, unauthorized in certain mine areas.

4

 Not all 

mine equipment is subject to the permissibility scheme—for 

example, “[m]echanical surveying equipment,” which “poses 

no risk of ignition,” requires no modification order for use.

Rosebud ALJ Order I at 5.5 For our review, the permissibility 

scheme breaks down into three categories: (1) nonpermissible equipment to which the non-use in certain mine 

areas restriction applies; (2) non-permissible equipment with 

a MSHA modification which removes the non-use restriction

and (3) equipment (like mechanical surveying equipment) for 

 

4 The parties stipulated that “[t]he concern with any electrical 

equipment is that if used in an explosive atmosphere it will produce 

a spark, fire or heating with enough energy that an ignition of 

methane and/or coal dust may result, possibly leading to a fire or 

explosion.” Stipulations ¶ 19, In re Rosebud Mining Co., Docket 

Nos. 2010 MSA-1, 2011 MSA-2, 2011-MSA-12, 2011 MSA-11 

(Dep’t of Labor Mar. 28, 2013) (hereinafter Stipulations). 

5 Relatedly—although not relevant for our review—MSHA 

deems permissible “intrinsically safe” equipment, that is, 

equipment “incapable of releasing enough electrical or thermal 

energy . . . to cause ignition.” 30 C.F.R. § 18.2. 
6

which no modification order is needed to authorize its use in 

certain mine areas.6 

The petitioners sought to use non-permissible equipment 

and petitioned for modification of the following MSHA safety 

standards: (1) 30 C.F.R. § 75.500, the standard requiring, 

inter alia, that electrical equipment used in or inby the last 

crosscut7constitute permissible equipment, (2) Id. § 75.507-1, 

the standard requiring that electrical equipment used in return 

 

6 As the parties stipulated, there is a difference between 

category two equipment and “permissible” equipment. The parties 

refer to category two equipment as “permitted” equipment—

meaning it is “non-permissible equipment allowed to be used at a 

particular mine pursuant to the granting of a petition for 

modification.” Stipulations ¶ 29. By contrast, permissible 

equipment has “a formal approval [without conditions] . . . issued 

by MSHA[].” Id. 

7

 Throughout the record, this area of the mine is referred to as 

“in or inby the last open crosscut.” See, e.g., Rosebud Order I at 17 

(emphasis added); see also FMC Wyoming Corp., v. MSHA, 16 

FMSHRC 1787, 1994 WL 445344, at *4 (Aug. 16, 1994) (“the 

term ‘last open crosscut’ is interchangeable with ‘last crosscut’ ”). 

MSHA defines “[t]he area of a coal mine inby the last open 

crosscut” as the “working place.” 30 C.F.R. § 75.2. The parties 

stipulated that the “the ‘last open crosscut’ is the last crosscut 

without a permanent stopping in a line of pillars containing the 

permanent stoppings that separate the intake air courses and the 

return air courses. This area includes the most advanced mining 

area in the mine, where the ventilating air reaches the areas of 

active coal removal and deepest penetration and starts its course 

back out of the coal mine.” Stipulations ¶ 10. “ ‘Inby’ refers to 

something facing the direction of the coal face. Conversely, 

‘outby’ refers to the direction facing the mine entrance (the 

surface).” Andalex Res., Inc. v. MSHA, 792 F.3d 1252, 1254 n.2 

(10th Cir. 2015).
7

airways8constitute permissible equipment and (3) Id.

§ 75.1002, the standard requiring that electrical equipment 

used within 150 feet of pillar workings or longwall faces9

constitute permissible equipment. In short, the modification 

petitions sought authorization to use non-permissible 

equipment in three mine locations where use of the equipment 

was otherwise off-limits. Each of the three described

locations is “more likely to have an explosive environment”

than other mine areas, thus triggering the applicable standard. 

Assistant Secretary’s Decision and Order at 27, Canyon Fuel 

Co., Case Nos. 2011-MSA-00006 to 00009, 2011-MSA00014 to 00021, 2013-MSA-00012, -00024, -00025, -00037 

(Dep’t of Labor Nov. 24, 2014) (Canyon Fuel Order). 

A. MSHA PROCEEDINGS REGARDING ROSEBUD AND 

PARKWOOD

Petitioners Parkwood Resources and Rosebud Mining 

filed identical modification petitions in December 2008 and 

January 2009.10 Each operator sought to use non-permissible 

 

8 Return air is “[a]ir that has ventilated the last working place 

on any split of any working section or any worked-out area whether 

pillared or nonpillared. If air mixes with air that has ventilated the 

last working place on any split of any working section or any 

worked-out area, whether pillared or nonpillared, it is considered 

return air. For purposes of § 75.507–1, air that has been used to 

ventilate any working place in a coal producing section or pillared 

area, or air that has been used to ventilate any working face if such 

air is directed away from the immediate return is return air.” 30 

C.F.R. § 75.301. 

9

Pillar workings and longwall faces are simply “areas in 

which miners extract coal.” Andalex Res., 792 F.3d at 1254.

10 The Parkwood and Rosebud petitions were subsequently

consolidated at the administrative level and we follow suit, 

hereinafter referring to them as the Rosebud petitioners. 
8

equipment—specifically, battery-powered (i.e., electrical) 

surveying instruments—11in or inby the last open crosscut and 

in return airways. See 30 C.F.R. §§ 75.500; 75.507-1. They 

maintained that the two applicable safety standards hampered

both their ability to accurately and quickly map the mines—

resulting in a “diminution of safety” to miners, see 30 U.S.C. 

§ 811(c)—12as well as their compliance with other MSHA 

regulations, see 30 C.F.R. § 75.372 (requiring “up-to-date 

map of the mine drawn to a scale of not less than 100 nor 

more than 500 feet to the inch”), id. § 75.1200 (requiring 

mine operator to maintain “accurate and up-to-date map” of 

mine “in a fireproof repository located in an area on the 

surface of the mine”), and state law, see 52 PA. STAT. ANN.

§ 690-224 (requiring “professional quality map of the mine on 

a scale of not less than 200 feet to the inch”), that require

current and accurate mine maps. To obtain the modification,

the Rosebud petitioners proposed seven conditions on their 

use of the NPESE, see generally S. Ohio Coal Co., 928 F.2d 

at 1202 (alternative must “promote the same safety goals as 

the original standard with no less than the same degree of 

 

11 This equipment is hereinafter referred to as non-permissible 

electronic surveying equipment (NPESE).

12 According to all six petitioners, accurate surveying is critical 

because it “prevents intersection of the mine with abandoned 

working of other mines which may contain water in large 

quantities, explosive gas or the absence of oxygen.” Pet’rs’ Br. at 

12. Surveying is also necessary to avoid “sealed areas,” id. at 13, 

which areas MSHA subjects to regular “monitoring.” See 30 

C.F.R. § 75.336. 
9

success”), one of which—no use when float coal dust13 is in 

suspension14—is of particular relevance to our review.

15

 

1. ADMINISTRATOR’S DECISION

The Rosebud petitioners’ “diminution of safety”

argument pressed that the NPESE was needed in order to 

accurately map mines because of its ability to obtain 

measurements superior to non-electric (mechanical) surveying 

equipment. The Administrator rejected the Rosebud 

petitioners’ arguments for two reasons. First, he determined 

that “when using [NPESE] the equipment need not be taken 

into return air or inby the last open crosscut if the surveying is

carefully coordinated with the mining activity.” 

Administrator’s Proposed Decision and Order at 5, Parkwood 

Res. Inc., Docket No. M-2008-054-C (Dep’t of Labor Jan. 

29, 2010). In other words, he found that the Rosebud 

petitioners could use their preferred surveying tools—the 

NPESE—without violating the permissibility regulations

because they did not need to use the equipment in the areas to 

which the permissibility regulations apply. Thus the 

regulations restricting the areas into which the operators could 

 

13 “Float coal dust” is defined as “coal dust consisting of 

particles of coal that can pass a No. 200 sieve.” 30 C.F.R. 

§ 75.400–1(b). 

14 MSHA regulations do not define the term “in suspension” 

but the parties stipulated that it means dust “suspended in the air 

during mining.” Stipulations ¶ 33.

15 The other conditions included: (1) regular examination of 

the NPESE, (2) continuous monitoring for methane during use of 

NPESE, (3) mandatory shutdown if methane concentration reaches 

a certain level, (4) changing and charging of batteries in fresh air, 

(5) proper training of personnel using NPESE and (6) use of 

NPESE after MSHA inspection only. 
10

use NPESE did not impair the miners’ ability to map the 

mines to the desired accuracy level and likewise did not 

(because of inaccurate mapping) result in a diminution of 

safety. Second, the Administrator determined that “levels of 

accuracy fully capable of protecting miners can be achieved 

using optical non-electric surveying equipment”—i.e., 

mechanical equipment—and “can achieve even higher levels 

of accuracy . . . through repetition of measurements and 

statistical applications.” Id. Thus, to him, use of NPESE was 

not necessary. 

In addition, the Administrator found the proposed 

conditions duplicative because many of them simply tracked 

MSHA regulations; those that did not were found insufficient

because they failed to ensure an adequate level of safety. 

Thus, the Rosebud petitioners’ proposed conditions did not 

“promote the same safety goals as the original standard with 

no less than the same degree of success.” See S. Ohio Coal 

Co., 928 F.2d at 1202. Regarding the proposed float coal dust 

ban, the Administrator found that its implementation was 

impossible unless mining were to cease during surveying. 

2. ALJ’S DECISION

The Rosebud petitioners sought ALJ review. The ALJ 

held two separate hearings on the consolidated petitions, 

made findings of fact and issued his decision on April 11,

2013. 

The ALJ first explained how methane and coal dust can 

result in a mine fire. First, he observed that methane is 

explosive at an aerial concentration between five and fifteen 

per cent. According to him, coal dust can also result in a 

mine fire but that, in order to ignite, the dust must be “in 

suspension . . . [and] sufficiently thick that you couldn’t see a 

light bulb that was turned on about four feet in front of you.” 
11

Rosebud ALJ Order I at 6 (alterations and quotations 

omitted). He next recognized that mechanical surveying 

equipment “poses no risk of ignition” and that, although 

NPESE does present such a risk, nonetheless “it has a low 

potential for ignition.” Id. at 5. For support on the latter 

point, the ALJ relied on the testimony of MSHA electrical 

engineer Chad Huntley and fire-and-explosion expert Noah 

Ryder. Huntley estimated “the possibility that both the 

methane detector would fail and the electronic surveying 

equipment would ignite at the same time is one in ten 

thousand.” Id. at 4. Ryder testified that the potential for a 

coal dust ignition “inside one of the[] [NPESE]” was 

“nonexistent” because, through water immersion and dust

swab tests, he found that dust would “settle

on . . . component[s]” in the devices and, “if it settled there, 

it’s not in suspension and won’t ignite.” Id. at 6 & n.9

(emphasis added). Ryder also testified that NPESE was less 

dangerous than other equipment MSHA has approved via

modification petitions. 

Some findings were in apparent tension with others. For 

example, Rosebud surveying manager Michael Groff testified 

that NPESE “does not get hot when it’s running” and that he 

had “never seen a spark or arc when removing the battery.” 

Id. at 5 n.6. But Huntley and Ryder both testified that 

sparking could occur when “the battery was physically 

disconnected” or if “an inside component broke.” Id. at 6. 

Huntley testified that NPESE could “overheat . . . and ignite 

methane” but also noted that it had “a thermal breaker for deenergizing the battery pack at a temperature below the 

ignition temperature for methane.” Id. at 5 n.6 (emphasis

added). Some NPESE equipment also came with a 

manufacturer safety warning indicating that it should not be 

used in an underground coal mine and that an explosion could 
12

result if so used.

16

 Because the manufacturer was unable to 

testify as to the basis of the warning, however, the ALJ gave it

no weight. The ALJ also recognized that Rosebud had been 

using NPESE “in all areas of [its] mine[s]” for over 20 years 

and that MSHA, by not issuing any citation during that time,

had “tacitly approved [its] use.” Id. at 13. 

 The ALJ, concluding that mechanical surveying 

equipment was “obsolete, far less accurate than electronic 

surveying equipment, and above all, not realistically available 

on the commercial market except in used condition,” id. at 2,

approved the petitions. He anticipated that the conditions he 

set out in his order “promote[d] the same safety goals as the 

original standard with no less than the same degree of 

success.” Id. at 14 (quoting S. Ohio Coal Co., 928 F.2d at 

1202). The ALJ’s conditions were substantially similar to 

those contained in the petitions, including the prohibition on 

surveying in the presence of float coal dust. He added a 

requirement that the Rosebud petitioners gradually phase out 

old equipment so that, within five years, the NPESE in use 

would be no more than five years old. The ALJ thought this 

condition would “prevent the degradation of [NPESE] seals”

through which float coal dust could enter and cause ignition. 

Id. at 17. He observed that his conditions closely replicated 

those included in an earlier MSHA consent decree allowing 

NPESE. Id. at 4 n.5; see Initial Decision Approving 

Settlement and Order of Dismissal at 2–4, Twentymile Coal 

Co., Case No. 2007-MSA-00002 (Dep’t of Labor Dec. 5, 

2007) (Twenty Mile Consent Order).

 

16 Specifically, the warning stated: “Safety Cautions; Warning; 

May ignite explosively. Never use an instrument near flammable 

gas, liquid matter, and do not use in a coal mine.” Rosebud ALJ 

Order I at 3. 
13

The ALJ also concluded that “granting [the] petitions for 

modification would engender a net gain in miner safety.” 

Rosebud ALJ Order I at 15 (emphasis in original); see also S. 

Ohio Coal Co., 928 F.2d at 1202 (asking whether 

“modification would achieve a net gain, or at least 

equivalence, in overall mine safety”), because, although 

“mechanical surveying equipment can meet . . . accuracy 

requirement[s],” “the use of mechanical equipment may 

require multiple set ups, increasing the length of surveyors’ 

exposure to hazardous conditions.” Rosebud ALJ Order at 

15. Moreover, “mechanical parts cannot be reliably calibrated 

or repaired . . . [and] surveyors are not currently trained in 

their use. . . . Therefore, application of the [permissibility] 

standard[s] is less safe than application of the modification, as 

it is unsafe to use equipment that is not calibrated or repaired 

properly, or that surveyors have not been trained to use.” Id. 

Finally, he reasoned that NPESE “is 8-10 times more accurate 

than mechanical equipment” and “greater accuracy leads to 

increased safety in the mines.” Id.17 

3. ASSISTANT SECRETARY’S DECISION

The Administrator appealed the ALJ’s order to the 

Assistant Secretary who, applying a de novo standard of 

review, conducted an independent analysis of the evidence

and rejected many of the ALJ’s factual findings. For 

 

17 The ALJ made no finding regarding diminution of safety, 

treating the case as one arising under the first prong of 30 U.S.C. 

§ 811(c) (asking whether “an alternative method of achieving the 

result of such standard exists which will at all times guarantee no 

less than the same measure of protection afforded the miners of 

such mine by such standard”). But, as noted, see supra n.3, the

Rosebud petitioners do not challenge MSHA’s application of both 

section 101(c)’s “alternative method” option and its “diminution of 

safety” option to their petitions. 
14

example, although MSHA never sanctioned Rosebud for its 

20-year use of NPESE, the Assistant Secretary declined to 

conclude that MSHA had thus tacitly approved thereof in 

view of the fact that Rosebud produced no evidence that 

MSHA knew of the use; moreover, MSHA had sanctioned 

other operators for similar use. The Assistant Secretary also 

disputed Ryder’s opinion that the Rosebud petitioners’

NPESE was “well-sealed against [methane] gas and [coal]

dust” ingress because Ryder had tested “none of . . . the 

specific instruments that [the Rosebud petitioners] identified 

in [the] petitions.” Rosebud Order I at 28–29. Moreover, the 

Assistant Secretary found Ryder’s assertion that he tested 

substantially similar equipment “suspect” given Ryder’s

failure to “take apart any of the specific instruments identified 

in the petitions” to determine their similarity vel non. Id. at 

29. In addition, the Assistant Secretary credited Huntley’s 

testimony that tended to discredit Ryder’s tests—specifically, 

that, according to International Electrotechnical Commission 

standards, “ingress protection tests” using “dust and moisture”

were not proper surrogates for gas. Id. at 30. And, even 

assuming Ryder’s tests were fair proxies, “moisture was 

detected inside all of the pieces of used equipment that Ryder 

tested.” Id. 

The Assistant Secretary also rejected the ALJ’s 

characterization of some of Huntley’s testimony. For 

instance, the “one-in-ten-thousand probability” of both the 

“methane detector failing and the electronic surveying 

equipment igniting” was based on a premise with which 

Huntley explicitly disagreed. Id. at 28–29 n.12. The 

Assistant Secretary also rejected the ALJ’s Ryder-supported

conclusion that coal dust did not present an ignition concern. 

Although “Ryder testified that coal dust . . . would settle on a 

component and not remain in suspension”—thus, not 

igniting—Huntley testified that coal dust can “enter non-
15

permissible electronic equipment, layer itself on internal 

components, and cause the equipment to overheat and ignite 

methane.” Id. at 32. The Assistant Secretary also disagreed 

with the ALJ’s conclusion that, “because the equipment has 

internal thermal breakers that are designed to de-energize the 

battery pack at a temperature below the ignition temperature 

of methane, coal dust layering on the internal 

components . . . is not a concern,” id. at 32–33, because, the 

Assistant Secretary opined, “thermal breakers can fail, and 

there [wa]s no evidence concerning their reliability,” id. at 33. 

Moreover, he noted the likelihood of a coal dust-based 

explosion even in the absence of the required aerial 

concentration because coal dust can “be rapidly placed in 

suspension, [and] even a vigilant surveyor may not have the

time to de-energize his instrument before it encounters an 

explosive concentration of coal dust.” Id. 

Finally, the Assistant Secretary disagreed with the ALJ 

on the importance of the NPESE warning. Although the 

manufacturer was unable to explain the reason for the 

warning, “[the Rosebud petitioners], not the Administrator, 

ha[d] the burden of proof in th[e] proceeding.” Id. at 34 

(citing 30 C.F.R. § 44.30(b)). 

On November 14, 2013, the Assistant Secretary issued 

his decision upholding the ALJ’s modification grant but

substantially modifying and tightening the conditions. In 

addition to prohibiting NPESE use when float coal dust was 

in suspension, the Assistant Secretary required that coal 

production shut down while the equipment was used in or 

inby the last open crosscut and in return air and that, if 

“viable” mechanical equipment became available, use of 

NPESE must cease. Rosebud Order I at 50. With these 

conditions in place, the Assistant Secretary concluded that the 

modification “promotes the same safety goals as [the 
16

standards] with no less than the same degree of 

safety. . . . [and] that the overall effect of the proposed 

alternative method, including the modifications . . . will 

achieve at least a net least [sic] equivalence in overall mine 

safety.” Id. at 14 (applying S. Ohio Coal Co. test, 928 F.2d at 

1202). 

The Assistant Secretary remanded to the ALJ to consider 

two conditions for which the record contained insufficient 

support (and which are not before us on appeal). The ALJ

subsequently approved a consent agreement applying four 

new conditions (in lieu of the remanded pair) and the Rosebud

petitioners then appealed to the Assistant Secretary to renew 

their objections to the originally disputed conditions and to 

facilitate judicial review therefrom.

18

 See 30 C.F.R. § 44.51 

(“Only a decision by the Assistant Secretary [is] final agency 

action for purposes of judicial review.”). On November 24, 

2014, the Assistant Secretary issued Rosebud Order II, once 

again rejecting the Rosebud petitioners’ arguments. 

The Rosebud petitioners argued in the second round 

before the Assistant Secretary that three of the unchanged 

requirements “[we]re unnecessary to meet [the modification] 

standard.” Rosebud Order II at 3. It was undisputed that, 

with the Assistant Secretary’s conditions, the modification 

grant “guarantee[d] no less than the same measure of 

protection afforded the miners of such mine by” the 

permissibility standards, see S. Ohio Coal Co., 928 F.2d at 

 

18 The Administrator asserted that the Rosebud petitioners’

objections “essentially reargue[d] matters already unsuccessfully 

litigated” and the Assistant Secretary accordingly treated them “in 

the nature of a motion for reconsideration.” Assistant Secretary’s 

Decision and Order at 3–4, Rosebud Mining Co., Case Nos. 2010-

MSA-1, 2011-MSA-2, -11, -12 (Dep’t of Labor Nov. 24, 2014) 

(Rosebud Order II). 
17

1202. The Rosebud petitioners argued that cessation of coal 

production while surveying took place was unnecessary 

because (1) “surveying will not be conducted in an entry 

where production is occurring,” Rosebud Order II at 4; (2) 

“surveying will not be set up close to the face” of the mine,

id.; (3) “surveying generally will be upwind of the . . . mining 

machine, and, even when it is downwind, methane and [coal]

dust will be removed by the ventilation system” and other 

safeguards, id. at 4–5; (4) “surveyors spend minimal time in 

or inby the last open crosscut or in the return,” id. at 7; (5) 

“surveying equipment . . . does not [cut into or] liberate 

methane or generate coal dust,” id.; and (6) the ALJ-imposed

condition that, “if one percent methane is detected,” use of 

NPESE was to cease, was sufficient to protect against 

methane explosions, id. at 8. 

The Assistant Secretary was not persuaded. He 

concluded that the first, second and fourth objections relied on 

factual assertions rebutted by the record.19 He found the third 

objection “d[id] not offset the decrease in safety from using” 

NPESE because the ventilation system and other safety 

features were “present whether surveyors use mechanical, 

permissible, or non-permissible surveying equipment.” Id. at 

5–6. Further, he reasoned that “ventilation systems do not 

always work effectively and [that] operators do not always 

comply with ventilation requirements.” Id. at 6. He rejected 

the fifth objection because, although it “might mean that the 

risk of using non-permissible surveying equipment is less than 

 

19 See id. at 4 n.2 (Rosebud surveyors testified only that

“usually we coordinate ourselves in different entries”) (emphasis in 

original); id. n.3 (“Rosebud Surveying Manager Groff testified that 

he has taken shots as close as 50 feet from the face.”); id. at 7 n.4 

(“Groff . . . acknowledged that he does not always set up in the 

middle of the entry.”).
18

the risk of using other types of non-permissible equipment,” it 

did not mean that NPESE was safe. Id. at 7–8. Finally, the 

Assistant Secretary criticized the methane monitoring 

condition because the “detectors may fail” and because there 

“is a lag time in methane detectors and that if there were a 

sudden inundation of methane, by the time the methane 

detector registered one percent methane, and by the time the 

surveyor reacted to shut the surveying equipment off, there 

might already be an explosive amount of methane 

surrounding the equipment.” Id. at 8. 

The Rosebud petitioners also argued that the prohibition 

on surveying when float coal dust existed was both unclear 

and unnecessary and that the requirement to switch to 

“viable” mechanical surveying equipment if it became

available was unreasonable. Regarding the first claim, the 

Rosebud petitioners asserted that float coal dust in suspension

always exists. But, as the Assistant Secretary observed, the 

condition could be implemented if production ceased. 

Moreover, he clarified and interpreted the condition to allow 

for a “visual determination of whether there is float coal dust

in suspension.” Id. at 11 n.7. As to the latter objection, the 

Assistant Secretary explained that mechanical equipment 

would be viable if “sufficiently accurate for use in 

underground mines” and that MSHA’s resources should not 

be spent on ensuring the NPESE’s compliance with 

conditions if viable mechanical equipment—i.e., equipment 

that can be used without conditions—exists. Id. at 15.

B. MSHA PROCEEDINGS REGARDING CANYON FUEL AND 

MOUNTAIN COAL (CANYON FUEL PETITIONERS)

On July 15, 2009 petitioners Canyon Fuel and Mountain 

Coal filed nearly identical petitions for modification, seeking 

to use NPESE in or inby the last crosscut, in return airways
19

and within 150 feet of pillar workings and longwall faces. 

See 30 C.F.R. §§ 75.500, 75.507-1, 75.1002. As did the 

Rosebud petitioners, Canyon Fuel and Mountain Coal claimed

that the mandatory standards resulted in diminution in miner

safety and inability to meet mapping requirements and they 

proposed comparable conditions, with one exception (the float 

coal dust condition was omitted). The Administrator denied 

the petitions for reasons substantially similar to his denial of 

the Rosebud petitioners’ petitions. 

 The MSHA ALJ held a hearing on the consolidated 

Canyon Fuel and Mountain Coal petitions and released a 

decision on April 3, 2014.20 In light of the intervening 

Rosebud Order I, MSHA agreed that the petitions should be 

granted if the Assistant Secretary’s conditions set forth in 

Rosebud Order I were imposed. See ALJ’s Decision and 

Order at 7, Canyon Fuel Co., Docket Nos. 2011-MSA-00006 

to 00009, 00014 to 00021, 2013-MSA-00024, -00025, -00037 

(Dep’t of Labor April 3, 2014) (“The issues have evolved 

since the petitions were first filed. No longer is the issue . . . 

whether the proposed modification should be 

granted . . . . The question now is simply what conditions are 

necessary.”). The ALJ subsequently revised the Rosebud

Order I conditions—as applied to Canyon Fuel—in three 

significant respects.

First, he found that it was “not appropriate” to disallow 

NPESE if and when “viable new mechanical surveying 

equipment” became available. Id. at 13–14. To him, the 

 

20 Petitioners Peabody Sage Creek and Bowie Resources had 

similar petitions pending and filed a letter with the ALJ agreeing to 

be bound by his decision in the Canyon Fuel case. Canyon Fuel 

references hereinafter include not only Canyon Fuel and Mountain 

Coal but also Peabody Sage Creek and Bowie Resources. 
20

accuracy of mechanical surveying equipment—even, 

apparently, “viable” mechanical surveying equipment—was 

inferior and reduced miner safety. He also found the ban on 

surveying when float coal dust was in suspension “vague and 

ambiguous” because the condition did not include a 

measurement of float coal dust and because surveying would 

be “impossible”—due to “visibility restrictions”— long

before an explosive quantity was in suspension. Id. at 20. 

Finally, he narrowed the restriction on surveying during coal 

production, requiring only that surveying not occur at “the 

longwall or a working face during production.” Id. at 23. 

The Administrator appealed once more to the Assistant 

Secretary who issued a final order simultaneously with the 

Rosebud II Order with identical conditions based on

materially similar reasoning. 

Both sets of operators timely filed petitions for review.21 

Our jurisdiction arises under section 101(d) of the Mine Act. 

30 U.S.C. § 811(d).22

II. ANALYSIS

Our review of the Assistant Secretary’s two final orders 

is pursuant to the Administrative Procedure Act, that is, we 

 

21 The Rosebud petitioners, however, did not petition for 

modification of 30 C.F.R. § 75.1002 (permissibility requirement for 

“equipment . . . located within 150 feet of pillar workings or 

longwall faces”). With this exception, both sets of petitioners 

challenge the same conditions and are therefore hereinafter referred 

to as the petitioners. Because Canyon Fuel made no discrete 

argument regarding 30 C.F.R. § 75.1002, we reject its challenge 

thereto without more. 

22 Both sets of petitioners filed a consolidated brief and we 

likewise consolidate the petitions for disposition.
21

determine “whether the granting of the petition for 

modification was arbitrary, capricious, an abuse of discretion 

or otherwise not in accordance with the law.” Int’l Union, 

United Mine Workers of Am. v. MSHA, 830 F.2d 289, 292 

(D.C. Cir. 1987) (Emerald Mine Corp.) (citing 5 U.S.C. 

§ 706(2)(A)). This “[h]ighly deferential” standard, AT&T 

Corp. v. FCC, 349 F.3d 692, 698 (D.C. Cir. 2003), is 

especially applicable when we review “technical 

determinations on matters to which the agency lays claim to 

special expertise.” Bldg. and Const. Trades Dep’t v. Brock, 

838 F.2d 1258, 1266 (D.C. Cir. 1988); see also Int’l Union, 

United Mine Workers of Am. v. MSHA, 407 F.3d 1250, 1258 

(D.C. Cir. 2005) (Jim Walter Res., Inc.) (equivalent safety 

determination is within Assistant Secretary’s expertise). We 

uphold the agency if it “considered the relevant factors and 

articulated a rational connection between the facts found and 

the choice made.” Nat’l Ass’n of Clean Air Agencies v. EPA, 

489 F.3d 1221, 1228 (D.C. Cir. 2007) (internal quotation 

marks omitted). Because the challenged orders involve “an 

area within the [Assistant] Secretary’s expertise,” Jim Walter 

Res., Inc., 407 F.3d at 1258, and because they are supported 

by “substantial evidence and . . . a reasoned explanation,” 

Bldg. and Const. Trades Dep’t., 838 F.2d at 1266, we deny 

the petitions for review. 

The thrust of the petitioners’ argument is that the three 

above-discussed conditions—the requirement that coal 

production cease while surveying with NPESE occurs in or 

inby the last open crosscut, in return air or within 150 feet of 

longwall faces or pillar workings (high risk areas), the bar on 

surveying with NPESE when float coal dust is in suspension 

and the instruction to use viable mechanical surveying 

equipment if it becomes available—are unnecessary and 
22

therefore arbitrary and capricious.

23

 But the Assistant 

Secretary weighed the relevant factors—whether the 

alternative “promote[s] the same safety goals as the original 

standard with no less than the same degree of success” and 

whether it improves “overall mine safety,” S. Ohio Coal Co., 

928 F.2d at 1202—and “articulated a rational connection 

between the facts found and the choice made,” Nat’l Ass’n of 

Clean Air Agencies, 489 F.3d at 1228 (internal quotation 

marks omitted). In so concluding, we note that “the Mine Act 

and its standards require redundant safety measures.” 

Rosebud Order II at 6 (emphasis added). 

A. CESSATION OF PRODUCTION

It is uncontested that the condition requiring coal 

production to stop while the NPESE is used in high risk areas

enhances mine safety. What is at issue is whether this 

 

23 The petitioners also contend that the Assistant Secretary’s de 

novo review of the ALJ orders and factual findings is ultra vires. 

Section 101(c) of the Mine Act provides that a petition for a 

modification hearing is subject to section 554 of the Administrative 

Procedure Act (APA). 30 U.S.C. § 811(c). Section 554 of the 

APA in turn cross-references section 557 which provides that “[o]n 

appeal from or review of [an] initial decision, the agency has all the 

powers which it would have in making the initial decision.” 5 

U.S.C. § 557(b) (emphasis added); see also Kay v. FCC, 396 F.3d 

1184, 1189 (D.C. Cir. 2005) (“The law is settled that an agency is 

not required to adopt the credibility determinations of an 

administrative law judge.”); id. (agency not in position analogous to 

appellate court reviewing trial court). We have suggested that 

findings dependent on “demeanor of witnesses” must be “given 

special weight,” Mathew Enter., Inc. v. NLRB, 498 F. App’x. 45, 46 

(D.C. Cir. 2012) (quoting 2 Richard J. Pierce, Jr., Administrative 

Law Treatise § 11.2 (5th ed. 2010)) (emphasis added), but 

demeanor is not at issue here. 
23

condition is unnecessary and, indeed, whether it is so

unnecessary as to fail arbitrary and capricious review. The 

objections of the petitioners break down into the following 

groups: (1) surveying equipment is not used to mine coal, (2) 

use of the NPESE must stop if the methane level approaches a 

level well below its explosive threshold, (3) even while 

production is ongoing, the NPESE will not come in contact 

with methane and coal dust, (4) the NPESE has a slight

potential for ignition, (5) it is unlikely methane or coal dust 

will enter the NPESE compartments that contain electrical 

components, (6) previously approved modification petitions

manifest that this condition is unnecessary and (7) the 

manufacturer’s warning about use of NPESE in coal mines 

was “not probative,” Pet’rs’ Br. at 61. We address the

objections in seriatim. 

1. Surveying equipment is not used to mine coal

The petitioners argue that the Assistant Secretary failed 

to appreciate the differences between NPESE and other—

riskier—mine equipment. For example, they claim that he 

failed to account for the fact that the NPESE does not cut 

coal, that it is peripheral in the mining process and that it does 

not cause methane to disperse or coal dust to be in suspension. 

But the Assistant Secretary addressed this argument. He 

reasoned that “[a]lthough these circumstances . . . might mean 

that the risk of using non-permissible surveying equipment is 

less than the risk of using other types of non-permissible 

equipment, nothing in the record convinces me that the 

circumstances would sufficiently offset the dangers of using” 

NPESE in high risk areas. Rosebud Order II at 7–8 (emphasis 

added). Moreover, MSHA has, by regulation, applied its 

permissibility requirements to equipment other than that 

which “cuts into coal.” Canyon Fuel Order at 41. See, e.g., 

30 C.F.R. § 75.500(d) (“All . . . electric face equipment which 
24

is taken into or used inby the last crosscut of any coal mine” 

must be permissible) (emphasis added). The petitioners’ 

contention that the NPESE—although non-permissible—is 

relatively safe suggests only that this condition is less 

necessary than others, not that it is arbitrary. In addition, the 

Assistant Secretary noted that the petitioners used the Twenty

Mile consent order, Case No. 2007-MSA-00002 (Dep’t of 

Labor Dec. 5, 2007), as a template for their petition and 

Twenty Mile included the same condition. 

2. Methane detection and shutdown requirement guards

against explosions

The petitioners next contend that, because the ALJ 

imposed a condition that operators cease using NPESE if the 

methane level reaches a 1% concentration and, because a 5% 

concentration is the minimum concentration necessary for 

ignition, the requirement that production cease during NPESE 

use is arbitrary. The Assistant Secretary amply rebutted this 

argument. He noted that although the 1% methane 

concentration condition “provide[s] some protection from the 

increased risk of a methane ignition posed by using nonpermissible equipment . . . [it is] not enough.” Rosebud Order 

I at 35–36. As he explained, the record indicated that 

methane detectors are not always properly calibrated and also 

may fail. Moreover, he cited testimony that a “lag time”

exists between an increase in methane concentration and its 

detection. Rosebud Order II at 8. Thus, if there were a 

“sudden inundation of methane,” the methane detector might 

not register it before an explosive quantity accumulated near 

the NPESE. Id. 

3. NPESE will not encounter methane or float coal dust

The petitioners next contend that, as a matter of practice, 

surveying generally does not occur in areas where methane 
25

and coal dust are present and that, even when it does, the 

ventilation systems will prevent an explosion. First, we note 

that much of this argument is equivocal.24 To second-guess

the Assistant Secretary on this ground would require us to 

weigh the evidence de novo and usurp MSHA’s statutorily 

conferred authority to determine whether a specific mine 

hazard—once its existence is conceded—is substantial

enough to impose restrictions. See, e.g., Partington v. Houck, 

723 F.3d 280, 291 (D.C. Cir. 2013) (“we do not substitute our 

judgment for that of the agency or evaluate de novo” its 

factual findings). 

In any event, the Assistant Secretary adequately 

addressed the objection with a reasoned explanation. First, he 

observed that the record was ambiguous about whether

surveying sometimes occurred in the areas the petitioners 

claimed to avoid.

25

 Moreover, he observed that nothing in the 

 

24 See, e.g., Pet’rs’ Br. at 44 (there is “little or no exposure to 

either” dust or methane) (emphasis added); id. at 45 (in “most 

instances, the surveying equipment will be positioned upwind of 

the continuous miner and thus not exposed in any way to methane 

or dust”) (emphasis added); id. (“surveyors are generally upwind of 

the entry where production is occurring”) (emphasis added); id. at 

46 (“it is clear that the instrument will not often be in close 

proximity downwind of the continuous miner”) (emphasis added). 

25 See Rosebud Order II at 4 n.2 (“Although initially stating 

that he did not survey in the entry where the continuous miner is 

mining, . . . Groff then testified that ‘usually we coordinate 

ourselves in different entries.’ ” (emphasis in original)); id. at n.3 

(“The evidence does not support Rosebud’s assertion that surveying 

is not conducted close to the face. . . . Groff testified that he has 

taken shots as close as 50 feet from the face.”); id. at 7 n.4 (“The 

evidence does not support Rosebud’s assertion that surveying 

equipment is always used in the middle of the entry. . . . [Groff] 
26

ALJ orders “require[d] that the equipment be used” only in

the areas identified by the petitioners—i.e., in different mine 

entries, a sufficient distance from the face or in the middle of 

mine entries. Canyon Fuel Order at 41–42. Regarding 

whether surveying often or always occurred upwind of 

production, the Assistant Secretary noted the same ambiguity, 

i.e., that the petitioners occasionally surveyed downwind. See 

id. at 42–43 n.18 (Canyon Fuel expert “testified that when one 

surveys in the longwall tailgate return production is ‘most 

always’ upstream.”) Moreover, the conditions of use did not 

require that surveying equipment be used only outside the 

designated areas—that the Assistant Secretary was unmoved

by the assertion that this would almost always be the case was 

not arbitrary.26 

Regarding ventilation, the Assistant Secretary noted that 

MSHA regulations already require ventilation so that it does 

not “offset the decrease in safety from using” NPESE. 

Rosebud Order II at 6. In addition, “ventilation systems do 

not always work effectively and operators do not always 

comply with ventilation requirements.” Id. Ventilation is but 

one of many “redundant safety measures . . . the Mine Act 

and its standards require” to guard “against ignitions and 

explosions.” Id. at 5–6; see also Canyon Fuel Order at 40 

 

acknowledged that he does not always set up in the middle of the 

entry.”). 

26 It is unclear from the record whether the risk of NPESE use 

is mitigated entirely if its use is limited to, inter alia, areas upwind 

of production or in entries where production is not occurring. The 

Assistant Secretary did not reach this issue and thus we need not 

reach it. The petitioners do not argue that it was arbitrary to impose 

the cessation of production condition in lieu of a condition 

requiring, for example, that surveyors always remain upwind of 

production.
27

(“One of the most frequently cited violations is the failure to 

comply with ventilation requirements.”). In addition, even if 

the ventilation system functioned properly, the Assistant 

Secretary concluded that it captured only “significant 

amount[s] of dust and methane”—not all of it. Id. Record 

evidence supports his conclusion. See id.at 40 n.14 (citing 

ALJ hearing transcript).

4. NPESE has low ignition potential

The petitioners also argue that NPESE is unlikely to 

cause an explosion. See, e.g., Pet’rs’ Br. at 52 (although 

NPESE is not “permissible,” it nonetheless “has a very low 

potential for ignition of methane or coal dust”); id. at 53 

(NPESE “does not generate heat”). Substantial evidence 

supports the Assistant Secretary’s rejection of this argument.

The Assistant Secretary considered—and rejected—

expert testimony on the relative ignition potential of the 

equipment. For example, he noted that as part of the test for 

determining whether equipment is permissible, “MSHA 

layers dust onto components to see if dust will smolder.” 

Canyon Fuel Order at 35. Smoldering corresponds to

overheating, which can result in ignition. Granted, record 

evidence suggested that if there is significant overheating, 

“components inside the devices would ‘likely’ fail, the 

equipment would not function, and there would be no safety 

hazard.” Id. But the Assistant Secretary observed that the 

evidence was equivocal and not supported with test results. 

There was also testimony indicating that “if there were 

internal sparking or overheating it would not be detected.” Id. 

at 36. The Assistant Secretary further observed that the safety 

warning contained in the manual indicated that certain 

equipment “[m]ay ignite explosively.” Id.
28

The petitioners supplement their argument about the 

equipment’s relative safety with the observation that it cannot 

create sparks. See Pet’rs’ Br. at 63 (“[U]nlike a continuous 

miner or roofbolter, [NPESE] creates no sparks.”). But see id. 

at 53 (“[T]he changing of batteries has a potential for creating 

sparks.”). They argue, therefore, that “dust or methane would 

necessarily have to enter the instrument” in order for an 

explosion to occur. Id. at 63. But the Assistant Secretary 

disagreed and record evidence supports his skepticism. For 

example, Ryder “acknowledged that non-permissible 

electronic surveying equipment can spark if there is 

something wrong with the device such as a loose connection.” 

Canyon Fuel Order at 28 n.8. And a MSHA witness “testified 

that batteries in the equipment can short out and cause an 

arc.” Id. 

5. Methane and dust will not enter NPESE electrical 

compartments 

Based on their dubious contention that sparking cannot 

occur, the petitioners argue that ignition can result only if dust 

or methane gets into the NPESE. See Pet’rs’ Br. at 63 (“dust 

or methane would necessarily have to enter the instrument” 

for ignition to occur). And the petitioners contend that the 

devices were adequately sealed and that the ALJ-imposed 

condition requiring updating of equipment sufficiently 

guarded against degradation of seals. The Assistant Secretary 

concluded that the record rebutted this claim. 

The premise that the devices were well-sealed was based 

on Ryder’s faulty water immersion and dust swab tests. As 

the Assistant Secretary explained, the test results were 

performed on equipment different from that the petitioners 

sought to use. Ryder claimed that the equipment he inspected 

was substantially similar to the petitioners’ but he “did not 
29

take apart” the latter; and Huntley testified that, absent such 

an examination, it would be difficult to conclude that it was

similar. Rosebud Order I at 29. Moreover, even assuming 

Ryder tested sufficiently similar devices, Huntley testified 

that it was “suspect” to use water as a surrogate for gas and, in 

any event, moisture was found in all of the equipment Ryder 

tested. Rosebud Order I at 30. Although Ryder testified that 

the water entered only because the seals were degraded, the 

Assistant Secretary observed that there was no record 

evidence documenting how long it took a seal to degrade. 

And, again, the petitioners had the burden of proof. 30 C.F.R. 

§ 44.30(b). 

The petitioners argue that, even if dust or methane can 

enter the electrical compartments, the openings “are 

sufficiently small in most cases to prevent the escape of flame 

outside the compartment.” Pet’rs’ Br. at 58. We once again 

note the petitioners’ equivocal language and also observe that 

the Assistant Secretary referenced testimony rebutting this 

contention. See Rosebud Order I at 31 (“I credit 

Huntley’s . . . testimony that internal pressures from an 

ignition could create larger openings.”). 

6. Other petitions

The petitioners next contend that the Assistant Secretary 

improperly analogized to other petitions in imposing the 

condition that coal production cease when surveying occurs in 

high-risk areas. We need make only two brief observations. 

First, we question the relevance of this claim. The petitioners

contend, for example, that MSHA “permits photography [in 

high-risk areas] with less extensive requirements than the 

[NPESE] petitions and permits cutting and welding under less 

extensive conditions which do not involve cessation of 

production.” Pet’rs’ Br. at 60 n.23. But we have no basis on 
30

this record to conclude either that that equipment poses the 

same (or greater) risk as the NPESE or that the conditions 

imposed on the use of that equipment, even if not identical, 

are not nonetheless more stringent. Even if we could reach 

those conclusions, they do not establish, on their own, that the 

condition MSHA placed on NPESE is arbitrary. Second, the 

petitioners apparently encouraged the Assistant Secretary to 

rely on other petitions such as Twenty Mile. See Canyon Fuel 

Order at 40 (“Canyon Fuel expert witness Hartsog 

acknowledged . . . reli[ance] on other granted-petitions [sic]

for modification of permissibility standards that allow the use 

of diagnostic and testing equipment in high risk areas as well 

as the modification in In re Twentymile Coal Co.”); Rosebud 

Order I at 39 (“Rosebud mining engineer Cobaugh 

acknowledged that the Twentymile consent agreement was a 

template for Rosebud’s petitions for modification in this 

case.”). And the Twenty Mile petition did involve NPESE. 

The petitioners now contend that Twenty Mile was “never 

subjected to the test of litigation and a decision by an 

impartial ALJ.” Pet’rs’ Br. at 60. Although accurate, their 

backtracking does little to establish that the conditions are

arbitrary or capricious. The Assistant Secretary’s conditions 

are supported by the record before him and his reference to

Twenty Mile was little more than an aside. See Rosebud 

Order I at 39 (“I also note that the same requirement is 

contained in the Consent Agreement in [Twenty Mile].”). 

7. Reliance on device warning

The petitioners also argue that the Assistant Secretary 

improperly relied on the manufacturer’s warning inasmuch as 

neither MSHA nor the manufacturer could explain its basis. 

The petitioners again overlook that they bear the burden of 

proof in the modification petition process. See 30 C.F.R. 

§ 44.30(b). And, in any event, it was not arbitrary for the 
31

Assistant Secretary to rely on the warning applicable to the 

very equipment the petitioners sought to use. The 

manufacturer, after all, “is in the best position to know about 

the ignition risks of the equipment it manufactures.” Rosebud 

Order I at 34; see also Canyon Fuel Order at 37 (“[T]he 

manufacturers of the equipment are in the best position to 

evaluate its ignition potential.”). 

B. FLOAT COAL DUST CONDITION

The petitioners separately argue that the condition 

prohibiting surveying in high-risk areas when float coal dust

is in suspension is arbitrary. It is uncontested that this 

condition enhances mine safety. What is at issue is whether 

the Assistant Secretary reasonably concluded that it is 

necessary. We note, first, that the petitioners’ arguments 

repeat earlier contentions. See Pet’rs’ Br. at 63 (“[T]here is 

nothing about use of a surveying instrument that liberates dust 

or methane.”); id. (“it creates no sparks”); id. at 65 (for 

explosion to occur “dust must still find its way into the insides 

of the electronic surveying instrument which is highly 

unlikely”). Only two contentions require analysis: the 

condition is unclear and impossible to implement and the 

condition is self-regulating because surveying becomes 

impossible at a dust concentration well below an explosive 

point. 

The petitioners rely on the Administrator’s statements in

his denial of their original petitions that “it is not possible for 

the petitioner to implement this action item [because] [f]loat 

coal dust cannot be entirely eliminated during the cutting 

process of mining. . . . Unless all mining were to cease, float 

coal dust would be generated.” Administrator’s Proposed 

Decision and Order at 6, Parkwood Res. Inc., Docket No. M2008-054-C (Dep’t of Labor Jan. 29, 2010). But, given that 
32

the Assistant Secretary has required coal production to cease 

while surveying is conducted in the high-risk areas, the 

petitioners’ point is weakened. And we have found no other

record support for this argument.27 Regarding whether the 

condition is clear enough to be implemented, the Assistant 

Secretary resolved its vagueness by noting that a “visual 

determination” suffices to determine if dust is in suspension. 

Rosebud Order II at 11 n.7.

The petitioners also contend that this condition is 

unnecessary because it is “self-regulating.” Pet’rs’ Br. at 63. 

They claim that “far less than a sufficient amount of dust to be 

explosive would preclud[e] surveying” by reducing visibility 

below levels necessary for surveying. Id. But the Assistant 

Secretary reasonably rejected this argument. As he explained, 

“coal dust can be rapidly placed in suspension . . . [and] even 

a vigilant surveyor may not have the time to de-energize his 

instrument before it encounters an explosive concentration of 

coal dust.” Rosebud Order I at 33. 

C. VIABLE MECHANICAL SURVEYING EQUIPMENT 

The final condition under challenge is that the petitioners

must switch to viable mechanical surveying equipment when 

it becomes commercially available. We first note that it is 

MSHA’s position that the use of NPESE, under the conditions 

of use imposed by the Assistant Secretary’s two orders, is no 

more dangerous than the use of mechanical surveying 

 

27 The petitioners argue in the alternative that the prohibition 

on surveying in high-risk areas while production is ongoing renders 

this condition redundant. But the record reflects that coal dust can 

also be placed in suspension from “methane explosions, bumps, 

fans, roof falls, brushing up against insufficiently rock-dusted float 

coal dust, and the exhaust from large pieces of equipment.” 

Canyon Fuel Order at 35. 
33

equipment. See Rosebud Order I at 44 (“I have found that the 

[NPESE], including the modifications and additional 

conditions in the [ALJ’s] decision and order, as modified and 

supplemented by the conditions in this decision and order, 

will at all times promote the same safety goals as the original 

standards [allowing mechanical equipment] with no less than 

the same degree of success.”). If that were not so, the 

modification grant here would be improper. See S. Ohio Coal 

Co., 928 F.2d at 1202 (modification must “promote the same 

safety goals as the original standard with no less than the 

same degree of success.”). And the petitioners contend that 

NPESE (with the conditions of use) is not only as safe as, but

safer than, mechanical surveying equipment. 

The petitioners make two arguments to suggest that 

mechanical surveying equipment, even when “viable,” is less 

safe than NPESE. First, they argue that surveying with 

NPESE is faster and thus surveyors are exposed to the 

dangers of mines for less time than they would be with

mechanical equipment. But the Assistant Secretary observed 

that this assertion was unsupported by data, see Rosebud 

Order I at 45 n.25 (“The evidence concerning the increased 

likelihood of injury from the asserted increase in exposure 

time is general and not quantified and does not establish that 

the increase in exposure time would result in anything more 

than an insubstantial decrease in safety.”), and it did not

consider “the additional time needed to comply with the 

conditions for use” of NPESE, id. 

The petitioners also assert that even “viable” mechanical 

surveying equipment will have inferior accuracy. The record 

supports this assertion, compare Rosebud Order I at 44 n.23 

(suggesting “1 foot-in-10,000 feet accuracy levels” viable) 

with Petition for Modification Stipulations ¶ 21, In re 

Rosebud Mining Co., Docket Nos. 2010-MSA-1, 2011-MSA-
34

2, -11, -12 (reflecting NPESE achieved 1 foot in 81,507 feet

accuracy), but, even assuming the accuracy gap is more than 

de minimis, we have no way to measure its impact on mine 

safety. See Rosebud Order I at 44 n.23 (expert testimony 

reflecting that “there are no safety issues when surveying 

equipment achieves 1 foot-in-10,000 feet accuracy levels.”). 

Thus, whatever accuracy gain is made by using NPESE, it is 

not plain that it improves mine safety more than would viable 

mechanical equipment.

Finally, the Assistant Secretary identified a mine safety

risk from the use of NPESE that would not exist with viable 

mechanical surveying equipment—the use of “MSHA’s 

limited resources . . . spent ensuring compliance with the 

terms and conditions” of use. Rosebud Order I at 45. 

Because MSHA must assess what effect modifications will 

have on “overall mine safety,” S. Ohio Coal Co., 928 F.2d at 

1202, the preservation of finite resources for use in ensuring 

compliance with other standards is a reasonable basis upon 

which to include this condition. 

For the foregoing reasons, we deny the petitions for 

review.

So ordered.