                 FOR PUBLICATION

  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT


CENTER FOR BIOLOGICAL                 No. 11-17843
DIVERSITY ; GRAND CANYON
TRUST ; SIERRA CLUB; KAIBAB             D.C. No.
BAND OF PAIUTE INDIANS;              3:09-cv-08207-
HAVASUPAI TRIBE ,                         DGC
           Plaintiffs-Appellants,

               v.                       OPINION

KEN SALAZAR, Secretary of the
Interior; UNITED STATES
BUREAU OF LAND
MANAGEMENT ,
           Defendants-Appellees,

              and

DENISON ARIZONA STRIP, LLC;
DENISON MINES (USA) CORP .,
       Intervenor-Defendants-
                   Appellees.


      Appeal from the United States District Court
               for the District of Arizona
      David G. Campbell, District Judge, Presiding
2       CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR

                   Argued and Submitted
         October 18, 2012—San Francisco, California

                      Filed February 4, 2013

         Before: J. Clifford Wallace and Carlos T. Bea,
          Circuit Judges, and Jane A. Restani, Judge.*

                    Opinion by Judge Wallace


                           SUMMARY**


                            Mining Law

    The panel affirmed the district court’s judgment in favor
of the Secretary of the Interior and the U.S. Bureau of Land
Management in an action challenging the decision to allow
Denison Mines Corp. to restart mining operations at the
Arizona 1 Mine.

    As a threshold issue, the panel held that a decision made
by a prior panel of this court affirming the district court’s
denial of appellants’ preliminary injunction motion did not
become law of the case as to any issue. The panel held that
the Bureau of Land Management did not violate the National
Environmental Policy Act, the Federal Land Policy and


    *
      The Honorable Jane A. Restani, Judge for the U.S. Court of
International Trade, sitting by designation.

  **
     This summary constitutes no part of the opinion of the court. It has
been prepared by court staff for the convenience of the reader.
     CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR           3

Management Act, and BLM’s own regulations, by permitting
Denison Mines to restart mining operations under a plan of
operations that BLM approved in 1988. The panel also held
that BLM’s update of the Arizona 1 Mine reclamation bond
should not be set aside. Finally, the panel held that BLM’s
application of the categorical exclusion for issuance of the
Robinson Wash gravel permit was not arbitrary and
capricious or otherwise not in accordance with law.


                        COUNSEL

Neil Levine (argued), Grand Canyon Trust, Denver,
Colorado; Amy Rae Atwood, Center for Biological Diversity,
Portland, Oregon; Roger Flynn, Western Mining Action
Project, Lyons, Colorado, for Appellants.

Ignacia S. Moreno, Mark R. Haag (argued), Environmental &
Natural Resources Division, United States Department of
Justice, Washington, D.C.; John L. Gaudio, United States
Department of the Interior, Office of the Solicitor, Phoenix,
Arizona, for Federal Appellees.

Michael K. Kennedy (argued), Bradley J. Glass, David J.
DePippo, Gallagher & Kennedy, P.A., Phoenix, Arizona, for
Intervenor-Appellees.


                        OPINION

WALLACE, Senior Circuit Judge:

   Appellants Center for Biological Diversity, Grand
Canyon Trust, Sierra Club, Kaibab Band of Paiute Indians,
4    CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR

and Havasupai Tribe contend that Appellees Ken Salazar,
Secretary of the Interior, and the U.S. Bureau of Land
Management (collectively, BLM) violated the National
Environmental Policy Act (NEPA), 42 U.S.C. § 4321 et seq.,
the Federal Land Policy and Management Act (FLPMA), 43
U.S.C. § 1701 et seq., and its own regulations, 43 C.F.R.
§ 3809, et seq., by permitting Denison Mines Corp. and
Denison Arizona Strip, LLC (collectively, Denison) to restart
mining operations at the Arizona 1 Mine in 2009, after a
seventeen-year hiatus, under a plan of operations that BLM
approved in 1988. We have jurisdiction under 28 U.S.C.
§ 1291, and we affirm.

                             I.

    The Arizona 1 Mine is a uranium mine located in Mohave
County, Arizona, thirty-five miles southwest of Fredonia,
Arizona, and six and one-half miles north of Grand Canyon
National Park. The history of the mine goes back nearly three
decades. In 1984, Energy Fuels Nuclear, Inc. submitted to
BLM a plan for uranium exploration activities on mining
claims it owned in Mohave County, Arizona. On October 4,
1984, BLM approved the exploration plan. Four years later,
in 1988, Energy Fuels submitted to BLM a plan of operations
to develop and operate a portion of its mining claims as the
Arizona 1 Mine.

    BLM reviewed the proposed plan of operations, took into
account public sentiment, and prepared an environmental
assessment of the mining activities’ impact. After a detailed
review, on May 9, 1988, BLM approved the plan,
determining that the proposed mining operations at the
Arizona 1 Mine would not “cause any undue or unnecessary
degradation of public lands” or “significantly affect the
     CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR           5

quality of the human environment.” The plan of operations
complied with the regulations found in 43 C.F.R. § 3809 (the
section 3809 regulations) then in effect. Important here, the
plan of operations contained a portion governing the interim
management of the Arizona 1 Mine “in the event of an
‘extended period of non-operation before mining is
completed.’” Such a shutdown, the interim management
portion of the plan stated, was, though unanticipated, a
“possibility.”

    Once the plan of operations was approved, Energy Fuels
actively developed the Arizona 1 Mine until a severe drop in
uranium prices made mining at the site economically
unjustifiable. As a result, Energy Fuels ceased mining
activities at the Arizona 1 Mine in 1992 and placed the mine
on “standby and interim management status.” In May 1997,
while mining operations remained on hold, International
Uranium Corporation, USA, acquired the Arizona 1 Mine. In
2007, International Uranium merged with Denison.

    During the period following the cessation of mining
activities at the Arizona 1 Mine, Energy Fuels, International
Uranium, and later Denison, followed the interim
management portion of the 1988 plan of operations. Among
other things, the companies maintained buildings, mine
shafts, gates, fences, and signage for the mine. The
companies also maintained a surety bond for reclamation and
paid utilities, property taxes, BLM maintenance fees, and
insurance premiums. Additionally, the companies sent
employees and contractors to the mine to ensure that the mine
complied with the 1988 plan of operations. Likewise,
throughout the interim period, BLM conducted field
inspections at the Arizona 1 Mine, which consisted primarily
6    CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR

of perimeter inspections as the mine gate remained locked
during the interim period.

    In 2007, Denison advised BLM of its intention to restart
mining operations at the Arizona 1 Mine. In preparation for
the recommencement of mining operations, Denison obtained
current Aquifer Protection and Air Quality Control permits
from the State of Arizona. Additionally, Denison updated its
financial guarantee with the Arizona Department of
Environmental Equality and the BLM. To update its financial
guarantee, BLM asked Denison to submit a revised
reclamation bond estimate, in accordance with a 2000
regulation amending the level of financial guarantee required,
see 43 C.F.R. § 3809.505, to cover the reclamation costs
outlined in the 1988 plan of operations. Denison submitted a
revised bond estimate to BLM. BLM checked that figure
using its cost-estimation software and concluded that Denison
had overestimated the amount of bond necessary. BLM
accepted Denison’s overestimate, requiring a bond of
$377,800.

    Denison also obtained a “Permit to Use Right-of-Way”
from Mohave County to perform needed improvements and
maintenance on Mount Trumbull Road, itself a right-of-way
that BLM had granted Mohave County some years earlier.
Mount Trumbull Road provides Denison employees access to
the Arizona 1 Mine and is therefore important to the mine’s
operation. The road also provides the public access to
recreation areas in the region. Prior to Mohave County
appointing Denison as its agent to maintain the Mount
Trumbull Road, the County obtained a “Free Use Permit”—at
Denison’s urging—to extract a certain amount of gravel from
the Robinson Wash to maintain the Mount Trumbull Road.
BLM determined that issuance of the gravel permit fell within
     CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR               7

a categorical exclusion to NEPA and determined that “no
extraordinary circumstances potentially having effects that
may significantly affect the environment” existed meriting
more exhaustive environmental analysis. Accordingly, no
further NEPA analysis took place before BLM issued the
“Free Use Permit” to Mohave County. With these measures
taken, Denison resumed mining operations in December
2009.

    Before mining resumed in full, in November 2009,
Appellants filed their initial complaint against BLM, arguing
that Denison could not begin operations under the 1988 plan
of operations because the seventeen-year cessation of mining
activities rendered that plan ineffective. Months later, in April
2010, Appellants moved for a preliminary injunction to
prevent Denison from operating the Arizona 1 Mine. The
district court denied the motion for preliminary injunction,
holding that the 1988 plan of operations had not become
ineffective and that BLM did not have to prepare a
supplemental NEPA analysis prior to Denison recommencing
mining operations. Center for Biological Diversity v. Salazar,
No. CV-09-8207-PCT-DGC, 2010 WL 2493988 (D. Ariz.
June 17, 2010). Appellants appealed from the denial of their
preliminary injunction. A panel of this court affirmed the
district court’s denial of the preliminary injunction in an
unpublished memorandum disposition. Center for Biological
Diversity v. Salazar, 431 F. App’x. 593 (9th Cir. 2011).

    After further proceedings in the district court, both parties
moved for summary judgment. The district court granted
summary judgment in favor of Appellees as to all of
Appellants’ claims, with one exception. The district court
determined that BLM “provided no more than a ‘cursory
statement’ of no cumulatively significant impacts in applying
8    CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR

the categorical exclusion” when issuing Mohave County the
“Free Use Permit” to remove gravel from Robinson Wash
and remanded the issue to the BLM. A short time later, BLM
provided further explanation as to its use of the categorical
exclusion. The district court found that BLM had presented
a rational explanation for its use of the categorical exclusion.
Accordingly, the district court concluded that use of the
categorical exclusion as to the gravel permit was not arbitrary
and capricious. The district court thus granted summary
judgment on the categorical exclusion issue in favor of
Appellees. Appellants now appeal the district court’s two
summary judgments.

                              II.

    We review summary judgment de novo, “applying the
same standards that applied in the district court.” Pit River
Tribe v. U.S. Forest Serv., 469 F.3d 768, 778 (9th Cir. 2006).
Under the Administrative Procedure Act, we review actions
of the BLM pursuant to FLPMA and NEPA to determine
whether they are “arbitrary, capricious, an abuse of
discretion, or otherwise not in accordance with law.” Id.
(quoting 5 U.S.C. § 706(2)(A)). We defer to BLM’s
“interpretation of its own regulations . . . unless plainly
erroneous or inconsistent with the regulations being
interpreted.” Long Island Care at Home, Ltd. v. Coke, 551
U.S. 158, 171 (2007) (internal quotation marks omitted).

                              III.

    We first address Appellees’ threshold question of whether
this court’s decision made by a prior panel affirming the
district court’s denial of Appellants’ preliminary injunction
motion became law of the case as to any issue. Appellees, and
     CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR              9

in particular Denison, argue that this prior affirmance works
as law of the case and thereby prevents Appellants from
arguing that the 1988 plan of operations is ineffective and that
if the plan is not ineffective, BLM should have supplemented
the 1988 environmental analysis BLM performed in
connection with its approval of that plan.

    The law of the case doctrine holds that “a court will
generally refuse to reconsider an issue that has already been
decided by the same court or a higher court in the same case.”
Gonzalez v. Arizona, 677 F.3d 383, 389 n.4 (9th Cir. 2012)
(en banc), cert. granted, 133 S. Ct. 476 (2012). In general,
however, “our decisions at the preliminary injunction phase
do not constitute the law of the case.” Ranchers Cattlemen
Action Legal Fund United Stockgrowers of Am. v. U.S. Dep’t
of Agric., 499 F.3d 1108, 1114 (9th Cir. 2007). This is true
for the reason that a preliminary injunction decision is just
that: preliminary. Id. “This rule acknowledges that ‘decisions
on preliminary injunctions . . . must often be made hastily and
on less than a full record.’” Id. (quoting S. Or. Barter Fair v.
Jackson Cnty., 372 F.3d 1128, 1136 (9th Cir. 2004)).

    We have repeatedly emphasized the preliminary nature of
preliminary injunction appeals. In Sports Form, Inc. v. United
Press International, Inc., 686 F.2d 750 (9th Cir. 1982), we
explained that “[b]ecause of the limited scope of our review
of the law applied by the district court and because the fully
developed factual record may be materially different from
that initially before the district court, our disposition of
appeals from most preliminary injunctions may provide little
guidance as to the appropriate disposition on the merits.” Id.
at 753; see also Melendres v. Arpaio, 695 F.3d 990, 1003 (9th
Cir. 2012).
10   CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR

    In the case before us, the prior panel’s complete decision
states:

           In this interlocutory appeal, Appellants
       challenge the district court’s denial of their
       motion for a preliminary injunction.
       Reviewing for abuse of discretion, we affirm
       for the reasons stated by the district court
       judge. Appellants failed to raise serious
       questions on the merits of their claims of
       violations of the National Environmental
       Policy Act, and the Federal Land Policy
       Management Act.

Center for Biological Diversity, 431 F. App’x. at 593
(citations omitted).

    This decision did not become law of the case as to any
issues presently before us on appeal. The prior panel’s
statement that it was affirming “for the reasons stated by the
district court” is not a clear determination of the meaning of
the statutes and regulations relevant to this case. Indeed, the
prior panel’s short decision is a far cry from the exception to
our rule and those preliminary injunction decisions that
become law of the case as to pure questions of law. See, e.g.,
Humanitarian Law Project v. U.S. Dep’t of Justice, 352 F.3d
382, 393 (9th Cir. 2003) (holding that four issues decided on
appeal from a preliminary injunction decision were
considered in full and resolved as matters of law and thus, the
law of the case doctrine prevented further review of that issue
in a subsequent appeal), vacated on other grounds by 393
F.3d 902 (9th Cir. 2004); see also Ranchers Cattlemen, 499
F.3d at 1114 (“A fully considered appellate ruling on an issue
of law made on a preliminary injunction appeal . . . become[s]
     CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR              11

the law of the case for further proceedings in the trial court on
remand and in any subsequent appeal”) (emphasis added).
But even such a result assumes that the factual record would
not materially change after a trial such that the law declared
at the preliminary stage is no longer relevant to the different
post-trial finding of facts. See Sportsform, 685 F.2d at 753;
Ranchers Cattlemen, 499 F.3d at 1114; S. Or. Barter Fair,
372 F.3d at 1136. This becomes relevant here when we focus
on the prior panel’s order.

    The prior panel’s statement that “Appellants failed to
raise serious questions on the merits” is not necessarily a
definitive conclusion as to any legal or factual question raised
in the preliminary injunction appeal and appears to be a
statement that the facts as then presented did not raise a
serious claim according the prior panel’s “limited” review of
the law. See Sports Form, 686 F.2d at 753. This left open the
possibility that additional facts could be introduced during the
further district court proceedings resulting in a different
outcome based on a full evidentiary record and a complete
review of the legal principles. As a result, we conclude that
the prior panel did not intend that its brief affirmation of the
preliminary injunction denial become law of the case. We
thus proceed to the merits of Appellants’ claims.

                              IV.

    Appellants’ chief contention is that the Arizona 1 Mine’s
1988 plan of operations became “ineffective” after the mine
closed in the early 1990s, thereby necessitating BLM
approval of a new plan of operations before mining could
recommence in 2009. In support of their contention that the
cessation of mining activities rendered the 1988 plan of
operations ineffective, Appellants rely on 43 C.F.R.
12   CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR

§ 3809.423, which provides that an operator’s “plan of
operations remains in effect as long as [the operator is]
conducting operations, unless BLM suspends or revokes [the]
plan of operations.” Under Appellants’ reading of this
regulation, because Energy Fuels stopped “conducting
operations,” BLM had to approve a new plan of operations
before Denison could resume mining at the Arizona 1 Mine.
Appellants thus conclude that BLM violated 43 C.F.R.
§ 3809.11 by allowing Denison to mine without having an
effective plan of operations and that BLM thereby failed to
comply with its duty under the FLPMA to ensure that the
Arizona 1 Mine does not cause “unnecessary or undue
degradation.” 43 U.S.C. § 1732(b); see also 43 C.F.R.
§ 3809.1.

    When viewed in isolation, section 3809.423 appears to
have rendered the 1988 plan of operations ineffective by
reason of Energy Fuels’ cessation of activities in 1992.
Nevertheless, we agree with the district court that we must
“interpret [a] regulation as a whole, in light of the overall
statutory and regulatory scheme, and not [] give force to one
phrase in isolation.” Norfolk Energy, Inc. v. Hodel, 898 F.2d
1435, 1442 (9th Cir. 1990) (internal quotation marks
omitted); see also Alaska Trojan P’ship v. Gutierrez, 425
F.3d 620, 628 (9th Cir. 2005). Upon reading the regulations
as a whole, it is clear, as BLM contends, that section
3809.423 does not mean that a temporary closure of a mine
immediately results in an ineffective plan of operations.

    To begin, the section 3809 regulations expressly provide
for periods of temporary cessation of mining activities. Each
mining plan of operations must contain a portion outlining an
“interim management plan” that governs during “periods of
temporary closure.” 43 C.F.R. § 3809.401(b)(5). Section
     CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR             13

3809.424(a)(1) provides that if a mine operator “stop[s]
conducting operations for any period of time” it must “follow
[the] approved interim management plan.” As the district
court explained, provisions requiring that an interim
management plan govern during periods of temporary closure
would be superfluous if a plan of operations was rendered
ineffective as soon as mining operations ceased. Additionally,
section 3809.424(a)(3) provides that after five years of
inactivity, “BLM will review [the] operations and determine
whether BLM should terminate [the] plan of operations and
direct final reclamation and closure.” Likewise, section
3809.424(a)(4), provides that BLM may determine that an
operator has abandoned mining operations and initiate
forfeiture of reclamation costs. These mechanisms, by which
BLM can terminate a plan of operations after five years of
inactivity or after abandonment, would be meaningless if a
plan of operations automatically became ineffective upon
temporary cessation of mining activities. We agree with the
district court that “[t]he obvious import of these provisions is
that a plan of operations remains effective for periods of
operation before and after temporary closures, with such
closures being governed by the interim management portion
of the plan unless BLM elects to terminate the plan” early.
Center for Biological Diversity v. Salazar, 791 F. Supp. 2d
687, 693 (D. Ariz. 2011).

    Appellants contend that this reading of the applicable
regulations—under which Denison is permitted to restart
mining activities despite years of inactivity—renders section
3809.423’s plain language meaningless. Appellants argue that
sections 3809.423 and 3809.424 should be read instead, as the
district court put it, to reflect a “step-down process” in the
ultimate winding down of mining operations. Under
Appellants’ theory, section 3809.423 provides that inactivity
14   CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR

renders the plan of operations ineffective. When a plan of
operations becomes ineffective, Appellants maintain, the
interim plan described in section 3809.424(a)(1) takes effect.
That interim plan governs until, after five years of inactivity,
BLM reviews a mine’s operations and determines whether to
terminate the interim management plan and “direct final
reclamation and closure.” Id. § 3809.424(a)(3). Under
Appellants’ theory, a new plan of operations would be
required before new mining activities could begin.

    Nevertheless—and unfortunately for Appellants—the
applicable regulations do not actually provide for such a
scheme. While the regulations provide for temporary closures
and identify what a mine operator must do when it “stop[s]
conducting operations,” id. § 3809.424, no regulation requires
approval of a new plan of operations before regular mining
activities may recommence following a temporary closure. If,
as appellants contend, the regulations provided for a “step-
down” process and required approval of a new plan of
operations before mining could restart following any
temporary cessation of mining activities, one would expect
them to do so clearly. They do not.

     Further, if, as Appellants contend, a temporary closure of
a mine immediately rendered a plan of operations ineffective,
section 3809.424(a)(3)’s provision permitting BLM to
terminate a plan of operations would be unnecessary.
Appellants argue that section 3809.424(a)(3) refers to
termination of the interim management portion of the plan of
operations and thus, section 3809.424(a)(3) is not
superfluous. Section 3809.423 does not, however, distinguish
or exclude the interim portion of the management plan from
its blanket statement that a plan of operations is “in effect as
long as [the operator] is conducting operations.” See also id.
     CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR            15

§ 3809.401. As a result, if Appellants are correct and a plan
of operations becomes immediately ineffective once mining
operations temporarily cease, then the interim management
portion of the plan would likewise become ineffective. Under
section 3809.424(a)(3), then, there would be nothing left to
terminate. That section would thus have no meaning.
Accordingly, there is no support for Appellants’ reading of
section 3809.423 in the language of the applicable
regulations.

    BLM’s interpretation of section 3809.423 is also
consistent with BLM’s statements when it promulgated the
current regulations. BLM explained that “[section] 3809.423
provides that the plan of operations approval is good for the
life of the project as described in the plan.” 65 Fed. Reg.
69998, 70053 (Nov. 21, 2000). BLM recognized that the life
of a mining project may include changes in mine ownership
and temporary periods of mine closure. Indeed, BLM
recognized that “an approved plan of operations has financial
value to the owner/operator and can be transferred to another
owner.” Id. at 70054. Additionally, BLM acknowledged a
commentor’s statement that mining activities are “sensitive
to world fluctuations of commodity prices, and may have to
be discontinued when prices are not high enough to make the
operation profitable.” Id. at 70055. BLM explained that the
“occurrence or length of these ‘down times’ . . . cannot be
determined in advance.” Id. From these statements, it is clear
that BLM did not promulgate section 3809.423 to terminate
a plan of operations immediately upon any disruption in
mining activities—such as changes in mine ownership or
temporary closures due to price fluctuations; rather, BLM
rejected issuing plan of operations approvals “with limited
periods of effectiveness,” and opted instead for plans that are
“good for the life of [a] project.” Id. at 70053. Further, BLM
16   CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR

explained that section 3809.424 “define[s] conditions of
temporary closure, and define[s] conditions under which
temporary closure becomes permanent.” Id. at 70054.
Nowhere in these statements does BLM suggest that a new
plan of operations is required before mining can be resumed
after a temporary closure.

    BLM’s interpretation also harmonizes sections 3809.423
and 3809.424(a)(3). Contrary to Appellants’ contention,
BLM’s interpretation recognizes that section 3809.423
permits a plan to remain in effect “as long as [the operator] is
conducting operations.” As the district court explained, “as
long as” connotes “during the whole time that.” See Salazar,
791 F. Supp. 2d at 695; see generally Oxford Dictionaries
Online, http://oxforddictionaries.com (last visited Jan. 25,
2011). The whole time that a plan of operations is valid
includes both active and non-active periods. Section
3809.424(a)(4) permits BLM to cut-short the time period of
a plan of operations after five years of inactivity. Thus, under
this plain reading of sections 3809.423 and 3809.424(a)(3),
both provisions have meaning. See Boeing Co. v. United
States, 258 F.3d 958, 967 (9th Cir. 2001) (explaining that a
court must construe regulations so as to give effect to each
provision).

    Nothing about BLM’s interpretation suggests that
approved plans of operations may “continue in perpetuity” as
Appellants fear. Plans of operations outline the life of a
particular project. The life of a project necessarily has finite
limits that are spelled out in the plan of operations. See 65
Fed. Reg. at 70053; see also § 43 C.F.R. 3809.401(b)
(requiring plans of operations to contain numerous details
“sufficient for BLM to determine that the plan of operations
prevents unnecessary or undue degradation”). As explained,
     CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR            17

BLM has several mechanisms to cut short a plan of
operation—particularly where there are long periods of
inactivity. See id. 43 C.F.R. §§ 3809.424(a)(3), (4),
3809.602(a). BLM also has the ability to require a
modification to a plan of operations where new concerns as
to unnecessary and undue degradation arise. Id.
§ 3809.431(b). Although BLM failed to cut-short or modify
the 1988 plan of operations, that plan remains bounded by its
own terms and is still subject to future actions by BLM to cut-
short or modify the plan, if appropriate. Under BLM’s
interpretation, then, neither the Arizona 1 Mine plan nor plans
generally remain effective indefinitely.

    In sum, because the section 3809 regulations provide for
temporary suspension of mining activities and because
BLM’s interpretation of section 3809.423 is consistent with
both the section 3809 regulations when read as a whole and
BLM’s expressed intent in promulgating the section 3809
regulations, BLM’s interpretation of the meaning of section
3809.423 is controlling. See Long Island Care, 551 U.S. at
171 (“[A]n agency’s interpretation of its own regulations is
controlling unless plainly erroneous or inconsistent with the
regulations being interpreted”) (internal quotation marks
omitted). Accordingly, we conclude that BLM’s decision to
allow Denison to resume mining at the Arizona 1 Mine under
the 1988 plan of operations was not “arbitrary, capricious, an
abuse of discretion, or otherwise not in accordance with law.”
5 U.S.C. § 706(2)(A).

                              V.

     Appellants next contend that BLM violated NEPA by
failing to supplement the 1988 environmental assessment
BLM conducted in connection with the approval of the 1988
18   CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR

plan of operations. Essentially, Appellants contend that the
1988 NEPA analysis became stale and outdated, necessitating
supplemental review of the Arizona 1 Mine’s environmental
impact.

     NEPA requires that federal agencies perform
environmental analysis before taking any “major Federal
actions significantly affecting the quality of the human
environment.” 42 U.S.C. § 4332(2)(C). Thus, whether NEPA
is triggered depends on whether there is a new, proposed
“major Federal action.” See 40 C.F.R. § 1502.5 (providing
that the timing for an environmental impact statement under
NEPA is during the proposal stage). Supplementation of a
prior NEPA environmental analysis is only required where
“there remains major Federal action to occur.” Norton v.
S. Utah Wilderness Alliance (SUWA), 542 U.S. 55, 73 (2004)
(internal quotation marks omitted); see also 40 C.F.R.
§ 1502.9(c)(1)(i)-(ii) (providing that agencies must prepare
supplements to an environmental impact statement if “[t]he
agency makes substantial changes in the proposed action that
are relevant to environmental concerns” or “[t]here are
significant new circumstances or information relevant to
environmental concerns and bearing on the proposed action
or its impacts”); Marsh v. Or. Natural Res. Council, 490 U.S.
360, 374 (1989) (whether supplementation should occur
“turns on the value of the new information to the still pending
decisionmaking process . . . and if the new information is
sufficient to show that the remaining action will affec[t] the
quality of the human environment in a significant manner or
to a significant extent not already considered”) (emphasis
added) (internal quotation marks omitted).

   Undoubtedly, the approval of the 1988 plan of operation
was a “major federal action” triggering NEPA’s
     CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR              19

requirements. See SUWA, 542 U.S. at 73. Nevertheless, as in
SUWA, “that action [wa]s completed when the plan [wa]s
approved.” Id.; see also Cold Moutain v. Garber, 375 F.3d
884, 894 (9th Cir. 2004). Before that action was complete,
BLM performed the requisite environmental analysis.
Accordingly, as far as the 1988 plan of operations is
concerned, appropriate NEPA review took place and “[t]here
is no ongoing ‘major Federal action’ that could require
supplementation,” SUWA, 542 U.S. at 75. See Cold
Mountain, 375 F.3d at 894; Greater Yellowstone Coal. v.
Tidwell, 572 F.3d 1115, 1122-23 (10th Cir. 2009).

     Appellants argue, however, that BLM’s issuance of a
gravel permit to Mohave County, requirement that Denison
obtain a new air quality control permit, and approval of an
updated reclamation bond each constituted a prerequisite to
mining and thus, “major Federal actions” triggering
supplementation of the 1988 environmental analysis. While
it is true that each of the above actions potentially constituted
a “major Federal action” that would have required NEPA
analysis—a question we address below as to the gravel permit
and reclamation bond—none of those actions affected the
validity or completeness of the 1988 approval of the Arizona
1 Mine’s plan of operations nor did they prevent Denison
from mining under that plan. These additional, independent
actions thus did not trigger NEPA supplementation of the
1988 environmental analysis. In sum, “because the [1988 plan
of operations] has been approved . . . [BLM’s] obligation
under NEPA has been fulfilled.” Cold Mountain, 375 F.3d at
894. We thus conclude that BLM did not “unlawfully
withh[o]ld” required agency action. See 5 U.S.C. § 706(1).
20   CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR

                             VI.

    Appellants next argue that BLM’s approval of the updated
reclamation bond triggered NEPA analysis as a “major
Federal action.” BLM’s “[a]pproval of [a] specific project[]”
may be a “major Federal action” requiring compliance with
NEPA where it has “effects that may be major.” 40 C.F.R.
§ 1508.18(b)(4). Here, Appellants contend that BLM’s
requirement that Denison update its financial bond
constituted an approval necessary before Denison could take
the Arizona 1 Mine off stand-by status. As such, Appellants
argue that this approval triggers NEPA analysis.

    While BLM required Denison to update its reclamation
bond before recommencing mining operations, that action did
not consist of an “[a]pproval of [a] specific project[].” Id.
BLM approved the Arizona 1 Mine plan of operations in
1988. That plan, as explained above, has not been invalidated
or modified since that time. It thus continues in effect and
controls activities at the mine. The plan of operations
contains a reclamation portion. As with the plan generally,
the reclamation portion remains valid and has not been
altered. It thus governs reclamation activities at the mine. In
requiring an update to the reclamation bond, BLM merely
reviewed the cost of reclamation based on the provisions of
the 1988 plan of operations and determined, after “crunching
some numbers,” that the amount of the reclamation bond
should be increased in accordance with newly-applicable
regulations. See 43 C.F.R. § 3809.505 (requiring an updated
reclamation bond for “each plan of operations approved
before January 20, 2001”); id. § 3809.552(b) (providing that
BLM “will periodically review the estimated cost of
reclamation . . . and require increased coverage, if
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necessary”). Thus, this action did not constitute approval of
a specific project necessitating NEPA review.

    On the contrary, BLM’s update of the Arizona 1 Mine
reclamation bond consisted of the ministerial tasks of feeding
reclamation data from the 1988 plan into BLM’s “SHERPA”
software program, comparing SHERPA’s reclamation
estimate with that of Denison, and then accepting Denison’s
proposed bond amount, which was greater than BLM’s
SHERPA calculation. Such post-project-approval functions
are the type of monitoring and compliance activities that this
court has determined do not trigger NEPA’s requirements.
See Sierra Club v. Penfold, 857 F.2d 1307, 1314 (9th Cir.
1988); San Francisco Tomorrow v. Romney, 472 F.2d 1021,
1025 (9th Cir. 1973). Accordingly, BLM’s update of the
Arizona 1 Mine reclamation bond should not be set aside as
“not in accordance with law” or “without observance of
procedure required by law,” as Appellants contend. 5 U.S.C.
§ 706(2)(A), (D).

                             VII.

    Appellants also challenge BLM’s application of the
categorical exclusion to its issuance of the Free Use Permit to
Mohave County for extraction of gravel from the Robinson
Wash. Categorical exclusions are classes of actions that an
agency has determined do not “have a significant effect on
the human environment.” 40 C.F.R. § 1508.4. Application of
a categorical exclusion is not an exemption from NEPA;
rather, it is a form of NEPA compliance, albeit one that
requires less than where an environmental impact statement
or an environmental assessment is necessary. Id. Indeed, even
where an action falls into a categorical exclusion, an agency
must nevertheless provide procedures for determining
22   CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR

whether “extraordinary circumstances” exist, such that the
action, though “normally excluded” from full NEPA analysis,
“may have a significant environmental effect.” Id.

    Under its regulations, BLM has determined that extraction
of gravel “in amounts not exceeding 50,000 cubic yards or
disturbing more than 5 acres, except in riparian areas,” is
entitled to a categorical exclusion to full NEPA analysis.
BLM NEPA Handbook Appx. 4, § F(10). Appellants do not
challenge the establishment of this categorical exclusion;
rather, Appellants contend that BLM unlawfully limited the
scope of NEPA analysis in invoking this categorical
exclusion by failing to analyze adequately “indirect” and
“cumulative” impacts of the gravel permit, as well as the
impact of “connected actions” under 40 C.F.R. § 1508.25.

    Section 1508.25 provides that in “determin[ing] the scope
of environmental impact statements,” an agency must
consider, among other things, “[c]onnected actions,” and
“indirect” and “cumulative” environmental “impacts” to the
proposed action. By its plain language, however, this
regulation applies only to environmental impact statements.
Id. Appellants, in a footnote, contend that although section
1508.25 explicitly applies to environmental impact
statements, it should also apply to all actions under NEPA,
including the application of a categorical exclusion.

   In support of this argument, Appellants point to a number
of decisions of this court in which we have applied
requirements for environmental impact statements to
environmental assessments. See Kern v. U.S. Bureau of Land
Mgmt., 284 F.3d 1062, 1076 (9th Cir. 2002); Price Rd.
Neighborhood Ass’n v. U.S. Dep’t of Transp., 113 F.3d 1505,
1509 (9th Cir. 1997); S. Or. Citizens Against Toxic Sprays,
     CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR           23

Inc. v. Clark, 720 F.2d 1475, 1480 (9th Cir. 1983). Appellants
contend that for the same reason that this court has applied
certain environmental impact statement requirements to
environmental assessments, the requirements of 1508.25
should also apply to application of categorical exclusions.

    We have explained, however, that where a proposed
action fits within a categorical exclusion, full NEPA analysis
is not required. Wong v. Bush, 542 F.3d 732, 737 (9th Cir.
2008). Appellants argue that Wong does not apply here
because it only addresses whether an agency must conduct a
NEPA “alternatives” analysis for categorical exclusions and
did not concern the “fundamental question” of what
requirements apply when determining whether significant
impacts exist that would preclude use of a categorical
exclusion. We disagree that Wong is so limited because its
case-specific holding that the alternatives analysis was not
necessary when invoking a categorical exclusion is merely
application of the general principle that “where agency action
falls under a categorical exclusion, it need not comply with
the requirements of an [environmental impact statement].”
Id.; see also 40 C.F.R. § 1508.4. Moreover, application of
section 1508.25’s requirements to categorical exclusions is
inconsistent with the efficiencies that the abbreviated
categorical exclusion process provides. See 40 C.F.R.
§§ 1500.4(p), 1500.5(k); Utah Env’t Congress v. Bosworth,
443 F.3d 732, 741 (10th Cir. 2006). Accordingly, we
conclude that section 1508.25’s requirements do not apply to
BLM’s categorical exclusion analysis in this case.

   To comply with NEPA, then, BLM had to determine first
whether the proposed action—issuance of the gravel
permit—fell under a categorical exclusion and then determine
whether “extraordinary circumstances” existed that would
24   CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR

prevent use of the categorical exclusion. 40 C.F.R. § 1508.4.
Though not required to do so by section 1508.25, under
BLM’s own regulations, this “extraordinary circumstances”
analysis required BLM to consider whether issuance of the
gravel permit would “[h]ave a direct relationship to other
actions with individually insignificant but cumulatively
significant environmental effects.” BLM NEPA Handbook
Appx. 5, § 2.6; 43 C.F.R. § 46.215(f). We conclude that BLM
appropriately found that issuance of the gravel permit fell into
a categorical exclusion and adequately explained why the
permit had no “cumulatively significant” environmental
effects preventing application of the categorical exclusion.

    BLM determined that issuance of the gravel permit fell
within its categorical exclusion for the “[d]isposal of mineral
materials, such as sand, stone, [and] gravel, . . . in amounts
not exceeding 50,000 cubic yards or disturbing more than 5
acres, except in riparian areas.” BLM then analyzed whether
approval of the gravel permit had “a direct relationship to
other actions with individually insignificant, but cumulatively
significant, environmental effects” and found none.

   Appellants contend that BLM’s conclusions that there
were no cumulative impacts and that the gravel permit is
unrelated to Mount Trumbull road work and the Arizona 1
Mine are “wholly undermined by the facts.”

    However, BLM explained that there were no significant
cumulative effects because the gravel lost from extraction
under the permit was naturally replenished by rain.
Additionally, BLM explained that the gravel extracted would
be used for the already-approved maintenance of Mount
Trumbull Road and thus, the impact of the road did not
increase through issuance of the permit. BLM also reasoned
     CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR           25

that because Mohave County had other sources of gravel to
maintain Mount Trumbull road, maintenance of the road did
not have a direct relationship to issuance of the Robinson
Wash gravel permit. Further, BLM explained that it had taken
no action to change the scope of the Mount Trumbull Road
right-of-way, issued in 1986 to Mohave County.

    BLM next explained that the gravel permit does not have
a direct relationship to any other activity that may involve
Mount Trumbull Road. Those activities, including ranching,
hunting, site-seeing, research, mining, accessing Native
American lands, and government and administrative uses, had
“long been conducted on the Arizona Strip,” location of the
Arizona 1 Mine, and thus, issuance of the gravel permit was
unrelated to those activities’ occurrence. As to mining in
particular, BLM explained that in approving the 1988 plan of
operations, it determined that mining would not have
significant environmental effects even when considering the
1986 grant to Mohave County of a right-of-way for the
Mount Trumbull Road. As a result, BLM concluded that
issuance of the Robinson Wash gravel permit, though related
to maintenance of Mount Trumbull Road, would not change
the impact of the Arizona 1 Mine.

    Appellants object to BLM’s reference to the impacts of
the 1988 plan of operations and 1986 right-of-way, arguing
that if BLM wished to invoke those environmental analyses
when reviewing “past” agency action, it had to follow NEPA
procedures for “tiering” or “incorporation by reference.”
“Tiering” is not mandatory; rather, it is merely encouraged by
the relevant regulation. 40 C.F.R. § 1502.20. Further, as with
section 1508.25, the regulation providing for “incorporation
by reference” is applicable to environmental impact
statements, not categorical exclusions. Id. § 1502.21. Thus,
26   CENTER FOR BIOLOGICAL DIVERSITY V . SALAZAR

we conclude BLM’s use of the prior analyses in evaluating
cumulative impacts of issuance of the gravel permit was
appropriate.

    Accordingly, we conclude from its comprehensive
explanation that BLM considered all appropriate factors,
including the cumulative impacts of the gravel permit, Mount
Trumbull Road maintenance, and mining at the Arizona 1
Mine, see id. § 1508.27(b). Further, we conclude that BLM
provided a rational explanation as to why Mount Trumbull
Road and the Arizona 1 Mine, though certainly relevant to the
issuance of the gravel permit, do not have contingent, “direct
relationships” such that issuance of the gravel permit would
“have a significant environmental effect” preventing use of
the categorical exclusion.

    Finally, Appellants argue that BLM violated its own
regulations in approving the gravel permit because it provided
Denison with a “free gravel source so it could rehabilitate
Arizona 1’s access roads for a ‘commercial purpose.’” See 43
C.F.R. 3604.12(a) (“BLM may issue free use permits to a
government entity without limitation as to the number of
permits or as to the value of the mineral materials to be
extracted or removed, provided that the government entity
shows that it will not use these materials for commercial or
industrial purposes.”). BLM issued the permit to Mohave
County, not Denison. Mohave County then authorized
Denison as its agent to use gravel from the Robinson Wash
and maintain Mount Trumbull Road. BLM’s regulations
permit a local government to “allow [its] agent to extract
mineral materials under [its] free use permit.” Id.
§ 3604.24(a). Additionally, Mount Trumbull road is a public
road. Its maintenance therefore benefits members of the
public who wish to access recreational and cultural sites in
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the area. Thus, although the maintenance of the road does
eventually benefit Denison’s commercial enterprise, that does
not mean that Mohave County is using the permit for
“commercial or industrial purposes,” id. § 3604.12(a).

    In sum, we conclude that BLM’s invocation of the
categorical exclusion was not arbitrary and capricious or
otherwise not in accordance with law. Alaska Ctr. for Env’t
v. U.S. Forest Serv., 189 F.3d 851, 859 (9th Cir. 1999). We
thus affirm the district court’s summary judgment against
Appellants as to BLM’s invocation of the categorical
exclusion for issuance of the Robinson Wash gravel permit.

   AFFIRMED.
