Eugene Baker v. Blackhawk Mining, LLC

RECOMMENDED FOR PUBLICATION
Pursuant to Sixth Circuit I.O.P. 32.1(b)
File Name: 25a0165p.06
UNITED STATES COURT OF APPEALS
FOR THE SIXTH CIRCUIT
EUGENE BAKER; LESTER BAKER; PATRICIA BAKER; RAYMOND BAKER;
RAYMOND G. BAKER; VADA BAKER; ALBERTA BUSH; CLAY FUGATE;
GREGORY CHASE HAYS; ANITA HENSON; ELLEN HENSON; LISA
HOLBROOK; BILLY JOE MULLINS; GEORGE MULLINS; SHERRY MULLINS;
JOHNNY E. MULLINS; BARBARA NEACE; JERVIS NEACE; LURANIE NOBLE;
MATILDA RANEY; JOHN ROBERTSON; MELVIN RUPERT; AARON WAYNE
WHITE; AARON PAUL WHITE; BRITTANY WHITE; DAVID WAYNE WHITE;
Y. DEBORAH WHITE; DELBERT WHITE; HAROLD RAY WHITE; RICHARD
WHITE; GRETA WHITE; MOLLIE WHITE; RACHEL WHITE; SHELVIN WHITE;
VAUGHN WHITE; VICE WHITE; WADE WHITE; JASON SCOTT WHITE; JAY
D. WHITE; JERSON WHITE; LISA WHITE; LORETTA WHITE; CARL W.
ASHER; FARMER EDWARD BAKER, administrator of the estate of Vanessa
Baker; JENNIFER BAKER; MICHAEL J. BAKER; ALICIA BAKER; BENJAMIN
CRAFT; BRUCE L. DRYDEN; MONICA FUGATE; REBECCA GIBSON; ANGELA
KAY HENSON; MASON HENSON, JR.; VICKIE HENSON; MASON LEE
HENSON; SHIRLEY HENSON; TIMOTHY DEAN HENSON; ARISSA HENSON;
WILLIE RAY HENSON; BARBARA HENSON; ELIZABETH MILLER; LOU
MILLER; FREDDIE WAYNE MULLINS; GERALDINE MULLINS; JOSHUA
MULLINS; MADRO M. NOBLE; CASSANDRA SCOTLAND; BRIAN STRONG;
BROWN STRONG; JAMES STRONG; WILLIAM THORPE; DARLENE THORPE;
ASHFORD WHITE; BIRCHEL WHITE; DEWEY WHITE, deceased; ELIJAH
WHITE; ETTA WHITE; FAYE WHITE; JEFFERY GRAN WHITE; RONALD
DARRIS WHITE; TONYA BAKER; LAVERNE NOBLE; JANICE MULLINS; RUTH
STRONG; TIFFANY WHITE; MISTY STRONG; CHRISTINE WHITE; GEORGE
FRANCIS, III; TONYA ASHER; DILLO NEACE; BRENDA STRONG; DAN
HENSON; SHANNON VAUGHN WHITE, administrator of the estate of Amy
LaDawn Henson,
Plaintiffs-Appellants,
v.
BLACKHAWK MINING, LLC
Defendant,
PINE BRANCH MINING, LLC
Defendant-Appellee.
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No. 24-5490 >

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No. 24-5490 Baker, et al. v. Blackhawk Mining, LLC, et al. Page 2
Appeal from the United States District Court for the Eastern District of Kentucky at Lexington.
No. 5:22-cv-00231—Danny C. Reeves, District Judge.
Argued: December 11, 2024
Decided and Filed: June 23, 2025
Before: SUTTON, Chief Judge; BUSH and MURPHY, Circuit Judges.
_________________
COUNSEL
ARGUED: Ned B. Pillersdorf, PILLERSDORF LAW OFFICES, Prestonsburg, Kentucky, for
Appellants. Grahmn N. Morgan, DINSMORE & SHOHL LLP, Lexington, Kentucky, for
Appellee. ON BRIEF: Ned B. Pillersdorf, PILLERSDORF LAW OFFICES, Prestonsburg,
Kentucky, for Appellants. Grahmn N. Morgan, Kristeena L. Johnson, James M. McClure,
DINSMORE & SHOHL LLP, Lexington, Kentucky, Ashley L. Pack, DINSMORE & SHOHL
LLP, Charleston, West Virginia, for Appellee.
_________________
OPINION
_________________
JOHN K. BUSH, Circuit Judge. In late July 2022, an unprecedented flood destroyed
numerous homes and other properties in Eastern Kentucky. Many of those who suffered brought
this suit against Pine Branch Mining, LLC. They allege that Pine Branch violated Kentucky
mining regulations in how it maintained a surface mine property, located relatively near
Plaintiffs’ lands. According to Plaintiffs, Pine Branch committed negligence per se.
To succeed at trial, Plaintiffs must prove that Pine Branch committed infractions that
substantially contributed to the flooding. But the district court excluded the opinion rendered by
Plaintiffs’ sole causation expert. In so ruling, the district court did not abuse its discretion, as we
explain below. Without competent expert proof, Plaintiffs lacked enough evidence to create a
jury question on causation. So, we agree with the district court that Plaintiffs cannot establish a
prima facie case of negligence per se. We therefore AFFIRM the district court’s grant of
summary judgment to Pine Branch.

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No. 24-5490 Baker, et al. v. Blackhawk Mining, LLC, et al. Page 3
I.
This case arises from a “historically unheard of” storm that devasted Eastern Kentucky.
R. 141, PageID 1248 (citation omitted); R. 141-3, PageID 1333. Upwards of 14–16 inches of
rain accumulated from July 25 to July 30. The five-day rain event resulted in 24 Flash Flood
Emergencies—designations that only the severest storms receive, when flooding immediately
endangers property and human life. See Baker v. Blackhawk Mining, LLC, 734 F. Supp. 3d 615,
619–20 (E.D. Ky. 2024) (Blackhawk II). Public research reports noted that nearly 9,000 homes
were damaged or destroyed, with more than 1,400 people requiring rescue.
Most of the rain fell during the evening of July 27 and into the hours before dawn on July
28. That night, the rate of rainfall surged to 4 inches per hour, overwhelming an already
saturated region. Per National Oceanic and Atmospheric Administration Regional Climate
Center data, the precipitation readings on July 27 and 28 were the highest and second-highest
daily levels, respectively, since 1981. The storm finally ended on July 30, but not before taking
the lives of 44 people across 13 counties.
The flooded properties at issue in this case are in the community of River Caney, located
in Breathitt County and named after a creek that runs through it to meet the Kentucky River.
The River Caney watershed is a 3,507-acre complex drainage system, with terrain of steep
forested mountains and narrow valleys. Plaintiffs’ properties and Pine Branch’s operation,
Combs Branch, share that watershed. The mine sits in its southern portion and actively operates
under two Kentucky surface mining permits: Permit No. 897-0568 and Permit No. 897-0569.
River Caney endured even more rainfall than neighboring areas—it received more than
750 percent of its normal precipitation levels over the five-day period. The flooding
significantly damaged Plaintiffs’ real properties and killed at least two people. A tidal wave of
water crashed down on their homes on July 28, sweeping residents to their deaths and houses
downstream. As the deluge of water descended throughout the night, residents fled to higher
ground. They feared for their lives as they witnessed continued rainfall. When the storm finally
stopped, it left ruin and devastation in its wake.

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No. 24-5490 Baker, et al. v. Blackhawk Mining, LLC, et al. Page 4
Soon afterwards, in August 2022, Plaintiffs filed suit in state court against Pine Branch
and its parent, Blackhawk Mining LLC. Defendants successfully removed the case to federal
court on diversity grounds, and the court later granted summary judgment to Blackhawk. As
noted, Plaintiffs allege negligence per se. They argue that Pine Branch’s failure to reclaim
disturbed land on its surface mine was “the main causative factor” for their losses. Appellant Br.
at 13.
The district court relied on Federal Rule of Evidence 702 and Federal Rule of Civil
Procedure 26(a)(2)(B) to grant Pine Branch’s motion to exclude Plaintiffs’ proposed expert
opinion. Baker v. Blackhawk Mining, LLC, No. CV 5:22-231-DCR, 2024 WL 643133, at *1
(E.D. Ky. Feb. 15, 2024) (Blackhawk I). That opinion, offered by Scott Simonton as a
preliminary report, was Plaintiffs’ sole expert disclosure. Id. at *2. In it, Simonton referenced
studies that analyzed the effects of mining on hydrology in the Kentucky towns of Pikeville and
Middlesboro, and in Mingo County, West Virginia. Id. at *3. Notably missing was any such
study conducted in River Caney. Also absent was any hydraulic (HEC-RAS) or hydrologic
(HEC-HMS) modeling. Id. Other than his own hydrologic modeling and permit files from areas
outside of River Caney, Simonton relied primarily on aerial observation and third-party
eyewitness and anecdotal accounts of the flooding. Id. at *4–5.
The district court concluded that Simonton failed to meet Federal Rule of Evidence 702’s
demands because (1) his preliminary report was not based upon sufficient facts or data about the
specific mining sites at issue, (2) he did not rely upon any form of scientific modeling or testing
to reach conclusions, (3) he struggled to apply principles and methods reliably to the facts of the
case by relying on extrapolations from studies conducted on outside sites, and (4) he failed to
consider alternative causes of the property damage. See id. at *5.
The proposed expert further failed to meet disclosure requirements under Federal Rule of
Civil Procedure 26(a). Id. at *8. The “fundamental problem” with the evidence, the district
court noted, was Simonton’s offering of it as a “summary of initial preliminary opinions”
without providing any form of later supplementation. Id. at *6. The disclosure rule is clear: a
party has a duty to provide “a complete statement of all opinions the witness will express.” Id.
(quoting Fed. R. Civ. P. 26(a)(2)(B)(i)). Plaintiffs did not satisfy this obligation here.

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No. 24-5490 Baker, et al. v. Blackhawk Mining, LLC, et al. Page 5
Having struck Plaintiffs’ expert testimony, the district court then denied Plaintiffs’
motion for partial summary judgment on their negligence per se claim and granted Pine Branch’s
cross motion for summary judgment. Blackhawk II, 734 F. Supp. 3d at 629. The court based
those rulings on Plaintiffs’ lack of competent and admissible evidence to prove causation. Id.
The court also determined that the proof was insufficient to show that Pine Branch violated
mining regulations because the Kentucky Energy and Environment Cabinet never issued a final
order declaring a violation. See id. at 623–26. But even if there had been a violation found by
Cabinet order, the court held that Plaintiffs had not provided sufficient evidence to show the
company’s violation was a substantial factor in causing their damages. See id. at 626.
II.
In this timely appeal, Plaintiffs argue that Simonton’s designated expert opinion should
not have been excluded.1 And they contend that even without the expert evidence, the district
court wrongly decided the negligence per se claim. We disagree.
We review the district court’s summary judgment rulings on a de novo basis. See Ellis v.
Chase Commc’ns, Inc., 63 F.3d 473, 475 (6th Cir. 1995). Summary judgment is appropriate only
if the record demonstrates that there exists no genuine dispute of material fact and the moving
party is entitled to judgment as a matter of law. Fed. R. Civ. P. 56(a). We view the actual
proof—not isolated, conclusory allegations—in the light most favorable to the nonmovant. See
Bishop v. Lucent Techs., Inc., 520 F.3d 516, 519 (6th Cir. 2008). The district court determined
that, as a matter of law, Pine Branch was not per se negligent because there was an insufficient
showing of causation, amongst other reasons. See Blackhawk II, 734 F. Supp. 3d at 626–27. For
our analysis, we assume, without deciding, that Pine Branch committed mining violations. Our
opinion focuses only on how Plaintiffs fell short in their presentation of evidence on causation.
1 The number of Plaintiffs has thinned since the district court’s judgment because the notice of appeal
named fewer Plaintiffs than the complaint. Compare Third Amended Complaint, R. 70, PageID 265–71, with
Notice of Appeal, R. 157, PageID 1829–31. Because of the “mandatory and jurisdictional” nature of Federal Rule
of Appellate Procedure 3(c)(1)(A), this court lacks jurisdiction to hear an appeal from any plaintiff not named in the
notice of appeal (when the intent to appeal is not otherwise clear). Isert v. Ford Motor Co., 461 F.3d 756, 759 (6th
Cir. 2006).

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No. 24-5490 Baker, et al. v. Blackhawk Mining, LLC, et al. Page 6
A.
We begin with review of the district court’s exclusion of Simonton’s proffered expert
opinion. We review this ruling for abuse of discretion, a standard that applies even when the
exclusion of testimony results in entry of summary judgment for the party who opposed its
admission into evidence. Adkins v. Marathon Petroleum Co., LP, 105 F.4th 841, 848 (6th Cir.
2024). To show abuse of discretion under Federal Rule of Evidence 702 or Federal Rule of Civil
Procedure 26(a), parties “face a daunting task.” Madej v. Maiden, 951 F.3d 364, 374 (6th Cir.
2020) (discussing Federal Rule of Evidence 702); see Goldblum v. Univ. of Cincinnati, 62 F.4th
244, 257 (6th Cir. 2023) (“Federal Rule of Civil Procedure 26” affords “wide discretion”). A
district court has “broad discretion” to admit or exclude expert evidence, and its “action is to be
sustained unless manifestly erroneous.” United States v. Demjanjuk, 367 F.3d 623, 633 (6th Cir.
2004) (citation omitted); Brainard v. Am. Skandia Life Assurance Corp., 432 F.3d 655, 663 (6th
Cir. 2005). Based on this standard, and as we explain below, the district court did not abuse its
discretion by excluding Simonton’s anticipated testimony.
The district court gave two separate reasons for this ruling: (1) Simonton’s testimony did
not meet Rule 702’s relevancy and reliability standards, and (2) it failed to comply with Rule
26(a)(2)(B)’s disclosure requirements. We address each ground for inadmissibility in turn.
1.
Federal Rule of Evidence 702. To be admissible under Rule 702, scientific testimony
must be “not only relevant, but reliable.” Kumho Tire Co., Ltd. v. Carmichael, 526 U.S. 137, 147
(1999) (citation omitted). As for relevancy, Rule 702 mandates that the expert’s scientific,
technical, or other specialized knowledge help the trier of fact understand the evidence or
determine a fact in issue. Fed. R. Evid. 702(a). As for reliability, Rule 702 only allows an
expert to testify when the opinion is (1) “based on sufficient facts or data,” (2) “the product of
reliable principles and methods,” and (3) “a reliable application” of those “principles and
methods to the facts of the case.” Fed. R. Evid. 702(b)–(d).
Unreliable expert testimony can involve inadequate facts, methods, or applications. This
leads courts to make four inquiries: “Is the technique testable? Has it been subjected to peer

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No. 24-5490 Baker, et al. v. Blackhawk Mining, LLC, et al. Page 7
review? What is the error rate and are there standards for lowering it? Is the technique generally
accepted in the relevant scientific community?” United States v. Gissantaner, 990 F.3d 457, 463
(6th Cir. 2021). In asking these questions, a district court should look for “[r]ed flags that
caution against certifying an expert,” like “reliance on anecdotal evidence, improper
extrapolation, failure to consider other possible causes, lack of testing, and subjectivity.” Newell
Rubbermaid, Inc. v. Raymond Corp., 676 F.3d 521, 527 (6th Cir. 2012). The purpose of this
scrutiny is to satisfy core requirements of Rule 702: “any relevant scientific or technical evidence
must be the ‘product of reliable principles and methods’ and must have been ‘reliably applied.’”
Gissantaner, 990 F.3d at 463.
To be sure, under Rule 702 an expert is “permitted wide latitude to offer opinions” that
“are not based on firsthand knowledge or observation,” unlike “an ordinary witness.” Daubert v.
Merrell Dow Pharms., Inc., 509 U.S. 579, 592 (1993). But this “relaxation of the usual
requirement of firsthand knowledge—a rule which represents a ‘most pervasive manifestation’
of the common law insistence upon ‘the most reliable sources of information’”—assumes “that
the expert’s opinion will have a reliable basis in the knowledge and experience of his discipline.”
Id. (citation omitted). So, a district court must scrutinize whether expert evidence is relevant and
reliable, mindful of the weight the “expert” designation carries and the expert’s lack of firsthand
knowledge.
On appeal we review this determination for an abuse of discretion, which can result from
“an erroneous view of the law or a clearly erroneous assessment of the evidence.” Ky.
Speedway, LLC v. Nat’l Ass’n of Stock Car Auto Racing, Inc., 588 F.3d 908, 915 (6th Cir. 2009)
(citation omitted). But our court only steps in when we have “a definite and firm conviction that
[the district court] committed a clear error of judgment.” In re Scrap Metal Antitrust Litig., 527
F.3d 517, 528 (6th Cir. 2008) (citation omitted). Otherwise, we will “not substitute our own
judgment for that of the district court” and will defer to the district court’s “ultimate decision of
admissibility.” Id. (citation omitted).

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No. 24-5490 Baker, et al. v. Blackhawk Mining, LLC, et al. Page 8
a.
We have dealt with expert testimony on causation before in cases analogous to this one.
Deficiencies such as an expert’s lack of specific and relevant data, lack of relevant testing,
overreliance on unhelpful studies unconnected to causation, failure to rule out alternative causes,
and failure to comply with court-ordered report submission deadlines have all justified excluding
proposed expert opinion. See Pluck v. BP Oil Pipeline Co., 640 F.3d 671, 680–81 (6th Cir.
2011); Baker v. Chevron U.S.A. Inc., 533 F. App’x 509, 519–21 (6th Cir. 2013). Time and
again, we have affirmed district court exclusion decisions, finding no abuse of discretion. See,
e.g., Newell Rubbermaid, 676 F.3d at 528–29 (finding that district court’s concerns regarding
proffered expert’s “anecdotal evidence, improper extrapolation, failure to consider other possible
causes, and, significantly, a lack of testing” were sufficient to warrant exclusion in defective
design case); Madej, 951 F.3d at 367 (affirming summary judgment against plaintiffs given that
their proffered medical expert’s diagnosis of multiple chemical sensitivity was not sufficiently
reliable and plaintiffs lacked any other causation evidence); Pluck, 640 F.3d at 675–80; Baker,
533 F. App’x at 511. A deeper dive into two of these cases—Pluck and Baker—is particularly
relevant for our current inquiry.
In Pluck, we upheld the exclusion of expert testimony in a suit against BP over benzene
contamination near the home of the plaintiff couple, the Plucks. 640 F.3d at 674–75. Between
1948 and 1962, BP’s pipeline leaked gasoline into nearby soil and groundwater. Id. at 673. By
1990, benzene levels in several wells exceeded safe limits, though the well at the Plucks’ house
seemed safe until 1996, when they moved in and tested it. Id. at 673–74. Prior to that 1996
testing, BP had monitored but not remediated the Plucks’ well. Id. at 674. But after detecting
benzene in their well and following Mrs. Pluck’s 2002 Non-Hodgkin’s Lymphoma diagnosis, the
Plucks sued. Id. They relied on proposed expert testimony from Dr. James Dahlgren to establish
specific causation. Id. at 675.
The district court excluded Dahlgren’s opinion and granted BP’s motions for summary
judgment. Id. at 675. It rejected Dahlgren’s testimony as unreliable, saying it “suffered
significant methodological flaws and [was] apparently based on speculation and conjecture
rather than evidence and data.” Id. The district court was alarmed that Dahlgren had formulated

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No. 24-5490 Baker, et al. v. Blackhawk Mining, LLC, et al. Page 9
his opinion “without any exposure data.” Id. On appeal, we had a similar concern and held that
the district court had not abused its discretion in excluding Dahlgren’s opinion. Id. at 680.
Exclusion rested on the purported expert’s inability to explain the methodology he used to
calculate Mrs. Pluck’s benzene dose, id. at 675, and his failure to “reliably ‘rule[] in’ the
potential causes of Mrs. Pluck’s NHL and ‘rule[] out’ alternative causes” like Mrs. Pluck’s
extensive smoking habit, id. at 678; see id. at 680; see also Tamraz v. Lincoln Elec. Co., 620
F.3d 665, 674 (6th Cir. 2010) (excluding expert opinion as unreliable because “his efforts to ‘rule
in’ manganese exposure as a possible cause or to ‘rule out’ other possible causes turned on
speculation, not a valid methodology”). Also, a review of the studies and literature underlying
Dahlgren’s causation opinion proved less supportive than initially framed: they indicated there
“‘was not a statistically significant increase in [NHL]’ following prolonged periods of benzene
exposure.” Pluck, 640 F.3d at 680 (citation omitted). And he filed an untimely supplementation
that contradicted previous testimony and employed “an entirely new differential diagnosis
methodology.” Id. at 678.
We noted that the “causation inquiries” in Pluck involved “scientific assessments that
must be established through the testimony of a medical expert” or else the claim “will fail.” Id.
at 677 (citation omitted). As Dahlgren’s opinion was unreliable and excluded, the Plucks’ claims
fell short at summary judgment.
Baker informs us as well. 533 F. App’x at 511. The relevant facts of Baker are
analogous to ours, and our opinion in that case correctly applied well-established principles from
our published cases. Although our opinion in Baker is unpublished, it drew heavily from the
district court’s reasoning in that case—the same reasoning our published opinion in Pluck relied
upon.
Like Pluck, Baker involved benzene contamination from seeping fuel. Id. at 511–12.
Over 55 years, roughly 8 million gallons of fuel leaked from a crude oil refinery near Hooven,
Ohio. Id. at 512. Chevron began remediation, and by 2006, both the EPA and Ohio Department
of Health found no ongoing health risks. Id. at 512–13.

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Despite this, over 200 residents filed a mass tort suit alleging Chevron’s emissions and
contamination caused personal injury, property damage, and heightened health risks requiring
medical monitoring. Id. at 511, 513. The district court bifurcated the plaintiffs based on their
injury type and, after excluding two expert opinions as unreliable, granted summary judgment
for Chevron on all claims. Id. at 511–16.
The plaintiffs’ property damage claim rested on expert testimony from Dr. Philip
Bedient. Id. at 513–14. The district court excluded his opinion as unreliable because he “did not
perform any analysis” to determine whether a soil vapor pathway existed from the plume to the
surface. Id. at 514. Without such analysis, the court found the remaining evidence of soil vapor
intrusion—Chevron’s theoretical model and plaintiffs’ odor complaint testimonies—insufficient
to prove causation. Id. We affirmed, emphasizing that neither Bedient nor plaintiffs’ remaining
expert completed “any vapor pathway analyses.” Id. at 524. Bedient’s reliance on an Ohio
Department of Health study, which deemed the plume’s health risks “indeterminate,” further
justified the exclusion as a proper exercise of discretion. Id. at 516. None of this was an abuse
of discretion.
The district court also excluded testimony from the plaintiffs’ personal injury expert, Dr.
Dahlgren, finding flaws in all four of his reports. See id. at 514–15.2 Of note, his reliance on
1977 short-term benzene exposure data in his fourth report was “wholly irrelevant” since none of
the plaintiffs then lived in Hooven. Id. at 516. The court also concluded that none of Dahlgren’s
cited medical studies “support[ed] an opinion that benzene can cause [] illnesses” at the low
exposure levels the plaintiffs suffered. Id. With no other causation evidence besides Dahlgren’s
inadmissible reports, the court entered summary judgment for Chevron.
2The first and second reports in Baker failed to meet Rule 26(a)(2)(B) disclosure requirements. 533 F.
App’x at 515. And Dahlgren adopted a “one-hit theory” stating that “there is no safe level of exposure to benzene.”
Id. The district court considered that to be “an unreliable causation theory” because it did not rule out an alternative
cause for their injuries: ambient benzene. Id. The third report fared no better: The district court excluded it because
Dahlgren “provided no justification for providing [it] five months late.” Id. As everything in that report could have
been included in the first report, the court considered the report an “attempt to correct the weaknesses of Dr.
Dahlgren’s opinions” and “not harmless error.” Id.

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No. 24-5490 Baker, et al. v. Blackhawk Mining, LLC, et al. Page 11
We upheld this ruling on appeal, holding that the district court did not abuse its discretion
in excluding Dahlgren’s reports.3 Id. at 520–21. The fourth report, in particular, relied on
outdated exposure data and studies having no clear link to the plaintiffs’ conditions. See id. at
521. The absence of any “accepted scientific methodology for ruling out non-benzene
explanations” for the plaintiffs’ injuries further undermined the opinion. Id. We noted that the
absence of such elimination methods “is fatal to the admissibility of an expert’s opinion.” Id.
(citing Pluck, 640 F.3d at 678–80; Tamraz, 620 F.3d at 674–76). These shortcomings resulted in
“simply too great an analytical gap between the data and the opinion proffered.” Id. at 520
(quoting Gen. Elec. Co. v. Joiner, 522 U.S. 136, 146 (1997)). We were left with no “definite and
firm conviction that the district court committed a clear error of judgment.” Id. at 521 (citing
Pluck, 640 F.3d at 678–80; Tamraz, 620 F.3d at 674–76).
b.
Like the district courts in Pluck and Baker, the court below did not abuse its discretion
and instead correctly spotted red flags in the proffered expert opinion on causation. Here, Dr.
Simonton’s testimony was deficient in all three reliability areas: it unreliably applied unreliable
methods to insufficient and even irrelevant data.
First, Simonton lacked site-specific data. His preliminary report referenced studies that
analyzed mining effects on hydrologic systems not in River Caney but instead in Pikeville and
Middlesboro, Kentucky, and Mingo County, West Virginia. Not only is River Caney’s
watershed topographically unique, but it experienced unprecedented rainfall compared to nearby
locations. The district court thus properly acted within its discretion to “question the relevance
of the studies.” Blackhawk I, 2024 WL 643133, at *4.
3We didn’t analyze the first or second report, as the plaintiffs did not “argue that the court abused its
discretion by excluding” them for “failing to comply” with Rule 26(a)(2)(B). Baker, 533 F. App’x at 520. As for
the third report, we recognized how district courts “have broad discretion to exclude untimely disclosed expert-
witness testimony,” id. (quoting Pluck, 640 F.3d at 681), and saw no issue with the district court’s ruling, given how
“prejudicially late” the opinion was and how it was a “transparent effort to reopen an opinion after its weaknesses
had been exposed” earlier. Id. at 519. Besides, the plaintiffs did “not specifically challenge the court’s conclusion
that the untimely [t]hird [r]eport was an obvious attempt to bolster a deficient opinion.” Id. at 520.

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No. 24-5490 Baker, et al. v. Blackhawk Mining, LLC, et al. Page 12
Simonton’s data exhibit deficiencies analogous to those in Dahlgren’s fourth report in
Baker. See 533 F. App’x at 516. That report relied on “wholly irrelevant” 1977 short-term
benzene exposure data, id., similar to Dr. Simonton’s reliance on off-point studies from places
outside of River Caney. Simonton also proposed an expert opinion like the one offered in Pluck,
which lacked “any exposure data.” 640 F.3d at 675. The district court here did not commit a
clear error of judgment in deciding that “Simonton’s preliminary report is not based upon
sufficient facts or data about the specific mining sites.” Blackhawk I, 2024 WL 643133, at *5.
Simonton further failed to conduct flood modeling. Such modeling is “the accepted
methodology to determine whether land disturbances caused or exacerbated flooding.” Id. at *3
(citation omitted). The district court adopted the view that “natural hydrologic systems are
inherently complex” and “can rarely be described in simple terms, nor can their behavior be
predicted with anything less than a computer based hydrologic simulation model.” Id. (citation
omitted). The complexity of the River Caney Watershed’s system “is magnified by the fact that
in almost all circumstances, certain inputs to the system like river flows and precipitation are not
predictable with any certainty.” Id. (citation omitted). That’s why “the task of attempting to
establish the behavior features of [hydrologic systems] is rarely performed without a simulation
model.” Id. (emphasis in original) (citation omitted).
It’s one thing to say courts do not per se require the use of HEC-RAS or HEC-HMS
modeling, which is true. See id. But it’s another thing to say that the district court committed a
clear error of judgment when deciding that Simonton’s methodology was unreliable—especially
when we consider that Simonton did not provide any quantifiable or objectively testable model
that is accepted by the relevant hydrologic engineering community. Simonton even testified
previously that experts in the field cannot reach conclusions about the impacts of surface
disturbances on flooding without first modeling. See id. He said he had “never seen” an opinion
“where modeling wasn’t included,” considering it “kind of the standard.” Id. (citing R. 116-4,
PageID 448:20-449:5). In addition, most of the studies that Simonton cited to serve as his
(insufficient) data involved hydrologic modeling, albeit at other locations under different storm
events. Id. That choice of studies shows that even he believes the hydrologic modeling method
is reliable and the industry standard.

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We again find parallels in Baker and Pluck. See 533 F. App’x at 511; 640 F.3d at 673.
Simonton’s lack of testing is like Bedient’s failure to conduct his own vapor pathway analysis—
something that alarmed both the district and this court in Baker. See 533 F. App’x at 524.
Simonton’s testing shortcomings are also like Pluck, where the expert could not properly “rule
in” benzene exposure as the cause of Mrs. Pluck’s cancer. 640 F.3d at 679. Instead, he relied on
less than helpful studies. See id. at 679–80. In both Pluck and Baker this court found no abuse
of discretion for exclusion based on faulty methodology. For similar reasons here, there was no
abuse of discretion.
Further, Simonton failed to “properly exclude potential alternative causes of the damage
that plaintiffs suffered.” Blackhawk I, 2024 WL 643133, at *5. More specifically, he did not
explicitly rule out, for example, the historic rainfall as causal. Id. That sounds like Dahlgren’s
fourth report in Baker again. This report did “not contain any differential diagnosis or other
accepted scientific methodology for ruling out non-benzene explanations for plaintiffs’
diseases.” Baker, 533 F. App’x at 521. And in Pluck, Dahlgren did not rule out alternative
causes for cancer, like smoking. 640 F.3d at 680. Such an absence in expert testimony is “fatal
to the admissibility of an expert’s opinion.” Baker, 533 F. App’x at 521.
Instead, the bases for Simonton’s opinion primarily consisted of “aerial observations,”
“studies and publications regarding other locations” that were only “presented in remarkably
general terms,” “reviews of relevant precipitation data,” and “examinations of Google Earth
imaging.” Blackhawk I, 2024 WL 643133, at *4–5 (citation omitted). Or, as the district court
categorized them, “anecdotal evidence” and “improper extrapolation.” Id. That court said it
best: Simonton struggled “to apply principles and methods reliably to the facts of the case by
relying on extrapolations from studies conducted on sites outside of the River Caney
Watershed.” Id. There was “too great an analytical gap between the data and the opinion
offered.” Id. at *4 (quoting Joiner, 522 U.S. at 147).
Simonton’s report raises those various red flags that caution against certifying his
opinion: reliance on “anecdotal evidence, improper extrapolation, failure to consider other
possible causes, and, significantly, a lack of testing.” Newell Rubbermaid, 676 F.3d at 528. We
cannot say that the district court’s understanding of the law and its application to the facts were

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manifestly erroneous to overcome the deferential standard we afford to a district court’s
decisions under Rule 702. The district court identified the correct legal standard and reasonably
considered Simonton’s testimony to fall short of Rule 702’s requirements. None of this suggests
“a clear error of judgment” on the part of that court. In re Scrap Metal Antitrust Litig., 527 F.3d
at 528 (citation omitted). So, we conclude the district court did not abuse its discretion in
excluding Simonton’s opinion under Rule 702.
2.
Federal Rule of Civil Procedure 26(a)(2)(B). There also was no abuse of discretion
when the district court excluded Simonton’s opinion for failure to meet disclosure requirements
under Federal Rule of Civil Procedure 26(a)(2)(B). If a party “fails to provide information or
identify a witness as required by Rule 26(a) or (e),” Federal Rule of Civil Procedure 37(c)
prohibits the party from using “that information or witness to supply evidence on a motion, at a
hearing, or at a trial, unless the failure was substantially justified or is harmless.”
Rule 26 mandates disclosure from each side of a case to enable the other side to prepare
for trial and to prevent surprise tactics from affecting the case’s outcome. See Fielden v. CSX
Transp., Inc., 482 F.3d 866, 871 (6th Cir. 2007). An expert disclosure, in particular, must
include “(i) a complete statement of all opinions the witness will express and the basis and
reasons for them; (ii) the facts or data considered by the witness in forming them; (iii) any
exhibits . . . used to summarize or support them; (iv) the witness’s qualifications”; (v) “a list of
all other cases” in which the witness testified as an expert; and “(vi) a statement of the
compensation to be paid for the study and testimony in the case.” Fed. R. Civ. P. 26(a)(2)(B).
The rule vests district courts with broad discretion to exclude materials from consideration if a
party does not comply with Rule 26. Brainard, 432 F.3d at 664; see Crawford–El v. Britton, 523
U.S. 574, 598 (1998). And it places a “level of rigor and detail” on disclosing expert testimony.
Adkins, 105 F.4th at 850. The expert opinion must “outline a line of reasoning arising from a
logical foundation” and “include the ‘how’ and ‘why,’ not just his conclusions.” Id. (citation
omitted).

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We find guidance from Adkins for applying these standards. Id. at 849–50. In Adkins,
the plaintiff (Brent Adkins) sought recovery for exposure to hydrogen sulfide while working for
the defendant’s barge, alleging the fumes caused his lung deterioration. Id. at 848–49. We
affirmed the district court’s exclusion of Adkins’s expert opinion from Dr. Charles Pue because
it was conclusory and did not meet the level of rigor and detail that Rule 26 requires. Id. at 850.
It simply stated that pulmonary function tests of Adkins showed his lung function worsened
during his employment and that “exposure to hydrogen sulfide and other toxic fumes caused that
deterioration.” Id. The report contained “no explanation of how hydrocarbon inhalation caused”
his decreased pulmonary function and was “without any elaboration.” Id. That was the “sole
causation theory Dr. Pue offered.” Id. Also, the report did not contain a complete statement of
Pue’s opinions. Id.
Brainard is also instructive. There, we upheld the district court’s exclusion of an expert
report submitted in support of the plaintiffs’ claim that an agency relationship had formed
between the relevant parties. 432 F.3d at 664. The report called for supplementation, yet the
plaintiffs failed to provide it. Id. And the court considered the expert opinion “conclusory” as it
lacked “substance or analysis.” Id.
For similar reasons, the district court acted within its discretion to exclude Simonton’s
opinion for lack of completeness. Pine Branch moved to exclude Simonton’s testimony on four
grounds. See Blackhawk I, 2024 WL 643133, at *6–7. First, his report was incomplete. See
Fed. R. Civ. P. 26(a)(2)(B)(i). Second, it reached conclusions without identifying their
supporting reasoning. Id. Third, Plaintiffs did not produce all of Simonton’s considered facts,
data, or exhibits. See Fed. R. Civ. P. 26(a)(2)(B)(ii)–(iii). And fourth, Plaintiffs did not produce
a comprehensive list of all the cases in which Simonton had testified. See Fed. R. Civ. P.
26(a)(2)(B)(v). All of these grounds were proper bases for exclusion under Rule 26, the district
court reasoned, and we agree. There was no abuse of the district court’s broad discretion.
Plaintiffs provided only a “Preliminary Opinion” of the Caney Creek Flooding in
Breathitt County, Kentucky. Although Plaintiffs now contend that the report was complete, we
remain unpersuaded. The opinion is only a summary of Simonton’s initial evaluation of
topography, existing sediment control structures, and sedimentary conditions that led to flooding.

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See Blackhawk I, 2024 WL 643133, at *6. Its “fundamental problem” is its status as just a
“summary of initial preliminary opinions” lacking additional supplementation. Id. (emphasis in
original). The district court did not commit a clear error of fact or law to require that the opinion
be a “complete statement.” Id. As in Brainard, a need for supplementation was sufficient
grounds for exclusion of the report under Rule 26. See 432 F.3d at 664.
Plaintiffs also unduly delayed providing Simonton’s supporting exhibits until after Pine
Branch had filed its motion to exclude. See Blackhawk I, 2024 WL 643133, at *7. By the time
Plaintiffs produced the materials, months had passed since the expert disclosure deadline. Id.
Nor did it suffice, as Plaintiffs contend, that much of the information Simonton considered
“derived from freely available public resources.” Appellant Br. at 60. Placing the burden on
Pine Branch to discover the bases of Simonton’s opinion from public sources does not cure
Plaintiffs’ Rule 26(a)(2)(b)(ii) and (iii) deficiencies.
Finally, Plaintiffs violated Rule 26(a)(2)(B)(v)’s disclosure requirement. They did not
give Pine Branch a comprehensive list of all the cases that Simonton has testified in during the
last four years. See Blackhawk I, 2024 WL 643133, at *7. Such information is not “worthless,”
but instead a disclosure requirement. Id. The district court did not abuse its discretion in
drawing the inevitable conclusion that the disclosure was deficient. Id.
When an expert disclosure is deficient under Rule 26(a), Rule 37 exclusion is “mandatory
unless there is a reasonable explanation of why Rule 26 was not complied with or the mistake
was harmless.” Bessemer & Lake Erie R. R. Co. v. Seaway Marine Transp., 596 F.3d 357, 370
(6th Cir. 2010) (citation omitted). Here, Plaintiffs made only a minimal effort to explain the
failure to disclose critical components of Simonton’s expert material. Blackhawk I, 2024 WL
643133, at *8. So, the district court’s exclusion of Simonton’s opinion soundly complied with
the mandates of Rules 26 and 37. None of the district court’s Rule 26 conclusions were
“manifestly erroneous,” either legally or factually. Because the district court did not abuse its
discretion, we defer to its decision to exclude.

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B.
Without Simonton’s testimony, Plaintiffs cannot prove causation to establish negligence
per se. Simonton was their sole expert. Kentucky requires expert testimony for “scientific or
specialized” issues that are beyond the “ordinary knowledge gained in the ordinary affairs of
life.” Com., Dep’t of Highways v. Robbins, 421 S.W.2d 820, 824 (Ky. 1967). We have
recognized that “causation of flooding is a complex issue which must be addressed by experts.”
Cox v. Tenn. Valley Auth., 989 F.2d 499, 1993 WL 72488, at *11 (6th Cir. 1993). Plaintiffs do
not dispute that Kentucky’s state-law rule concerning expert testimony applies or that flood
causation involves scientific questions requiring expert testimony at Kentucky law. So we can
assume that Kentucky’s rule is “substantive” and extends to this federal proceeding and that it
directs Plaintiffs to provide expert testimony. See Erie R.R. Co. v. Tompkins, 304 U.S. 64, 78
(1938); Madej, 951 F.3d at 373–74.
We have affirmed (or directed) summary judgment against parties who failed to offer
expert evidence when it was required to prove causation. See, e.g., Adkins, 105 F.4th at 852;
Madej, 951 F.3d 364; Pluck, 640 F.3d at 677. In Pluck, we noted that claims involving
“causation inquiries” and “scientific assessments” required “testimony of a medical expert” at
Ohio law. 640 F.3d at 677. Without it, the “claim will fail.” Id. Then in Baker, having
“excluded Dr. Dahlgren’s opinions—plaintiffs’ only evidence of causation—the district court
granted Chevron’s motion for summary judgment” and we affirmed that decision. 533 F. App’x
at 516. We do the same now with respect to a summary judgment that similarly turns on the
exclusion of Plaintiffs’ sole causation expert opinion.
Even if we thought Plaintiffs somehow could prove causation without an expert,
Plaintiffs’ remaining evidence would be insufficient to place the issue in the hands of a jury. The
district court was right that the evidence “is thin.” Blackhawk II, 734 F. Supp. 3d at 628.
Plaintiffs point to an aerial photo depicting “the barren landscape created by [Pine
Branch’s] surface mining operation” and identify the “moonscape-like topography” making it
“clear that there is no vegetation on the permit area.” Appellant Br. at 43; R. 137-2, PageID 961.

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But that is a mere conclusory allegation that does not establish causation. It fails to establish a
genuine dispute of material fact. Fed. R. Civ. P. 56(a).
Nor do the “mine inspection reports” and Notices of Violation testimony from Cabinet
Inspector Wilson create a jury issue on causation. The mine inspection reports relied upon by
Plaintiffs to prove causation are for Permit Nos. 813-0410 and 813-0413, which are “not permits
held by Pine Branch.” Appellee Br. at 50 (emphasis omitted). Permit Nos. 897-0568 and 897-
0569 are the only active surface mining permits in the River Caney Watershed and not the ones
Plaintiffs cite. Also, Wilson testified he had never issued cessation orders to Pine Branch. Even
viewing the facts in the light most favorable to Plaintiffs, neither the warnings contained in the
mine inspection reports nor the Notices of Violation show causation of Plaintiffs’ injuries so as
to create a genuine dispute of material fact.
Finally, Plaintiffs refer to deposition testimony from Pine Branch’s Regulatory Affairs
Director, Don Gibson, and accompanying Notices of Non-Compliance. But the relevance of
those notices is unclear because they mostly postdate the flood. Besides, the ponds of sediment
buildup did not reach the requisite “clean-out” level prior to the flooding event. Blackhawk II,
734 F. Supp. 3d at 623. And the notices noted that “the erosion the [Kentucky Energy and
Environment Cabinet] sought to remedy was caused by the flooding event rather than apparent
maintenance deficiencies.” Id. Again, Plaintiffs’ proof failed to create a genuine dispute as to
material fact in support of causation.
By contrast, testimony of Pine Branch’s expert, Dr. Ricci, was the only admissible expert
evidence, and it conclusively rebutted Plaintiffs’ causation argument. Unlike the Simonton
Report, the Ricci Report met the evidentiary standard of Rule 702 by employing industry
modeling. It documented pre-flood and pre-construction files to show sediment control and
other site-specific data. Plus, it considered the local rain gauge data from the storm. The report
concluded that “no pond associated with any mining operation . . . is designed to withstand the
July 2022 storm event”—any would “be overtopped by a storm of this magnitude.” Ricci
Report, R. 141-1, PageID 1297.

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In light of the Ricci Report, and with Simonton’s opinion on causation excluded,
Plaintiffs lack sufficient evidence to create a genuine dispute of material fact as to causation, an
essential element of their claim. So, the district court correctly granted summary judgment to
Pine Branch.
III.
We sympathize with Plaintiffs for all that they lost in the flood. But the district court did
not abuse its discretion when it excluded their proffered expert testimony under Federal Rule of
Evidence 702 and Federal Rule of Civil Procedure 26(a)(2)(B). Without that testimony,
Plaintiffs cannot prove that Pine Branch’s alleged negligence was a substantial factor that
contributed to the flooding of their properties. We therefore AFFIRM the district court.

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