Opinion for the Court filed by Circuit Judge HARRY T. EDWARDS.
This appeal presents issues that have been certified by the District Court for interlocutory review pursuant to 28 U.S.C. § 1292(b). The action before us involves a suit brought by the Trustees (the “Trustees”) of certain United Mine Workers of America (“UMWA”) pension trusts to require pension fund contributions from several coal companies (the “Coal Companies”). The District Court granted summary judgment in favor of the Trustees on the issue of liability,
see In re UMWA Employee Benefit Plans Litigation,
The parties do not dispute and we agree that the case is properly before this court under 28 U.S.C. § 1292(b). Finding no error in the judgment of the trial court, we affirm and remand for further proceedings.
I. Introduction
The underlying facts, including the history of this litigation, are recited in the opinion of the District Court.
See In re UMWA,
Briefly, this case involves the interpretation of the so-called “evergreen clause” 1 in *472 the pension trust and collective bargaining agreements between the UMWA and the Coal Companies’ bargaining representative, the Bituminous Coal Operators’ Association (“BCOA”). The evergreen clause was first added to the trust agreements in 1978, and it was incorporated by reference into article XX(d) of the 1978 “National Bituminous Coal Wage Agreement” (“NBCWA”), and in all subsequent collective bargaining agreements between the parties. The clause provided that participating employers (including the appellants) were bound to make continuing contributions to the trusts, and that the amounts of contribution would be as specified in future NBCWAs.
The dispute in this case arose upon the expiration of the NBCWAs to which the appellant Coal Companies were signatories. 2 Instead of entering into successor NBCWAs, the Coal Companies withdrew from the BCOA and negotiated individual labor agreements with the UMWA which included modifications of their contribution obligations to the trusts. The Trustees then brought this suit, contending that the evergreen clause obligates the Coal Companies to continue contributing to the trusts at the levels established in successor NBCWAs. 3
On cross-motions for summary judgment, the Trustees submitted declarations from witnesses who participated in the 1978 negotiations, along with corroborating documents generated shortly after those negotiations. In response, the Coal Companies argued that it was noteworthy that the Trustees never previously had sought to enforce a claim premised on “perpetual obligations” under the evergreen clause; rather, according to the Coal Companies, the Trustees always had defined claims against other allegedly defaulting employers solely pursuant to “withdrawal liability”.
4
After considering the language of the relevant trust and collective bargaining agreements, as well as the interpretive evidence before it, the District Court upheld the Trustees’ interpretation of the evergreen clause and granted their motion for summary judgment on the question of liability.
In re UMWA,
Defendant Rawl moved the District Court to reconsider its decision and defendant PCG moved for amendment of the District Court’s order to satisfy the conditions for interlocutory appeal under 28 U.S.C. § 1292(b). In conjunction with its motion, Rawl submitted new evidence to the District Court; this evidence consisted of declarations of persons familiar with the *473 1978 negotiations who denied that the evergreen clause was understood to create ongoing obligations. In addition, Rawl argued that it had been unfairly denied adequate discovery and that it had several affirmative defenses that should have survived the summary judgment order.
The District Court refused to consider the “new evidence" offered by Rawl, and it denied the motion for reconsideration.
UMWA 1974 Pension Trust v. Pittston Co.,
II. The Construction of the Evergreen Clause
The Coal Companies claim that the District Court erred as a matter of law in construing the evergreen clause. We disagree. The District Court, relying on the words of the agreements and the extrinsic evidence properly before it, concluded that the only reasonable interpretation of the evergreen clause is one premised on a principle of “perpetual obligation.” Accordingly, the District Court granted summary judgment for the Trustees. We have reviewed this judgment
de novo, Shields v. Eli Lilly & Co.,
In cases requiring the court to construe the meaning of a contract, the dispute may be resolved as a matter of law if the contested agreement admits of only one reasonable interpretation.
Link Coal Co.,
Applying this analytical framework to the contract provisions at hand, we conclude that the District Court was fully justified in granting summary judgment in favor of the Trustees. The language of the relevant provisions in the applicable trust and collective bargaining agreements unambiguously obliges signatory employers to contribute to the trusts at the rates specified in the current NBCWA, irrespective of the employer’s failure sign that NBCWA. The evergreen clause in the trust documents clearly does not include a durational limitation to the employer’s duty to contribute to the trusts. See note 1, supra. Although the clause does allow for modifications in “successor agreements,” the structure of the clause and the reference to the current NBCWA, through the use of “thereto,” indicate that only a subsequent NBCWA can qualify as such a sue- *474 cessor agreement. Furthermore, section XX(d) 5 of the NBCWAs, which incorporates the evergreen clause by reference, comprehends only the termination of the particular NBCWA and the contribution rates specified therein; it does not, contrary to the Coal Companies' protestations, provide for the general termination of the duty to contribute to the trusts. , Thus, by accepting the terms of section XX(d), these employers agreed to be bound by the evergreen clause to make continuing contributions to the trusts; and this obligation included an agreement to make contributions at rates specified in subsequent NBCWAs, without regard to whether the employer was still a party to the subsequent agreements. The Coal Companies cannot now rely on their refusal to sign successor NBCWAs to release them from a previously agreed-upon perpetual obligation. 6
This plain construction of the evergreen clause is corroborated by voluminous extrinsic evidence submitted by the Trustees. First, the Trustees submitted the sworn declarations of five people who were directly involved in the negotiations that led to the inclusion of the evergreen clause in the 1978 trust documents. 7 In addition, the Trustees submitted copies of notes and minutes prepared contemporaneously with those negotiations which indicate an intention to create a continuing obligation, see, e.g., BCOA Proposals (Jan. 23, 1978), reprinted in J.A. at 689 (protection for BCOA against withdrawals from trusts), and various BCOA and UMWA documents prepared shortly after the negotiations were concluded, see, e.g., Memorandum of B.M. Shaner, Manager of Employee Benefits for Bethlehem Steel Corporation, to John O’Connell, Vice President for Labor Relations, Bethlehem Steel Corporation (May 23, 1978), reprinted in J.A. at 594-95 (evergreen clause structured to prevent withdrawals from the funds). Finally, the District Court was provided with public statements made by negotiators of the evergreen clause which confirmed the Trustees’ posited interpretation. See, e.g., Multiemployer Pension Plan Amendments Act of 1979: Hearings on H.R. 3904 Before the Subcomm. on Labor-Management Relations of the House Comm. on Educ. and Labor, 96th Cong., 1st Sess. 418 (1979) (statement of Donald Pierce, economist, UMWA). Thus, not only is the language of the evergreen clause clear in its effect of permanently binding signatory employers to the contribution rates established in current NBCWAs, but it appears that negotiators on both sides of the bargaining table at the 1978 negotiations understood the import of that language.
*475 Confronted with this well supported motion for summary judgment, the Coal Companies were able to respond only with a counter-intuitive reading of the pertinent language and references to the Trustees’ failure to previously enforce the perpetual obligations explicit in the contract provisions. The Coal Companies’ first argument — that section XX(d) of the NBCWAs provides for the termination of the contribution obligation at the expiration of the agreement — is directly at odds with the language of that section. Section XX(d) plainly does not purport to define the dura-tional limits of the contribution requirement, but instead details the amounts due to be paid during specified periods by employers already bound to contribute. See note 5, supra. Similarly unconvincing is the Coal Companies’ argument that the evergreen clause allows for the modification of contribution requirements in non-NBCWA labor agreements. As mentioned above, the phrase allowing for modifications in successor agreements clearly refers to the prior NBCWA, leading us to the natural inference that the only “successor” agreement to an NBCWA is another NBCWA. Hence, we are not persuaded that the plain language of the relevant provisions accommodates the Coal Companies’ interpretation. 8
Moreover, the Coal Companies provided no extrinsic evidence to substantiate the reasonableness of their interpretation. While the case was being considered on summary judgment, the Coal Companies relied almost exclusively on the Trustees’ supposed inconsistent conduct in an attempt to demonstrate that the Trustees have only recently invented the perpetual obligations interpretation of the evergreen clause. This conduct was comprised primarily of the Trustees’ use of withdrawal liability rather than suits under the evergreen clause in several earlier instances in which signatory employers failed to contribute to the funds at the rates specified in the NBCWA.
See, e.g., Connors v. Peles,
In sum, the Trustees provided the District Court with a compelling argument and specific evidence indicating that theirs was the only reasonable interpretation, of the
*476
evergreen clause and that no material factual dispute remained for trial. The Coal Companies responded with an untenable reading of the contractual language and general evidence that the Trustees’ interpretation of the evergreen clause is of recent origins. This evidence falls far short of what is necessary to undermine or contradict the Trustees' evidence.
See, e.g., Bias,
III. Rawl’s Motion for Reconsideration
For many of the same reasons already mentioned, we find no basis upon which to reverse the District Court’s refusal to reconsider its decision in light of the alleged “new evidence” belatedly produced by Rawl. Under the Federal Rules of Civil Procedure, a District Court may reconsider its final judgments based on newly discovered evidence if that evidence was unavailable at the time of the judgment.
See
Fed.R.Civ.P. 60(b)(2) (due diligence required);
see also Stoller v. Marsh,
Here, it is undisputed that most, if not all, of the information that Rawl belatedly sought to submit with its motion for reconsideration was available before the District Court ruled on summary judgment. Rawl maintains, however, that the parties agreed in an earlier phase of the litigation 11 to forego discovery because the court could decide the case without considering extrinsic evidence, and that the court had entered an order reflecting that agreement. Upon reviewing both the order staying discovery and the transcript of the scheduling conference that led to that order, we find no indication that the court precluded the consideration of extrinsic evidence in ruling on the summary judgment motions. See UMWA 1974 Pension Trust v. Rawl Sales & Processing Co., No. 3:90-0890 (S.D.W.Va. Jan. 24, 1991) (order suspending time frame order pending decision on summáry judgment); UMWA 1974 Pension Trust v. Rawl Sales & Processing Co., No. 3:90-0890 (S.D.W.Va. Jan. 14, 1991) (transcript of scheduling conference). Indeed, Rawl’s putative reliance on such an agreement is belied by its own submissions of extrinsic evidence in support of its cross-motion for summary judgment. Thus, it does not appear that Rawl was in any way misled about the scope of the District Court’s inquiry in disposing of this case on summary judgment.
Furthermore, Rawl has failed to demonstrate that it was prejudiced by the supposed lack of discovery. Rawl rested its motion for reconsideration primarily on af *477 fidavits from individuals involved in the 1978 negotiations who averred that they were not aware of the continuing obligation aspect of the evergreen clause at that time. See, e.g., Affidavit of E. Morgan Massey, Director of the BCOA in 1978 (Feb. 13, 1992), reprinted in J.A. at 838. In addition, Rawl submitted a document created by the Trustees which allegedly evidenced the Trustees’ policy of pursuing withdrawal liability rather than continuing contributions under the evergreen clause. See Minutes of the 281st Meeting of the UMWA Board of Trustees (Aug. 26, 1981), reprinted in J.A. at 1069. Rawl frankly admits that it could have obtained most of this material prior to the District Court’s summary judgment ruling. See Rawl Brief at 14. Thus, Rawl’s objection to the lack of discovery rings hollow.
In any event, even if we were to consider the material belatedly offered by Rawl, we would still conclude that the District Court did not abuse its discretion by refusing to reconsider its judgment. A party opposing summary judgment, when faced with specific evidence that demonstrates the absence of a material factual dispute, cannot defeat the motion simply by offering general denials.
See Bias,
IV. Subsidiary Issues
We briefly address the remaining claims by the Coal Companies only to reaffirm the law of this Circuit.
A. Judicial Estoppel
The Coal Companies maintain that judicial estoppel should bar the Trustees from asserting their present interpretation of the evergreen clause because of the tension between it and their litigating position in the withdrawal liability eases. However, we have not previously embraced the doctrine of judicial estoppel in this circuit
12
and we decline to do so in this case. In the circuits that recognize the doctrine, judicial estoppel is used to preclude a party from taking a position that is inconsistent with one successfully asserted by the same party in a prior proceeding.
See, e.g., Astor Chauffeured Limousine Co. v. Runnfeldt Invest. Corp.,
B. Issue Preclusion
The Coal Companies also argue that the Trustees’ claims are barred by issue preclusion resulting from the disposition of the withdrawal liability cases. Issue preclusion prohibits a party from relitigating an issue in a subsequent proceeding if the issue was actually litigated in an earlier proceeding and determined by a court of competent jurisdiction, and if the preclusion would not be unfair to the precluded party.
See Montana v. United States,
C. Rawl’s Waiver of Defenses
Rawl next complains of the District Court’s holding that Rawl waived several affirmative defenses by not raising them in opposition to the Trustees’ motion for summary judgment.
See UMWA 1974-Pension Trust v. Pittston Co.,
In addition, Rawl argues that it did not raise other affirmative defenses at the summary judgment stage because those defenses required discovery to develop. As a general rule, though, the failure to raise an affirmative defense in opposition to a motion for summary judgment constitutes an abandonment of the defense.
See, e.g., Attorney General
of
United States v. Irish People, Inc.,
D.Waiver of Bargaining Rights
Finally, the Coal Companies argue that the Trustees’ interpretation of the evergreen clause cannot have the effect of precluding employers from renegotiating contribution rates because, under
Metropolitan Edison Co. v. NLRB,
As we explained in detail in
Link
Coal, the “waiver” argument misses the distinction between the waiver of a right and the exercise of a right that extends into the future.
V. CONCLUSION
For the reasons set out above, we hold that the District Court properly granted the Trustees’ motion for summary judgment on the issue of liability. The judgment of the District Court is therefore affirmed and the case is remanded.
So ordered.
Notes
. The evergreen clause in the 1981 trust, reprinted in Joint Appendix ("J.A.”) at 967, is exemplary and reads in full:
Any Employer who employed any participant eligible for coverage under, or who received or receives benefits under, the 1950 Pension Plan, or any Employer who was or is *472 required to make, or who has made or makes contributions to the 1950 Pension Plan and Trust, is obligated and required to comply with the terms and conditions of the 1950 Pension Plan and Trust, as amended from time to time, including, but not limited to, making the contributions required under the National Bituminous Coal Wage Agreement of 1978, as amended from time to time, and any successor agreements thereto, including, but not limited to, the National Bituminous Coal Wage Agreement of 1981.
. The defendants that now comprise the Rawl Companies ("Rawl”) were signatory to either the 1978 or 1981 NBCWA or "me too” contracts identical thereto. The defendant PCG Companies ("PCG”) were signatory to the 1978, 1981 and 1984 NBCWAs. It is undisputed that the NBCWAs to which the Coal Companies agreed have now expired.
. The Trustees’ "perpetual obligation” interpretation was advanced in a different context in
Connors v. Link Coal Co.,
.Under the Employee Retirement Income Security Act of 1974 ("ERISA”), 29 U.S.C. §§ 1001 et seq. (1988), as amended by the Multiemployer Pension Plan Amendments Act of 1980 ("MPPAA”), 29 U.S.C. §§ 1381 et seq. (1988), the trustees of multiemployer pension funds may collect "withdrawal liability” from employers who withdraw from the fund. Withdrawal liability typically involves a one-time payment that represents the withdrawing employer’s proportionate share of the trust’s vested liability that is unfunded in order to prevent a later shortfall.
. Section XX(d) of the 1981 NBCWA, reprinted in J.A. at 971, is typical and contains the following language:
During the life of this Agreement, for the periods of time indicated below, each signatory Employer engaged in the production of coal shall contribute to the Trusts referred to in this Article the amounts specified below. ...
(i) Into the 1950 Pension Trust: for the period beginning June 7, 1981, and ending June 6, 1982, 95.0 per ton on each such ton; for the period beginning June 7, 1982, and ending June 6, 1983, $1.11 per ton on each such ton; and for the period beginning June 7, 1983, and ending when this agreement is terminated, $1.11 per ton on each such ton....
. We have no reason to question the propriety of an employer agreeing to be bound to contractual duties beyond the life of a specific collective bargaining agreement.
See Litton Fin. Printing Div. v. NLRB,
— U.S. -, -,
.See Declaration of Donald E. Pierce, Jr., Consultant to the UMWA members of the Benefits Subcommittee of the 1978 negotiations (Feb. 27, 1991), reprinted in J.A. at 563; Declaration of B.M. Shaner, Benefits Subcommittee member during the 1978 negotiations (Mar. 4, 1991), reprinted in J.A. at 587; Declaration of David W. Kempken, Benefits Subcommittee member during the 1978 negotiations (Mar. 5, 1991), reprinted in J.A. at 596; Declaration of K.L. Young, Benefits Subcommittee member during the 1978 negotiations (Mar. 5, 1991), reprinted in J.A. at 619; Declaration of Roger M. Haynes, Chairman of the Benefits Subcommittee for the 1978 negotiations (Mar. 7, 1991), reprinted in J.A. at 639.
.The Coal Companies also make a contextual argument based on changes made to the 1988 NBCWA, reprinted in J.A. at 998, that provide for withdrawal liability in the event that an employer ceases to be obligated to contribute to the trusts. This argument, too, is flawed. First, the language in the 1988 NBCWA creating withdrawal liability only applies if the employer is not otherwise obligated to contribute to the funds (e.g., no new NBCWA is enacted); it does not imply that the drafters of the 1988 agreement understood that employers have the right to terminate their obligations. More fundamentally, the understanding of the drafters of the 1988 NBCWA is immaterial for the purpose of divining the intent of the drafters of the 1978 NBCWA.
. For instance, in
Peles,
the Trustees filed suit against Pelbro Fuel in 1983 for withdrawal liability,
Combs v. Pelbro Fuel, Inc.,
No. 88-1524 (D.D.C. May 27, 1983), and the company was out of business by 1985,
Peles,
. Since the evergreen clause was not litigated in the withdrawal liability cases, it appears that no court has ever concluded that the evergreen clause does not require continuing contributions by signatory employers.
. The Trustees originally sued Rawl in the United States District Court' for the Southern District of West Virginia, See UMWA 1974 Pension Trust v. Rawl Sales & Processing Co., No. 3:90-0890 (S.D.W.Va. filed Sept. 19, 1990). In that suit, the parties filed cross-motions for summary judgment. The District Court, with the agreement of the parties, entered an order staying discovery pending disposition of the summary judgment motions, unless the parties agreed to conduct discovery or unless the court granted permission to conduct discovery for good cause shown. See UMWA 1974 Pension Trust v. Rawl Sales & Processing Co., No. 3:90-0890 (S.D.W.Va. Jan. 24, 1991) (order suspending time frame order pending decision on summary judgment).. Prior to ruling on the motions for summary judgment, the case was transferred by the Judicial Panel on Multidis-trict Litigation to the District of Columbia where it was consolidated with the PCG cases. See In re UMWA Employee Benefit Plans Litigation, No. 886 (J.P.M.L. Dec. 12, 1991) (transfer order). In this District, Rawl filed a motion for oral argument on its pending motion for summary judgment, but did not move for additional discovery. See Memorandum in Support of Rawl’s Motion for Oral Argument (Jan. 2, 1992), reprinted in J.A. at 302.
.
See Konstantinidis
v.
Chen,
