The Board of Supervisors of Shenango Township (Board of Supervisors or appellant) appeals from an order of the Court of Common Pleas of Lawrence County (Common Pleas), dated May 24,1990, reaffirming its prior opinion and order of January 31, 1990, and dismissing appellant’s motion for post trial relief.
*473McClimans, et al., landowners of parcels of land, together comprising approximately one thousand acres (property), in Shenango Township, Lawrence County, Pennsylvania, executed leases to Amerikohl Land Company (landowners and lessee, hereinafter collectively referred to as appellees) to strip mine coal on their property. The property is zoned R-l Residential. Under the then existing terms of the Shenango Township Zoning Ordinance (zoning ordinance), adopted May 22, 1967 and effective May 27, 1967, surface mining was not a permitted use in an R-l Zone.1
Appellees filed with the Board of Supervisors a challenge to the validity of the zoning ordinance and a request for curative amendment to the zoning ordinance to rezone the property as a special uses district, allowing surface mining as a matter of right. Following a public hearing, the Board of Supervisors by written decision dated March 8, 1985, rejected the validity challenge and denied the request for curative amendment. Appellees appealed to Common Pleas which, by opinion and order dated January 29, 1986, affirmed the Board’s decision. Upon further appeal, this Court in McClimans v. Board of Supervisors of Shenango Township, 107 Pa. Commonwealth Ct. 542, 529 A.2d 562 (1987) (McClimans I), remanded to Common Pleas for the taking of additional evidence or for further remand to the Board of Supervisors “for a determination of whether the Township’s zoning ordinance conclusively [prevented Appellees] from gaining access to their subsurface property, thus rendering the ordinance invalid as a taking without just compensation.” Id., 107 Pa.Commonwealth Ct. at 559, 529 A.2d at 570 (footnote omitted).
The McClimans I Court further stated:
If a ‘taking’ is found to exist, the Township of course has the option of retaining the ordinance as is and paying the owners of the coal estate just compensation. If there is a *474‘taking’ and the Township subsequently amends the ordinance to allow the strip mining, the Township would then be required to pay just compensation for the harm caused to the [appellees] by the ‘temporary taking.’ ... This just compensation would include damages [appellees] could prove as a result of the delay in extracting the coal caused by the Township’s ordinance.
Id,., 107 Pa.Commonwealth Ct. at 558, 529 A.2d at 570 (citation omitted).
On remand, Common Pleas held several hearings on the issue of whether the coal could be extracted from the property without violating the zoning ordinance. Both parties presented expert testimony on the issue. In addition, appellant presented testimony from two lay witnesses who had participated in and were familiar with mining operations in Shenango Township involving the same coal deposit that is the subject of this controversy. Common Pleas resolved credibility in favor of appellees’ experts and concluded that appellees had met their burden of proving by a preponderance of the evidence that the zoning ordinance conclusively prevented them from gaining access to their coal. Therefore, by opinion and order dated January 81, 1990, Common Pleas held that the zoning ordinance effected a taking of appellees’ property without just compensation. On March 9, 1990, Common Pleas granted appellant’s motion for reconsideration; and on May 24, 1990, Common Pleas reaffirmed its prior decision of January 31, 1990 and denied appellant’s motion for post-trial relief. This appeal followed.2
In light of the fact that prior to oral argument the zoning ordinance was amended February 8, 1990, to allow surface mining, this matter would be moot. However, it *475was contended by appellees at oral argument on this matter that they would be entitled to damages for a partial taking for the period of time from which this action was initiated until the amendment of the zoning ordinance. Therefore, we will address the merits.
Appellant presents the following issues for our review: (1) whether Common Pleas erred in applying a preponderance of the evidence standard of proof in determining whether the zoning ordinance conclusively prevented appellees from gaining access to their subsurface property; (2) whether state and federal environmental and safety regulations enacted subsequent to the zoning ordinance prevented appellees from gaming access to their coal estate, rather than the zoning ordinance; and (3) whether the zoning ordinance conclusively prevented appellees from gaining access to their subsurface coal estate.
Where, as here, Common Pleas takes additional evidence, we are limited to determining whether Common Pleas abused its discretion or committed an error of law. Lamb v. Zoning Board of Adjustment of the Borough of Ambridge, 111 Pa.Commonwealth Ct. 534, 534 A.2d 577 (1987). We may conclude that Common Pleas abused its discretion only if its findings are not supported by substantial evidence. Valley View Civic Ass’n v. Zoning Board of Adjustment, 501 Pa. 550, 462 A.2d 637 (1983). Substantial evidence has been defined as “such relevant evidence as a reasonable mind might accept as adequate to support a conclusion.” Id., 501 Pa. at 555, 462 A.2d at 640.
Appellant argues that Common Pleas applied the wrong evidentiary standard in weighing the evidence presented by appellees on the issue of whether they were conclusively prevented from accessing their coal estate. Common Pleas adequately addressed this issue in both its January 31, 1990 and May 24, 1990 opinions. Common Pleas correctly noted that although the courts have characterized the burden in these matters as a heavy one, there is no case law suggesting that proof by more than a prepon*476derance of the evidence is required. Although use of the word “conclusively” in McClimans I3 has apparently created some confusion, we emphasize that “conclusively” merely describes that which must be proven, while preponderance of the evidence refers to the standard or degree of persuasion which must be achieved. Therefore, we hold Common Pleas committed no error in applying that standard.
Appellant’s next contention, that “State and Federal regulations prevented the Appellees from gaining access to their coal estate by deep mining, rather than Appellant’s Ordinance,” is without merit. First, appellant’s brief is devoid of any specific citation to any such state or federal regulations. We can only presume that this argument is the same one that was presented below as to whether portions of the Township’s zoning ordinance which regulate surface mining have been superseded by the Surface Mining Conservation and Reclamation Act (SMCRA), Act of May 31, 1945, P.L. 1198, as amended, 52 P.S. §§ 1396.1-1396.31 and are, therefore, void. Both the Board of Supervisors and this Court on appeal in McClimans I correctly determined that SMCRA “did not supersede the portions of the Township’s zoning ordinances which deal with strip mining.” McClimans I, 107 Pa.Commonwealth Ct. at 551, 529 A.2d at 567.
Lastly, appellant argues that appellees have failed to meet their burden of proving that the zoning ordinance conclusively prevented them access to their coal estate. Appellant maintains that because it presented evidence to show that appellees could reach the coal by underground mining, that there had been no taking.
This Court stated in McClimans I that:
[i]n order to be a ‘taking’ of the coal estate, the coal’s exclusion must be conclusively prevented by the zoning *477ordinance. In Mutual Supply Co. Appeal,[4] the Pennsylvania Supreme Court even went so far as to say that if underground mining can be accomplished at all, even if the surface opening for the mine is only available in another municipality, the fact that mining operations are not permitted and/or feasible in the municipality whose ordinance is being attacked does not constitute a ‘taking.’
Id., 107 Pa.Commonwealth Ct. at 557-58, 529 A.2d at 569-70. The court in Mutual Supply Co. Appeal, stated that the mere fact that access to coal available through other means was more expensive and less convenient did not support a conclusion that the zoning ordinance’s exclusion of industrial use on the surface estate conclusively prevented the company from mining and removing its coal.
Appellant is interpreting these cases as standing for the proposition that any evidence it presents to show that the coal can be accessed through underground mining is sufficient to defeat appellees’ burden. The fact finder in zoning matters, herein Common Pleas, is the arbiter of credibility and may reject the testimony of an expert witness. We will not disturb those findings on appeal except where there has been an abuse of discretion. Berman v. Manchester Township Zoning Hearing Board, 115 Pa.Commonwealth Ct. 339, 540 A.2d 8 (1988), petition for allowance of appeal denied, 520 Pa. 619, 554 A.2d 511 (1989). Following a thorough review of the testimony presented before Common Pleas, we can find no abuse of discretion in Common Pleas credibility determination in favor of appellees’ expert. Further, we conclude that Common Pleas’ findings are supported by substantial, competent evidence of record.
Accordingly, we affirm the opinion and order of Common Pleas.5
*478ORDER
AND NOW, this 25th day of September, 1991, the opinion and order of the Court of Common Pleas of Lawrence County is affirmed.
. We note here that the Shenango Township Zoning Ordinance was amended February 8, 1990, to allow surface mining on the subject property of which this Court takes judicial notice.
.- Motions for Allowance to File Amicus Curiae Briefs Nunc Pro Tunc filed by the Pennsylvania Coal Association in support of appellees’ position and by the Pennsylvania State Association of Township Supervisors in support of appellant’s position were granted by this Court. Subsequently, by order of this Court dated January 8, 1991, a Motion to Quash was granted in part, thereby striking "pages 5 and 7 through 20” from the Pennsylvania State Association of Township Supervisors’ amicus curiae brief.
. See also Mutual Supply Company Appeal, 366 Pa. 424, 77 A.2d 612 (Pa.1951) and G.M.P. Land Company v. Hegins Township Board of Supervisors, 72 Pa.Commonwealth Ct. 591, 457 A.2d 989 (1983), wherein the same terminology is used.
4. 366 Pa. 424, 77 A.2d 612 (1951).
. By this opinion, we are not holding that appellees are entitled to monetary damages. Furthermore, any claim for monetary damages is not properly before this Court and must be pursued under the provisions of the Eminent Domain Code, Act of June 22, 1964, Sp. *478Sess., P.L. 84, as amended, 26 P.S. §§ 1-101 — 1-903. See also McClimans I, 107 Pa.Commonwealth Ct. at 559 n. 5, 529 A.2d at 570 n. 5.