Opinion by
This is an appeal by the Duquesne Light Company (Duquesne) from an order of the Workmen’s Compensation Appeal Board (Board). That order affirmed a referee’s decision which awarded compensation for total disability to Albert Zalar (Claimant). We affirm.
This case has an extended and somewhat complex procedural history and presents the following scenario. Claimant was employed by Duquesne in the bituminous *498coal industry from 1935 until April 28, 1977. With, the exception of the last five years during which Claimant worked in a machine shop near the mine, his entire period of employment with Duquesne was underground in the mines. On July 29, 1977, Claimant filed a Petition for Compensation under Section 108 of The Pennsylvania Workmen’s Compensation Act (Act)1 alleging that he had become totally disabled due to coal miner’s pneumoconiosis caused by his continued exposure to coal dust during his employment with Duquesne. On August 17, 1978, a referee awarded Claimant compensation for total disability. Duquesne appealed that decision to the Board which, on March 22, 1979, set aside the referee’s decision and remanded the case back to the referee for the appointment of an impartial physician. That impartial physician was to examine Claimant and the record, prepare a report, and appear and testify before the referee. Referee Frank Roney appointed Dr. Jerry D. Silverman as the impartial physician, over the objection of Duquesne. Dr. Silverman examined Claimant on October 17, 1979 after which he submitted his report to the referee. On February 22, 1980, the referee entered a decision which again awarded Claimant compensation for total disability to date from July 1, 1977. Duquesne appealed that decision to the Board which, on September 4, 1980, remanded the matter back to the referee for a second time for the purpose of holding an evidentiary hearing. On May 11, 1981, after holding the additional hearings, the referee entered his decision which awarded Claimant compensation for total disability to date from July 1, 1977 and also directed Duquesne to pay the costs of the deposition of the impartial physician. Duquesne appealed that decision to the Board alleging bias on the part of Dr. Silverman as well as *499contesting the evidentiary support for the decision and the imposition of the costs of the deposition of the impartial physician upon it. On June 9, 1983, the Board affirmed the referee’s decision in its entirety and Duquesne filed a timely petition for review with this Court.
In this appeal, Duquesne contends that: (1) the referee erred in his appointment of Dr. Silverman as an impartial physician in light of its evidence of bias; (2) the finding that Claimant is totally disabled as of July 1, 1977 is not supported by substantial evidence; and (3) the referee improperly imposed upon Duquesne the costs of the deposition of the impartial physician. We shall address these issues seriatim.
Duquesne’s allegation of bias on the part of Dr. Silverman to favor workmen’s compensation claimants is based solely upon Duquesne’s listing of the numerous instances in which Dr. Silverman has testified in workmen’s compensation cases, predominantly in favor of the claimants, and that he had testified against Duquesne as a claimant’s expert witness in an unrelated case. We have previously held that an attack on the bias of an expert witness is a matter of credibility which is to be determined solely by the referee. Armco Steel Corp. v. Workmen’s Compensation Appeal Board (Kolar), 60 Pa. Commonwealth Ct. 195, 431 A.2d 363 (1981); Westinghouse Electric Corp. v. Workmen’s Compensation Appeal Board (Bencloski), 41 Pa. Commonwealth Ct. 610, 399 A.2d 1178 (1979). Our review of the record, including the voir dire of Dr. Silverman by Duquesne’s counsel, convinces us that the referee did not abuse his discretion when he appointed Dr. Silverman as an impartial physician in this case. An employer cannot conclusively establish bias on the part of a physician so as to disqualify that physician from being an impartial *500physician appointed under Section 420 of the Act2 in a particular case simply by showing that this physician had testified in numerous unrelated workmen’s compensation cases in the past and the physician’s testimony usually favored the claimants. Cf. Armco Steel Corp. (bias charge against claimant’s expert- witness based upon witnesses’ testimony history of favoring claimants in workmen’s compensation cases rejected as going to credibility). We must, therefore, reject Duquesne’s challenge to the referee’s appointment of Dr. Silverman as an impartial physician.
Duquesne’s next contention is that the referee’s findings as to Claimant’s total disability and the date of that disability are not supported by substantial evidence.3 “Substantial evidence” has been defined as *501such relevant evidence as a reasonable mind might accept as adequate to support a conclusion. Consolidated Edison Co. v. NLRB, 305 U.S. 197 (1938); Norfolk & Western Railway Co. v. Pennsylvania Public Utility Commission, 489 Pa. 109, 413 A.2d 1037 (1980). We are satisfied that the report and deposition of Dr. Silverman contains substantial evidence to support the referee’s finding that Claimant became totally disabled from coal miner’s pneumoconiosis as of June 8, 1977. While Dr. Silverman did not examine the Claimant until October 1979, he had at his disposal the medical reports and history prepared by Dr. Cho in 1977.4 In his deposition, Dr. Silverman refers frequently to Dr. Cho’s 1977 observations to express his medical opinion as to Claimant’s disability. Dr. Silverman also stated that his anthracosilicosis, even in the absence of any other medical problem, would preclude the Claimant from returning to the type of work he performed for Duquesne, or any similar type of employment. Viewing the evidence as a whole, we must reject Duquesne’s challenge to the referee’s findings as to Claimant’s total disability.
We now turn to Duquesne’s final contention which is that the referee erred when he imposed the costs of deposing the impartial physician upon it under Section 440 of the Act.5 Duquesne argues that Section *502420 of the Act6 mandates that all costs associated with an impartial physician are to he paid by the Department of Labor and Industry (Department). This is an incorrect reading of the statute. The second paragraph of Section 420 of the Act reads as follows:
The Board or referee, as the case may be, shall fix the compensation of such physicians, surgeons, and experts, which when so fixed, shall be paid out of the sum appropriated to the Department of Labor and Industry for such purpose. (Emphasis added.)
The statute clearly limits its coverage to the compensation, or fees, paid to impartial physicians appointed under Section 420 for their services7. The costs of transcribing the testimony of such impartial physicians is clearly not compensation to them for services they rendered pursuant to their appointment. Rather, such costs are those normally associated with prosecuting a workmen’s compensation case which are governed by Section 440. Accordingly, the referee and the Board were correct in imposing the cost of deposing Dr. Silverman, $59.00, upon Duquesne.
Having found the referee’s findings supported by substantial evidence, no error of law committed nor constitutional right violated, we shall, therefore, affirm the decision of the Board.
Order
And Now, May 24, 1985, the order of the Workmen’s Compensation Appeal Board at Docket No. A-81495, dated June 9, 1983, is hereby affirmed.
Judge Williams, Jr., did not participate in the decision in this case.