sitting in place of MR. JUSTICE BOTTOMLY, delivered the Opinion of the Court.
This is an appeal from a judgment of the district court of the fourteenth judicial district, Musselshell County, denying compensation to appellant herein under the Workmen’s Compensation Act.
Appellant Philip Bender filed his written claim for compensation with the Industrial Accident Board on July 17, 1957, claiming permanent total disability as a result of an alleged industrial accident occurring on January 30, 1957. Appellant, a helper on a joy loader in the respondent’s coal mine in Roundup, Montana, claimed that while attempting to remove some rock from the coal, a piece of the rock broke off causing him to slip and fall on his back, thereby wrenching and injuring it. Appellant further claimed that from five to seven days after the alleged accident when he went to pick up his paycheck he *308informed an employee of respondent, one Sid Clark, of the accident and injury.
Thereafter appellant Bender filed a formal petition with the Industrial Accident Board requesting a hearing on his claim, and on May 6, 1958, such hearing was held by the Industrial Accident Board at Billings, Montana, before Robert F. Swan-berg, Chairman of the Board. On April 6, 1959, the Board entered its findings of fact, conclusions of law and order denying compensation.
Appellant’s application for rehearing before the Board being denied, appeal was taken to the district court of the fourteenth judicial district, Musselshell County, and came on for hearing at which time additional testimony was taken by the district court. Upon this testimony and the certified transcript of the proceedings before the Board, the district court upheld the Board’s findings and order, and entered judgment denying and dismissing appellant’s claim for compensation.
Both the district court and the Board held that appellant had not complied with the provisions of section 92-807, R.C.M. 1917, in. that he did not give written notice of the alleged accidental injury within 30 days thereafter, and that there was no actual knowledge of the claimed accident and injury on the part of the employer.
Section 92-807, at the time of the alleged accidental injury, provided as follows:
“No claims to recover compensation under this act for injuries not resulting in death shall be maintained unless, within thirty days after the occurrence of the accident which is claimed to have caused the-injury, notice in writing, stating the name and address of the person injured, the time and place where the accident occurred, and the nature of the injury, and signed by the person injured, or someone in his behalf, shall be served upon the employer or the insurer, except as otherwise provided in section 92-602; provided, however, that actual knowledge of such accident and injury on the part of such employer or his *309managing agent or superintendent in charge of the work upon which the injured employee was engaged at the time of the injury shall be equivalent to such service.”
The provisions of section 92-807 are mandatory and compliance with its requirements is indispensable to maintaining a claim for compensation under the Workmen’s Compensation Act. Maki v. Anaconda Copper Mining Co., 87 Mont. 314, 287 P. 170; State ex rel. Magelo v. Industrial Accident Board, 102 Mont. 455, 59 P.2d 785; Dean v. Anaconda Co., 135 Mont. 13, 335 P.2d 854.
Appellant admitted in his testimony before the Industrial Accident Board, and it is conceded by counsel for both parties, that no notice in writing of the alleged accident and injury within 30 days thereof was given to the employer. Thus the question before the Board and the district court was whether the employer, his managing agent or superintendent in charge of the work on which appellant was engaged at the time of his alleged injury, had actual knowledge of the accident and injury. Both the Board and the district court answered this question in the negative and all specifications of error are based on this finding.
A review of the record indicates that appellant Bender testified that a few days after the alleged accident he told one Sid Clark, an employee of respondent, that he had had an accident in the mine, hurt his hack and had been in the hospital. Appellant’s testimony in this regard was corroborated by his wife. Sid Clark testified that he had no recollection of any such statements being made to him by appellant, that if appellant had made such statements to him he would have referred appellant to his foreman and that he had no recollection of referring appellant to his foreman.
This court has previously held that the testimony of a witness that he does not remember whether a certain event or conversation took place does not contradict positive testimony that such event or conversation did take place. Lasby v. Bur*310gess, 88 Mont. 49, 289 P. 1028; Lindblom v. Employers’ Liability Assurance Corp., 88 Mont. 488, 295 P. 1007; Blaser v. Clinton Irrig. Dist., 100 Mont. 459, 53 P.2d 1141; In re Nelson, 103 Mont. 43, 60 P.2d 365. Thus we have the uncontradicted positive testimony of appellant and his wife that Sid Clark had actual knowledge of appellant’s accident and injury within a week after it is claimed to have occurred.
But it does not follow that the trial court in all cases is bound by the positive and uncontradicted testimony of a witness. While it is undoubtedly the general rule that a trial court may not disregard and reject uncontroverted credible evidence (State ex rel. Nagle v. Naughton, 103 Mont. 306, 63 P.2d 123; Higby v. Hooper, 124 Mont. 331, 221 P.2d 1043; In re Minder’s Estate, 128 Mont. 1, 270 P.2d 404, 45 A.L.R.2d 898), the credibility of the witness and the weight to be given his testimony are questions to be determined by the trial court even though the witness’ testimony is not directly controverted by other verbal testimony. For a discussion of this rule and its various ramifications see 8 A.L.R. 796; 20 Am.Jur., Evidence, § 1180, p. 1030; 32 C.J.S. Evidence § .1038, pp. 1093-1094; O’Sullivan v. Simpson, 123 Mont. 314, 212 P.2d 435.
It is well-settled that in appeals under the Workmen’s Compensation Act, the Supreme Court must affirm the findings of the Industrial Accident Board and the district court if the evidence is sufficient to sustain their findings. Landeen v. Toole County Refining Co., 85 Mont. 41, 277 P. 615; Nigretto v. Industrial Accident Fund, 111 Mont. 83, 106 P.2d 178; Morgan v. Industrial Accident Board, 133 Mont. 254, 321 P.2d 232; Birnie v. United States Gypsum Co., 134 Mont. 39, 328 P.2d 133; Dean v. Anaconda Co., supra.
Is there sufficient evidence in the record to sustain the findings of the Industrial Accident Board and the district court that neither the employer, his managing agent, nor superintendent in charge of the work had actual knowledge of an acci*311dent and injury to appellant? "We believe there is. The following undisputed facts appear in the record:
(1) That on the night of the alleged accident, appellant went home without complaint to his foreman or anyone else in authority at the mine.
(2) The foreman’s absentee report shows absence due to “illness” and not to “accident”.
(3) That during the five days that appellant was hospitalized, appellant at no time indicated to his attending physician that he had suffered any accidental injury.
(4) That appellant’s medical and hospital expenses were paid by the United Mine Workers who do not pay such expenses in Workmen’s Compensation cases.
(5) That when appellant returned to work at the mine after the alleged accident, he handed the foreman a medical slip> from his doctor stating he was now able to return to work and that he had been “ill”, and at that time appellant did not indicate to the foreman he had suffered any injury.
(6) That after appellant returned to work he worked regularly and continuously at the mine for about two and one-half months without any complaint of accidental injury until he was laid off along with 50 to 60 other miners due to a reduction in the work force.
(7) That the first written claim of any accidental injury to appellant was some five and one-half months after the alleged accident, and approximately one month before his unemployment compensation benefits ceased.
Further, there are direct contradictions of parts of appellant’s testimony. Appellant testified that after the accident he rode out of the mine in one of the mine cars with a group of other miners, that he didn’t see his foreman either in the mine or above the ground after the accident, and that the only person connected with the mine that he ever told about the accident was Sid Clark when he returned several days later to pick up his paycheck. His own foreman testified that he saw appellant and *312checked him out as he came out of the mine after the alleged accident, and that appellant didn’t say a thing about any accidental injury. Appellant also testified that he had no back trouble prior to the alleged accident, but Dr. Berg’s letter which was admitted in evidence indicates that appellant told him that he had back trouble for two years prior to the alleged accident.
In addition it must be pointed out that appellant and his wife had a direct pecuniary interest in the outcome of the claim and were in serious financial straits at the time of the hearing. Also the Board had an opportunity to observe their appearance, demeanor and manner of testifying which we do not have.
The credibility of the witness and the weight to be given his testimony is exclusively for the trier of the facts. Dean v. Anaconda Co., supra; Rentfro v. Dettwiler, 95 Mont. 391, 26 P.2d 992; Wallace v. Wallace, 85 Mont. 492, 279 P. 374, 66 A.L.R. 587; Bowen v. Webb, 37 Mont. 479, 97 P. 839. We cannot say that the Industrial Accident Board and the trial court were not justified in disregarding and rejecting the testimony of appellant and his wife on this basis after viewing, testing and comparing such testimony with the undisputed facts and the contradictions in the evidence set out above. When so viewed a substantial doubt is cast upon their testimony which was resolved against them by the Board and the district court. In this we find no error.
There is yet another reason why appellant cannot prevail. Section 92-807 provides that actual knowledge of the accident and injury by the employer, sufficient to excuse the filing of written notice by the injured workman must be knowledge ‘ ‘ on the part of such employer or his managing agent or superintendent in charge of the work upon which the injured employee was engaged at the time of injury”. Was Sid Clark the employer, the managing agent of the employer or the superintendent in charge of the work upon which appellant was engaged at the time of the alleged injury? The following uncontradicted evidence appears in the record:
*313(1) Sid Clark was not an officer or stockholder of respondent corporation and had no interest of any kind therein.
- (2) Sid Clark was retired, drawing social security benefits and was paid $1,200 per year for advisory services, helping out the office force occasionally and assisting with the book work; that Sid Clark was “an old firehorse” who couldn’t leave the job after-he retired so he went to respondent’s office every day because “it is like going to church or a poolhall or any place else, it is a good place to loaf”.
(3) Sid Clark had no authority to accept accident reports, fill out the forms or anything of that nature.
(4) Joseph Fisher was the managing agent of the employer and Frank Oset, Jr., was the superintendent in charge of the work, i. e., the foreman in the mine, at the time of the alleged accident and injury.
(5) That at the time appellant claims he told Sid Clark about the accident and injury, Sid Clark was paying, assisting and helping in the paymaster’s office and “kind of acting as an assistant to fill in for the assistant secretary-treasurer.”
The purpose of the notice requirement or actual knowledge in lieu thereof is to enable the employer to protect himself by prompt investigation of the claimed accident and prompt treatment of the injury involved with a view toward minimizing its effects by proper medical care. See 2 Larson, Workmen’s Compensation Law, § 78.00, et seq. Thus the only common sense interpretation of that portion of section 92-807, quoted above, is that there must be actual knowledge of the accident and injury on the part of someone in authority in respondent’s business occupying a supervisory status as a representative of the employer, so that in the ordinary course of business, steps will be taken to protect the employer in line with the purpose of the statute. It is clear that Sid Clark did not occupy such status and was not the employer, his managing agent or superintendent in charge of the work upon which appellant was engaged at the time of the alleged injury.
*314The record contains sufficient credible evidence to sustain the findings of the Industrial Accident Board and the district court. Such conclusion renders unnecessary the consideration of other specifications of error.
The judgment of the district court is affirmed.
MR. CHIEF JUSTICE HARRISON and MR. JUSTICE CASTLES concur.