here rests upon the plaintiff to prove that she was the widow of the deceased and dependent upon him at the time of his death, that she has not remarried, that he was entitled to benefits at the time of his death or that he died before January 1, 1974, due to pneumoconiosis or was at that time totally disabled due to pneumoconiosis. 30 U.S.C. § 921(a); 20 C.F.R. 410.210. It is undisputed that plaintiff was the decedent's widow and dependent upon him at the time of his death, that he died prior to January 1, 1974, and, therefore, was not entitled to benefits at the time of his death. It is also undisputed that the decedent's death was not the result of pneumoconiosis. According to the death certificate he died at work on November 13, 1944, as a result of a pulmonary thrombosis. True, the death certificate was prepared and signed by a coroner who was not a physician. However, it is the only evidence as to the cause of death. The decedent was never the subject of lung studies either at or prior to the time of his death.
Although obviously suffering for years from the symptoms of pneumoconiosis and/or anthracosilicosis, otherwise described as "black lung", a condition resulting from almost fifty (50) years' employment in the anthracite mines, he did not, according to the best and only evidence of record, die from that condition, but rather suffered a sudden death in the mines as a result of a pulmonary thrombosis. That he obviously suffered a pneumoconiosis does not establish that he suffered a "complicated" pneumoconiosis and, accordingly, the plaintiff can only prevail by establishing that the decedent, at the time of his death, was totally disabled from pneumoconiosis or a respirable disease presumed to be pneumoconiosis.
Thus, we are brought face to face with the crucial issue in this case -- was the decedent totally disabled at the time of his death. The record clearly establishes that he worked with regularity until the date of his death when he died in the mines as the result of an embolism. The plaintiff testified:
"Q. Well, he passed away, on November 13, 1944, according to the death certificate. That was a pretty busy period. That was during the war. The mines was relevantly busy at the time.