The recent increasing trend of the severity and the frequency of the explosion incidences in the coal mine has been drawing our attention, especially where the demand of the coal production has been increased due to the dim prospect of the petrolium supplied by world market constraints. There has not been reports on the principles of the treatment as well as the prioritization method for the mass drum perforations by explosions. The authors attempted to make a report on the treatment principles based on the experiences treating 57 perforations (48 patients) from a certain coal mine explosion incidence in April 1979 and 37 perforations (34 patients) visited the clinic during May. 1979 through 1980. 1) It was classified in 4 grades according to the perforated drum size. 2) The treatment procedure were developed according to the factors of presence or absence of the foreign body in the middle ear cavity, perilymph fistula, inversion of the perforated margin or hearing gain owing to the patch test and grouped as follows; Group I : Spontaneous healing group which regularly observed and cured by cautery of the perforated margin. Group II : Healing group with paper patch graft. Group III : Healing group with tympanoplasty. Group IV : A group of which tympanoplasty was delayed due to injury of any other organ. A group of which tympanoplasty was equally needed to both perforated drum. A group which was treated by delayed tympanoplasty due to failure of the previous treatment using the method in group I, II, III. 3) Group I includes those of which stated are Grade I in its perforated drum, positive patch test, no foreign body in middle ear cavity, no sign of perilymph fistula and no inversion of perforated drum margin. 4) Group II includes Grade II perforations meeting the Group I criteria. 5) Group III are the Grade III or IV with negative patch test, neither foreign body in the middle cavity, sign of perilymph fistula nor inversion of the perforated drum margin. 6) It was considered that the above described treatment principles were appropriate due to no difference in the result of each group treatment: Group I (90%), Group II (88.8%), Group III (90.5%). 7) Although the larger the perforated drum was, the more healing duration was apt to be delayed, there was no significant difference in cure rates according to degree of the perforated sizes. 8) In prioritization method for mass drum perforation, operation was performed as following order. At first dizzy patient due to perilymph fistula, then C.S.F. otorrhea, foreign body in middle ear cavity, inversion of the perforated drum, ossicle disruption, and the last choice was the simple perforation. The authors concluded that it is quiet approach of a small staffed otolaryngologic clinic to treat mass perforation by the above classification after the accurate microscopic diagnosing.