一、卫生学调查简况我公司于1950年恢复生产,1962～1963年为式干凿岩,空气中粉尘浓度高达88～1118毫克/立方米,平均为366毫克/立方米,超过国家最高允许浓度43～588倍。游离二氧化矽含量为15～43%,粉尘分散度<5毫微米占80～97%。于1962年某矿的凿岩工几乎全部患尘肺病,且病情重,进展快。平均发病工龄4.32 First, a brief survey of hygiene I resume production in 1950, 1962 ~ 1963 for the type of dry rock drilling, the air dust concentration as high as 88 ~ 1118 mg / cubic meter, an average of 366 mg / cubic meter, more than the national maximum allowable concentration 43 ~ 588 times. Free silica content of 15 ~ 43%, dust dispersion <5 nm accounted for 80 to 97%. In 1962, almost all the miners in a mine were suffering from pneumoconiosis and were seriously ill and advanced rapidly. The average length of service is 4.32