炭鉱における防じん対策の研究

抄録

1) On the counter-measure against dust hazards in coal mines, not only dust from rock but mixed dust must be considered.
2) In case of rock driving, complete wet system throughout the course of driving is very effective to prevent dust hazard. When the distance between driving surface and the aperture of air duct is not more than 7m, the preventive effect is remarkable. These mean that dust concentration of working environment can be controlled less than maximum allowable concentration with the employment of respirator under the preventive measures above-mentioned. The prevalence of pneumoconiosis can be cut down to about 3% under this condition.
3) In case of seam driving, the type of driving is not wet one. The dustiness, however, is much lower than in case of rock driving. Therefore, the incidence of pneumoconiosis is found as 3% in the period of 10.11 years of work.
4) In case of “stall”, if the complete wet system can be employed the dust concentration could be contrlled under the level suggested as maximum allowable limit. However, the satisfactory wet stalling of coal surface is practically not easy to carry out, so that, the prevention of pneumoconiosis is found being rather difficult with 4.5% of the incidence of the disease in the period of 12 years of work.
5) Ventilation is understood very effective and important measure against dustiness. The prevention of leak of ventilation system and the determination of appropriate velocity and volume of air used should he considered in addition to the abolition of serial ventilation system.