The sizes of cross-section are related to the drivage costs , maintenance costs and ventilation electric costs .

井巷断面大小直接关系到掘进费、维护费和通风电费。

Stress is laid on analyais of main factors affectomg development of roadheaders in china , and problems existing in the fields of integration of drivage and bolting , randomized water-spraying dust suppression , improvement of hydraulic system and operating reliability of medium aed small-sized roadhead ers .

本文着重分析了国内影响掘进机生产发展的主要因素，总结了国内掘进机掘错一体化、喷雾降尘设备随机化、完善液压系统和进一步提高中小型机可靠性等问题。