The II3123 face is a lighttype caving face of three-soft coal seam. the roof is cracked, sloughing and roof fall often occur.
前言： 石台煤矿II3123工作面为“三软”煤层轻放工作面，顶板破碎易掉，片帮、冒顶时常发生。
2
The model of choosing and matching light-type equipment and mining technology of top caving face was set up. The better effects of technology and economy were achieved by practices.
通过实践，建立了适合轻型综放设备选型配套及开采工艺的模式，获得了较好的技术经济效果。
3
A new type of photo isolator has been developed by packing light emitting devices with silicon photo negative resistance devices face to face to realize electrical isolation.