Japan, etc. have already implemented the tracking and orientation technology of mining personnel in whole ore, but the cost of this way is very high.

美国、日本等国家的一些煤矿已实现了全矿下井入员的跟踪定位，但这种方式造价非常高。

youdao

S. A., Japan, etc. have already implemented the tracking and orientation technology of mining personnel in whole ore, but the cost of this way is very high.

美国、日本等国家的一些煤矿已实现了全矿下井入员的跟踪定位，但这种方式造价非常高。

youdao