冶金部于1978年11月25日在湖南瑶岗仙钨矿召开了TYZ500型天井牙轮钻机鉴定会。会议期间,代表们听取了长沙矿山研究院、瑶岗仙钨矿、水口山铅锌矿、下垅钨矿关于天井牙轮钻机与钻具的设计、工业试验和使用情况的介绍,并参观了瑶岗仙钨矿、下垅钨矿的试验现场。 TYZ型天井牙轮钻机自1972年开始研制,先后进行了三次改进。自1973年10月至1978 Metallurgy Department on November 25, 1978 held in Hunan Yao Gang cents tungsten TYZ500 type patio roller rig identification. During the meeting, delegates listened to the introduction of the design, industrial tests and usage of the patio roller rigs and drilling tools at the Changsha Mining Research Institute, Yao Gang Xian Tungsten Mine, Shoushoushan Pb-Zn Mine and Xiandao Tungsten Mine and visited Yao Gang cents tungsten mine, the next test tungsten mine site. TYZ-type patio roller rig developed since 1972, has made three improvements. From October 1973 to 1978