A contract was placed for the construction of a 7.6 m- diameter rock tunnel boring machine. Disk cutters or rippers can be employed as dictated by the rock conditions. All cutter changes are effected from within the machine. The first 1.5 km of a 14.5 km tunnel with a 20% decline were completed at the Donkin-Morien Mine, Nova Scotia. The average rate of advance of the machine was 1.8 m/h and its usage has been quite satisfactory.
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机译：签订了建造7.6 m直径岩石隧道掘进机的合同。根据岩石条件，可以使用圆盘切割机或裂土器。所有切刀更换均在机器内部进行。新斯科舍省Donkin-Morien矿完成了14.5公里隧道的前1.5公里，下降了20％。机器的平均前进速度为1.8 m / h，使用情况令人满意。
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