Performance of a 7.6m diameter full-face tunnel-boring machine designed for a Canadian coal mine.

In driving the haulageways for the new Donkin-Morien mine, a number of design criteria were specified for the construction of a 7.6m diameter rock tunnel-boring machine. The deposit is situated off shore beneath the Atlantic Ocean and the equipment is required to negotiate gradients from -20% to near horizontal and to be readily removed from the tunnel. Varying rock compressive strength (10 to 100MPa) requires that the machine be designed to use disc cutters in the hard rock and rippers in the very soft rock. The resulting machine is a full-face, fully shielded design, which can be dismantled within a tunnel cut by itself and reassembled in a similar chamber. Disc cutters or rippers can be employed as dictated by the rock conditions. All cutter and bit changes are effected from within the machine. The tunnel support, with use of steel ribs, thrust beams and wire mesh, is also assembled within the safety of the machine shield. In mining on the 20% decline, through competent sandstone, rates of 1.8m/hour and overall average progress of 1m/hour have been achieved.
In driving the haulageways for the new Donkin-Morien mine, a number of design criteria were specified for the construction of a 7.6m diameter rock tunnel-boring machine. The deposit is situated off shore beneath the Atlantic Ocean and the equipment is required to negotiate gradients from -20% to near horizontal and to be readily removed from the tunnel. Varying rock compressive strength (10 to 100MPa) requires that the machine be designed to use disc cutters in the hard rock and rippers in the very soft rock. The resulting machine is a full-face, fully shielded design, which can be dismantled within a tunnel cut by itself and reassembled in a similar chamber. Disc cutters or rippers can be employed as dictated by the rock conditions. All cutter and bit changes are effected from within the machine. The tunnel support, with use of steel ribs, thrust beams and wire mesh, is also assembled within the safety of the machine shield. In mining on the 20% decline, through competent sandstone, rates of 1.8m/hour and overall average progress of 1m/hour have been achieved.