9781439834220.ch10

Under these conditions the mass of rock cut per unit

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Unformatted text preview: chunks. Under these conditions the mass of rock cut per unit of energy improves dramatically. (a) (b) Comparison of two cutting systems: (a) Milling (auger) type cutter head can mine narrow bands and lenses selectively (b) Ripper type cutter head having 25–30% higher rate of production (c) Total weight 70 t. Total installed power 353 kW. Length – 12.28 m. Min. Height – 2.15 m. Cutting thrust up/down 100 kN. Cutting power 115/230 kW. (Courtesy: Paurat, Germany) Figure 10.1 Roadheaders’ – working principle. © 2005 by Taylor & Francis Group, LLC 238 SURFACE AND UNDERGROUND EXCAVATIONS (a) Bar type (b) Ripper type 2.40 m (c) Milling type 1.50 m (d) Opening’s shape obtained by a partial face tunnel borer Figure 10.2 Roadheaders – some models. Basically a roadheader consists of a cutting unit, a gathering unit and a delivery unit (figs 10.1, 10.2, 10.3, 10.4). This equipment is very mobile and versatile compared with a full face TBM. It can cut a variety of cross sections; change diameters at will, change directions quickly, and move to and from a face...
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This document was uploaded on 02/12/2014.

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