Shield support systems are used in longwall faces under all kinds of geological and mining conditions. For each application, widely varying, extreme boundary conditions like flat, sloped or steep stratification, small or large seam thickness, brittle and loose hanging walls or massive sandstone strata, soft or expanding footwalls, large hanging wall bursts or existing geological faults inevitably lead to a customised adaptation of the shield support system.
Various shield support systems are available in two system widths, 1.5 m and 1.75 m, for adjustment areas from 0.8 to 4.7 m and support resistance forces up to 17,500 kN. Applications in steep stratifications up to 35°, but also in parallel or inclined driving operations up to ±20°, have already been successfully realised. Proof can be provided as a reference. According to the type and structure of the hanging wall and depending on the type of coal extraction, three different cap types exist, each with their own clear advantages according to application.
In the case of the high-performance shield-type support used today in international underground bituminous coal mining, two hydraulic props with double or triple strokes with up to 3,540 kN setting force are used. Tested and certified shock valves guarantee the maximum degree of safety according to customer desire and public regulations. Hydraulic or electro-hydraulic control systems are used as the hydraulic control system in coordination with the user.
In the development of the shield support systems, the latest 3D CAD technology has been used in combination with today's commonly used fine element analysis (FEA) for the dimensioning of components. The large-scale welding certificate according to EN ISO 3834 is the basic requirement for certified welded constructions manufactured at high quality. Independent testing institutes provide for inspection, approval and certification according to international standards including tests for changes in the permanent load and overload tests, as well as complex testing programs for the hydraulic prop.
Becker has many years experience in the manufacture of supports for a variety of mine haulage and tunnel applications. TH steel arches offer simple installation, balanced statistical values, high carrying capacity and yielding of the segments, a long working life and repeat installation capability.