S e c t i o n 1 0 - P a g e 1 5 May 2013 Star Plates For general use (may r equir e spherical seat washer) • special grade deep draw steel • 25 ton capacity • A = 6 " diameter • B = only 3 / 16 " thick • C = 1 " diameter • weighs only 1.6 lbs (730 g) Star Plate Specications The most important featur es of any r oof plate ar e stif fness, yield str ength and ar ea of contact with the r ock, especially under high loads. To determine these parameters the DSI Resear ch and Development team have developed a testing method which very closely simulates under gr ound coal mining conditions. Figure 1 illustrates the performance of the new Star Plate (and compar es it with other common r oof plates) for conditions commonly encounter ed in Australian under gr ound coal mines. The Star Plate yield load is close to the yield str ength of the most widely used AX type bolt. Apart fr om the high str ength of the Star Plate (despite its r elatively thin plate thickness of 5mm) it has the additional advantage of pr oviding a lar ger bearing ar ea when heavily loaded as shown in Figure 2 . The Star Plate is a further example of DSI Resear ch and Development T eam’ s world leading technology in Strata Reinfor cement Pr oducts, that seeks safe, cost-ef fective solutions for the under gr ound mining industry . * 150X150X8mm Domed Plate Figure 2: Plates under heavy load. Figure 1: T ypical Load vs. Displacement characteristics of ST AR PLA TE used with wir e mesh compar ed with two conventional domed plates tested on a at surface of medium str ength bed of 25-30Mpa compr essive str ength. * 150X150X10mm Domed Plate * 150X5mm Star Plate www .dsiundergr ound.com