S e c t i o n 1 3 - P a g e 7 May 2013 VTS Pr ops The Salzgitter Hydraulic Pr ops, now pr oduced by VTS and marketed in North America by DSI Under gr ound Systems Inc., of fer safety on the face. They can be easily maintained and operated, and, accor ding to the r equir ements and depending on the pr op type, r eadily extended with slip-on extension pieces. The VTS Pr ops ar e set by hydraulic pr essur e pump and fed into the setting gun via a setting line installed in the face. The setting gun will be put on the flling valve of the pr op, mechanically secur ed with a one-hand locking mechanism, and operated by one hand. The pr essur e ows thr ough the setting gun and flling valve into the interior of the pr op and causes the inter nal pr op and the piston to telescope. After having been set against the support (articulated bar) the pr op is braced with the setting for ce existing in the setting line, thus immediately supporting the r oof. Due to the r ock pr essur e the pr op can now be loaded till the set pr essur e on the operating valve will have been r eached. If the nominal pr essur e is r eached, the operating valve will open and some hydraulic uid will be sprayed of f till a pr essur e spring will close the operating valve again. Thispr ocess r epeats itself every time the nominal pr essur e is r eached. Thus, the pr op r emains always pr otected fr om overload by the r ock pr essur e. Lar ge lifting heights permit a lar ge range of conver gences. Due to the possible extensions accor ding to the pr op types, the pr op length can be r eadily adapted under gr ound to the changes of the face heights. The pr op can be withdrawn with a r eleasing key that — extended by means of a r ope or a chain — actuates the r eleasing valve fr om a safe place of the miner and lets the hydraulic uid escape fr om the cylinder . An installed r etur n spring rapidly r etracts the inter nal pr op. Her ewith, the pr op is r eady for use again for a new setting operation. continued www .dsiundergr ound.com