S e c t i o n 1 - P a g e 1 0 May 2013 the placement and spacing of bolts. T or que measur ements can be r ecor ded on the wall or plate of the bolt which will permit monitoring of the load on the bolt during the mining cycle. If necessary , bolts can also be r e-tor qued if loss in tension occurs. T or que testing is best done by a cr ew supervisor (or dedicated technician) while visiting work ar eas during his r ounds. Education - Pr oper education of mining personnel and supervisors is mandatory . As manpower tur nover is r elatively fr equent in bolting cr ews, education must be continuous. For get this and you waste money . Packaging - V endors must package bolting pr oducts in an acceptable manner both for con- venience of use as well as pr evention of damage to the pr oduct during shipping and handling. Particular car e must be paid to wrapping of the thr ead ends to pr event damage and corr osion. Good packaging costs mor e but is worth the added cost by r educing wastage on site. continued Installation Quality Guidelines continued Overtor quing - Overtor quing of the bolts must be avoided. With for ged head bolts, the heads can be weakened or shear ed of f. Overtor quing may tension the bolt past it’ s yield point which is undesirable. Undertor quing - Undertor quing can r esult in poor anchorage. Under tensioned bolts ar e particularly susceptible to blasting damage. Bolts will not apply suf fcient compr essive for ce to the gr ound as per design r equir ements. Monitoring - In practice, r ock bolt tension often dr ops after installation. Expansion shells can slip due to blasting vibrations, shells can move as high str ess concentrations along the leaves cause localized failur e of the gr ound, and fnally , the r ock can fail under the plate washer . The installation of any gr ound support system must be monitor ed to ensur e pr oper pr ocedur es and installation quality ar e maintained. For r ock bolts this r equir es verifying tor que and www .dsiundergr ound.com