... .used for in mines,tunnel 3.ISO,SGS,BV.professional factory 4.low price, good quality mining rock bolts(grooved bolt ... Grooved bolt includes 3½ paddle configuration to mprove resin mixing and consequetly provide high bond strength in larger diameter borholes.2 ... galvanized.6. length as your requirements.2, Accessories: different sizes plate, 120mm,150mm,200mm,250mm,300mm square. thickness, 4mm,5mm,6mm ...