Sandvik DS421 is capable of installing up to 25 meter long cable bolts with several steel strands per hole. The drill rig is provided with an on board cement mixer, cement bag platform and steel strand reel. It is therefore autonomous for more than a shift. The drill rod handling system has a capacity for 19 pieces of 1 ¼” diameter, round MF drill rods. The recommended drill hole size for this application is 51 mm. However alternative hole size can be selected with advice from your local Sandvik contact. The steel strand diameter is normally 15.2 mm, of either plain steel or bulb anchor strand. The bolting operation is performed by a single operator located away from the drilling, grouting and cable installing module (CBH Cable Bolting Head). As all the Sandvik drill rigs based on the NC7 carrier family, the Sandvik DS421 is designed for safety. For example, most of the daily and routine checks are done with both feet on the ground.