WorldWide Drilling Resource

18 JULY 2022 WorldWide Drilling Resource® SERVING THE CONSTRUCTION INDUSTRY Serving the Drilling Industry 257 Caroline Street Punxsutawney, PA 15767 800-927-0560 • 814-427-2555 Fax: 814-427-5164 Booth 812 Boxhole Boring Machines at Work in Chile Adapted from Information by DMC Mining Services and Herrenknecht DMC Mining Services Chile recently expanded its fleet by adding a fifth boxhole boring machine (BBM). This latest version of BBM-1500 equipment incorporates modern elements of innovation and technology. Based on DMC’s previous experience operating four boxhole machines since 2019, the newly designed BBM-1500 MI-052 offers multiple improvements. Due to its compact design, the BBM can be used under space constraints in gold, copper, and other underground ore mines. Applications include excavating ventilation shafts and creating ore passes for conveyance from production levels to transport levels. BBM technology was developed by Herrenknecht for the rapid and safe construction of vertical and inclined raises or shafts, also known as slot holes. It can be used in stable rock formations and enables drilling diameters up to about six feet with a maximum drilling length of approximately 229 feet. Additionally, it has navigation cylinders which monitor the direction of excavation, minimize deviations, and allow excavation at angles up to 60 degrees. The BBM concept is based on pipe jacking technology. A drilling unit at the head of the pipe string is pressed forward from the launch point. Jacking pipes are installed one after the other in the pipe string and pushed forward, lengthening the jacking route. A cutterhead excavates rock at the tunnel face, which then falls through the center of the rig due to gravity. The removed material is transferred to a muck chute at the jacking frame through channels introduced into the jacking pipes. From there, the material can be transported out of the tunnel. After each jacking stroke, the drilling process is stopped for a short time to secure the pipe string and drilling unit; then, the next jacking pipe can be installed in the jacking frame. When the desired drilling length is reached, the drilling unit is retracted. Jacking pipes are removed one by one until the complete pipe string is dismantled and the drilling unit has returned to the jacking frame. The BBM can then be quickly moved to the next drilling location by a crawler. This mobility advantage, along with high excavation performance, helps to significantly reduce time required per completed raise or shaft. DMC’s boxhole equipment is a unique part of Chile’s mine operations. It has safely developed 16 chimneys and one shaft with full mechanized shielding, and looks to create more in the future. MIN