Achieving rapid development in underground mines
By Shannon Katary
CEMI – Centre for Excellence in Mining Innovation – is now in its 10th year.
It continues to co-ordinate and direct step-change innovation through the strategic areas of exploration, deep mining, mine productivity, underground mine construction and environmental impact. CEMI’s objective is to lead innovation to help generate significant improvements in the performance of mine operations in Ontario, Canada and around the world.
In the last 30 years, advance rates of development headings in underground mines have declined steadily. This decline was driven by two factors: the increased size of access drifts (tunnels) to accommodate larger production equipment and the need for more support to ensure safety and stability. Both of these make the ground control component of the development cycle longer. The result is slower advance rates, increased capital cost, an increase in the time to first production from the new ore-body and a depressed ore-body net present value (NPV).
Phase 1: Mine Development Canopy System
The Mine Development Canopy System (MDCS) is the first phase of CEMI’s strategic project on rapid development in underground mines. The primary goal of the Rapid Development Project is to reduce the time to first production in new underground ore-bodies and reduce overall mining cost by increasing the effective utilization of the face, not the utilization of the equipment. In addition, it improves safety and productivity. CEMI’s MDCS provides a physical barrier to the rock-related hazards in development headings in high-stress conditions, enabling simultaneous activities in the heading and effectively reducing the development cycle time. Current drift development practice generally involves four sequential activities: removal of blasted rock (mucking), installation of the ground control system (bolting), drilling the face holes and charging them with explosives. This four-stage sequence of activities requires the re-entry of four pieces of equipment, and critical time is often lost between the re-entries. No face activity can be carried out until the ground control is complete and in some cases, support has to be installed on the face of each heading after each blast. This increases the duration of the development cycle and further reduces the advance rate.
The robust, engineered, movable canopy can be brought into the development heading to protect personnel and equipment from rock falls and rock-bursts and allow simultaneous activities in the heading. The MDCS is comprised of three individual canopies. The front canopy, with a face shield when necessary, will protect the face drills and the drill carrier from rock-related hazards and allow equipment to return to the face as soon as the mucking cycle is complete.
The canopy is designed to allow for the necessary lookout to drill the wall and roof control holes. The back canopy protects the equipment and operators and allows ground support activity to be completed while the face is being drilled and charged. The middle canopy protects workers as they travel between the front and back canopies.
CEMI has developed the MDCS for single-heading lateral development. Functionality and strength tests have been performed on prototypes both above and underground. Nordic Minesteel Technology (NMT) of North Bay, Ont., has been involved with the design and testing of the system components. The System is in the final stages of pre-commercialization, undergoing operational field testing, to be completed in 2017. NMT will construct commercial units and will market the MDCS to the mining industry.