The development of the DPIS-1-HD-KRMG3 for narrow-vein mining
During preliminary evaluations of narrow-vein mining operations in Latin America, the engineering team consistently encountered the same assessment: mechanized bolting could not be deployed due to insufficient heading dimensions. Although operators expressed a clear need for the productivity and safety improvements associated with mechanization, the geometric constraints of the headings prevented the use of conventional bolt modules and drifter systems. These conditions shaped the inception of the DPIS-1-HD-KRMG3, a system conceived not by reducing the scale of an existing jumbo, but by reconceptualizing how drilling and bolting systems could be designed to function within extremely restricted profiles.
Rather than beginning with a predetermined carrier and adapting the bolt module to it, Fletcher and Cannon Mining designers reversed the design sequence. They examined the narrowest operational environments and established the minimum feasible envelope for a mechanized bolt installation system. This design approach led to the development of the KRMG3 remote bolt module, the shortest mechanized bolt module available on the market. Its overall length—equivalent to bolt length plus approximately 27 inches—was achieved by structuring the system around the compact HV32 hydraulic percussive drill. The HV32’s notably short body permitted the mast, travel mechanism, and housing to collapse into an exceptionally small footprint. When integrated with the Fletcher N3016-AD/E carrier (five feet and four inches in width) and the Cannon DPIN carrier (five feet and 11.5 inches in width), the resulting platforms could access headings that had previously been inaccessible to mechanized support equipment.
However, minimizing system dimensions alone did not resolve the operational challenges. Narrow headings inherently increase the impact of misalignment, vibration, and off-axis loading, causing minor collar deviations to become significant errors over the course of a six- to eight-foot bolt hole. To address this, the engineering team incorporated several precision-oriented mechanical features into the module. These included 18 inches of independent crowd on each mast, variable feed rate capability suitable for hard-rock conditions, a hydraulic stinger for module stabilization, and centrally aligned drill-steel paths designed to preserve bushing and seal integrity. Collectively, these measures allowed operators to achieve accurate collaring and drilling in environments where handheld equipment had historically been the only practical solution.
Selection of the drifter was equally consequential. The engineering team chose to support both the Fletcher HV32 and Cannon CH32 drifters, designing the KRMG3 so either unit could power both the drilling and bolt-feed functions. This design decision reduced inventory requirements, simplified training, and lowered maintenance complexity. The HV32 provided an additional advantage: its compact form factor reduced overall module length and operates without nitrogen accumulators, eliminating a common cause of vibration surges, rebuild-related downtime, and additional maintenance expense. Operator feedback substantiated these benefits, citing strong hammer durability, favourable bit and steel life, and consistently stable performance in hard-rock drilling conditions.
Upon returning to the narrow-vein operations that had originally deemed mechanized bolting infeasible, the engineering team demonstrated that the DPIS-1-HD-KRMG3 could enter, drill, and bolt within the available heading dimensions without modification. The system effectively introduced mechanized support into areas previously limited to handheld practices, expanded mechanization opportunities within the LATAM narrow-vein market, and delivered improved safety and control without compromising precision or penetration rate.
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