CAPE TOWN (miningweekly.com) – JSE-listed Master Drilling has launched its new South African-developed mobile tunnel boring system, which is suitable for the excavation of various types of tunnels.
Master Drilling executive director Koos Jordaan explained at the unveiling of the system at the Investing in African Mining Indaba, in Cape Town, on Tuesday, that Master Drilling had conceptualised the machine to be novel and has patented it internationally.
The company collaborated with Italy’s Seli Technologies on the development of the system.
Notably, the system has “the potential of exponential production rates, giving mining owners the ability to access underground orebodies faster and with higher returns”.
Further, the system allows for continuous operation, with full-face cutting, as well as simultaneous rock support and material handling. The nonexplosive process also increases face time.
The cutting principle of the system is based on conventional tunnel boring, thereby reducing the conceptual risk of hard rock cutting methods.
Further, the system is flexible for different types of infrastructure and will be used in operations with different mining methods.
The system’s equipment will be available in a modular configuration, which increases the mobility and reduces the complexity of design and maintenance.
The system includes 17’’ disc cutters, backloading cutters, a 1 m advanced stroke, a finger shield, a probe drill and a support drill.
Features include an onboard dry dust scrubber, a ventilation extension cartridge, and 1 300 kW installed power, as well as a 1 500 kVA onboard transformer, a 14 m3 bunker capacity, a cutter head and shield assembled in a starting frame, and positioned by a 15 t capacity wheel loader with manipulator attachments for placing.
The system also has a 20 t to 30 t capacity dumper truck capability.
The mobile tunnel boring system in the 5.5 m diameter configuration, is 31 m long and weighs 300 t. Together with the bunker unit, it allows for seamless production while trucks are switched to load and provides material handling through the inclines, turns and breakaways to the point of discharge, which eliminates secondary material handling.
The smaller and shorter 4.5 m diameter configuration of the system, which is 23 m long and weighs 240 t, is used for reef drives and contact tunnels that are often used on sublevel caving, block caving and steep shallow dipping narrow-vein mining.
Manufacturing of the system is currently under way, with Jordaan noting that the group aims to commission the system in the third quarter of this year and to have it operational at a project by the fourth quarter of this year.