UNDERGROUND DRILLING
Facing the future
Paul Moore reviews news in underground drilling from operating in the most challenging conditions, to rock drill performance and contractor innovation
Increasingly, with deeper mines being developed, the ability to stand up to extreme conditions is paramount in underground drilling. Mechanised drilling rigs made by Mine Master operate in the most challenging mining conditions according to the company, featuring ambient temperatures exceeding 35 ° C and air humidity up to 98 %. The rigs that are used in areas with high salt content watercourses must be fitted with subassemblies featuring a high IP( 67).
“ In such extreme conditions the so called human factor becomes more and more unreliable. Improving the work effectiveness needs to rely on automation and monitoring of the production process. Computer-aided drilling may result in obtaining a better geometry of excavation, and improving the quantity of mined material with a reduction of explosives needed and the level of supportive works.”
Mine Master now offer the following monitoring systems: Basic Monitoring System( BMS), Drilling Monitoring System( DMS), Feeder Guiding System( FGS), Bolt Counting System( BCS) and semi-automatic and fullautomatic systems supporting the drilling and bolting process. Each can be upgraded with different functions, according to individual customer needs.
“ The system monitors the work of the machine and gives information about its current condition. It helps to diagnose the problems occurring in different systems in a prompt and very precise way. The on-line connection with the machine allows quick and professional diagnosis without losing time while waiting for qualified services. It contributes to the greater availability of the equipment.”
Face Master 1.7L drilling rigs with the FGS system are operating in Poland’ s KGHM copper operations in the area G-32 of O / ZG of Polkowice-Sieroszowice mine. The mine utilises only rigs with FGS. Six months of results showed significant improvement of mining figures in the following areas: n The increased surface area of each blast [ m 2 ] by 10 % n More ore per one blast [ mega grams / one blast ] by 10 t n Increase in depth by 30 cm n Better geometry of the face n Smother roof( easier to bolt)
Another challenge is to design a drilling machine that can work in permafrost. Such conditions exist in Chukotka, Far East Russia in the Arteli Staratelej Schachter gold mine, where Mine Master delivered six units of the Face Master 1.7D drilling rig.“ These rigs replaced previously used manual drills. In the average
Photo of the face drilled with FM 1.7L with FGS system at the KGHM O / ZG Polkowice- Sieroszowice mine( courtesy of KGHM)
Mine Master Face Master 1.7D on its way to a mine in Chukotka, Far East Russia
temperature from-15 ° C to-10 ° C the drilling process is conducted without water flushing and debris is removed by an using air flushing system.” The achieved results with the new equipment are as follows: n drilling length L = 3.2 m n drilling diameter ø = 45 mm n hole drilling time 25-35 seconds
Besides the reduction of labour costs the client also benefitted from savings on material costs of diesel and energy.
Bolting condition improvements
The underground mining environment is a unique challenge. Roof drilling and bolt installation in underground mining is labour intensive, repetitive and exposes the operator to many hazards that can result in injury. To improve the comfort of the operators, the KGHM O / ZG Rudna mine has been testing the Mine Master bolting rig Roof Master 1.7A with automatic mast developed in co-operation with JH Fletcher in the US. The rig can operate in galleries from 2.5 m height for bolts of 1.6 m and in galleries from 2.7 m height for bolts 1.8 m up to maximum 4 m height.“ The model has a safe and ergonomic cabin, allowing working in extremely difficult conditions and provides excellent visibility. With this rig the operator can install eight bolts without replacing a roof bit( average number of bolts per 1 bit – 9.2 bolts). During the automatic drilling the lifespan of the bit is extended due to the applied tool safety system.”
16 International Mining | june 2017