While a fairly uncom mon sight within the Australian min ing industry, scaling rigs provide an essential function in under ground mining.
In removing unstable slabs of rock hanging from the roof and sidewalls, the machines protect workers and equip ment from potential damage.
However, at a number of mines jumbo drills are utilised for this function instead, bring ing with them the downside of reduced reliability as well as in creased maintenance costs for these machines which are not designed to undertake this work.
In normal operations the walls and backs are scaled back during the bolting process with the face being scaled during the face drilling process.
Cadia East in collabora tion with Atlas Copco has been developing and testing new scaling technology and methods which are designed to make the process safer and more precise.
At the Cadia East mine, bolting is completed after shot creting, which allows for the maximum shotcrete cure time.
Scaling of the walls and backs was completed by a process of hydroscaling where the rock walls are washed down with high pressure water as the first element of the shot crete phase.
The introduction of a scal ing machine such as Atlas Cop co’s Scaletec LC has allowed for the introduction of an addi tional step in the development cycle for a fit for purpose, mechanised scaling machine.
This latest machine adds to a project by providing a ready to go work place for the subsequent cycle compo nents, which include shotcret ing and face drilling.
The Scaletec LC has also allowed for a number of addi tions to the machine in what Atlas has called “softer options” for the high vibration machine.
One of these is the options is a world first, the addition of laser profiler equipment or Total Station Theolodite which will have the ability to scan the tunnel in three dimensions.
This scanning then allows the scaling machine to know where it is within the tunnel and calculate the appropriate volumes and rock dimensions of the tunnel’s section, as well as how the rock may poten tially break when scaled.
The scanner will then allow each heading to be classified as being excavated or not according to the mine design without the use of surveyors.
After being assessed the machine can then carry out the appropriate scaling, and then a heading can proceed with shotcrete, bolts and mesh without the potential issues arising from the face being under excavated.
This system is included in the Scaletec LC which has been updated to provide a fast tramming scaling rig which has a vertical lift of 375mm as well as a 15 degree tilt to provide a greater overview of the working area.
It is expected that this revo lutionary new addition of total station and laser profiler equip ment to scaling rigs can also be installed on drilling jum bos for a number of purposes.
Current predictions see this technology enabling the drilling jumbo to align itself with preci sion in three dimensions within the mine so that it can drill with greater accuracy than it can now with the existing one dimension laser beam.
Application of the three dimensional laser scanning technology for the drills is likely to follow on from the successful use in the Scaletec trials carried out through May this year.