The hole must be collared at the right location and maintain the correct alignment, as well as end at the predetermined depth – which may or may not make an allowance for sub-drilling below the required final level.
Modern hole alignment instruments offer greater drilling precision, with automatic depth control and drill feed stop. This leads to less overdrilling, better fragmentation, and the formation of flat benches after blasting, all of which add up to lower drilling and blasting costs. In addition, ground vibration will be minimized, which is particularly important in urban areas.
Dimension stone quarry process
The way an individual quarry is operated can vary enormously. The physical characteristics of the rock mass (how homogeneous it is, and whether there are defined lines of weakness such as regular fracturing or lamination), the size of both the resource and the market for its products, and the financial resources of the operator, all play a role in deciding the quarry design and capacity. In a large-scale operation, the first stage in production is to loosen individual blocks that may contain thousands of cubic meters of material, from quarry benches 10 m or more in height.
Conversely, a small-scale quarry may have a very limited output, produce raw blocks weighing 5–10 t, and have a lower bench height that is suited to available production technology.
Planning ahead results in fewer surprises. The hole angles and the blasting direction are set in the drill plan which is transferred to the rig. When you have drilled according to the drill plan, you can run the information that the rig has gathered to plan the blast.
The Hole Navigation System uses the information and helps you to drill parallel holes to the correct depth. This gives you uniform benches. A well controlled blast results in better fragmentation, which reduces the number of boulders. Fewer boulders mean less secondary breakings.
With good fragmentation, it is easier to fill the loader buckets. Full buckets mean fewer trips to fill the transportation unit. Effectively loaded transportation units, thanks to good fragmentation, mean fewer trips to the crusher.
A quarry is typically defined as being a surface excavation for the production
of rock as the principal product. As such, it differs from an open cast, open-cut,
surface or open-pit mine in that the rock itself is the valuable commodity, rather
than a specific mineral within the rock mass.
The most commonly used commercial stones today include
marble, granite, slate and sandstone, all of which can be
found in a vast array of visual and physical properties. This
is by no means an exhaustive list, however, with rocks such
as limestone, basalt, gabbro, travertine and tufa also widely
used where their properties are suitable.
HNS help the operator to achieve parallell holes to the correct depth.