In modern construction engineering, drilling is an indispensable work. The rotary drilling rig and the down-the-hole drill are the best perforating equipment. Rotary drilling rigs are widely used in large and medium-sized open-pit mines for their large drilling hole diameter and high perforating efficiency. Down-the-hole drills are widely used to drill holes with a diameter of 80 to 250 mm, but with the improvement of the design and manufacturing level of down-the-hole drills and drilling tools, can large diameter down-the-hole drills be used instead of rotary drilling rigs in the drilling method of large open-pit mines?
What is a DTH Drilling Tools?
The DTH drilling tools are a kind of rock drilling equipment that uses compressed air as the power source, submerges the rock drilling impacting power part into the rock drilling hole, controls the piston for round-trip motion through the air distribution device of the hammer, impacts the DTH bit configured at the front of the hammer, and transfers the impact energy to the bit, which breaks the rock.
DTH drilling tools are used in construction sites such as open-pit and underground mines, quarries, hydropower projects, water well drilling, mineral exploration, rock mass cable anchorage, geothermal excavation, and side pile support for subway engineering excavation. Due to a series of features such as high drilling straightness, smooth hole wall, good rigidity of drill pipe and hammer, no reliance on high axial thrust, unlimited drilling depth and low investment in equipment, and easy maintenance, the down-the-hole drill is generally valued by the rock drilling engineering industry.
Compared with rotary drilling tools, DTH drilling tools have incomparable advantages in terms of safety, reducing the labor intensity of workers, improving the working environment, increasing rock drilling rate and production efficiency, and increasing enterprise benefits.
The Characteristics of Down-the-hole Drill and Rotary Drilling Rig
Features of Down-the-hole Drills
1. Small axial pressure.
2. The drilling direction can be changed in a wide range, which is very meaningful for dealing with open-pit slopes and graded mining, reducing dilution losses, and formulating rational rock drilling and blasting process parameters.
3. The drilling aperture has a wide range of variation, and the drilling of blast holes with a diameter of 80~254mm in the open air and underground is mainly done by the down-the-hole drill, especially for the operation of small and medium apertures, the down-the-hole drill has the superiority of being cheap and reliable.
4. The performance of the DTH hammer can be changed with the air supply pressure, so the efficiency of the down-the-hole drill can be improved by improving the DTH drilling tools.
5. Because of the strong applicability of down-the-hole drill, it can be used not only in the quarry but also in slope treatment and crushing areas of large open-pit mines.
Features of Rotary Drilling Rigs
The main reason for using the rotary drilling rig as the blast hole drilling equipment is the big adaptable hole diameter of the rotary drilling rig. In the traditional understanding, 254mm-400mm is the advantageous drilling size of the rotary drilling rig, so the blasting volume of linear meters is large. The labor productivity of blasting work is also high.
The main disadvantages of using rotary drilling rigs compared to down-the-hole drills are:
1. The initial investment is high, and it is mainly used to drill vertical holes, which makes the rotary drilling rig not as good as the down-the-hole drill in terms of flexibility in use.
2. Large blast holes can easily cause ore and rock to mix and increase depletion loss.
3. The drill rig has to be moved back and forth frequently, which reduces the productivity of the drill rig, which is not conducive to the advantages of the rotary drilling rig.
In summary, in actual use, large-diameter down-the-hole drill and rotary drilling rig have their scope of application. The rotary drilling rig and the down-the-hole drill have advantages and disadvantages. Therefore, whether the large-diameter down-the-hole drill can replace the rotary drilling rig should be carefully analyzed according to the actual situation of drilling and technical and economic analysis.
