used in modern times. People call George Lena’s rock drill a major breakthrough in
the history of rock drill development.
In 1938, the German-manufactured air leg and tungsten carbide bits. The
expandable air leg was used to exert thrust on the bits to support the body weight of
the rock drill, thus greatly reducing the physical consumption of workers. The
tungsten carbide bit greatly reduces the number of grinding, and the drilling depth
increases from 0:6 $ 0:9 to 9 $ 12 m after one grinding. The application of tungsten
carbide opens a way for deep hole rock drilling.
Ingersoll-Rand Company of the United States noticed that the impact energy of
the deep hole connecting rod drill lost in the drill rod was larger, and proposed the
idea of putting the drill into the bottom of the hole, which was patented in 1932.
However, due to various constraints, it was not until the late 1940s that open-pit
mines began to be tried out.
In 1951, Belgian Engineer Andrei Stannuiko designed and manufactured a DTH
impactor similar to the modern DTH impactor (At that time, it was called a
down-the-hole drill.). The DTH impactor not only makes full use of the impact
energy of the equipment, but also greatly reduces the noise, improves the working
environment and reduces the heavy manual labor of the workers. Because the
efficiency of open-pit drilling is 2 $ 3 times higher than that of steel rope percussive
drilling rig, it has been recognized as economical and effective drilling equipment
for drilling hard ore.
Subsequently, the down-hole equipment was continuously improved, and the
large aperture of open-pit mine was extended to the small aperture of underground
mine. Compressed air pressure used in foreign countries increased from
0:5 $ 0:6 MPa in the initial stage, 0:7 $ 0:88 MPa in the 1960s and 1:4 $ 1:75 MPa
in the early 1970s to 2:1 $ 2:6 MPa in the late 1970s.
In the 1980s, pneumatic DTH hammer has been applied to the field of geological
core exploration abroad, and the depth of the blasting hole in DTH hammer construction has been extended from several meters to tens of meters to hundreds of
meters of exploration boreholes. Developing DTH hammer blasting hole from
without core-taking into core-taking sampling drilling, and the development from
ordinary positive circulation drilling to central sampling drilling, namely, CSR
(center sample recovery) drilling method. With the application of DTH hammer in
exploration, foreign drilling technicians began to study penetrating DTH hammer
and reverse circulation drilling technology.
The College of Construction Engineering of Jilin University (formerly
Changchun University of Science and Technology) has studied pneumatic DTH
hammer for more than 30 years. Penetrating pneumatic DTH hammer, reverse
circulation penetrating DTH hammer, single large diameter wet reverse circulation
penetrating DTH hammer and combined diameter DTH hammer have been
developed. The diameter of the borehole reaches 600 $ 1200 mm. The rock entry
equipment currently used in China is basically percussive drilling, which has poor
drilling ability, low efficiency, easy collapse, and serious mud pollution. DTH
hammer drilling technology is one of the most efficient drilling methods in hard
rock at present. With the enlargement of drilling diameter and the increase of
196
11 Pneumatic Down-the-Hole Hammer
the history of rock drill development.
In 1938, the German-manufactured air leg and tungsten carbide bits. The
expandable air leg was used to exert thrust on the bits to support the body weight of
the rock drill, thus greatly reducing the physical consumption of workers. The
tungsten carbide bit greatly reduces the number of grinding, and the drilling depth
increases from 0:6 $ 0:9 to 9 $ 12 m after one grinding. The application of tungsten
carbide opens a way for deep hole rock drilling.
Ingersoll-Rand Company of the United States noticed that the impact energy of
the deep hole connecting rod drill lost in the drill rod was larger, and proposed the
idea of putting the drill into the bottom of the hole, which was patented in 1932.
However, due to various constraints, it was not until the late 1940s that open-pit
mines began to be tried out.
In 1951, Belgian Engineer Andrei Stannuiko designed and manufactured a DTH
impactor similar to the modern DTH impactor (At that time, it was called a
down-the-hole drill.). The DTH impactor not only makes full use of the impact
energy of the equipment, but also greatly reduces the noise, improves the working
environment and reduces the heavy manual labor of the workers. Because the
efficiency of open-pit drilling is 2 $ 3 times higher than that of steel rope percussive
drilling rig, it has been recognized as economical and effective drilling equipment
for drilling hard ore.
Subsequently, the down-hole equipment was continuously improved, and the
large aperture of open-pit mine was extended to the small aperture of underground
mine. Compressed air pressure used in foreign countries increased from
0:5 $ 0:6 MPa in the initial stage, 0:7 $ 0:88 MPa in the 1960s and 1:4 $ 1:75 MPa
in the early 1970s to 2:1 $ 2:6 MPa in the late 1970s.
In the 1980s, pneumatic DTH hammer has been applied to the field of geological
core exploration abroad, and the depth of the blasting hole in DTH hammer construction has been extended from several meters to tens of meters to hundreds of
meters of exploration boreholes. Developing DTH hammer blasting hole from
without core-taking into core-taking sampling drilling, and the development from
ordinary positive circulation drilling to central sampling drilling, namely, CSR
(center sample recovery) drilling method. With the application of DTH hammer in
exploration, foreign drilling technicians began to study penetrating DTH hammer
and reverse circulation drilling technology.
The College of Construction Engineering of Jilin University (formerly
Changchun University of Science and Technology) has studied pneumatic DTH
hammer for more than 30 years. Penetrating pneumatic DTH hammer, reverse
circulation penetrating DTH hammer, single large diameter wet reverse circulation
penetrating DTH hammer and combined diameter DTH hammer have been
developed. The diameter of the borehole reaches 600 $ 1200 mm. The rock entry
equipment currently used in China is basically percussive drilling, which has poor
drilling ability, low efficiency, easy collapse, and serious mud pollution. DTH
hammer drilling technology is one of the most efficient drilling methods in hard
rock at present. With the enlargement of drilling diameter and the increase of
196
11 Pneumatic Down-the-Hole Hammer