At present, the application of patio drilling rig has been quite popular, in many countries has replaced the traditional method of patio drilling and blasting. Compared with the general method of patio driving, the patio drilling rig has the advantages of construction safety, short well completion period, shortening the workload of horizontal roadway driving, smooth well wall and low noise. With the increasing perfection of large diameter and large torque patio drilling rigs of major brands, patio drilling technology is not only limited to underground mines, but also has been successfully used in horizontal drilling abroad. For example, a number of horizontal connecting tunnels between the two main tunnels in the English Channel were drilled with Rhino patio drilling rigs produced by Tamrock Company. The coal system uses drilling method to drill large coal bunkers and advance shafts for large-diameter shaft excavation. Ventilation shafts in railway tunnels and power station projects, underground warehouses drill transportation channels and shafts, etc. The use of low-rise drilling opportunities to reduce the cost of drilling rig working chamber excavation, and easy to assemble, handling, the world's underground mines (especially small and medium-sized mines) will increase the demand for such drilling rigs. With the progress of industry and the continuous innovation of technology, the scope of use of patio drilling rig is expanding, and it will certainly meet the higher requirements of people for its performance.

Overview of Patio Rig

Patio drilling rig is the use of rotary drilling to break the rock into a hole and reverse reaming wellbore excavation machinery and equipment. Patio drilling rig tunneling refers to the method of using patio drilling rig and reaming cutter to complete the patio tunneling operation. At present, the construction process of the patio drilling rig is fully mechanized and operated outside the patio. Compared with other methods, the drilling rig driving method has the advantages of fast driving speed, high labor productivity, safe operation, low labor intensity, and can realize microcomputer remote control. But the patio drilling rig price is high, the general mine is difficult to purchase. And if mismanaged, the cost per unit of footage can be high.

According to the drilling method, it is divided into three types: up-expansion method, down-expansion method and full-section surface drilling method. According to different drilling methods, the patio drilling rig is roughly divided into standard patio drilling rig, reverse circulation patio drilling rig and blind patio drilling rig.

Standard patio rigs are installed on the upper level or surface of the pre-drilled barrel. First, drill down a pilot hole with a diameter of 200~300mm with a roller cone drill bit. After the hole is opened, replace the reaming cutter head horizontally at the bottom, and then form a patio with a diameter of 0.5~6m from bottom to top.

The drilling mode of reverse circulation patio drilling rig is opposite to that of standard patio drilling rig. The drilling rig is installed at the lower level, drill the pilot hole upward, replace the reaming cutter head at the upper level, and ream the hole from top to bottom. However, it is difficult to discharge ballast when reaming, and there are also problems such as installation and operation inconvenience.

Blind patio drilling rigs are generally installed in the lower level. Blind hole cutter head is used for upward full section drilling, and the well is directly completed without drilling pilot hole. There are also blind patio drilling rigs that move into the well to drill through wired or wireless remote control, without the need for drill pipes, and the drilling inclination angle is expanded to drill into horizontal wells.

Development of Patio Drilling Rig at Home and Abroad

In the 1950 s, some countries began to use patio drilling rigs to drill patios with a diameter of 6m and a depth of 1000m by the 1980 s. The comprehensive well completion speed is 2~4m/shift. In the 1960 s, China began to study the patio drilling method and began to apply it to production in the late 1970 s. Two kinds of patio drilling rigs, common type and low type, have been developed and applied successively, of which the low type is more widely used and can drill patios with a diameter of 1~2m and a depth of 100~120m. When the rock firmness coefficient is 12~14, the drilling speed of the guide hole is 5~7 m/h, the reaming speed is 1~1.5 m/h, and the patio deflection rate is less than 1%. In the late 1980 s, the processing quality and technical performance indexes of the whole machine of China's patio drilling rig, as well as the material and durability of rock breaking tools, have been greatly improved, so as to further expand the scope of application of the patio drilling rig to create the conditions.

The United States began to apply patio drilling rigs in 1962. By the early 1990 s, foreign underground mines used drilling methods to excavate various patios for various purposes have been rapidly promoted, and patio drilling rigs have been effectively applied. The drilling method has actually replaced the ordinary tunneling method, and the use area is mainly concentrated in Australia, Canada, Mexico, South Africa, the United States and Zambia. However, with the development of world mining to deep, mining methods are constantly changing, so that the height of the middle section continues to increase, and the original tunneling method can no longer meet the requirements. Therefore, in recent years, major foreign manufacturers have made patio drilling rigs with large torque and large push-pull force for deep mining and hard rock. With the progress and development of patio drilling rig technology, the power of patio drilling rig has been developed from 75kW to 750kW, the reaming aperture can reach 7.1m, and the drilling depth can reach 1500m.

Development Trend of Patio Drilling Rig in China

Development of electric drive patio drilling rig

Foreign electric drive patio drilling rig is widely used. There have been data showing that 118 of the 217 patio drilling rigs sold by Robibns companies are electrically driven patio drilling rigs, accounting for more than 54% of the total. Because, compared with the hydraulic drive, electric drive features significantly.

Energy saving, low operating costs. Since hydraulic drive is more than electric energy conversion, the efficiency of hydraulic components is relatively low, and the back pressure of the hydraulic system loses 5% to 8% more energy, resulting in hydraulic drive losing 20% to 28% more energy than electric drive.

Long life. Due to the continuous innovation and development of technology, although the service life of domestic motors is similar to that of oil pumps and motors with larger capacity, large-flow high-pressure rubber hoses are consumables, and their service life is much worse than that of motors and needs to be replaced frequently. Therefore, the service life of electric drive patio drilling rigs is still longer.

In addition, the electric-driven patio drilling rig also has the characteristics of less failure, high equipment operation rate, low maintenance cost and low fuel consumption. Therefore, considering the supporting level of our country, the ability of mine use and maintenance and energy saving, the electric drive patio drilling rig is more in line with the national conditions and is easy to popularize.

Development of inclined patio drilling rig

Many domestic mines, especially non-ferrous, gold and other mines, its 30 ° ~ 50 ° gently inclined ore body accounts for a large proportion, and the coal mine "up and down the mountain" only between 20 ° ~ 30 °, with ordinary methods to dig into the inclined patio is extremely difficult. Therefore, it is necessary to develop inclined patio drilling rig.

Development of blind patio drilling rig

According to statistics, China's non-ferrous metal underground mines need to excavate patios of different specifications and uses up to 250000 m per year, of which blind patio projects account for nearly 20% of the patio project volume. In some mines, due to the needs of mining methods, blind patio projects account for a higher proportion. Therefore, blind patio tunneling has become one of the key problems in mine production. Using blind patio drilling rig to drill the patio not only has the advantages of high speed, low consumption, labor saving and safety of patio drilling rig, but also brings great convenience for horizontal development, and has great versatility. It can not only drill into blind patio, but also drill into patio. It can not only drill into hard and stable rock layers, but also drill into loose and broken rock layers.

Development of high patio drilling rig

With the development of mining technology, some new and advanced mining methods often need to enlarge the height of the middle section, thus increasing the length of the first excavation of the patio. In particular, some old mines that need to be transformed have many longer patios that need to be excavated. Therefore, the development of more than 400m patio drilling rig is also the trend.

Development of large diameter patio drilling rig

The diameter of foreign patio drilling rigs has reached 6.2m, and there are many patios with a diameter of more than 3m in large and medium-sized mines in China, so it is necessary to vigorously develop large-diameter patio drilling rigs.

Development of an automatic drilling system

In recent years, electronic computers have developed rapidly in our country. The computer is applied to the automatic control of the drilling parameters of the patio drilling rig, and the computer is used to replace the manual operation, and the drilling parameters are automatically adjusted according to the drilling feedback information, so that the ideal perforation speed and tool life can be obtained in any rock formation and drilling depth, and various drilling parameters and indicators can be accurately printed. In order to further improve the technical level of domestic patio drilling rig, the automatic control system of patio drilling rig should be continuously developed and improved.