With the continuous expansion of the scale of mining projects and the development of the mining machinery manufacturing industry, hydraulic rock drill jumbos have gradually become the primary equipment for mechanized rock drilling. The hydraulic rock drill jumbo is a heavy-duty mechanical equipment widely used in tunneling, underground engineering, and mining industries. Its primary function is to use drilling manipulators and rock drills for drilling and crushing. During the use of hydraulic rock drill jumbos, rock drilling tools are critical drilling tool, their performance and quality directly affect drilling efficiency and rock crushing effects. Therefore, the requirements for rock drilling tools are particularly crucial.
Basic requirements for rock drilling tools
Material
The material of rock drilling tools should have high strength, wear resistance, and toughness. Since hydraulic rock drill jumbos need to drill and break rocks for a long time during work, the material of the rock drilling tool is crucial. We should choose rock drilling tools’ materials and heat treatment processes with high strength, wear resistance, and toughness to ensure the long-term use of rock drilling tools.
Impact resistance and high-temperature resistance
When rock drilling, the rock drilling tool will be subject to intense impact loads. Therefore, rock drilling tools should have excellent impact resistance to prevent them from breaking or being damaged under impact loads. At the same time, rock drilling tools should have excellent high-temperature resistance to avoid annealing or deformation at high temperatures. To improve the impact and high-temperature resistance of the rock drilling tools, we can adopt measures such as optimizing the material composition and improving heat treatment quality can be adopted.
Rock drilling efficiency
In the operation of rock drill jumbos, except for labor compensation and purchase cost of rock drilling tools, other working hours costs are considered fixed costs, and the cost of rock drilling tools accounts for a lower proportion of the total cost in rock drilling operations. Therefore, increasing rock drilling speed means reducing construction costs. High-efficiency rock drilling tools can shorten rock drilling time and improve production efficiency. Foreign users attach great importance to choosing different types of rock drilling tools and increasing the speed of rock drilling.
Quality
In foreign projects, the calculation of working hour costs is given great importance in the whole project because of the high labor compensation. For example, the production of hydraulic rock drill jumbos usually allocates the cost of equipment, production system cost, and per capita compensation required for each working hour by year. The average working hour cost of a drill jumbo in Sweden amounts to 380~450 USD/hour. Therefore, the loss due to non-productive time is very high.
In foreign countries, hydraulic rock drill jumbos operate in a single shift, with a single arm drilling about 50,000 meters of gun hole progress per year. Generally, the service life of shank adapter is required to be more than 3000 meters to reduce the time for dismantling and replacing the shank adapter. The requirements for drill rods and rock drill bits are also quite high because a broken drill rod will not only lose rock drill bits but also cause waste holes. At the same time, due to the high degree of automation of hydraulic rock drill jumbo, operators do not need to pay a lot of labor intensity during normal production, while dismantling the machine to replace shank adapter, salvaging the broken drill rod or resharpening rock drill bit not only wastes working hours but also increases the labor intensity of operators. Therefore, when foreign users choose rock drilling tools, they not only pay attention to the price of the product but also pay more attention to the quality of the product.
Special requirements for rock drilling tools
Adaptability
Rock drilling tools should be compatible with the drilling manipulator and rock drill of the hydraulic rock drill jumbo. It includes rock drilling tools’ connection method, size, and shape. It is the only way to ensure that the rock drilling tool is installed smoothly on the machine and remains stable during operation.
Durability
Since the hydraulic rock drill jumbo is required to perform continuous drilling operations, the rock drilling tool should have a long service life. Rock drilling tools with good durability can maintain good performance during continuing operation, thereby improving the overall working efficiency of hydraulic rock drill jumbos.
Reliability
Since hydraulic rock drill jumbos work in underground engineering or mining environments, rock drilling tools should have high reliability. Even in harsh working environments, highly reliable rock drilling tools can maintain stable working performance and prevent failure of rock drilling tools from affecting the working efficiency of the entire hydraulic rock drill jumbo.
Blast hole deflection
In medium and deep hole rock drilling and blasting, the deflection of blast holes means less charge and shorter hole spacing, which leads to lower mining volume. Therefore, foreign users have high requirements for the straightness of blast holes, which are usually controlled within a small range of errors. The main reasons for the blast hole deviation are the hole entry error during drilling, the calibration blast hole error, and the straightness error generated during the rock drilling process of rock drilling tools. The first two errors can be eliminated in fully hydraulic rock drill jumbos or computer-controlled hydraulic drill jumbos, while the skewing of the hole caused by the structure of rock drilling tools becomes the main reason. With the deepening of the drilling depth, the skew will be aggravated, which will eventually cause the waste hole. The best way to reduce or eliminate the skew of blast holes is to use guided rock drilling tools.
Conclusion
Hydraulic rock drill jumbos are vital equipment for mining, construction, and road engineering, which requires more and more rock drilling tools to improve productivity and reduce costs. Therefore, when selecting and using rock drilling tools, we should fully consider the actual needs to ensure the best results. At the same time, we also need to strengthen the maintenance and repair of rock drilling tools to improve their service life and reduce costs. In the future, with the continuous development of science and technology, it is believed that the performance and efficiency of hydraulic rock drill jumbos and rock drilling tools will be further improved, making more contributions to the sustainable development of mining and other industries.
