Some explanations of boreholes after drilling of rock drilling rigs
The use of rock drilling rigs to open boreholes is mainly divided into two situations, see the gun mining or blasting. 1, shot mining face The commonly used blasthole configuration of general rock drilling rigs is the following three types: 1. Single row of eyes, generally used for thin coal seams or coal seams with soft coal and joint development. 2. Double-row eyes, which are arranged in the form of eyes, trichomes, and triangular eyes, are generally applicable to the mining of small medium-thick coal seams. Hard coal can be used when the eyes are hard, when the coal quality is soft, available for the third eye, when the upper coal is soft or when the roof is broken, triangular eyes can be used. 3, three rows of eyes, also known as streaky eyes, used for coal hard or high medium thick coal seam. The blasthole angle should meet the following requirements: (1) The horizontal angle between the borehole and the coal wall is generally 50 degrees to 80 degrees. The soft coal has a large value and the hard coal has a small value. In order not to collapse the bracket, the horizontal line of least resistance should be oriented toward the neutral between the two pillars. (2) The top of the eye is raised 5 degrees to 10 degrees in the direction of the top plate in the vertical plane. It depends on the condition of the hard and soft coal and the sticky top of the coal seam, and should ensure that the integrity of the top plate is not damaged; (3) The bottom eye maintains a declination of 10 degrees to 20 degrees in the direction of the bottom plate on the vertical surface, and the fundus is close to the bottom plate so as not to lose the bottom coal. The depth of the borehole drilled by the rock drilling rig is determined by each progress. Generally each progress has three kinds of 0.8 meters, 1 meters, 1.2 meters. The amount of charge for each blasthole depends on the hardness and hardness of the coal, the location and depth of blastholes, and the blast sequence, which is usually 150 to 600 grams. Blasting uses a series method. The number of blastholes for each detonation should be based on the stability of the roof and the safety of the working face. When conditions are good, dozens of eyes can be detonated at the same time; if the conditions are poor, the top plate is unstable, and only a few eyes can be blasted at a time, even with the method of leaving the coal-fired interval blasting. 2, blasting work surface The blastholes in the face of the rock drilling rig can be classified into three types: stern eyes, auxiliary eyes, and peripheral eyes according to their use and location. Different types of blastholes have different positions on the working surface and different blasting sequences. Therefore, they play different roles in the blasting work and the layout principles are different. (1) Slot eyes. The role of rock drilling rigs is to first crush and throw a certain part of the rock on the working surface, and to collapse the second free surface on the basis of the first free surface to create favorable conditions for the blasting of other blastholes. The effectiveness of the guttering plays a decisive role in the loop footage. Therefore, the arrangement of the eyelet is the most critical. The slothole is generally arranged near the bottom of the roadway in the center of the cross section of the roadway, so that it is easy to grasp the direction when drilling the hole, and it is advantageous for most other blastholes to break through with the weight of the rock. If there are significant explosive rock formations in the excavation section, the gullet holes should be placed in these soft rock formations. Pit holes should be deepened by 150 to 200mm more than other blastholes, and the charge volume should be increased by 15% to 20%; if it is the oppositely inclined borehole, the distance between the fundus should be 100 to 200mm apart. (2) Rock drilling rig auxiliary eye. The auxiliary eye, also known as the collapsed eye, is a blasthole that causes large amounts of rock to fall and continues to enlarge the gutter. Auxiliary eye to be evenly arranged between the eye and the surrounding eye, the eye distance is generally 500 ~ 700mm, the direction of the blasthole is generally perpendicular to the work surface, the charge factor (charge length and blasthole depth ratio) is generally 0.45 ~ 0.60 . If smooth blasting is used, the auxiliary eye next to the surrounding eye will create an ideal light burst for the surrounding eye. (3) Rock rig peripheral eyes. The surrounding eyes are the boreholes of the cross-section design contour of the rock surrounding the collapsed roadway. Whether the surrounding eyes are arranged or not is a direct influence on whether the roadway forming is regular. Peripheral eye can be divided into top eye, eye and bottom eye. The top eye and the helper eye should be arranged on the contour of the design, but to facilitate the drilling of the eye, it is usually skewed outwards by a certain angle. This angle is adjusted according to the depth of the blasthole and the eye bottom does not exceed 100 mm beyond the design contour. In the field operation, the angle is determined by using the brazed shoulder and the contour line as a reference to control the distance from the eye line to the contour line. The minimum line of resistance of the bottom eye and the distance between the blastholes are usually the same as those of the auxiliary eye. To avoid the foundation left after the blasting and to create favorable conditions for laying the track, the bottom of the bottom of the rock drilling rig should be 150mm below the floor to facilitate drilling and To avoid water in the borehole, the eye opening should be 150-200mm higher than the floor of the tunnel. Gutter eyes can be shot with the bottom eye. For more information, please pay attention to China Deep Hole Rig Trading Website http://skzj.99114.com Sung Precision Mould & Plastic Co., Ltd. , https://www.injectionmoldingfactory.com