The blasting work needs to excavate some small holes in the rock that are suitable for the placement of the explosives. After the explosives are blasted, the ore rock can be cracked to different degrees or part of the ore rock can be directly dropped from the whole, which is convenient for the excavation equipment. As a kind of mechanical equipment widely used in the open-pit mining process, drilling rigs have formed a relatively complete process in terms of mechanical structure, usage methods, and handling of specific problems. According to the different working principles of various drilling rigs, the widely used modern drilling rigs are mainly divided into three categories: down-the-hole drilling rigs, roller cone drilling rigs and rotary drilling rigs. According to some specific situations that may be encountered in the open-pit mine operation site, starting from the drilling principle and basic operation of the drilling rig, this paper explores the solutions to the specific problems encountered by the drilling rig driver on site.
1 Overview of the structure and working principle of the drilling rig
To respond quickly to the problems encountered at the perforation site and properly solve the problems encountered, the drilling rig operator is required to have a careful grasp of the structure and working principle of the drilling rig. This paper expounds the structure and working principle of the drilling rig in layers. The most widely used mining rig is generally composed of six parts: power device, electrical system, working device, traveling mechanism, wind pressure system and hydraulic system. The coordinated operation of each system ensures the smooth development of perforation work. The power system of a drilling rig is divided into two categories: diesel engine and electric motor according to the different power sources. The diesel engine system also includes the crank connecting rod mechanism, the body and the cylinder head, the valve train and the intake and exhaust system, the diesel supply system, the lubrication system, the cooling system, the starting system and other subsystems. Motors are divided into two categories: DC motors and AC motors, among which AC motors are further divided into synchronous motors and asynchronous motors. Compared with the diesel engine, the three-phase asynchronous motor has the advantages of simple principle structure, low manufacturing cost, firmness and durability. Due to the existence of these advantages, the three-phase asynchronous motor is currently the most widely used. The three-phase asynchronous motor works by using the interaction between the rotating magnetic field generated by the three-phase current in the stator winding and the induced current in the rotor conductor. The power system of the drilling rig uses more basic knowledge of physical electricity. For example, the drilling rig circuit involves the knowledge of the host control system, the main transformer system, and the control circuit. The structure of the working devices of different drilling rigs is generally similar, and they are generally composed of drilling tools, slewing mechanism, pressurized lifting mechanism, drill pipe connecting and unloading mechanism, drilling frame lifting mechanism, platform, hydraulic outrigger, machine room, driver. Room, dust removal device, etc. The definition of the drilling rig air pressure system is the operating system that discharges the dust generated during the operation of the drilling rig out of the hole by means of compressed air during the operation of the drilling rig. The air pressure system is an important factor in measuring the performance of the drilling rig, and the dust discharge ability directly affects the drilling efficiency of the drilling rig and the maintenance cost of the drilling rig. The hydraulic transmission system of the drilling rig mainly uses high-pressure oil to realize the transmission of energy. The composition of the traditional hydraulic system is relatively complex, and the linkage device has strong mobility, which provides strength support for the perforation operation.
2 Problems in drilling rig operations and their solutions
2.1 Construction preparations before drilling
It is not as smooth as imagined, and the actual work is relatively complicated. Before the drilling work begins, relevant preparations should be done. For example, basic work such as external machinery and equipment required for drilling operations, water and electricity supply during the work process, and energy allocation should be done in an orderly manner before the official drilling work. In the actual drilling operation, there are often phenomena such as disorderly arrangement of wires, unintentional disconnection of wires, and wrong connections. The reason is that the preparations before drilling are not perfect. In a series of preparatory work before drilling, drilling rig positioning and burying steel casing are the core of the work, because whether the drilling rig positioning is accurate or not,
The correctness of the burial of the steel casing directly affects the accuracy of the drilling process and the robustness of the drilled hole. Drilling rig positioning requires coordination and communication between professional engineering surveyors and rig drivers to minimize deviations caused by drilling work and effectively improve drilling accuracy. The work of burying the steel casing is mainly done manually. At present, the steel casing buried by manual operation has high accuracy. However, there is also an obvious disadvantage of artificially burying the steel casing—the time required for burying is too long. In the specific construction process, according to the needs of the project progress, the buried hole of the steel casing can be excavated by an excavator. The excavator excavates the buried hole of the steel casing with high efficiency, but the accuracy is low, which is mainly reflected in the larger diameter of the buried hole of the steel casing. Therefore, after the positioning of the steel casing is completed, the excess part around the buried hole of the steel casing is filled with clay. After filling, use relevant equipment to compact the filling soil to prevent the steel casing from collapsing due to the mud infiltrating the soil layer around the buried hole.
2.2 Treatment of slurry leakage and hole collapse at the drilling site
In the mining process of open-pit coal mines, the problem of slurry leakage has always been a common problem encountered by most drilling rig drivers during the construction process. The main reason for the problem of slurry leakage is that there are corresponding karst caves under the corresponding holes. In order to properly deal with the problem of slurry leakage, the geological records of the operation area should be carefully checked before drilling operations (if there are no records, relevant personnel can be arranged to conduct geological surveys), and use this as a reference to deeply bury the steel casing. This method can play a good role in dealing with the problem of slurry leakage, but it needs to invest more human resources and equipment funds. The serious manifestation of slurry leakage is hole collapse. The reasons for hole collapse are similar to slurry leakage, which are all produced by karst caves. Larger karst caves in the borehole will lead to large-scale slurry leakage when the drill bit and the karst cave meet. At this time, the liquid displacement in the borehole decreases rapidly, and the pressure on the inner wall of the hole decreases, so that the hole wall collapses. When encountering this serious leakage problem, the current approach is to backfill completely and leave it in for a period of time to relocate the borehole.
3. Treatment measures to prevent the coal drill from clamping the rod and after the rod is clamped
Generally speaking, when using the DM45 drilling rig to work on the coal seam, the problem of clamping the rod occurs from time to time, and sometimes it can be lifted, but when it cannot be lifted, the drill pipe can only be cut off. If the drill pipe is in the hole, there will be the following disadvantages: waste of drill pipe , the cost increases and the drill pipe left in the coal seam brings a lot of inconvenience to the mining equipment. During the mining process, it is necessary to always pay attention that the drill pipe is not installed in the crushing station. The tape is torn, and at the same time, it is necessary for the production technicians to perform GPS positioning on the position of the dropped rod, which causes a lot of waste of manpower and material resources. In the event of a clamp bar accident, we should analyze the principle and preventive measures of the clamp bar.
3.1 Prevention of pinching in the coal seam
(1) Strengthen management and further improve the driver's sense of responsibility. The roof conditions of the coal seam are good, but the driver's sense of responsibility is not in place, resulting in the phenomenon of pinching the rod. The front and co-drivers will be punished according to the severity of the situation.
(2) Strengthen the cleaning work of the working face, vigorously improve the working conditions of the drilling rig, and thoroughly clean the working face before drilling holes. For the cleaning work of special sections, it is necessary to check with the operation foreman to ensure that the coal seam roof is free from "empty holes". “Quantity” or leave less “empty quantity” in special areas.
(3) Strengthen the communication with the production department, and adjust the front row holes, especially the holes on the edge of the ballast, in time to ensure that the holes of the front row holes and the edge holes are not cracked, and the explosion volume "virtual volume" should be encrypted if necessary. The form of holes can increase the eye spacing and hole row spacing.
(4) Throwing blasting at high steps should further strengthen the hole depth work of the drilling rig, so that each drilling rig will not damage the coal roof during the perforation process, and at the same time, it will not damage the ultra-deep holes.
To backfill, make sure the coal roof is not damaged.
4 Treatment measures after clamping the rod Once the rod is clamped during drilling, do not rush to lift the rod.
What is the reason for the breakage of the clamp rod.
(1) Clamping rods caused by excessive "virtual volume" or punching holes on the edge of the slag,First, clean the orifice pulverized coal to prevent it from falling into the hole again. Turn off the wind, give the rotation (forward and reverse) repeatedly, and then move the drilling tool up and down until the drill pipe can move, whether it is up and down or rotating, even if it only needs to move a little, stop at the rotation point of the drill pipe and repeatedly rotate the drill pipe. The rotation amplitude is increased little by little, so as to rotate a full circle, the axial pressure shows normal and then the wind can be supplied, and the drill pipe is lifted up.
(2) Due to the clamp rod caused by the falling block, it is necessary to clean up the floating block at the orifice and move the drill rod up and down during the drilling process. Just move it a little and stop at the active place, and the positive and negative rotation will be ground by the clamped block. Raise the drill pipe.
(3) Handling the clamp rod requires patience. It takes a certain amount of time to find a point that can be rotated. When the temperature of the hydraulic oil is high, stop for a period of time to prevent the pipe from bursting. When the oil temperature drops, the rod can be lifted.
(4) In the process of lifting the rod, the method of pouring water and oil into the hole can also be used, so that the drill pipe can shake and lift the drill pipe.
5 How to judge the kaolin, blasting heap, fissure and goaf and preventive measures
(1) Judgment of hitting kaolin: the speed of the pressurized chain increases instantly, the partial pressure suddenly increases within a few seconds, the rotational pressure increases, the slag discharged from the orifice is brownish red (blocky in winter, spherical in summer), and the rotational speed Decreased, abnormal rotation sound;
Preventive measures: reduce the axial pressure, increase the rotation speed, and move up and down if necessary. The co-driver monitors the ground well, and lifts the drilling tool in time when it is found that the slag is not discharged.
(2) When the perforation reaches the explosion pile: the lowering is accelerated, the wind pressure remains the same, the rotating pressure gradually increases, and the slag discharge is not smooth; preventive measures: in addition to reducing the axial pressure, reduce the rotating speed, and repeatedly lift the drilling tool until the hole is placed in the hole. After the rock powder is exhausted, the operation can be continued, and the ground monitoring should be done well; the blasting pile that occurs when the hole is drilled will collapse and fall off when the hole is drilled, resulting in stuck drill. In this case, the rock block at the hole should be cleaned up. , If the orifice drops and collapses seriously, the drilling rig should be moved to re-drill the hole.
(3) Hit the fissure: the drill pipe shakes and the speed is reduced, and the abnormal sound of grinding the drill pipe is still heard, and the wind pressure remains unchanged: Preventive measures: reduce the axial pressure, move the drill pipe up and down, and pull the drill pipe out of the hole if necessary. Drill again. If the crack is too large to continue drilling, move the drilling rig and drill again. The co-driver should monitor the ground.
(4) Goaf: the drilling speed is accelerated instantly, no slag is discharged, and the wind pressure is normal; there is no resistance when the wind is stopped, and the rotation is stopped; preventive measures: the wind is stopped and the rotation is stopped, and the drill pipe is lowered at a slow speed, if the drill pipe can fall freely , and there is a pungent smell overflowing, the drill pipe should be pulled out of the hole immediately. Do not continue drilling at the same speed and pressure, otherwise the drill pipe will bend in the hole. For the proven goaf, the drilling rig continues to drill holes at the lower holes. When drilling, be sure to drill through them, and expand the surrounding area to drill holes until there is no drill drop, no rock powder, etc. As far as the drilling of abnormal conditions, the surrounding normal holes should be drilled for 15 meters, in order to make the goaf fall completely. When working on the goaf, the driver must be careful and careful, and the assistant driver must monitor the work well to prevent the accident of clamping the rod and bending the drill pipe.
6 Treatment of blocked drill
During the operation of the drilling rig, it often encounters difficult drilling positions such as kaolin, and there is water in the clay. If we are a little careless in the operation, the drilling will be blocked. Don't worry when the drilling is blocked. First, lift the drill out of the hole, and then use tools such as steel rods to poke the eye of the drill. When poking the eye of the drill, you must pay attention to the face away from the drill pipe, and the height of the head must be higher than the height of the drill (that is, it is flush with the waist when squatting and upper body upright).
7 Handling of drill tools clamped in the flat plate of rock work
Once the clamping of the drill occurs, first find out the cause of the clamping and take corresponding measures.
(1) The pinch drill caused by the chip and the falling block, the general drilling tool can be rotated in the blast hole, but cannot be lifted. Do not forcibly pull out the drilling tool, let alone stop the gas supply.
Slowly move up and down, rotate the drilling tool repeatedly, and crush the sandwiched rock before it can be drilled.
The drill is brought up.
(2) Replacing the large drill bit causes the drill to be clamped, and the drill tool can neither rotate nor lift out of the hole. Especially in faults, rock formations with many cracks, scumming areas on the upper part of the boreholes and old mining areas, the hole wall will appear framing phenomenon. This phenomenon not only reduces the drilling efficiency, but also makes it difficult to discharge the powder, resulting in a pinch drill accident. At this time, in addition to reducing the axial pressure, reducing the speed and careful operation, it is necessary to maintain the hole wall with clay.
(3) Drilling caused by too much rock powder, the rock powder is often not blown out during the gas supply, and the gas supply must be stopped, and the drilling tools should be handled while rotating. If necessary, water or oil can be poured into the hole. Generally, it takes several hours for oil or water to infiltrate. After feeling infiltration, rotate forward and reverse repeatedly until the drill pipe can rotate, and continue to rotate forward, and the drill pipe shakes violently. Then lift the drill up. Handling pinch drills should not be rushed.
8 Precautions for drilling rigs before drilling in the spring and rainy seasons
(1) In spring, due to the thawing of frozen soil, the steps are unstable and easy to slip off. Therefore, it is necessary to increase the distance of the side holes. During the operation, it is necessary to work vertically or adjust the angle to stabilize the vehicle. The minimum angle should not be less than 45°.
(2) When working after rain, it is necessary to pay more attention to the sliding of the steps, especially where there are umbrella eaves, especially to increase the distance between the side holes. When working, it is necessary to work vertically or adjust the angle to stabilize the vehicle. The minimum angle should not be less than 45°.
9 How to drill holes in the goaf
9.1 Determining the gob
When the hole is drilled, leave 10 meters on the east and west sides of the hole to continue drilling. After a normal hole appears, go back 5 meters and punch another one. In this way, the boundary of the goaf is controlled within 2.5 meters. The spatial location of the zone provides more accurate data.
Through the analysis of drilling data, the production technology department shall determine the distribution of gobs
9.2 Gob drilling in goaf
When the drilling rig is working on the goaf, it is necessary to drill through the holes and expand the surrounding areas until there are no abnormal holes such as drill drop and rock powder return. In order to ensure that the gobs fall completely, additional holes should be drilled between the normal holes with gobs. When there is gas leakage, high temperature holes (temperature greater than 60°C) or fire holes, they should be blocked at the orifice in time. Operators should wear protective equipment to prevent poisoning.
10 Ways to deal with the problem of dropped drills and drills
The main reason for the problem of drill drop is the fracture of the joint between the drill bit and the drill pipe joint, which is caused by the wear and tear of the long-term use of the drill bit. The problem of drill drop mainly occurs in reverse circulation percussion drills. After the problem of drill drop occurs, the drill bit usually falls into the hole. Drilling rig drivers should pay attention to salvage the drill bit (fishing hooks can be used), but should pay attention to taking necessary safety precautions during the salvage process. Explosive drilling refers to the phenomenon that cracks appear on the surface of the drill bit due to repeated impact on the rock formation during the long-term operation of the drilling rig. The problem of blasting drills can easily cause fragments from the drill bit to fall into the hole, and these fragments are much stronger than the rock formation. When a drill burst occurs, it is not advisable to continue the operation. The debris of the drill bit should be cleaned up in time, and the drill bit or drilling rig should be replaced.
Do your homework.
Drilling rig drivers should be familiar with the working performance and adaptable working conditions of each main body of the drilling rig, and have an understanding of some common problems that occur frequently in the construction process, so that they can be dealt with in a timely and proper manner when problems occur.
Contact Person: Ms. Lily