Perforation work is the first process of open-pit mining, throughout the open-pit mining process
The cost of perforation accounts for about 10%-15% of its total production expenses.
angle change range, high degree of mechanization, reduce auxiliary operation time, improve the operation rate of drilling rig, and DTH drilling rig is flexible, light equipment weight, low investment cost, especially by drilling various oblique holes to control ore grade, can eliminate the root, reduce large blocks, improve the blasting quality. Therefore, DTH drilling rigs are currently widely used in small and medium-sized mines at home and abroad, and are suitable for perforating medium and hard ore rocks.
Tooth wheel drilling rig is a modern new type of drilling equipment developed on the basis of rotary drilling rig, with high perforation efficiency, low operating cost, mechanization, high degree of automation, etc., suitable for various hardness of ore perforation operations, at present, has become the world's open-pit mine commonly used perforation equipment.
Rock drilling trolley is a new type of rock drilling operation equipment that has emerged with the development of the mining industry. It is to install one or several rock drills together with automatic thrusters on a special drilling arm or bench, and there is a walking mechanism to mechanize the rock drill operation.
purpose of blasting work is to break hard solid ore rock and provide excavation with suitable block size for mining work. Blasting costs account for about 15%-20% of the total cost of open-pit mining. The quality of blasting not only directly affects the efficiency of equipment such as mining, transportation, and coarse crushing, but also affects the total cost of the mine.
used in shallow hole blasting is small, generally about 30-75 mm, and the depth of the gun hole is generally below 5 meters, sometimes up to about 8 meters, such as drilling with rock drilling trolleys, the hole depth can also be increased.
Shallow hole blasting is mainly used for the production of small open-pit mines or quarries, stone, tunnel excavation, secondary blasting, new open-pit mine package treatment, the formation of open-air single-wall trench transportation channels on hillsides and other special blasting.
Deep hole blasting is a blasting method in which a deeper borehole is drilled with drilling equipment as a charge space for mining explosives. Deep hole blasting in open-pit mines is mainly based on step production blasting.
Drilling equipment for deep hole blasting is mainly used for DTH drilling and dental drilling. The drilled holes can be drilled vertically deep holes or inclined gun holes. The charge of the inclined gun hole is relatively uniform, and the blasting quality of the ore rock is better, which creates good conditions for the mining and loading work.In order to reduce the
seismic effect and improve the blasting quality, under certain conditions, measures such as differential blasting in large areas, spaced charge in the gun hole or spaced charge at the bottom air can be taken in order to reduce the blasting cost and achieve better economic benefits.
Chamber blasting is a method of blasting a large amount or a large amount of explosives in the roadway of the blast chamber. Open-pit mines are used only during the capital construction period and under specific conditions, quarries are adopted when conditions and when mining is in high demand.
In recent years, with the sharp increase in excavator bucket capacity and open-pit mine production capacity, the amount of blasting required for normal mining blasting of open-pit mine is increasing, for this reason, large-scale blasting methods such as multi-row hole differential blasting and multi-row hole differential extrusion blasting are widely used in open-pit mining at home and abroad.
Advantages of multi-row hole differential blasting:
The amount of blasting at one time is large, which reduces the number of blasting times and the time of gun avoidance, and improves the utilization rate of stope equipment;
Improve the crushing quality of ore, and its bulk rate is 40%-50% less than that of single-row hole blasting;
Improve the efficiency of perforation equipment by about 10%-15%, which is due to the increase in working time utilization coefficient and the decrease in the number of perforation equipment and blasting post-charging zone operations;
Improve the efficiency of procurement and transportation equipment by about 10%-15%.
It refers to the multi-row hole differential blasting when there is a residual burst on the working surface. The existence of ballast pile creates conditions for extrusion, on the one hand, it can extend the effective action time of blasting and improve the utilization and crushing effect of explosives; On the other hand, it can control the width of the blast pile to avoid the scattering of ore. The interval time between multi-row porous differential extrusion blasting is 30%~50% larger than that of ordinary differential blasting, and China's open-pit mines often use 50~100ms.
The advantages of multi-row perforated differential extrusion blasting are:
(1) The ore crushing effect is better. This is mainly due to the front slag pile blocking, including the first row of drilled holes can increase the charge and fully crush under the squeeze of the slag pile;
(2) The explosion pile is more concentrated. For mines using railway transportation, the road can not be dismantled before blasting, so as to improve the efficiency of mining and transportation equipment.
The disadvantages of multi-row perforated differential extrusion blasting are:
(1) Large consumption of explosives;
(2) The working platform is required to be wider to accommodate the ballast pile;
(3) The height of the blast pile is large, which may affect the safety of the excavator operation.
As the open-pit mine extends downward, the problem of slope stability becomes increasingly prominent. In order to protect the slope, the blasting of the adjacent slope should be strictly controlled. According to the experience at home and abroad, the main measures are the use of differential blasting, pre-crack blasting and smooth blasting .
One of the main effects of differential blasting is to reduce the seismic effects of blasting. In order to fully exploit the shock absorption effect of differential blasting, the key is to try to increase the number of bursting segments and control the interval between particles.
Pre-cracking blasting of adjacent slopes involves drilling a dense row of parallel drilled holes along the slope boundary, filling each hole with a small amount of explosives, and detonating before the mining zone is blasted, so as to obtain a crack with a certain width and through each borehole. Since this pre-crack separates the mining zone from the slope, the seismic waves from the subsequent mining blast will produce strong reflections on the fracture surface, greatly weakening the seismic waves passing through it, thus protecting the slope.
Smooth blasting near the slope is to drill a dense row of parallel drilling holes along the boundary line, fill the hole with a small amount of explosives, and then blast after the mining hole is blasted, so as to form a parallel rock wall along the dense borehole. The place where smooth blasting differs from pre-crack blasting is mainly in the initiation time. The detonation of the smooth gun hole is later than the first few rows of mining holes, usually lagging 50~75ms.
In addition to this, there is a measure to control the blasting of the last rows of boreholes. The amount of medicine and resistance line of the last rows of drilling holes near the slope should be reduced, which is called "buffer blasting", which can reduce the damage of drilling and blasting to the slope.
Mining and loading operations are the use of loading machinery to excavate ore directly from the ground or blast pile, and load it into the carriage of the transport machine or directly unload it to a designated location. It is the central link of the open-pit mining process, and other production processes such as bursting, transportation, etc. are for mining.
Main equipment: excavator, cable blade, hydraulic shovel and tire front loader.
capital construction investment of mine transportation accounts for about 60% of the total investment in mine infrastructure, and the transportation cost and labor volume account for more than half of the total ore cost and total labor respectively, which shows the important position of transportation in open-pit mining.
Open-pit mine transportation methods: automobile transportation, railway transportation, tape transportation, slope bucket lifting transportation and combined transportation methods, among which dump truck transportation is the most common.
Procurement and transportation are inseparable, and the two influence and restrict each other. At present, the development trend of procurement and transportation technology is mainly reflected in the large-scale collection and transportation equipment, the integration and continuity of procurement and transportation links, and computer automation.
Rock drainage process: railway transportation rock drainage, road transportation rock drainage, tape transportation rock drainage.
Dumping site (waste rock site): a place where stripped materials are stacked, which refers to a place where mine mining waste is discharged centrally.
According to the order of stacking, the dumping yard can be divided into: single-step dump, covered multi-step dump, and slope-type multi-step dump.
According to the soil dumping process, the dumping site is mainly divided into: road transportation dump, railway transportation dump, tape transportation dump and hydraulic transportation dump.