Since reform and opening of China's coal industry, mining technology and equipment has made great progress, in which the development of open-pit mining in terms of technical equipment is changing. At present, China has built six modern open-pit coal mines - Huolin River, Yimin River, Pingyi Antaibao, Anjialing, Yuanbaoshan and Zhungeer. The commissioning of these coal mines has generally achieved good economic and social benefits, especially the beautiful open-air environment has left a profound impact on people from all walks of life - open-pit mining is not actually destroying the environment, but is beautifying the environment and increasing its reputation. .
I. Introduction to the mining process of six open-pit coal mines in China
The current stripping and coal mining techniques of Huolin River, Yimin River, Pingyi Antaibao, Anjialing, Zhungeer Heigougou and Yuanbaoshan are briefly introduced.
Characteristics of the mining process of the six open pit mines:
(1) The coal mining of the six large open pit mines generally adopts a semi-continuous process, namely the single bucket-truck- crusher -belt conveyor process. This process has basically become a fixed trend.
(2) The stripping body is a single bucket-truck process, but it also exhibits a certain continuous process tendency, such as the topsoil mining of Yuanbaoshan and Heidonggou.
(3) The technical characteristics, mining intensity and production capacity of the stripping single bucket-truck process have been fully recognized. The overall economic impact of mining is recognized. The shortcoming of high truck transportation costs is the common concern of the industry. It is expected to change the status quo of this process and add to the open-air mining.
Second, several mining technologies that can be noisy and promising
(1) Bucket excavator - cantilever type earthmoving machine discharging technology
1,20 early 1960s the Soviet Union Dnieper near Izhevsk former manganese ore, using a cantilever on the release Dump machine with bucket wheel excavators and stripped across the abandoned pit stripping technology system, made more prominent Technical and economic effects. This process was affirmed by later industry players and was also known as the Soviet mining method.
The basic characteristics of the process:
(1) The bucket excavator stands on the roof of the beneficial deposit, and the dumper is at the same level or below the bucket excavator;
(2) The exploitation of beneficial minerals is usually in the form of single bucket-trucks, transport passages with two ends, and intermediate trenches;
(3) The bucket excavator can use the transfer machine for joint operation.
2. The cantilever type of earthmoving machine made by the former Soviet Union has three types: crawler type, step type and track type.
From the step of the dumping field formed by the cantilever type earth-moving machine, the corners of the earth-moving machine can be used to divide the steps to form a plurality of earth-moving steps.
Compared with the traditional bucket-belt conveyor-discharger excavation process, this kind of process is mainly based on the fact that a cantilever type earth-moving machine can be used to replace the traditional process. Machine (working surface + end help + earth drain line) + earth-moving machine and all its power supply facilities, etc., from the surface form, the superiority of the cantilevered earth-moving machine is large (the utility value of the model ощр5000/190 and below) is relatively large.
3. The practical effects of the former Soviet Union
Since the 1960s, three manganese mines have been carried out on the stripping-cantilever type earthmoving machine, and the conventional wheel-belt conveyor-discharge machine discharging process practice, they summarized and analyzed The stripping cost of the two processes will help us understand this new process.
The first comparison is the combination of the Fuqin manganese mine: this group compares the cost of a 4500-90 cantilever dumper with a M5000 type dumping bridge and a 5km belt conveyor + 90m discharge arm. The former has obvious advantages. ;
Group 2 Comparative Group Gorushev Manganese Mine: This group compares the cost of a medium-duty bucket-medium-sized long-arm dumper with the cost of a small wheel bucket +1.7km belt conveyor + short-arm earth-moving machine, the latter Obviously at a disadvantage;
The third comparison group Zaporozhin manganese ore: the contrast is the ratio of medium-sized wheel bucket + medium-sized long-wall dumper and medium-duty bucket +5km belt conveyor transport + medium-loader dumping cost, because the former data is less, not easy Make an accurate assessment.
From the data of the first and second comparison groups, the superiority of the longwall cantilever tractor is obvious.
It should be noted that the 1970s large-scale development of metallurgical technology, nickel element and fine grain steels applications have greatly reduced the weight of the boom or row Dobashi dump machines, the superiority of its application more prominent.
(2) Continuous mining process of bucket excavator
Bucket excavator - belt conveyor - earthmoving machine dumping and bucket excavator - belt conveyor - splitting station coal mining technology belongs to this category, can coexist at the same time, or can exist in different parts. The basic content of the continuous mining process of the bucket excavator is well known. This paper only introduces the basic direction of the selection of the bucket excavator and some major problems of the compact model.
1. The basic direction of the selection of the bucket excavator
There are three types of bucket excavators, such as extra large (double suspension), normal (C-frame) and compact. According to China's national conditions, most of the open-air peers believe that for a relatively long period of time, if the development of open-pit mining in China is selected, the basic selection direction should be compact. The main basis is:
(1) The compact bucket wheel arm frame is short, the luffing mechanism is simple, the structure is compact, the machine weight is light, and the cost is low. The technical economy of the compact bucket excavator can be seen from Hoffman's relative economic indicators. For example, Yuanbaoshan's C-frame type with a capacity of 3100m 3 /h weighs 2300t, and Zhungeer's compact bucket excavator with a cutting force (120kN/m) and a capacity of 3150m 3 /h. Not more than 400t, the difference between the two is more than 4 times, but the latter performance is superior;
(2) Simple operation and convenient maintenance.
To this end, this paper analyzes the structural characteristics, advantages and disadvantages of the compact wheel bucket.
2. Structural features and advantages and disadvantages of compact bucket excavator
(1) Structural features: The excavation radius and unloading radius of the compact bucket shovel are short; the hydraulic cylinder is used for amplitude modulation; the running mechanism is simplified to the double track type; the balance frame of the equipment is located under the body and connected to the platform by a flange. Side, so the height of the body is reduced.
(2) Advantages and disadvantages of compact excavator: Due to the small excavation radius and small height of excavation, in order to meet the needs of mining step height, it is necessary to be equipped with a transfer machine to assist the operation, forming a combined step operation mode, and the equipment utilization rate is better. Low; due to the small digging radius, the mining width is small, and the double-widthing operation is adopted; the stratified propulsion is not large, the auxiliary working time in the mining process is increased, and the effective production capacity utilization coefficient is lower than that of the full linear parameter. % or so; due to the small degree of stratification, the delamination time of each stratification is small, so it is not suitable for side work surface operation, and is not suitable for the selection of working face with large workload; practice shows that the production capacity of the shovel The square of the diameter of the bucket wheel is proportional to the relationship (Q+h=CD 2 ) and the effective production capacity utilization coefficient is proportional to the ratio of the length of the excavating arm to the diameter of the bucket wheel (L/D). The three types of effective production capacity utilization factors are (full linear parameter 0.79, L/D=4; semi-compact 0.75, L/D=3.5; compact 0.63, L/D=2). The compact bucket excavator has an important advantage. In addition to the standard model, it can increase the driving rate and weight in a certain range, and form a variety of enhanced cutting force and high production capacity. There is a large room for optimization in the selection of equipment. There is only one characteristic curve for the bucket excavator with full linear parameters, and the compact type has a number of enhanced characteristic curves in addition to the basic characteristic curve.
(3) Design practice
1. Yuanbaoshan stripping process: bucket excavator + connecting bridge + diversion station + dumping machine dumping;
Coal mining technology: bucket excavator + connecting bridge + diversion station, deep coal seam is semi-continuous process, the broken coal enters the diversion station and goes to the coal preparation workshop.
2. Compact excavator with enhanced surface soil layer in Heilongjiang, standard transfer machine and earth-moving machine. The current production is normal.
3. The Shengli Open-pit Mine has been fully exploited by continuous process (except for the 5 # coal seam due to the existence of a large number of stripping and selection reasons, the open-pit mining machine process) and the large interlayer between the 5 # and 6 # coal seams are stripped by the bucket. The mining scheme is compared and compared with the basic scheme of single bucket-truck and stripping outsourcing.
Evaluation of the above three options:
(1) As a starting point for the promotion and guarantee of the construction of open pit mines, the single-dump comprehensive scheme has many advantages, and the economic evaluation indicators are within the reasonable range, which is the first plan;
(2) From the perspective of long-term development and development, the number of buckets should be counted. Although the investment is large, a low-cost factor can largely compensate for the shortcomings and achieve reasonable evaluation indicators. The large mezzanine scheme points out a realistic direction and measure for the mine during the mining process or the turning to the mining project.
(4) Bucket shovel stacking process
The shovel dumping process is about 50% in the United States and about 25% in Russia. Many experts in the industry in Russia have advocated multiple piles of piles, and the number of repeated piles is reasonably repeated 4 to 5 times. In addition to the application of small dragline shovel in the extraction of alkali in China, the practice of this process has not been carried out.
Hookegou open pit mine bucket dumping
1, 1 shovel dumping plan (simple stacking)
2, 2 shovel dumping scheme (complex inverted stack)
3, the problem of the reverse heap plan
(1) 1 shovel dumping in the pile proves that the 2750W or 2750WS shovel is suitable for the section height of 45m; the 2 shovel stacks have a reasonable height of 50m. 45m, 50m or not, the most important thing is to prove technically that this type of bucket shovel can be used for reverse stacking in the black trench, which can be a promising process;
(2) The economic analysis of 2 shovel complex inverted piles shows that the stripping cost of the single-dump integrated process is higher than the cost of the new process by more than 3 yuan (the new process cost is 58% of the old process cost), the difference is Very large, proven to be economically secure as a developable process.
Third, summary
(1) The application of semi-continuous coal mining in open pit mines has been successful, and the problem of the capacity of crushers is worth studying.
(2) In the conditional mines (mines with a small scale and short working lines), the application research of single bucket-transfer machine-mobile crusher is recommended.
(3) In terms of the stripping process, the above three mining processes have development prospects, and it is worthwhile to continue to conduct in-depth research and conduct more specific research work in open-pit mines with suitable conditions.
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