1、附录AGENERAL COMMENTSThe Present Situation and Its Developments of Mining Technique in ChinaSince the founding of the peoples republic of China, remarkable successes have been achieved in Chinas coal industry. The annual raw production is 980million tons in 1988, which is about 30 times that of 194.,a
2、nd located in the forefront of the world.China is one of the countries with richest coal reserves in the world. Her proved coal-bearing area is about 0.55millon square kilometers and her proved reserves are totally 782,234million tons. The coal fields are mainly located in the six coal deposit regio
3、ns ,such as the north-west region, the north-china region the north-east region and so on. Almost all kinds of coal depositions have been found. The amount of coking coal is about 31.55% of the total coal reserves and the amount of coal consumption accounts for more than 70% of the nations total con
4、sumption of energy resources.The management system of Chinas coal mines is a multi-level structure, which consists of the state-run coal mines, the local government-operated coal mines, the coal mines pertaining to village and town collective ownership and the local mines pertaining to individual ow
5、nership. State-run coal mines are the mainstay of the nations coal industry, they are equipped with advanced equipment and technology. While the local government-operated coal mines and the coal mines pertaining to village and town collective ownership are also playing an important role in the devel
6、opment of Chinas coal industry now. In 1988,the amount of raw coal produced by three kinds of coal mine ownerships mentioned above accounts for 44.5%, 24.2%, and 31.3% respectively. IN our country, coexistence of modernization, mechanization and semimechanization still seems to be the technique stru
7、cture of coal mines in a coming long period. In China, the deposit conditions of the coal seams are various, and the mining conditions are complex. Therefore, our country is one of the countries in the world, which have practiced maximum kinds of mining methods. After forty-year improvements, the sy
8、stem of mining methods mainly characterized by longwall mining has been developed, and it goes on a scientific and standard route gradually. In 1988,the coal production produced by the state-run coal mines with standard mining methods accounts for 96.28%, creating the best level in nations coal mini
9、ng history, and the situation of safe production is also the best.Mining technique is the heart of coal mining method and the major factor to innovate and develop the mining method, therefore the innovation and development of coal mining technique to extract gently inclined and inclined seams, form
10、the point of view of its importance, represents the progresses of coal mining technology in our country. The coal mining technique of longwall caving method in gently inclined and inclined seams is innovated and developed in parallel with the innovation and development of equipment for mining operat
11、ion such as cutting, loading, transporting and supporting, etc. The principal criteria to evaluate the advantages of various coal mining technique is based on safety, economy (high production, high productivity efficiency and low consumption) and high extraction rate.The goal of innovation and devel
12、opment of the coal mining technique is to perform full mechanization in the mining operations.With the development of the national economy and the enhancement of the capability to manufacture mining equipment in our country, the mechanization level of longwall faces is immproved continuously, especi
13、ally in the last decade, the speed is even faster.In1988, for instance, the degree of mechanized mining in the state-run coal mines reached 58.32%, of which the fully mechanized mining is 31.36%. In recent year, the development of the coal mining technique of mechanized mining with fully mechanized
14、equipment is continued and with individual hydraulic props is attention to and applied widely as the same time in our country. In 1988,for instance, in the state-run coal mines the mechanized longwall faces with individual hydraulic props contributed 18.19%of the total production of raw coal.The tec
15、hnique of mechanized mining with friction metal props limits the efficiency of cutting machines because of their bad mechanized characteristics and inconvenient setting of the friction metal prop. Hence the application of this technique decrease gradually and will be abandoned in the state-run coal
16、mines, but in the local government-operated coal mines and coal mine pertaining to village and town ownership, the technique is still used now.Up to now, coal mining technique with blasting which is simple for the need of equipment used suitable for various geological conditions is widely applied in local government-operated coal mines in complex geological conditions, even though the technique is unsatisfactory. Recently, this technique has been improved and
