Strong gentle strata in the USSR and abroad are developed mainly by inclined layers with roof collapse. In this system of development rack fasteners in cleaning faces allows to lay in each upper layer of wooden planking or metal mesh, which eliminates coal losses in the thickness of the seam and provides high completeness of excavation. But the use of rack support requires significant costs, heavy manual labor and reduces the production capabilities of the system, which in this form can not meet the requirements of the current period. ...
Проблема разработки мощных крутых пластов с закладкой приобрела особую остроту в Кузбассе, где из-за целого ряда обстоятельств технического характера требуется значительно расширить ее применение, между тем как добыча угля с закладкой развивается здесь весьма медленно. Непопулярность закладки в Кузбассе объясняется, в первую очередь, низкой эффективностью применяющихся там систем разработки. Так, выемка мощных крутых пластов с закладкой ведется до сих пор старыми системами, с делением на слои ...
Сыпучую породу характеризует следующее: 1) массив сыпучей породы состоит из отдельных, не связанных друг с другом кусков твердой породы; 2) куски породы достаточно малы по сравнению с шириной вы рцботки, что практически исключает возможность сводообразования; 3) форма кусков и их расположение определяют возможность возникновения сил бокового распора путем взаимного расклинивания под действием нагрузки. Нередко приходится поддержизать выработки под обрушенной породой или закладкой, свойства которых часто близки к сыпучим породам.
В течение последнего десятилетия гибкие щиты получили широкое распространение при разработке крутопадающих угольных пластов в Кузбассе, где они успешно конкурируют с другими способами разработки. Щитовая разработка в рудной промышленности во многих случаях может заменить малопроизводительную и дорогую разработку слоевым обрушением.
Разработка слоевым обрушением во многих случаях является единственно приемлемой, поэтому вопросы повышения эффективности ее имеют большое практическое значение для рудной промышленности. Однако для этой системы характерны малая производительность забоев и высокая трудоемкость работ, в частности, крепления очистных забоев. Поэтому весьма заманчивым и перспективным является изучение возможности производить отработку слоев с применением только одного гибкого перекрытия . В этом случае рабочее пространство очистного забоя будет находиться между провисающей частью аб гибкого перекрытия и стенкой забоя ав. Успешное решение задачи дало бы возможность отрабатывать слои весьма простым и дешевым способом и тем значительно повысить эффективность системы слоевого обрушения.
Improving the systems and methods for developing thick flat dipping seams is one of the most difficult and at the same time urgent tasks facing the coal mining industry at the present time. The most rational system for developing such seams is usually considered to be inclined layer mining with roof caving, which has become widespread in the industry. Engineering analysis shows that this system has a number of shortcomings. The issue of creating a rational system for developing thick flat dipping seams cannot be considered resolved. A rational system for developing thick flat dipping seams should provide for the exclusion of manually erected support in the working face, as well as the use of a large seam thickness. Among the possible solutions to this problem, the system for developing thick flat dipping seams with forced coal caving is particularly simple.
The greatest difficulties in the coal industry are presented by the development of thick steeply dipping seams. Development of thick seams usually involves high labor costs, significant timber consumption and entails greater coal losses than when developing seams of average thickness. Cases of self-heating of coal and underground fires occur more often when developing thick seams. Therefore, significant material costs are incurred for carrying out preventive measures and extinguishing fires, which increases the cost of coal and often leads to very significant losses of minerals. A major achievement of Soviet mining technology is the shield system of Professor N. A. Chinakala. It has found wide application in the mines of Kuzbass. The decisive factor that determined the high degree of reliability of the shield of Professor N. A. Chinakala, the rapid and wide introduction of this shield in the mining industry, is the direction of its movement down the dip of the seam. The proposed work is an attempt to shed light on issues related to the improvement of the design of shields and the possibility of their use in the development steeply dipping, very powerful strata.
The urgent task is to create and implement reliable and highly productive methods of mechanized fastening of working faces. The article presents various types of shield support for the development of thin and medium-thickness steeply dipping seams in strips down the dip: 1) sectional shield support; 2) U-shaped shield; 3) L-shaped flexible shield; 4) self-braking shield. The horizontal arrangement of the working face and the development of the seam in strips down the dip significantly facilitate the creation of a simple and efficient shield support. In order to reduce the load on the shield elements, reduce metal consumption and ensure the most reliable operation, it is necessary to prefer flexible shields consisting of support frames or short sections (0.5-1.0 m) connected by a flexible connection. With a seam thickness from 0.6-0.8 to 3.0-4.0 m, the use of L-shaped shields is most appropriate. U-shaped shields are less rational due to their excessive bulkiness and difficulty in controlling them when lowering. The proposed shield support can be used in the development of steeply dipping seams with a thickness of 0.6-0.8 to 3.0-4.0 m, with an angle of incidence greater than 50-55° and with medium-hard and strong wall rocks.
In the coal mining industry, the development of thick seams presents the greatest difficulties. In the matter of improving the methods of developing thick steeply dipping seams, the most promising direction should be considered the improvement of known and the creation of new systems that provide for the development of the seam without dividing it into layers with maximum use of natural conditions: high seam thickness, steep dip, etc. Systems for developing thick steeply dipping seams without dividing them into layers, in turn, can be divided into three groups: 1) systems that provide for the development of the seam with chambers (systems of engineers I. N. Koznin, G. A. Lomov, and others); 2) systems that provide for the development of the seam in strips along the dip or rise (the system of Professor Chinakal, the VUGI system); 3) systems that provide for the development of the seam with long columns along the strike (the system of engineer P. I. Kokorin, and others). The proposed article is devoted to the third group of systems that provide for the development of thick steeply dipping strata with long columns along the strike without division into layers. These systems are distinguished by their greatest simplicity, versatility and high efficiency.
The main disadvantage of the existing methods of developing thin and medium-thick steep coal seams is the use of wooden supports in the working faces. Support of the working faces is carried out exclusively by hand and is the most dangerous, difficult and labor-intensive operation. Thus, labor costs for support, timber delivery and control of rock pressure usually make up 50 to 80% of the total labor costs in the working face (see article). A miner spends about two thirds of the net working time on support. If we also take into account timber delivery and work on managing rock pressure (installation of organ support, etc.), then the total time spent on these operations, including support, will amount to approximately 80% of the total labor costs in the working face for coal mining. In the Donbass, chipping hammers are predominantly used, which determines a significantly higher labor intensity of coal mining work. Therefore, work related to support and rock pressure control here makes up approximately 50-60% of the total labor costs in the working face. But in the future, in connection with the introduction of combines, the specific weight of these works will increase significantly and will also reach 80-85%.
