What are the prevention and treatment measures for hard and difficult roof accidents?

Posted on

Roof plate Hardness refers to directly or substantially no thin top, coal layer is covered directly hard sandstone, conglomerate, and a large thickness. After the coal is returned to the column under such a hard roof, thousands of square meters, even tens of thousands and hundreds of thousands of square meters of suspended ceiling can be formed without falling. However, at a certain time, the roof of the roof was pressed and suddenly fell, causing a strong storm impact, causing strong vibrations in the formation, which could destroy the roadway and the working surface, causing casualties.

In order to prevent large-scale roof collapse, some mines use the coal pillar support method to manage the roof, that is, a coal pillar with a width of 5 meters per 30 to 50 meters along the strike, support the roof with coal pillars, and the goaf and the working face. Separated and forcedly placed in the goaf adjacent to the production work surface. A well-placed goaf is generally no longer exposed to large areas. If the goaf is closed, it can be drilled from the ground to the goaf, deep hole blasting and forced topping. In this way, in the area of ​​pressure display, the top plate can be caused to fall down early and reduce the pressure of the top plate; in the area where the pressure is not obvious, some of the top plate can be collapsed, causing cracks in the roof plate, forming an artificial weak plate of the roof plate, so as to facilitate the pressure after the pressure. drop.

The fundamental way to eliminate the roof accident of hard roof is to adopt the longwall all-fall coal mining method. That is, when the working surface is advanced by 20 to 30 meters, the work faces the top plate and the first charge is performed. Later, with the advancement of the working surface, when the overhang is too large, the deep hole blasting is forced to be topped. This greatly eliminates the danger of large areas of pressure and fall on mines and people.

In addition, the use of top plate pre-filled water softening, destroying the integrity of the hard rock formation, reducing its strength, is also a good way to deal with hard and difficult roof.

Spray Dryer

Liquid material is pumped into the top installed centrifugal disc atomizer by mono pump and atomized into fine droplets inside the drying chamber. Meanwhile, clean hot air is blown into the air distributor at the same time. The evenly and swirly distributed hot air completely contacts with droplets for heat transfer. The droplets are dried into powder in several seconds and sucked out into the cyclone for discharging via exhaust fan.
LPG series spray dryer has been widely used in health products, chemical, feedstuff, ceramics, plastic and foodstuff industry for drying liquid material into fine powder.

Spray Dryer,Centrifugal Spray Dryer,Spray Drying Machine,Atomizing Spray Dryer

Changzhou Bole Tech Co.,Ltd , https://www.boledrying.com