Prevention and control technology of roof fall acc

Prevention and control technology of mine roof fall accident

in mining production activities, the most common accident is roof fall and caving accident. Roof fall and caving are caused by the instability of ore and rock. When strong ground pressure is transmitted to the roof or two sides, the ore and rock are damaged

most roof falling accidents are caused by local falling and pumice, while large-scale falling and falling accidents are relatively few. Therefore, sufficient attention must be paid to the prevention of local falling and pumice. The main causes of roof fall and caving accidents are: poor geological conditions of the deposit, unreasonable mining methods and poor roof management, lack of effective support, poor inspection and negligence, improper handling of pumice, ground pressure activities, etc

(I) prevention of roof falling accidents

to prevent roof falling accidents, we must strictly abide by the safety technical regulations and take comprehensive preventive measures from many aspects. Wang wants to take the following measures

(1) selecting reasonable mining methods, selecting reasonable and safe mining and beneficiation methods, formulating specific safety technical operation procedures, and establishing normal production order and operation system are important measures to prevent roof falling and caving accidents

(2) do a good job in geological investigation. The geological structure of the working face promotion zone should be investigated clearly, and reliable safety measures should be taken when passing through the dangerous zone

(3) to strengthen the management, support and maintenance of the roof of the working face, the distance between the permanent support and the heading face must be shortened as far as possible. Temporary supports must be erected between the heading face and the permanent supports. All shafts and roadways should be checked regularly. If there are bent and skewed supports whose hardness indicates the ability of the material to resist hard objects pressing into its surface, and which are decayed, broken or broken, they must be replaced or repaired in time. To choose a reasonable support method, the support should have sufficient strength. The support should be timely, and do not work under the empty roof

(4) handle the goaf mining in time. The relationship between mining and goaf treatment should be handled well, and the correct mining sequence should be adopted to fill, support or collapse the goaf in time

(5) adhere to the regular circular operation, speed up the work progress and reduce the roof exposure time

(6) strengthen the inspection and treatment of roof and pumice. The load of pumice permanent elongation reaching a specified value is very common and common after blasting in stope and heading face. Pumice should be strictly inspected and cleaned to prevent pumice from falling and causing casualties. Simple methods and instruments can be used to inspect and observe the roof. Commonly used simple methods include wooden wedge method, marking method, listening judgment method, vibration method, etc. In addition, roof alarms, mechanical dynamometers, steel string piezometers, geophones and other instruments can also be used to observe roof and ground pressure activities

(II) treatment of roadway roof fall

roadway roof fall mostly occurs in the soft zone of rock formation and broken zone. The treatment of roadway roof fall should take corresponding measures according to the actual situation and local conditions, mainly including the following common treatment methods

(1) anchor spray method. When there is a pressurized air system in the roadway and the surrounding rock conditions permit, the anchor shotcreting method is widely used to deal with roof fall, which not only saves time and materials, but also works safely

(2) Wedge impact method. Wedge impact method is a kind of advance support method. Under the cover of advance support, the roadway top plate can be completely not exposed. This method requires that each support should be firm and reliable, and the front and rear supports must be connected as a whole with braces and nails

(3) wooden pile method. When the scope of caving is small and the roof of the caving area can still maintain a balanced state within a certain period of time, the wooden pile method can be used

(4) the principle of penetrating the beam and protecting the top is pulse reflection method (also known as radar method). When the height of the roof fall is not high but the length is large, and it is difficult to deal with it by the wooden pile method, the beam passing roof protection method can be used

(5) artificial false roof method. When the roadway roof fall is serious and other methods are difficult to deal with, the method of drilling and grouting to form artificial false roof can be used