SU836364A1 - Method of preventing dynamic phenomena at working of coal beds - Google Patents

Description

I

The invention relates to the mining industry, in particular, to methods of preventing dynamic phenomena, including rock blows during the development of thick beds, as well as suites of very closely spaced coal beds with very strong lateral (host) rocks of considerable thickness. .

Methods are known for the prevention of various dynamic phenomena, including rock bursts; using advanced and targetless mining of the protective layer (layer), as well as by changing the physicomechanical elastic properties of the coal massif by camouflet blasting, water injection and drilling of relief wells 1.

However, the experience of developing coal deposits with very strong and powerful host rocks, especially at great depths, shows that these methods do not always prevent various dynamic manifestations, including rock blows, due, for example, to the hang of very strong and powerful rocks. roofs on large areas,. and then their sudden collapse as well

the formation of pressure cracks (fracture) in strong and powerful soil rocks.

There is a method of preventing rock bursts, which in the sequential development of two contiguous layers from the bottom of the lower layer into the rocks of the roof and at an angle to the normal of the layer, inclined explosive wells are drilled towards the zone of maximum stresses located at the lower boundary stopped at the upper the seam of the bottom pillar or left pillar, t, e. carry out the torpedoing of the enclosing rocks 2.

However, this method has a relatively limited scope and does not exclude dangerous dynamic manifestations, including rock bursts, for reasons related directly to the reservoir under development, for example, in the marginal parts of arrays, or very strong host rocks mentioned above roof hangs or cracks in the soil.

Claims (3)

The aim of the invention is to improve the safety and efficiency of mining in the development of powerful and very close coal seams with very strong enclosing rocks of considerable power, by eliminating dangerous freezes and sudden collapse of the roof, as well as the formation of cracks in the soil. This is achieved by the fact that the wells in the roof of the reservoir are located at an angle of 10-25 ° to the formation normal, and additional wells are drilled in the Ilast Soil: perpendicular to the bedding to a depth exceeding half the thickness of the hard rocks and torpedoing them. In addition, after torpedoing, water is injected under pressure of 150–200 atm. During the development of the overburden layer (layer) with long pillars along the strike, the roof rocks are torpedoed before the start of the cleaning works for the entire length of the excavation section from the excavation drift, passed at the roof of the reservoir. During the development of the overburden layer (layer) with a continuous system, the roof rocks are torpedoed from the excavation drift following the advancement of the clearing hole with a lag of 15-25 meters behind it. In FIG. Figure 1 shows the layout of wells in the section across the stretch. no coal strata; in fig. 2 shows a section Ai-.A of FIG. 1. The method is carried out as follows. The wells 1 in the rocks of the developed stratum or very closely spaced strata during the development of the upper overburden layer (layer) with long pillars along the direction of the drill are at an angle of 10-25 ° to the reservoir normal, the explosive charges are placed in them and the preheater is exploded before the entire length of the excavation of the excavation drift 2, passed at the roof of the reservoir. With a continuous well development system, 1 is also drilled. from the excavation drift and explode following the advancement of the clearing slab with a lag of 15-25 m. a break in the sandstones of the soil after working on a depth exceeding half the thickness of the hard rocks of the sandstones. Moreover, the drilling and blasting of them is carried out before the start of the cleaning works on the excavation field (plot), followed by the drift drift for a distance corresponding to the length of the excavation floor (plot). The distance between the wells along the strike of the coal strata is determined empirically. In order to increase the efficiency of torpedoing of strong host rocks, it is recommended that after injection of explosive charges, injection of water into wells under pressure of 150-200 atm is carried out. The cracks formed by blasting downhole charges will favor the penetration of water into powerful host rocks and their further weakening. The blasting of wells and the injection of water into them are carried out singly or in groups of 3-4 wells in each group. Torpedoing of strong and powerful roofs of rocks eliminates their dangerous sticking and high concentrations associated with them, the stresses in the marginal zones of the masses, caused by their collapse in large blocks and dangerous shock loads on the worked out layers (layers). Torpedoing of soil rocks eliminates the sudden formation of cracks in them and the resulting dynamic manifestations and destruction of arrays. The use of this method will improve the safety and efficiency of mining in the development of powerful and very close coal seams with very strong host rocks of considerable power. Claim 1. A method of preventing dynamic occurrences in coal mining, consisting in the torpedoing of interfering rocks by charges placed in wells, drilled; x in the roof rocks at an angle to the normal of the reservoir, characterized in that, in order to improve safety and efficiency mining in the development of powerful and very close coal seams with very strong interfering rocks of considerable power by, eliminating dangerous freezes and. sudden collapse of the roof, as well as the formation of fractures in the soil, / kneaded wells, are positioned at the top of the reservoir at an angle of 10-25 ° to the normal of the reservoir; the power of sturdy rocks and their torpedoing. 2. A method according to claim 1, characterized in that after torpedoing water is injected into the wells under a pressure of 150-200 atm. 3. Method according to Claims 1, 2, characterized in that during the development of the overburden layer (layer) with long pillars along strike, the roof rocks are pre-punched before the start of the cleaning works for the entire length of the excavation section from the roof of the reservoir.