DEFINITION of the OPTIMUM SIZES of BARRIER COAL BLOCK AT CLOSING MINES.

Pitalenko E.I.

Questions of definition of the optimum sizes barrier coal block are considered at closing mines. Application of the offered technique will allow to count the block, capable to keep operational properties during all service life.

Barrier coal block are called for prevention mutual influences the next mines, first of all from an overflow of underground waters. Their value has increased especially last years as it is begun enough intensive closing of collieries and cases of the neighbourhood closed and operating mines have become frequent. Cases receipts waters from the flooded developed space of the closed mine in developments of operating mine that has led to occurrence of emergencies are already noted. These events have put before a science and practice some questions, demanding the immediate sanction. First, has not appeared the question of long reliability block in conditions of the large depths, presence of a water pressure and influence technogenesis of the factors (influence of mountain jobs on own and adjacent layers) is investigated.

Now barrier blocks pay off under the formulas received in conditions of job of mineson small (200-300 ì) depths, i.e. for depths, where the working pressure on block are less than strength óãëÿ on compression.

With increase of depth of mountain jobs the geomechanical processes in a mountain file undergo not only quantitative, but also qualitative changes.

As it is visible from the submitted dependences, with increase of a level of pressurein a mountain file the character geology of processes changes also. The stage A corresponds instant warping of a sample of mountain breed, stage B - warping with variable speed, stage C - warping with constant speed, stage D- acceleration warping before destruction. The curves 1, 2, 3 correspond to a various degree of the intense condition dirt of a sample: ?/Rcm- 0,4; 0,6; 0,8 durabilities on uniaxial compression.

The coal layers during the genesis are exposed to action of the raised pressure. In result they and the containing breeds appear broken by system or several systems fissuring, focused, as a rule, it is normal to a plane stratification. During improvement of a coal layer in his regional part under action of a zone of basic pressure the system technogenesis of cracks is formed which, usually, are focused approximately normally to a plane stratification and in parallel lines clearing coalface. Distance between cracks makes from several centimeters up to meters. On mine "Toretskaya" on a layer ê8 "Kamenka" the researches stratification of lateral breeds and layer were executed. For this purpose from drift on normal to a layer (the corner of fall of a layer makes 38°) hole of a chink on depth 12 m with selection coal core. As a result of study selected coal core the system endogenous is revealed fissuring with a step of 0,8-0,9 m. In a coal layer the system of cracks located under a corner 87° to stratification and a step 0,5-0,6 m is revealed.

At conducting mountain jobs with the help long clearing coalfaces in a regional part of a layer the zones of basic pressure are formed. In them the pressure, which above initial in 2-3 times work. In a case, when they exceed strength of coal, in a regional part there is an education of new cracks to intensity till 10-12 1/m.

Fig. 1. A stratification of breeds of ground and roof of a layer l3 at them earn additionally (on the data of gaugings through the equipment "Spectrum"): - - place of the established contacts

During a collection of a coal layer occurs not only redistribution of pressure(voltage) in a mountain file, environmental development(manufacture), but in movement there come breeds of ground and roof. In result the cracks of a stratification are formed which are conductors drained of gas and water. For study of process of a stratification of breeds standard is the method deep [4], developed in VNIMI I.M. Petuhovim and F.N. Voskoboevim, and also kind optical, mechanical or electronic indicator chink [2]. For their realization obligatory drilling chinks is, in which are placed references points or devices, that is very labour-consuming and expensive. Therefore now most accessible is the application of the equipment "Resonance" [3] or more modern - "Spectrum" of a design ÎÔÒÃÏ ÄîíÔÒÈ ÍÀÍÓ. In a basis of a method the effect of different resonant frequencies at various rock of layers is fixed, is especial at presence of stratifications. Primary seismic signal is created by impact of a ham mer in a roof (ground) of development. On mine by Artema IU "Dzerginskcoal" the gaugings in clearing coalface on a layer l3, equipped lining KGU were executed. The layer was earlier earn additionally clearing face on a layer l21-b in, taking place on distance 25 m in ground.