A method of mining the deposits with maintenance of permanent control of deformation of the surface, especially within the range of the influence of mining

Description

[0001] The subject of the invention is a method of mining the deposits with maintenance of permanent control of defor­mation of the surface, especially within the range of the influence of mining.

[0002] At the present time mining of deposits of useful minerals, especially with the roff-fall lining system, brings about considerable deformations of the ground surface. The range of the influence of the surface being deformed depends on the thickness and the dimensions of the deposit being mined. Abatement of the influence on the ground surface is necessary in the case of mining under objects requiring protection, such as industrial plants, bridges, overpasses, housing estates, etc. In such cases mining should be carried out with the appli­cation of the hydraulic filling which considerably raises the mining cost, e.g. in the case of mining coal beds, and creates also additional hindrances in carrying out the unterground mining. Besides, each mining causes degradation of the natural environment, in the form of gangue dumps, washing tanks in which postfloatation was­tes deposit, as well as settling tanks of silty impurities coming from the hydraulic filling. Every year the quan­tity of solid impurities produced in the result of mining works in hard coal -, ores-, iron-, salt- and other use­ful mineral mines, increases. Superficial protection categories for particular objects under which or within the reach of which mining is carried out impose the mining system. In the coal mining there are two basic methods thereof, i.e. with the roof-fall or with the filling. The roof-fall system of the lining is applied only when the surface does not require special protection. Those skilled in the art know also the method of preventing the deformation of mine heading lying above the coal bed being mined by means of the roof-fall system according to the Polish patent specification no. 124391, consisting in hydraulic gapping of the rock mass between the protec­ted heading and the mining, following the progress of the mining front below the higher level, and then filling the gap thus formed, for example, with the solution of bentonite or the solution of bentonite silt whose com­position is selected so that solid parts are slowly isolated as time passes, to form a hydraulic cushion in the rock mass.

[0003] The object of the invention is to work out a method of mining the deposits, which would enable permanent control of deformation of the surface, depending on the requirements. The present invention solves the problem unknown in the hitherto existing mining practice and science, namely, it enables carrying out the roof-fall mining in any place and site, utilizing for this aim the zone of deflections of rock masses over the field being mined in an vertical distance determined by lithology of rocks over the heading and holes drilled from the surface in areas whose sides are approximately equal to the length of the front of the wall being mined, into which solid impurities with water are forced. Skew or vertical holes are drilled from the surface ahead of the mining fronts, so that after passing of the fronts it is possible to start forcing in impurities such as silty parts, postfilling parts, profloatation sludges, ground stone, etc. Impurities with water are forced by means of pressure pumps. On the other hand, holes are cased with steel tubes, and from the top a holder tube is mounted in the hole. The active part of the hole, through wich solid impurities are forced in, is provided with a perforated tube or the said part is not cased, if geological formations are of a considerable strength. The amount of forced-in solid impurities present on the surface depends on the mined colume. Forcing in the solid impurities which can form a so-called pulp will bring about filling the produced void over the mining area in the section close to the section of the semiellipsoid. The area of the semiellipsoid is a little bigger from the area of the mined field, and its size results from the angle of the range of the mining influence. Solid impurities (wastes) form the material filling the semiellipsoid. The filling material may be other solid impurities degrading the environment, as well as various chemical compounds meeting the requirements of filling materials. Forcing of filling materials is carried out through conduits and frequency thereof as well as time of continuous forcing-in depend on the time of subsidence of the rock mass strata and the di­mensions of the void formed or of delamination. Filling the formed voids or delaminations enables permanent con­trol of deformation of the surface, and thus roof-fall-­or filling mining under objects requiring protection. Each hole may be utilized for mining of one or more beds of a useful mineral. Then, the hole, after filling the volume of the area resulting from one bed, is not liquidated but is left for mining of the next bed. In the said area the whole of the surface of the bed or beds planned for mining is divided into areas having sides approximately equal to the length of fronts of the wall. In the said areas in the points of intersection of the diagonal holes are drilled for forcing-in the filling materials. In the case when the filling should be equal to the volume of the hydraulic filling, additional holes should be drilled between areas. Forcing in the filling medium to the rock mass over the mining enables to eliminate the expensive hydraulic filling and to improve considerably safety of traffic in mines, as well as to limit further degradation of the natural environ­ment. The invention enables carrying out roof-fall mining under objects requiring protection of the surface.

Claims

1. Method of mining the deposits with maintenance of permanent control of deformation of the surface, especially within the range of the influence of mining, with the application of waste materials as the filling medium, characterized in that ahead of the mining front from the surface holes are drilled to the strata subject to deflection in the result of mining and then after passing of mining through the said holes filling media are fed, which form in the overlaying strata a filling in the form of an irregular semiellipsoid whose size is directly proportional to the function of pressure in a hole or holes.

2. Method of mining the deposits with maintenance of permanent control of deformation of the surface, especially within the range of the influence of mining, with the application of waste materials as the filling medium, characterized in that holes are arranged over mining areas so that the filling material covers to the sufficient degree the whole mining area, whereby to each hole an area is subordi­nated, preferably the square whose side is equal to the length of the mine heading front, depending on the depth of the kind of rocks overlaying the mining.

3. Method according to claim 1, characterized in that free unfilled spaces between irregular semiellipsoids are liquidated by drilling in these places additional filling holes having the depth of the basic holes.

4. Method according to claims 1 and 3, characterized in that at drilling the basic and the auxiliary holes full tube-casing is applied.

5. Method according to claims 1 and 3, characterized in that at drilling the basic and the auxiliary holes tube casing with the lower part perforated is applied.

6. Method according to claims 1 and 3, characterized in that at drilling the basic and the auxiliary holes only partial tube casing is applied.

7. Method according to claims 1 and 3, characterized in that as the filling material spreads in the rock mass a solid additional supplementary filling is applied till complete subsidence of the rock mass.