An aggregate slinger for an underground void stabilization system, the aggregate slinger comprising a vertically extending shaft and a number of dispersing members. The vertically extending shaft is inserted through a ground hole into an underground void and rotated about a vertical axis in the ground hole. The dispersing members are configured to extend radially from a lower end of the vertically extending shaft in the underground void so that the dispersing members radially spread aggregate descending into the underground void from the ground hole to form a radially enlarged support column of aggregate in the underground void.

Treatment technology directed to using mine waste as a raw material to manufacture a mine filling product for use as a suitable precursor product or mine filling product to be used as a backfill material to close a mine. The precursor product or mine filling product retains its metals and is not be able to generate acidity. According to the disclosure, the precursor product or mine filling product, when placed in a mine, may also remove metals from mine fluids in the mine it contacts, and still retain the metals it hosted when it was a mine waste prior to it being used as a raw material to manufacture the precursor stowing backfill product.

A method for recovering room-mining coal pillars by solid filling in synergy with artificial pillars. Solid materials and cementing materials on the ground are conveyed through a feeding well and a pipeline to a room-and-pillar goaf, a plurality of artificial pillars is cast at an interval in a coal room area, and gangue is cast to fill other regions of the coal room using a gangue casting machine. Under joint support by the artificial pillars and the coal room filler, coal pillars are recovered using a continuous coal mining machine, artificial pillars are cast in the original coal pillar area after recovery, and gangue is cast to fill the original coal pillar area using the gangue casting machine. A system for recovering room-mining coal pillars by solid filling in synergy with artificial pillars mainly includes a material conveying system, a joint support system, and a coal pillar recovery system. By constructing pillar grooves, casting artificial pillars, casting gangue to fill a goaf, and recovering coal pillars, the recovery rate of coal resources can be increased, and room-mining coal pillar recovery theories and technologies in China can be enriched while harmonious development of environmental protection and resource exploitation is promoted.

The present invention discloses a dendritic reverse underground mining method for a thin coal seam at an end slope of a strip mine. The method includes the following steps: step S1: using a continuous coal mining machine to excavate a main adit toward a boundary of the strip mine along a seam floor; step S2: excavating secondary adits on two sides of the main adit obliquely in a forward direction of the main adit; step S3: transporting the excavated coal out of the main adit by the self-moving belt conveyors; step S4: after the excavating of a secondary adit of the secondary adits is ended, withdrawing the continuous coal mining machine and the self-moving belt conveyor from the secondary adit, and then excavating subsequent secondary adits of the secondary adits in a similar way; step S5: filling the secondary adits, and filling a goaf of the main adit.

Polyamide foams which inhibit the spread of fires for filling cavities in mining Polyamide foams which do not propagate fire are obtained by mixing (i) a liquid isocyanate component which comprises at least one polyisocyanate and in which the molar ratio of aromatic isocyanate groups to the sum of aromatic and aliphatic isocyanate groups is at least 60 mol %, with (ii) at least one liquid isocyanate-reactive component which comprises a reactive diluent, and the reactive diluent comprises (a) a chain-extending and/or crosslinking reactive diluent selected from among aliphatic branched C.sub.24-66-polycarboxylic acids, alicyclic C.sub.24-66-polycarboxylic acids and partial esters of polycarboxylic acids having at least two unesterified carboxyl groups and/or (b) a chain-terminating reactive diluent selected from among aliphatic branched C.sub.24-66-monocarboxylic acids, alicyclic C.sub.24-66-monocarboxylic acids and partial esters of polycarboxylic acids having one unesterified carboxyl group, and (iii) optionally a solid isocyanate-reactive component, where the liquid isocyanate-reactive component and/or the solid isocyanate-reactive component comprises an aromatic C.sub.8-18-polycarboxylic acid and/or an anhydride thereof. Reactive diluents are dimeric fatty acids or trimeric fatty acids, which are optionally hydrogenated. The foams are suitable for filling cavities in mining, tunnel construction, civil engineering or in oil and gas recovery, as fire protection foam, thermal insulation or acoustic damping.

The present invention provides for a compressible grout mix for filling an annular gap between a tunnel rock wall surface and a tunnel liner of a tunnel in a rock formation subject to time dependent deformation after excavation and a method of filling the annular gap between a tunnel rock wall surface and a tunnel liner of a tunnel in a rock formation subject to time dependent deformation after excavation utilizing the compressible grout mix for resilient absorption of forces in the hardened state of the compressible grout mix exerted by the time dependent deformation of the rock wall surface into the tunnel opening. The method includes: a. providing the compressible grout mix comprising hydraulic binding agent, bentonite clay, polymer foam particles, water-reducing admixture, water and air, b. placing the compressible grout mix in the annular gap between the tunnel wall rock surface and the tunnel liner, and c. allowing the compressible grout mix to set, wherein the compressible grout mix in the hardened state has a compressible ratio greater than the anticipated time dependent deformation.

The present invention provides for a compressible grout mix for filling an annular gap between a tunnel rock wall surface and a tunnel liner of a tunnel in a rock formation subject to time dependent deformation after excavation and a method of filling the annular gap between a tunnel rock wall surface and a tunnel liner of a tunnel in a rock formation subject to time dependent deformation after excavation utilizing the compressible grout mix for resilient absorption of forces in the hardened state of the compressible grout mix exerted by the time dependent deformation of the rock wall surface into the tunnel opening. The method includes: a. providing the compressible grout mix comprising hydraulic binding agent, bentonite clay, polymer foam particles, water-reducing admixture, water and air, b. placing the compressible grout mix in the annular gap between the tunnel wall rock surface and the tunnel liner, and c. allowing the compressible grout mix to set, wherein the compressible grout mix in the hardened state has a compressible ratio greater than the anticipated time dependent deformation.

The present invention provides for a compressible grout mix for filling an annular gap between a tunnel rock wall surface and a tunnel liner of a tunnel in a rock formation subject to time dependent deformation after excavation and a method of filling the annular gap between a tunnel rock wall surface and a tunnel liner of a tunnel in a rock formation subject to time dependent deformation after excavation utilizing the compressible grout mix for resilient absorption of forces in the hardened state of the compressible grout mix exerted by the time dependent deformation of the rock wall surface into the tunnel opening. The method includes: a. providing the compressible grout mix comprising hydraulic binding agent, bentonite clay, polymer foam particles, water-reducing admixture, water and air, b. placing the compressible grout mix in the annular gap between the tunnel wall rock surface and the tunnel liner, and c. allowing the compressible grout mix to set, wherein the compressible grout mix in the hardened state has a compressible ratio greater than the anticipated time dependent deformation.

An I-patterned filling method for an initial stage of coal mining based on roof fracture characteristics is provided. A relationship between an overburden load borne by a main roof and an overhang size is determined based on principle of virtual work and a surgery theory when an overhang distance of the main roof reaches an initial weighting interval to enter a plastic limit state with an advance of a working face to obtain the initial weighting interval. An initial fracturing interval of an immediate roof is obtained in the same way. According to a subsidence law of the main roof in an inverted hip roof form, the filling is performed at a key position around an internal plastic hinge line through I-patterned three-strip filling. Size parameters of the I-pattered filling are designed to prevent the immediate roof and the main roof from being fractured.

Disclosed is a method for designing supporting parameters of a transition support for a mixed mining face of filling and fully-mechanized mining. The method includes: first, determining a total length of a mixed mining working face and a length of a filling section according to requirements of a coal mining production capacity of the mixed mining working face and a filling capacity of the filling section working face; then, establishing a mixed mining numerical model of filling and fully-mechanized mining by using three-dimensional distinct element software, and simulating and calculating a caving height of a roof of a transition section and a stress influence range of the transition section when a filling rate of a mined-out area of the filling section changes; based on a result of numerical simulation and calculation, performing curve fitting according to a correlation coefficient to obtain a functional relationship between the filling rate and the caving height and a functional relationship between the filling rate and the stress influence range of the transition section; and finally designing supporting parameters of a transition support in combination with actual engineering geological parameters. The method can provide a reference for supporting design of a support, and enables a smooth transition between a filling support and a fully-mechanized mining support for a mixed working face, thereby further enriching filling mining theories and expanding the application range of filling mining.