Abstract: Disclosed is a method for determining a whole macro-micro process of rock deformation and failure based on a four-parameter test, including following steps: firstly, obtaining acoustic emission data and deformation data of a sample in a compression test, and then calculating the deformation data according to a finite deformation theory to obtain a mean rotation angle ? at each stress level; using Grassberger-Procaccia (G-P) algorithm to calculate the acoustic emission data, and obtaining a fractal dimension of a temporal distribution DT of an acoustic emission signal and calculating a fractal dimension of a spatial distribution DS; obtaining a microscopic morphology of a fracture surface by scanning electron microscope (SEM) test after the compression test, and calculating a fractal dimension DA of the fracture surface; finally, obtaining a mathematical trend relationship between ? and DT, DS and DA according to a comprehensive analysis of DT, DS, DA and ?.

Abstract: Provided is a gas-solid fluidized bed dry beneficiation process using a beneficiation density gradient, including: in a dry beneficiation system of a gas-solid fluidized bed, selecting coarse particles and fine particles; placing the coarse particles at a bottom of the dry beneficiation system, and placing the fine particles above the coarse particles, wherein the coarse particles and the fine particles are separated under an initial condition; under an effect of a gas flow, the coarse particles and the fine particles being fluidized to form a high-density beneficiation region and a low-density beneficiation region, respectively, and the coarse particles and the fine particles being mixed at a contact interface to form an intermediate-density beneficiation region; and feeding minerals to be beneficiated from an upper portion of the dry beneficiation system to pass through the low-density beneficiation region, the intermediate-density beneficiation region, and the high-density beneficiation region in sequence.

Abstract: A method for constructing a dam inside a dump of an inner-dump strip mine includes: taking an upper surface connection line of a primary water-resisting layer as upper filling reference datum boundary of an artificial water-resisting layer; arranging a dam foundation pit and a trapezoidal abutment on a midline of the dam foundation pit; building and reinforcing a step-shaped retaining dam core wall on the artificial water-resisting layer; laying a foundation impervious layer, waterproof geotextile, and an earth blanket on one side, close to the primary aquifer, of the retaining dam core wall; strengthening advance of a dumping working face on one side, away from the primary aquifer, of the retaining dam core wall, and dumping overburden of a strip mine to form a support; filling a space between the earth blanket and the primary aquifer to form a blocker; and proceeding with construction and forming a continuous retaining dam.

Abstract: The present disclosure relates to the field of mineral processing and separation, and in particular, to an underground coal hypergravity field separation system and a separation process. The separation system includes a grading hydrocyclone group, hypergravity field separators, feeding pumps, and conveying pumps. Coal collected underground is graded through a grading hydrocyclone first, then is fed into the hypergravity field separators for separation, and finally, is conveyed to a next link for dehydration through the conveying pumps. The separation system of the present disclosure has less supporting equipment, small floor area, and no complex pipeline, and is suitable for a downhole operation. In addition, the hypergravity field separators can provide a high-strength centrifugal acceleration, which can realize rapid separation of coal gangue particles in a radial direction and a tangential direction, and realize effective separation of fine coal gangue particles.

Abstract: A sealing method for a drilled hole in three zones of overburden comprises: blocking the fissure zone and the caving zone with at least one filling bag; and transporting prepared cement slurry to the drilled hole through a hollow drill pipe, so as to block the curved subsidence zone. The three zones of overburden comprise a fissure zone, a caving zone and a curved subsidence zone.

Abstract: An experimental method for coal desulfurization and deashing using permeation and solvating power of a supercritical fluid includes the following steps. The coal sample is ground and loaded into an extraction kettle with a cover. An inlet valve and an outlet valve of the extraction kettle are opened to circulate the supercritical CO2 fluid in the extraction kettle. The extraction kettle is sealed. By adjusting a temperature and a pressure in the extraction kettle, the supercritical CO2 fluid is kept at its critical point and permeates the coal sample to dissolve organic sulfur, inorganic sulfur and ash in the coal sample. The extraction kettle is depressurized, and the temperature in the extraction kettle is adjusted to gasify the supercritical CO2 fluid. The organic sulfur, the inorganic sulfur and part of the ash are separated from the supercritical CO2 fluid and precipitated at a bottom of the extraction kettle.

Abstract: A monitoring device and a monitoring method for dynamic development of an overburden mining separated bed are provided. The monitoring device includes a settlement magnetic ring assembly and a mounting conduit. The settlement magnetic ring assembly includes an anchor strap assembly, a magnetic induction iron ring and a magnetic ring sleeve sleeved outside the magnetic induction iron ring. The anchor strap assembly is arranged at the outer circumference of the magnetic ring sleeve and has a contraction state and an expansion state. The anchor strap assembly in the contraction state can move in a monitoring hole, and at least two fixing points at different heights are formed in the anchor strap assembly in the expansion state and the wall of the monitoring hole in a vertical direction. Two ends of the mounting conduit are connected to a drill rod and the magnetic ring sleeve respectively.

Abstract: A frictional force monitoring system for middle troughs of a scraper conveyor, comprising a scraper conveyor system and a sensing detection system. The scraper conveyor system consists of a machine body, middle troughs, thrust lugs, scrapers, a double chain, a sprocket, a speed reducer, an electric motor and a frequency converter. The sensing monitoring system consists of force receiving modules, a three-dimensional force sensor, and a pre-embedded temperature sensor. The frictional force monitoring system is able to monitor impact loads, frictional forces, friction coefficients, temperature, etc. between an annular chain, coal bulk, and middle troughs of the scraper conveyor under complex and severe operating conditions, and to provide the technical means for the design, safety early-warning and health evaluation of the scraper conveyor, and can provide a data basis for studying friction wear and fatigue breaking mechanism of middle troughs of a scraper machine.

Abstract: An in-situ methane explosion shaped charge perforating device with a molecular sieve is provided and includes a body, an end of the body is fixedly connected to the molecular sieve, two sides of the molecular sieve are fixedly connected to two baffles respectively, each baffle is embedded with several first check valves inside, an end of the body far away from the molecular sieve is fixedly connected to a fixing plate, a center of the fixing plate is embedded with an ignition device, a bottom of the fixing plate is embedded with a concentration sensor, a portion of the fixing plate between the ignition device and the concentration sensor is formed with an air extracting hole, inner walls of a top and a bottom of the body are symmetrically embedded with second check valves, and the ignition device and the concentration sensor are electrically connected to an external controller.

Abstract: The present invention is directed towards a process for upgrading lignite comprising: prior to production pre-assess the calorific value of the coal, by selecting a relational expression between a calorific value of lignite and a degree of metamorphism, a moisture content and an ash content thereof based on a ratio of the ash content to the moisture content, pre-assess the calorific value of the coal; combining a relational expression between a production cost and the ash content and moisture content to make a cost budget; determining degrees of deashing and drying; selecting and implementing a lignite ash reduction pretreatment process; and implementing dry sorting first and then drying. The upgrading process has high sorting efficiency, high drying efficiency and low production cost, and meets the requirement for the surface moisture of the raw coal in the dry sorting operation.

Abstract: The present disclosure relates to a technical field of coal mining, particularly to a method of no-pillar mining with gob-entry retaining adapted for fully-mechanized top coal caving in a thick coal seam, which comprises the following steps: reinforcing support on a roof and two sides of a roadway; performing roof slitting blasting to form a pre-splitting slit; erecting a temporary support device and a gangue retaining device in the roadway along the retained entry; performing no caving within a range of a preset distance at an end of the working face near the retained entry side; and removing the temporary support device in the roadway after entry forming stabilizes, and closing the goaf to complete entry retaining.

Abstract: An intelligent control method for a dry dense medium fluidized bed separator includes supplying air to fluidize a bed; estimating an initial bed density according to a washability curve of a raw coal; detecting a magnetic material content in the bed to obtain a real-time bed density, and adjusting the real-time bed density according to a result from an analysis on a deviation from the initial bed density; during separation, adjusting a medium addition amount and a scraper discharge speed to maintain a stability of a bed height; separating the raw coal in the dry dense medium fluidized bed separator to obtain a clean coal product; and detecting a product ash content of the clean coal product, comparing the product ash content with a target ash content, and if a difference between the product ash content and the target ash content exceeds an expectation, adjusting the initial bed density.

Abstract: Provided are a system and a method for monitoring bearing compression rate of a filler in a coal mine gob area. An ground information processing system, a vibration source control system, and a monitoring system are arranged on the ground according to a buried depth of the filler in the gob area. The vibration source control system generates vibration, and transmits a signal to the filler. The monitoring system on the ground receives different reflected waves according to different elasticities of the fillers under different compaction degrees. Final data is transmitted to the ground information processing system for data processing. The monitoring of the filler starts when the filler is filled in the gob area; the filler is gradually compacted. The filler is monitored until the thickness of the filler does not change. Finally, a bearing compression rate formula is utilized to calculate the bearing compression rate of the filler.

Abstract: 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.

Abstract: Disclosed is a device and method for distributed detection of straightness of a working face of a scraper conveyor based on optical fiber sensing. The device includes a broadband light source, a first optical fiber circulator array, a second optical fiber circulator array, a collimator array, a reflecting film array, a third optical fiber circulator array, and an optical path analyzer. During transmission of light emitted from the broadband light source, the light with different wavelengths is separated via several optical gratings etched on a single-mode optical fiber (SMF), and reaches reflecting films adhered to the working face of the scraper conveyor through first optical fiber circulators, second optical fiber circulators, and collimators. The light with the different wavelengths is then reflected back from the reflecting films, enters the SMF through third optical fiber circulators, and finally enters the optical path analyzer.

Abstract: An electro-hydraulic proportional valve includes: a valve core; a valve sleeve, sleeving an outside of the valve core; a valve body, sleeving an outside of the valve sleeve and fixedly connected to the valve sleeve; a left end cap, covering an end of the valve body, a left sensitive cavity being defined by the left end cap, the valve body, and the valve sleeve; a right end cap, covering the other end of the valve body, a right sensitive cavity being defined by the right end cap, the valve body, and the valve sleeve; a driving mechanism disposed out of the valve body; and a transmission mechanism connected to the driving mechanism and the valve core.

Abstract: Disclosed is an underground coal preparation process adopting a water medium, comprising: feeding exploited raw coal into a ?25 mm raw coal classifying screen for screening; performing dry coal preparation on a classifying screen oversize product with a particle size greater than 25 mm and feeding a classifying screen undersize product with a particle size less than 25 mm into a special underground compact jigging machine for sorting to obtain jigging machine overflow clean coal, jigging middling coal and jigging gangue; screening and dewatering the jigging machine overflow clean coal to obtain a clean coal product, and screening and dewatering the jigging middling coal to obtain a middling coal product, sorting slime water to be sorted and generated during sorting to obtain coarse clean coal slime and coarse middling coal slime, and performing circulating water treatment on a final liquid.

Abstract: An automatic coal mining machine and a fluidized coal mining method are provided. A first excavation cabin is configured to cut coal seam to obtain raw coal and to be transported to a first coal preparation cabin for separating coal blocks from gangue. Then, the obtained coal blocks are transported to a first fluidized conversion reaction cabin. The first fluidized conversion reaction cabin converts the energy form of the coal block into liquid, gas or electric energy, which is transported to a first energy storage cabin for storing. Coal mining and conversion are carried out in underground coal mines, so it is not necessary to raise coal blocks to the ground for washing and conversion, thereby reducing the transportation cost of coal, improving the utilization degree of coal, and avoiding the pollution of the ground environment caused by waste in the mining and conversion process.

Abstract: An experiment system and transparent experiment method for replicating fluid displacement in a pore structure of a natural rock mass are provided. The natural pore structure is extracted and a digital porous model corresponding to the natural rock mass is reconstructed with the image processing method. Based on the digital porous model, a three-dimensional pore structure model with a transparent and visible internal structure is printed by a 3D printing device, such that the pore space inside the three-dimensional pore structure model is visible. In this way, the whole fluid flow during the displacement-seepage process within the natural rock mass can be replicated and visually observed from the outside when performing the displacement-seepage experiment. Further, temperature, flow rate, and pressure can be accurately controlled, to replicate various experiment conditions, so as to perform quantitative analysis on distribution features of a seepage field and a fluid speed field.

Abstract: A hoisting apparatus for a mine vertical shaft, a hoisting system for a mine vertical shaft and a controlling method thereof are provided. The hoisting apparatus includes a driving device provided at a wellhead and a guiding device provided in a vertical shaft. A position of the guiding device corresponds to a position of the driving device and a transmission rope is wound around the driving device and the guiding device. Moreover, the driving device is drivingly connected to the guiding device via the transmission rope; and a tension regulating device is provided in the vertical shaft. The guiding device is movably provided at the tension regulating device that is for regulating a distance between the driving device and the guiding device. The tension regulating device controls a tension of the transmission rope by regulating the distance between the driving device and the guiding device.