Mine water in some areas contains excessively erosive SO42- and Mg2+, which significantly affects the stability of coal gangue cement backfilling paste(CGCBP). In this paper, strength evolution process cured filling paste transformation chemical products formed under sulfate erosion was studied. A large number built-in pore generated CGCBP after for 28 d. During MgSO4 solution soaking 0~60 d, that is, early stage magnesium erosion, expansion such as calcium gypsum mainly occurred,...

A neutrophil-extracellular-trap mimic nanoparticle effectively eliminates bacteria in a trap & kill manner.

Filling mining is an effective way to settle the dilemma of “Three Down and One Above” in coal mining. Fly ash gangue can be used as filling materials with significant social, economic, environmental benefits. Using coarse fly base cementing material aggregate, orthogonal experiment paste was conducted this study. The range analysis performed for strength transportation requirements paste, optimum proportion determined by comprehensive balance method. In order verify effect, a dynamic...

After the previous exploitation of coal resources below villages, a large number Residual Strip Coal Pillars (RSCP) have been left. How to mine RSCP without obvious secondary mining deformation on surface has become new direction green at present. In this paper, Cemented Paste Backfill (CPB) is designed replace RSCP. Considering pumpability and strength, orthogonal test conducted comprehensively analyze variation trend different indexes under factor levels, reasonable proportion obtained...

In order to research the influence of high-sulfate mine water on filling paste, macroscopic and microstructural changes paste in sulfate environment were analyzed by uniaxial compression tests, X-ray diffraction (XRD) scanning electron microscope (SEM). The mechanism deterioration cracking was discussed. experimental results show that there are numerous gelling materials specimen during curing period, which can increase strength specimen. After cured soaked solution for less than 90 days,...

Gangue filling in the goaf is an effective measure to control surface subsidence. However, due obvious deformation of gangue compression, effect deserves be further studied. To this end, coal analyzed by theoretical analysis, large-scale crushed rock compression test, and field investigation. Through test rock, behaviour characteristics energy dissipation obtained analysed. The influencing factors predicted amount main are summarized. Besides, equation subsidence coefficients obtained. was...

To assess the impact of sulfate mine water on filling material performance, an accelerated erosion process was used to analyze effects various concentrations, aging periods, and cation types macroscopic properties paste. These encompassed apparent phenomena, mass changes, alterations in uniaxial compressive strength. Observations revealed erosion, causing formation white substances salt crystals specimen surfaces. Initially, all solution-eroded specimens exhibited increased Over time, 5 10%...

In order to study the effects of different concentrations sulfate on strength fly ash‐based coal mine filling paste, using variable control, mechanical analysis, and other means, changes in uniaxial compressive strengths paste blocks soaked sodium solution for durations are studied, their stress‐strain curves discussed. The hydrated products each block analyzed at stages by XRD, results indicate that have after soaking durations. A with a concentration 5% had an activator effect enhanced...

In this paper, simulation tests were conducted with similar materials to study the distribution of residual voids in longwall goaf. Short-time step loading was used simulate obvious deformation period later stage arch breeding. Long-time constant rheological forming. The results show that irregular caving zone is key area old goaf for subsidence control. evolution process stress and fracture stope can be divided into two stages: breeding forming stage. stage, broken rocks are initially caved...

To address the problem of surface subsidence caused by compression filling gangue in deep mines, a layered compaction test was designed based on zonation failure overburden goaf and property gangue. The deformation characteristics natural water-bearing states were obtained. during 0~100 kN loading stage an approximately positive S-type, which reflects relative “advancement” terms deformation. 100~500 inverted “lag” In state, load-time curves dead load consistent. Under condition, curve for...

In order to investigate the effect of different water filling times on compression deformation filled gangue, a large-scale crushed gangue testing system was utilized, and two sets gradient loading experiments were designed. Through rigorous experimental analysis, distinct patterns during constant load stages are elucidated, with particular focus influence timing. Quantitative assessment reveals that early induces rapid deformation, primarily stages, while later exhibit heightened impact...

The disposal of tailings has always been a focal point in the mining industry. Semi-dry stockpiling, specifically high-concentration emerged as potential solution. To enhance stability stockpiling and minimize its costs, incorporation low-cost curing agent into is essential. Therefore, this study focuses on development for unclassified stockpiling. composition system determined based theoretical analysis, reaction mechanisms each are researched. Subsequently, an orthogonal experiment...

In order to reduce the filling cost and improve coefficient of utilization fly ash in coal mine paste, influence desulfurization gypsum quicklime on setting time uniaxial compressive strength (UCS) paste with large quantity were studied using control variable method, mechanical analysis, other means.The hydration products microstructures corresponding age analyzed by X-ray diffraction (XRD) scanning electron microscopy (SEM), results indicate following: can ash-filling plays an important...

Abrasion ratio is an important parameter to estimate the wear resistance of abrasive belt grinding, reacting relationship between material removal and wear, also, its value basis instruct process grinding. The mathematical model obtained by analyzing basic mechanism theory centerless cylindrical grinding in this paper, impact curve which react abrasion ration or cutting depth using software Mathematica. testified paper experiment test for titanium alloy, 45# steel 304# stainless steel,...

Abstract Different methods of longwall full mining partial filling have been extensively studied to meet the special requirements pressure coal resources and residual resources. The research aims reduce production costs, ensure safe efficient mining. Three technologies are proposed: room-pillar mining, parallel strip vertical Numerical simulation Analytic Hierarchy Process (AHP) model utilized analyze effects these methods. results demonstrate that exhibits smallest surface deformation most...

<b><sc>Abstract.</sc></b> <b> Holboellia latifolia is a nutritious fruit, which peel can be processed into tea, fruit pulp made jam, and seed used to extract oil. However, among the existing peeling machine on market, no one separate from of latifolia. Therefore, this research tried design for purpose peeling. The designed equipment mainly composed cutting unit, spinning an automatic identification unit size control system. This also adjust rotation stroke in real time according processing....

Abstract Based on the field measurement of end resistance support during initial weighting basic roof and macroscopic mine pressure behavior period 101,22211,103 301 fully mechanized caving face in Changchun Xing Coal Mine, law working is summarized compared, relationship between length ( strength ) obtained. In range 126-230 m, with increase length, end-of-cycle gradually increases dynamic load coefficient when increases, strata changes from strong to very strong. When short 126-140.5m ),...