煤矿井下矸石填充工艺流程的探讨

把矿井的矸石全部填充到井下巷道内 ,国内无先例可鉴 ,文中对此提出几种工艺流程 ,并对其优缺点进行分析 。

东曲煤矿矸石填充方案设计研究

基于东曲煤矿矸石场地选址难度增大,以及环保政策收紧对矿井生产的制约,本文通过技术革新建立了“地面洗选井下回填”一体化协作系统,将地面选煤厂水洗矸和井下煤矸石通过刮板输送机和推压装置完成了采空区的矸石填充,实现了矿井矸石的合理化处理,降低了固态废弃物在地面的堆积排放,改善了矿区周边的生态环境。

矿井废弃巷道矸石填充技术

针对矿井采掘活动中矸石升井处理难、污染环境等问题,平煤股份十矿结合生产实际对利用废弃巷道开展矸石填充工艺技术进行了研究与应用。通过研究矸石运输路线、充填方案及设备等,实现了矸石不升井处理,具有良好的社会和经济效益。

建筑物下煤矸石充填开采技术及实践

煤炭是支撑我国能源生产的基础资源,煤炭的持续、大规模开采造成了许多问题,如矿区生态破坏、建筑物沉降。因此,建筑物下回填控制地层和地表下沉的技术非常重要。目前,煤层颗粒物质、胶结材料和高含水率材料主要用于回填。总结了煤矿使用的回填材料CGFB的类型以及回填过程,提出了矸石充填开采技术的指导原则。实验结果表明随着工作面倾斜长度的增加,沉陷区和待回填区的面积增加。根据模拟结果,提出了煤矸石运动时间的优化方案,并对矸石回填采矿法进行了优化设计,确定了工作面倾斜长度,并缩短工作面以获得较高的充填率,保障了建筑物的安全性。

煤矸石充填复垦区土壤重金属污染程度评价

煤矸石作为采煤排放的固体废弃物,常被用作充填物料填埋于采煤塌陷区或用于构筑堤坝路基。在天然雨水淋溶作用下,煤矸石会析出污染物质对土壤造成影响,因此以创大生态园为例,对复垦区山顶、山腰、山脚三块区域土壤进行布点采样,利用电感耦合等离子体质谱仪(ICP-MS)检测土样中重金属含量,并采用单因子指数法、内梅罗污染指数法和区域综合污染负荷指数法进行污染程度评价,探究煤矸石充填区土壤重金属污染程度及分布规律。结果表示:复垦区土壤主要重金属污染元素为Cd、Cu、Pb;复垦区山顶、山腰和山脚土壤重金属污染程度逐渐加重,山顶和山腰污染程度为尚清洁,处于警戒线水平,山脚污染程度为轻度污染。

深部大采高综采面矸石充填开采技术探究

根据工程开采地质条件,研究矸石充填基本原理与设备,探讨大采高综采面矸石充填工艺、流程和监测与评价工作,展望矸石充填效益分析与推广前景,以期对相关工作有所借鉴。

矸石充填采煤中的矿压显现规律分析

现目前我国能源供应一直处于紧张局面,能源的开采尤其是煤炭资源开采所才到的污染也日益加重,所以为了能够提升我国煤炭资源开采的利用效率和环保性。基于此,本文主要针对我国矸石填充采煤中的实际情况,探讨了矸石填充采煤方式,重点分析了矿压显现的规律,和以往广大同行交流的全过程,从而起到促进我国煤炭开采作业技术水平进一步的发展,予以有关单位参考与借鉴。

Performance of cemented coal gangue backfill

Possibility of cemented gangue backfill was studied with gangue of Suncun Coal Mine, Xinwen Coal Group, Shandong, and fly ash of nearby thermal power plant, in order to treat enormous coal gangue on a large scale and to recovery safety coal pillars. The results indicate that coal gangue is not an ideal aggregate for pipeline gravity flow backfill, but such disadvantages of gangue as bad fluidity and serious pipe wear can be overcome by addition of fly ash. It is approved that quality indexes such as strength and dewatering ratio and piping feature of slurry can satisfy requirement of cemented backfill if mass ratio of cement to fly ash to gangue is 1:4:15 and mass fraction of solid materials reaches 72%-75%. Harden mechanism suggests that the cemented gangue fill has a higher middle and long term comprehensive strength.

Effects of curing under step-by-step load on mechanical and deformation properties of cemented gangue backfill column

A step-by-step load was utilized to mimic the load history of the backfill column in the in-situ curing process.The inner damage of the specimen during curing and uniaxial compressive testing was monitored by electrical resistivity and ultrasonic equipment.Results show that:1)Uniaxial compressive strength(UCS)and elastic modulus(EM)of the samples curing under pressure are higher than those of the control samples without pressure,ranging in ratio from 0.5%to 20.2%and 7.1%to 52.3%,respectively,and are influenced by the initial loading age(ILA)and stress strength ratio(SSR).The SSR during curing should not exceed 80%.2)The earlier the ILA is,the higher the total strain becomes.The higher the SSR applies,the larger the total strain gets.The creep strain increases with the increase of SSR and can be described by Burger’s viscoelastic creep model.When SSR is less than 80%,the earlier the ILA is,the smaller the creep strain becomes after the last step-loading.3)The stability of the early age backfill column under pressure can be monitored based on the change of ultrasonic pulse velocity(UPV)and electrical resistivity.

Biology Migration and Distribution Characteristics of Trace Elements in Reconstructed Soil with Coal Gangue Filling

With mixed gangue,coarse gangue and washed gangue as well as the maize in the reclaimed land in Luling Mine of Huaibei as the research object,the biology migration and distribution characteristics of trace elements in the reconstructed soil with different types of coal gangue filling were studied,the contents of Cu,Pb,Zn,Sn,Hg,Cd and Cr were determined,and the distribution characteristics of the trace elements in the coal gangue and different organs of the maize were analyzed.The results showed that the contents of trace elements were the highest in washed gangue and the least in coarse gangue in the gangue used for the reclamation,and there were significant differences in the enrichment ability of trace elements in different organs of maizes that were planted in reclamation land,of which fruit was weaker than other organs,while leaf presented strong absorption ability.

Analysis of floor failure depth by using electric profiling method in longwall gangue backfill mining

In underground mining, floor failure depth accompanying mining phases usually results from changes in the advance abutment pressure in the coal mass, and changes in stress redistribution in the areas that have already been mined. Although a variety of techniques have been applied to determine the failure depth, and a number of studies have provided the evidence for the decreasing of failure depth under backfilling, these methods and interactions have not been unequivocally identified. Based on the premise of one possible relation between the failure depth and filling body, which is that the filling materials （gangue） in the gob area can not only restrain the movement of the overlying strata effectively, but also can help to decrease failure depth of the floor in the coal mine. The failure depth in a specific longwall gangue backfilling mine was measured using the mine electricity profiling method. These electrode cables are arranged in a crossheading order to measure the depth and position of the destroyed floor using the DC method. After this, several different methods were used to interpret the recorded data from the field study for gaining failure depth, and the results were compared to the theoretical calculation values. And finally, the authors analyzed the reasons for failure depth form values recorded not indicating a large decrease trend when compared to the theoretical calculation. In this area, it is found that： ① The results using the mine electricity profiling method turns out to be robust and can be used in predicting floor failure depth, and the horizontal position of the maximum destroyed in working face of longwall backfilling. The maximum destroyed position and failure space of the floor can be identified by using this method. ②There is a time-delay processing between the advance of the working face and the failure of floor strata in the mining processing. ③Additionally, based on the data collected from field measurements, which includes three different test electrode spacing approaches （single, double and triple electrode spacing）, and the theoretical value from theoretical calculations. The premise mentioned above cannot be supported during the specific field test, and the role of the filling body in the mined area cannot decrease the floor failure depth effectively in comparison to the theory predictions. Basically, the failure depths in the two different methods have similar results and it is possible that there will not be a direct correlation between the filling body and failure depth. ④Although the failure depth cannot decrease effectiveness when using gangue backfilling in the field testing, due to gob gangue, filling materials being able to deliver the abutment pressure from the overburden in most cases, once they were compacted and rammed by the overburden pressure, it still can make the fracture of the gob area clog and be further consolidated. In this way, it is assumed that water-bursting accidents can be prevented effectively under backfill mining. For this reason, gangue backfilling may make a significant contribution to safety mining.

Failure mechanisms and destruction characteristics of cemented coal gangue backfill under compression effect of non-uniform load

Backfill mining is one of the most important technical means for controlling strata movement and reducing surface subsidence and environmental damage during exploitation of underground coal resources. Ensuring the stability of the backfill bodies is the primary prerequisite for maintaining the safety of the backfilling working face, and the loading characteristics of backfill are closely related to the deformation and subsidence of the roof. Elastic thin plate model was used to explore the non-uniform subsidence law of the roof, and then the non-uniform distribution characteristics of backfill bodies’ load were revealed. Through a self-developed non-uniform loading device combined with acoustic emission (AE) and digital image correlation (DIC) monitoring technology, the synergistic dynamic evolution law of the bearing capacity, apparent crack, and internal fracture of cemented coal gangue backfills (CCGBs) under loads with different degrees of non-uniformity was deeply explored. The results showed that: 1) The uniaxial compressive strength (UCS) of CCGB increased and then decreased with an increase in the degree of non-uniformity of load (DNL). About 40% of DNL was the inflection point of DNL-UCS curve and when DNL exceeded 40%, the strength decreased in a cliff-like manner;2) A positive correlation was observed between the AE ringing count and UCS during the loading process of the specimen, which was manifested by a higher AE ringing count of the high-strength specimen. 3) Shear cracks gradually increased and failure mode of specimens gradually changed from “X” type dominated by tension cracks to inverted “Y” type dominated by shear cracks with an increase in DNL, and the crack opening displacement at the peak stress decreased and then increased. The crack opening displacement at 40% of the DNL was the smallest. This was consistent with the judgment of crack size based on the AE b-value, i. e., it showed the typical characteristics of “small b-value-large crack and large b-value-small crack”. The research results are of significance for preventing the instability and failure of backfill.