Roof filling control technology and application to mine roadway damage in small pit goaf

To recover coal resources that have been damaged by traditional mining methods and ensure stability of the lower roadway in a small pit goaf,the goaf area must be filled and reinforced.In this research,the 1202 working face of the Hanzui mine is considered as an example for classifying the roof of the mining tunnel under the small kiln destruction zone,the effect of the goaf on the roadway is determined based on the radio tunnel penetration method,a mechanical model to determine the roof filling control mechanism was established,and the duct foaming system and roof filling process were designed.The results show that the scope and degree of influence of the goaf on the mining lane are large,but safe tunneling can be ensured through the use of a steel shed and advanced grouting techniques.When the roof conditions are not similar,materials with different filling heights and filling strengths can be used to control the roof filling of the roadway.By combining field experience and laboratory tests,it was determined that a high-foaming material with a water-cement ratio of 1:0.6,a suitable high-foaming additive,and a water volume ratio of 1:30 is cost-efficient for filling and meets the filling strength requirements.Finally,the reliability of the proposed technology was verified by field experiments,which provide a reference for filling operations in similar mines.

Research into stope roof control of compound roof by solid backfilling mining

Based on the analysis of the failure characteristics and backfilling effect of the compound roof at 1801 backfilling workface in Taiyuan coal mine,China,we propose a method of controlling the presubsidence of a compound roof by using pre-stressed bolts to improve the backfilling ratio of the workface so as to maintain the global stability of the stope roof.In addition,PHASE simulation software was employed to analyze the influence law of pre-stressing force,length,and interval on roof subsidence at the workface.On the basis of the numerical simulation results,a model for calculating the pre-stressing force and length of the bolts,the interval between the bolts,as well as roof subsidence at the workface,was established by using SPSS regression analysis software.Moreover,the research results were applied successfully to the 1801 filling workface.According to the monitoring data of roof closure,it was found that the final subsidence value for the goaf roof was 350 mm and the filling ratio at the workface was 86%,which could fully meet the demand for safety production at the workface.The safe and effective control of the stope roof was therefore realized,which achieves the goal of safe and efficient backfilling mining under a compound roof.

Preventing roof fall fatalities during pillar recovery:A ground control success story

For decades, pillar recovery accounted for a quarter of all roof fall fatalities in underground coal mines.Studies showed that a miner on a pillar recovery section was at least three times more likely to be killed by a roof fall than other coal miners. Since 2007, however, there has been just one fatal roof fall on a pillar line. This paper describes the process that resulted in this historic achievement. It covers both the key research findings and the ways in which those insights, beginning in the early 2000 s, were implemented in mining practice. One key finding was that safe pillar recovery requires both global and local stability.Global stability is addressed primarily through proper pillar design, and became a major focus after the2007 Crandall Canyon mine disaster. But the most significant improvements resulted from detailed studies that showed that local stability, defined as roof control in the immediate work area, could be achieved with three interventions:(1) leaving an engineered final stump, rather than extracting the entire pillar,(2) enhancing roof bolt support, particularly in intersections, and(3) increasing the use of mobile roof supports(MRS). A final component was an emphasis on better management of pillar recovery operations.This included a focus on worker positioning, as well as on the pillar and lift sequences, MRS operations,and hazard identification. As retreat mines have incorporated these elements into their roof control plans,it has become clear that pillar recovery is not ‘‘inherently unsafe." The paper concludes with a discussion of the challenges that remain, including the problems of rib falls and coal bursts.

Overburden fracture evolution laws and water-controlling technologies in mining very thick coal seam under water-rich roof

Considering the danger of water inrush in mining very thick coal seam under water-rich roof in Majialiang Coal Mine,the universal discrete element(UDEC)software was used to simulate the overburden fracture evolution laws when mining 4#coal seam.Besides,this study researched on the influence of face advancing length,speed and mining height on the height of the water flowing fractured zones(HWFFZ),and analyzed the correlation of face advancing length and change rules of aquifer water levels and goaf water inflow.Based on those mentioned above,this research proposed the following water-controlling technologies:draining the roof water before mining,draining goaf water,reasonable advancing speed and mining thickness.These water-controlling technologies were successfully used in the feld,thus ensured safely mining the very thick coal seam under water-rich roof.

矿井采煤工作面顶板事故防治策略研究

随着中国采煤工作面深度和开采规模不断扩大,顶板事故不断增多,给矿井生产带来了极大的影响。如何有效防治顶板事故,成为了亟须解决的问题。论述了矿井采煤工作面顶板事故防治的重要性,通过对事故成因的分析,提出了相应的防治策略,通过对比,证实了研究方向的准确性,可以为矿山安全生产提供有益的参考。

Undersea safety mining of the large gold deposit in Xinli District of Sanshandao Gold Mine

The exploration of undersea resources becomes popular as land resources decrease. Researches were conducted with emphasis on the safety and efficiency of undersea mining of the large gold deposit in Xinli District of Sanshandao Gold Mine. A series of tests for the physical and mechanical characteristics of rock mass were carried out, and the three-dimensional geo-stress distribution was tested in the mining area. Further, a similar experimental simulation platform, which revealed the mechanism of water inrush and ascertained the reason- able thickness of the safety isolate layer, was established for the undersea mining. Meanwhile, the feasibility of cancelling the ore pillars and the safety conditions was checked by numerical simulation. The simulation results show that it is safe to exploit the ore body below the -85 m level （presently, the exploitation level is below -160 m in Xinli District）, and the ore pillars can be cancelled below the -560 m level. Fur- thermore, a novel backfill method was designed to reduce the rock strata disturbance and settlement, and the settlement of roof strata was monitored during the mining process. Engineering practice shows that the settlement of roof strata was small and that no disaster happened. This indicates that the undersea safety mining technology of the large gold deposit is achieved in Xinli District.

双厚组合坚硬顶板定向长钻水力压裂评价体系研究

针对双厚组合坚硬顶板厚煤层工作面开采过程中的强矿压显现问题,本文提出了定向长钻水力压裂方案,并基于压力实测、瞬变电磁及钻孔窥视方法从孔内、孔外、动态、静态四个方面对定向长钻水力压裂裂缝扩展进行可视化监测评价。研究成果表明:压裂过程包括钻孔周围微裂隙发育扩展,出现宏观裂缝,宏观裂缝周围微裂隙发育,出现新的宏观裂缝,直至压裂完成;钻孔径向20m范围内岩层电阻率较低,大裂缝较为发育;设计的3个钻孔压裂后影响范围基本可以覆盖整个顶板治理区域;长钻孔内各压裂段裂隙可以实现贯通,钻孔内纵裂隙、横裂隙交替发育形成三维裂隙网络;压裂后顶板微震事件总能量和总次数都显著降低,压裂层位顶板能量提前释放,表现为“高频低能”显现,工作面来压强度明显改善。

大巷煤柱回收工作面顶板控制技术研究

针对轿子山煤矿9717大巷煤柱回收综采工作面实际生产情况,综合运用现场监测、数值模拟和理论分析手段,开展大巷煤柱回收孤岛工作面矿压显现规律及控制方法研究,进行工作面预裂爆破强制放顶参数设计,并在该工作面进行工程应用,对回采期间顶板及工作面超前段回采巷道进行矿压监测,分析工作面矿压显现特征,达到保障工作面安全生产目标。研究成果将对类似地质条件下的煤柱回收工作面的回采具有一定的借鉴意义。

综采工作面顶板控制技术

综采工作面顶板控制对于安全开采十分重要。结合407工作面的实际情况,分析了回采过程中采用的顶板控制技术。首先,对工作面顶板进行支护设计,主要包括支护设备和支护强度的确定;然后,探讨了回采过程中采用的顶板控制方式,主要包括顶板管理、端头支护、超前支护和退锚方法;最后,探讨了回采过程中的矿压观测内容和方法,并进行矿压分析。可以为综采工作面回采过程顶板控制提供一定的技术参考。

特殊地质条件下综采工作面顶板控制技术

在特殊地质条件下,煤矿生产作业中利用综采工作面顶板控制技术,加强对生产安全的保障,是我国煤矿事业发展中要着重加强重点研究的问题,结合特殊地质条件环境,以保障矿井生产安全为目的,需要在综采工作面中,合理的使用顶板控制技术,结合不同的生产阶段,提高技术应用水平。本文分析了特殊地质条件下综采工作面顶板控制技术应用的重要性,提出了综采工作面顶板控制技术的要点。

浅谈煤矿采煤工作面顶板控制措施

主要探讨了煤矿采煤工作面顶板控制措施。通过分析顶板控制对采煤工作面稳定性的影响、对确保采煤工作面安全和生产效率的重要性,以及顶板控制失效的情况,提出了一系列有效的顶板控制措施,包括选择支护方式、实施预防性支护和建立灾害监测预警系统。研究对煤矿采煤工作面的顶板控制具有重要的理论意义和实际应用价值。

煤矿顶板风险动作原因及控制策略研究

中国属于世界范围内的煤矿大国,煤矿安全生产对于中国能源安全具有相当重要的现实意义,随着煤矿企业安全技术的不断提升,中国煤矿企业安全状况明显改善,但仍旧存在很多问题亟待解决,其中,煤矿顶板事故仍旧是困扰众多工作人员的问题。通过对相关文献进行查阅,从风险动作角度着手,对煤矿顶板事故的原因进行分析,并提出特定控制策略,以期提升相关单位对煤矿顶板安全事故的管理质量。

缓倾斜中厚矿体采矿方法研究

该文以国外某缓倾斜中厚铅锌矿体赋存条件及开采技术问题为背景,提出一种高效的垂直分条嗣后充填采矿法,并对该采矿法成功应用存在的技术问题进行分析。针对矿体上盘围岩条件差、下盘三角矿体回收困难,提出双进路出矿巷道2步骤回采控顶技术和预控顶垂直分条嗣后充填采矿法2种解决技术方案,以争取实现此类缓倾斜中厚矿体的安全高效开采。

掘进工作面冒顶防治技术研究

在煤矿工作面掘进过程中,冒顶对安全生产危险巨大,为此,需要对冒顶进行综合防治。首先分析了掘进工作面发生冒顶的原因,主要有靠近地质构造区域、空顶距过大、掘进速度过快和支护不合理等;然后分析了防治冒顶的技术,主要有加强地质探测、加强顶板支护、控制掘进速度和选择合适的掘进方式等。可以为煤矿的安全掘进提供一定的参考。

我国不同类别煤层顶板水害致灾机理与防控路径

我国是世界上成煤和赋存条件最复杂的国家,煤层顶板水文地质条件的多样性和复杂性,采动覆岩裂隙场与渗流场耦合的相互性和时变性以及煤层顶板突水的独特性和危害性,造成顶板水害是我国尤其是西部煤矿区的主要矿井灾害之一。为了更好地认识顶板水害和推广现有技术和探索新技术防控此类矿井灾害,在全面分析近年来我国煤层顶板水害事故规律与顶板充水含水层的赋存条件、突水模式、动力特征、力学行为等基础上,系统划分了顶板水害的类型、特征、主要类别的致灾机理及梳理了现有顶板水害的防治技术,并展望了未来顶板水害防治领域的发展方向。研究发现:①顶板水害主体架构包括巨厚基岩含水层涌(淋)水、薄基岩弱胶结层水-砂耦合溃涌、离层空间蓄水储能突水、天窗补给型突水、围岩烧变增透致突等5种类别,集中分布于秦岭—淮河沿线以北地区,陕、蒙、宁是顶板水害主要聚集地。②采动诱发巨厚基岩含水层下覆岩原生裂隙互馈-贯通发育“Z”型离层空间,导致采场出现大面积涌(淋)水现象;基于复合关键层破断力学条件,阐明了薄基岩弱胶结层水-砂耦合溃涌致灾的动力源;构建了离层失稳突水临界判别准则,将离层突水划分为静载扰动、“动+静”载复合扰动、复合煤层开采重复扰动3种模式;红土隔水层缺失及红土薄弱区采动劣化损伤是产生天窗越流补给的主要根源;围岩烧变增透,孔隙度增大,接受临近水源补水后形成新的含水结构体,在采动诱发下烧变岩水涌入采场发生水害事故。③梳理了当前煤层顶板水害“探-放-治”三位一体的解危防控技术体系,提出了井上下共轭联动、钻-采(掘)高位协同地质勘探系统,以防治水“三区”划分为导向的地质保障工作,“煤-水-生态”多目标齐抓共管的绿色开采和防治水理念,以及数智化、透明化矿山水文地质灾害信息维护系统等未来发展方向。

综采工作面高效过断层群工艺研究及应用

针对采煤工作面过断层群构造期间破岩多、顶板管理困难、运输机坡度控制差等问题,以官地煤矿22612综采工作面为例,采用理论分析、工程实践方法,在对采煤工作面过断层构造的分析基础上,提出了过不同性质断层群工艺,明确了运输机坡度沿推进度及切眼方向两个参数选择依据,同时提出了一种运输机坡度测量方法,可科学有效地实现对运输机坡度的测量与控制,明确了过断层构造期间破碎顶板管理措施。应用结果表明:破岩架数降低了35.3%;日割煤刀数提高1~1.5刀,每月增加产量2万t,同时采煤机截齿、三机配件消耗量也均下降了20%,整个过构造期间顶板管理安全有效。

坚硬顶板强矿压动力灾害超前区域控制技术研究

厚层坚硬顶板条件下大采高综放工作面采场矿压显现强烈,极易引发冲击地压、矿震等灾害。为掌握坚硬顶板大采高综放开采条件下覆岩破断演化规律,采用理论分析、数值模拟、现场监测等方法,揭示了坚硬顶板岩层呈现大“悬臂梁”形式垮落及破断冲击能致灾机理,并提出了坚硬顶板分段压裂超前弱化解危技术。研究表明:低位坚硬岩层在覆岩运移过程中常以“悬臂梁”结构出现,该结构不易垮落,进而导致能量积聚,引发矿压动力灾害。而在水力压裂超前弱化技术治理后,顶板垮落步距显著减小,平均降幅54%,来压强度降幅21.67%,且有效改变了低位坚硬顶板破碎程度,扩大了工作面垮落带范围,增加了采空区矸石充填程度,达到了顶板结构改造及动力灾害有效控制的目的。

超长大采高回撤通道破坏特征及主被动协同控制技术

针对超长大采高工作面预掘回撤通道大变形失稳导致巷道破坏、设备回撤受阻等安全问题,采用理论分析、数值模拟、现场试验等方法,基于回撤通道破坏特征分析,提出“控顶固帮”主被动协同控制技术。建立了超长工作面采动支撑压力顶帮联合失稳力学模型,基于超长大采高顶板断裂位置与围岩稳定关系,揭示回撤通道破坏机理。利用UDEC数值模拟对超长大采高回撤通道区域环境进行验证,提出了“实时断顶+垛式支架+锚杆索”协同控制方案,保障回撤通道稳定。该技术在黄玉川煤矿226_(上)03综采工作面回撤通道成功应用,监测结果表明:工作面贯通后,回撤通道顶板下沉量为75.6 mm,底板鼓出量95.7 mm,两帮变形量103 mm,变形量小、支护效率高、成本低,实现了黄玉川煤矿超长大采高工作面回撤通道稳定安全高效的目的。

杭来湾煤矿30201综采面矿压显现及支架适应性分析

综采面顶板控制是矿井安全生产中面临的关键问题,有必要对综采面矿压显现规律和支架适应性开展研究,以保障综采面安全生产。通过对杭来湾煤矿30201工作面矿压显现规律进行现场观测和分析,发现工作面支架工作阻力整体表现为“中间大、两头小”的分布规律;上、中、下部支架平均工作阻力分别约为31.76 MPa、37.91 MPa和45.44 MPa,平均动载系数分别为1.228、1.413、1.291,支架安全阀平均开启次数分别为7.8、29.5、8.6;建立了工作面正常开采期间与周期来压期间支架-顶板力学模型,给出了相应的支架临界工作阻力计算方法,计算得到正常开采期间支架所需载荷为14700 kN,周期来压期间所需载荷为17050 kN。经验证,30201工作面ZY21000/36/75D号支架能够满足安全生产要求,研究成果可为后续矿井开采设计、顶板控制等提供借鉴。

同忻矿山小煤柱工作面矿压综合治理技术试验研究

同忻矿8210小煤柱巷道虽处于采空区侧向应力降低区内,围岩应力环境较好,但同时也伴随着巷道围岩整体松软破碎,小煤柱整体完整性较差,承压能力弱,不利于巷道维护,也为矿山工作面安全管控带来一定隐患。因此,同忻矿山决定开展小煤柱工作面矿压综合治理研究,采用初采切眼爆破放顶、尾巷爆破切顶卸压及头巷水力致裂工艺降低矿压影响,提升初采期间顶煤回收率,控制巷道变形。试验结果表明,初采切顶爆破效果良好,初次来压步距及来压强度得到有效缩短弱化,初采可放煤距离大大缩短。尾巷切顶卸压成功爆破400个孔,围岩控制率提高了37%。头巷超长孔定向水力压裂效果良好,裂隙发育充分,达到预期效果。