Non-explosive mining and waste utilization for achieving green mining in underground hard rock mine in China

Innovations of mining technologies were proposed by beneficial utilizations of unfavorable factors such as high geostress,high geotemperature and high mining depth to achieve green mining as mining depth increases inevitably.Cuttability of deep hard rock was investigated by experimental and regressed analyses to find the reasonable stress adjustment method to improve non-explosive mechanized fragmentation for hard ore-rock.A non-explosive mechanized and intellectualized mining method was proposed to continuously and precisely exploit phosphate underground,which promoted the high-recovery,low-waste and high-efficiency exploitation of phosphate with recovery rate over 90%,dilution rate near 5%and cutting efficiency about 107.7 t/h.A circular economy model and the backfill system were proposed to conduct resource utilizations of solid waste,by which the utilization amount of waste increased year after year.In 2018,the utilization amounts of phosphogypsum,yellow phosphorus slag and waste rock increased to 1853.6×10^3 t/a,291.1×10^3 t/a and 1493.8×10^3 t/a,respectively.

Mining pressure monitoring and analysis in fully mechanized backfilling coal mining face-A case study in Zhai Zhen Coal Mine

Fully mechanized solid backfill mining(FMSBM) technology adopts dense backfill body to support the roof. Based on the distinguishing characteristics and mine pressure control principle in this technology, the basic principles and methods for mining pressure monitoring were analyzed and established. And the characteristics of overburden strata movement were analyzed by monitoring the support resistance of hydraulic support, the dynamic subsidence of immediate roof, the stress of backfill body, the front abutment pressure, and the mass ratio of cut coal to backfilled materials. On-site strata behavior measurements of 7403 W solid backfilling working face in Zhai Zhen Coal Mine show that the backfill body can effectively support the overburden load, obviously control the overburden strata movement, and weaken the strata behaviors distinctly. Specific performances are as follows. The support resistance decreases obviously; the dynamic subsidence of immediate roof keeps consistent to the variation of backfill body stress, and tends to be stable after the face retreating to 120-150 m away from the cut. The peak value of front abutment pressure arises at 5-12 m before the operating face, and mass ratio is greater than the designed value of 1.15, which effectively ensures the control of strata movement. The research results are bases for intensively studying basic theories of solid backfill mining strata behaviors and its control, and provide theoretical guidance for engineering design in FMSBM.

Settlement behavior of coal mine waste in different surrounding rock conditions

In order to investigate the influence of complex conditions of in-situ surrounding rocks on the settlement behavior of nubbly coal mine waste subjected to high gravity pressure,four kinds of loading chambers made of different similar materials with different elastic moduli in experiments were used to simulate the deformation features of in-site rocks,including soft,moderate hardness,hard and extra-hard rocks. The results show that all the settlement-axial load (or axial strain-stress) curves obtained under four different surrounding rock conditions present power-exponential function feature. The final settlement of coal mine waste under the same axial load is closely related to the lumpiness gradations and the deformation behavior of chamber materials used to simulate behaviors of different in-situ surrounding rocks. In the same surrounding rock condition,the final settlement under the same maximum axial load decreases with the decrease of the proportion of larger gradation of coal mine waste. While for the same lumpiness gradation case,the settlement increases with the decrease of elastic modulus of simulated surrounding rocks and the lateral pressure induced by axial load increases with the increase of elastic modulus of loading chambers that are used to simulate different surrounding rocks. The test results also reveal that both the compaction curve and lateral pressure curve show a three-stage behavior,and the duration of each stage,which is closely related to gradations and the deformation feature of loading chamber materials,decreases with the increase of the proportion of the small size of coal mine waste and elastic modulus of the simulated rock materials.

Waste-filling in fully-mechanized coal mining and its application

A fully-mechanized coal mining (FMCM) technology capable of filling up the goaf with wastes (including solid wastes) is described. Industrial tests have proved that by using this technology not only can waste be re-used but also coal resources can be exploited with a higher recovery rate without removing buildings located over the working faces. Two special devices, a hydraulic support and a scraper conveyor, run side-by-side on the same working face to simultaneously realize mining and filling. These are described in detail. The tests allow analysis of rock pressure and ground subsidence when backfilling techniques are employed. These values are compared to those from mining without using backfilling techniques, under the same geological conditions. The concept of equivalent mining height is proposed based on theoretical analysis of rock pressure and ground subsidence. The upper limits of the rock pressure and ground subsidence can be estimated in backfilling mining using this concept along with traditional engineering formulae.

基于3Dmine的采空区治理工程实践

通过对某金矿采空区资料收集及现场调查,利用3Dmine软件建立了该金矿采空区+巷道三维数字模型,准确获得了各中段采空区的实际边界和采空区形态等相关信息。针对采空区情况,结合矿区生产实际,经综合分析研究,提出了采空区治理方案,即:对矿区已经贯通连成一体的采空区群/塌陷坑(四中段以上)采用地表废石充填,四中段未贯通的采空区采用中深孔强制崩落顶板,将上部自地表“灌入”的废石充填到采空区,同时采取密闭隔离的方式联合治理;对于其余地段的采空区,已经结束回采且无法进入的区域采取在中段石门密闭隔离的方式进行治理,尚在开采的其他采空区采取施工措施工程进行坑内毛石回填并密闭隔离方式治理。通过多项措施的综合运用,彻底消除了发生大面积地压活动并引起地面塌陷的隐患,为井下正常生产作业创造了良好的条件。

Recovery of Mining Wastes in Building Materials: A Review

The use of materials from waste in buildings compensates for the lack of natural resources, solves the problem of waste management and provides an alternative technique for protection of the environment. There are a large number of industrial wastes that are used for full or partial replacement of raw materials in some construction materials. This review assesses mining waste in concrete as a substitute for aggregates and cement;in fired bricks as a substitute for soil;and in road backfill as a substitute for soil. This paper reviews some mining tailings, mine waste rocks and some slags obtained in the exploitation and/or processing of some ores including iron, gold, lead, phosphate, copper, coal, etc. Different physical properties, mechanical properties, chemical properties, heavy metal content, mineralogic composition, geotechnical properties and environmental properties (leaching test) of the mine wastes were examined. The physical, mechanical and environmental properties of the materials obtained by substitution of raw materials by mine waste were examined and compared to reference materials. Mining waste in cementitious materials offers good compressive strengths, while the porosity of the concrete and/or mortar is a factor influencing its toxicity. As for the waste in fired bricks, fired at a temperature of 900°C or more, it offers convincing compressive and flexural strengths. The few research studies obtained on the use of mining waste in road embankments have shown that mining waste can be used as a sub-base layer and backfill as long as it is not toxic. In addition, several other mining wastes require special attention as substitutes for raw materials in construction materials, such as coltan, cobalt.

两次采动影响下小煤柱巷道切顶卸压围岩控制技术

为解决多次采动影响下留小煤柱巷道矿压显现剧烈、围岩变形量大的问题,提出了“切顶卸压+顶、帮锚索补强”联合控制技术。以贾家沟煤矿10115运输巷为工程背景,分析了切顶卸压位置、高度与巷道围岩垂直应力分布的关系,给出切顶卸压关键参数,并研究了留小煤柱巷道在切顶卸压后受两次采动影响下的矿压显现规律。结果表明:切顶卸压后,煤柱上的应力峰值随切顶深度的增加呈指数降低;10115运输巷在邻近工作面一次采动过程中巷道围岩变形依次呈现出无变形、缓慢变形、快速变形和围岩稳定的变化规律,本工作面二次采动过程中巷道围岩变形依次呈现出明显变形和剧烈变形的规律;巷道围岩在受二次采动影响时变形更加剧烈,巷道变形量为一次采动时的3.0~7.5倍。

不同加载速率下废石胶结充填体的力学特性及破裂特征研究

为研究不同加载速率与骨料粒径级配对废石胶结充填体的力学特性以及破裂特征变化规律;对不同骨料粒径级配的废石胶结充填体进行不同加载速率的单轴压缩试验,分析其力学特性的变化规律;并辅以声发射系统,研究废石胶结充填体内部裂纹的发展演化规律。结果表明:废石胶结充填体的单轴抗压强度与弹性模量随着加载速率的增大呈线性增长趋势;废石胶结充填体的单轴抗压强度与弹性模量随着骨料级配指数的增大呈现先增长后降低的趋势;随着骨料级配指数和加载速率的增大,试样破坏模式由张拉破坏逐渐转变为剪切破坏,破坏程度加剧,完整度降低;试样内部裂纹的发展演化总体分为压密阶段、弹性阶段、稳定扩展阶段及非稳定扩展阶段。

某磷矿房柱法开采空区治理技术研究与应用

某磷矿采用脉内开拓盘区房柱法开采,在开采过程中形成了一定规模的采空区,给未来生产造成了较大的安全隐患。为了消除或减小采空区对矿山安全开采的危害,针对采空区存在的现状,进行工程地质调查,采空区治理及安全监测措施等研究,提出了采用废石干式充填方法进行空区治理方案,并对充填准备和充填步骤进行详细部署;同时,对空区封堵工艺及封堵墙规格进行设计,根据采空区分布特点布置位移监控报警仪和地压监测报警仪,实现采空区地压活动实时监测和预警预报。研究结果为矿山的采空区治理和安全有序生产提供决策依据和技术保障,也为类似条件矿山提供一定的借鉴。

切顶卸压沿空留巷无煤柱开采技术实践

为缓解晋邦德煤矿采掘接替紧张的问题,消除区段煤柱应力集中,提高煤炭采出率,保持巷道的稳定性,以10404回风巷为研究对象,通过理论分析、数值模拟、现场测试等方法,对综放工作面沿空巷道的顶板结构特征、顶板切顶参数、围岩控制技术与配套设备、沿空巷道的矿压显现规律等进行深入研究,形成一套适合综放工作面的切顶留巷技术。通过矿压监测结果分析可知,在滞后工作面80 m距离时,由于采空区一侧的顶板随回采的进行逐渐被切落、充填和挤压,巷道的围岩变形逐渐变得稳定,证明取得了良好的留巷效果,保证下一工作面综放开采的顺利开展。

浅埋深大采高工作面矿压规律与影响因素分析

为研究浅埋深大采高工作面矿压规律,分析其主要影响因素,以大柳塔煤矿1-2上煤层开采为背景,结合统计分析、物理模拟、数值计算与工程实践的方法,掌握了工作面初次来压与周期来压的矿压显现规律,揭示了煤层采高、埋深对来压规律的影响。研究表明,来压期间支架工作阻力随采高的增大而增大,动载系数、周期来压步距与采高没有直接的关系。来压期间支架平均工作阻力、动载系数随埋深的增大而增大,周期来压步距与埋深没有直接的关系。1-2上煤层工作面开采的初次来压步距为60 m,平均周期来压步距为12 m,来压期间支架工作阻力一般在6500~8500 k N,少数支架工作阻力会升到9300 kN左右,工作面支护效果良好。

厚顶煤软岩巷道破坏规律与支护技术

以马兰矿为工程背景,在煤厚多变和围岩“三软”条件下,对马兰矿厚顶煤软岩巷道矿压显现规律和软岩巷道锚固失效原因进行分析。现场调研发现,回采巷道顶底板变形明显,顶板锚固失效;在理论分析的基础上,认为围岩强度低和水对锚固剂、围岩的弱化作用是造成回采巷道锚杆(索)失效的主要原因;针对锚固失效问题,现场试验扩孔锚固效果,扩孔锚固后,锚固力整体提高25.0%~93.8%;在以上数据基础上,依据顶煤厚度的不同,提出差异性支护方案,以“端锚+注浆全长锚固”作为锚固增效技术手段,掘进期间巷道顶板下沉量相对较小。

矸石(固体废物)直接充填采煤技术发展现状

总结了矸石直接充填采煤的技术框架,系统地介绍了综采矸石充填技术、普采矸石充填技术和掘巷充填技术的充填开采系统布置、关键设备及充填开采工艺;研发了矸石直接充填采煤技术中矸石自地表向井下运输的大垂深投料系统,并对其进行了优化设计;以综采矸石充填技术为例,分析矸石直接充填开采矿压规律的等价采高模型,得到了充填综采采场所需支护强度,以及充填综采与传统综采支护强度修正系数η,并对充填开采后的地表沉陷进行了预计和实测分析,得出了充填开采较传统综采采场矿压显现减弱、地表变形等级仅为轻微的结论;从实现煤炭资源绿色开采应重视的基础科学研究、重点技术攻关等方面对今后矸石(固体废物)直接充填采煤技术相关研究进行了展望.

矸石充填综采工作面矿压显现规律

在分析充填综采顶板运动特征的基础上,建立了充填综采基本顶关键块力学模型,并通过分析矸石充填体与破碎直接顶压实变形规律,推导出了充填综采工作面支护强度力学关系式。对比传统综采,引入了充填综采工作面支护强度修正系数η,理论分析得出工作面采高变化在1.6～3.5m时,修正系数η的变化范围为0.49～0.84,得出充填综采工作面所需支护强度明显小于传统综采的结论。现场工程应用进一步证实了充填综采工作面没有明显的矿压显现。

巷道矸石充填控制覆岩变形的力学机理研究

建立了巷道矸石充填的力学模型,并应用Ritz法求解了煤柱位移场的弹性解.根据弹性-黏弹性对应原理,通过引入Maxwell体流变模型,求解了煤柱位移场的黏弹性解.得到了煤柱的压缩变形、侧向变形等随时间及充填体材料特性的变化规律,由此可确定充填巷采煤柱的变形特征,并估计了煤柱最终变形量及变形稳定时间等.将研究结果与某矿区充填开采实测变形规律比较,两者具有较好的吻合.

煤矿井下高浓度胶结充填开采技术

为有效控制煤层开采引起的地表移动,进一步提高煤炭资源采出率,结合煤矿充填开采现状,提出煤矿高浓度胶结充填开采方法。运用相似模拟方法,从上覆岩层的移动形式、超前支承压力的影响范围、工作面周期来压强度及合理支架工作阻力等多个方面,研究了高浓度胶结充填开采工作面的矿压显现规律。以此矿压显现规律为依据,设计出与之相适应的充填开采液压支架和隔离支架,使之能够在形成较大充填空间的同时,减小工作面充填前顶板下沉量。同时阐述了高浓度胶结充填工作面布置形式及充填基本工艺,实现采煤和充填材料凝固平行作业,有效提高了工作面充填效率。

充填开采工作面矿压显现规律数值模拟分析

为了研究充填开采工作面矿压显现规律,以新阳矿10203充填开采工作面为试验背景,运用数值模拟软件,对工作面不同推进距离下,沿倾斜和走向方向的受力以及充填体上覆岩层的垂直位移进行了模拟分析。结果表明:与传统垮落法开采相比,充填开采来压步距增大,矿压显现缓和;采后及时充填可降低顶板下沉量。

矸石-粉煤灰充填采煤覆岩结构与变形规律

矸石-粉煤灰充填采煤可解决"三下"压煤和固体废弃物排放造成的环境污染问题。根据充填采煤工作面覆岩移动规律,提出矸石-粉煤灰充填采煤覆岩存在3类结构;在弹性地基薄板理论基础上,建立了基本顶力学模型,推导出了基本顶弯曲下沉的理论公式,给出了基本顶破断的临界条件;据此,分析了基本顶变形影响因素,并进行了工程实践。结果表明,基本顶最大下沉量理论计算值与实测值基本一致,各因素对基本顶弯曲下沉影响大小依次为:基本顶弹性模量、覆岩载荷、直接顶弹性模量、充填体弹性模量。邢台矿7606工作面采空区基本顶的最大下沉量为234 mm,沿专用铁路线地表最大下沉量为16 mm,仅直接顶产生了局部裂隙和离层,基本顶完整性较好,覆岩属于第II类结构,地表变形得到了有效控制。

智能化高强度开采超长工作面围岩灾变预警技术

针对高强度开采工作面矿压显现剧烈,难以精准预测,围岩控制手段薄弱等一系列技术难题,提出基于顶板状态动态感知、片帮形态实时判识及采场多源监测信息相融合的智能化工作面围岩灾变预警策略;开发了工作面顶板状态实时监测与动态感知技术,实现了顶板来压位置、持续时间及来压强度的模式识别;研发基于大数据平台的矿压数据智能自学习技术,结合岩层柱状图可实时反演覆岩关键层断裂、结构形成及失稳等状态,实现工作面顶板大面积来压的精准预测;研发基于三维激光扫描的煤壁稳定性判识技术,可实现煤壁位移变化及节理裂隙演化进程的高精度监测,还可对煤壁失稳后片帮体的形态、位置及片帮强度实现定量化描述,突破以往工作面大面积来压和煤壁片帮无法准确预测的难题;进一步将采煤机割煤速度、支架工作阻力与瓦斯体积分数等采场多源监测信息相互融合,构建工作面回采工艺与煤壁片帮、瓦斯不均衡涌出、顶板大面积失稳垮落耦合联动的智能感知系统;该技术思路在阳煤集团寺家庄矿15106智能化超长工作面得到成功验证,保障了工作面安全。

冶炼铜选尾渣对废石粗骨料充填料浆特性改性研究

针对废石粗骨料高浓度自流充填料浆离析、充填体分层严重,及冶炼铜渣污染大、处理难的矿山实际难题,本研究以铜渣尾砂作为细骨料对废石粗骨料充填料浆进行改性为指导思想,通过强度试验、塌落扩展度、分层度及泌水率试验研究了铜渣尾砂对废石高浓度充填的影响。结果表明,添加铜渣尾砂细骨料对充填体的早期强度几乎没有影响,但能大幅提高充填体的中后期强度;可使用扩展度代替塌落度表征自流高浓度料浆的流动特性,整体上铜渣细骨料增加了料浆黏度从而流动性降低,但合适的掺量下能使料浆达到均质状态从而使影响降到最低;分层度受铜渣及水化的影响;铜渣尾砂掺量在20%~25%时料浆的泌水率在5%~10%的理想范围内,形成了具有良好保水性、稳定性及不离析的均质流体状态。