碎软煤层底板梳状孔分段压裂抽采瓦斯技术

为提高煤层的瓦斯抽采效果,以阳泉矿区15#碎软煤层为研究对象,对煤层及其底板岩层特征进行分析,融合煤层底板梳状长钻孔和分段水力压裂技术,形成针对各个梳状分支孔的分段压裂方式,并理论分析了该方式水力压裂裂缝扩展延伸规律。试验研究了满足分段压裂技术要求的梳状长钻孔设计与施工工艺,构建了基于裸眼封隔器+滑套投球分段压裂工具组合的压裂参数设计和压裂施工工艺流程,最终形成梳状长钻孔主孔长度534 m,分支孔5个,主孔下入分段压裂工具串490 m,实现了4个分支孔分段压裂,单段最大注水量611 m³,最大泵注压力17.18 MPa;与常规的穿层钻孔瓦斯抽采技术对比,试验后瓦斯抽采浓度提高了10.53倍,百米钻孔瓦斯抽采量提高了2.02倍。     

巷道注浆钻孔设计关键参数确定方法探讨

针对煤矿注浆钻孔设计存在随意性强、注浆效果差的问题,以赵庄煤业33072巷注浆加固为工程背景,采用钻孔窥视方法确定了深层和浅层钻孔的深度,采用不同注浆压力下浆液扩散半径试验确定了钻孔间排距和最小注浆压力,浅层和深层钻孔深度分别确定为3 m和10 m;浅层钻孔排距2 m,间距1.1 m,最低注浆压力6 MPa,深层钻孔排距4 m,间距1.5 m,最低注浆压力8 MPa.注浆后钻孔窥视结果说明,浆液扩散效果良好,未发现未被填充的裂隙。     

煤矿井下梳状定向孔钻进技术与装备

为解决松软煤层瓦斯抽采孔成孔性差、抽采距离短、抽采区域小等难题,利用梳状定向孔钻进技术在松软煤层稳定的顶底板岩层施工长距离主孔,再从主孔开梳状分支孔进入目标层位,实现对松软煤层瓦斯远距离与区域抽采。根据梳状孔在松软煤层施工特点,研制了梳状孔施工所需钻探设备,研究出不同梳状孔类型的施工工艺。梳状定向钻技术在朱仙庄和九里山煤矿应用效果表明：该技术满足孔深大于500 m施工要求,可实现软煤中本煤层和采空区卸压瓦斯治理,在采空区卸压瓦斯治理中单孔最高日抽采瓦斯纯量4 224.3 m3,为松软煤层瓦斯治理提供了新的技术途径。     

基于光纤光栅监测的松散地层深部注水试验

为了探索厚松散地层深部失水层位的钻孔注水特性，采用一种新型的光纤光栅传感系统实现了某矿松散层注水过程中应变的在线监测。介绍了在深度+115.83～+135.15 m处松散层注水实施过程，及通过2个钻孔对注水层位应变和水位监测的光纤Bragg光栅系统及水位监测系统，注水试验注水压力值依次为0.1，0.2，0.3 MPa和总注水量达到4 226.84 m 3。分析了注水压力、注水量和松散层应变变化的关系，松散层在注水前后和过程中松散层应力应变状态。试验表明，随着注水压力升高和注水量增加，松散层压缩状态得到改善，较注水前，注水后注水层位呈明显拉伸状态。光纤光栅监测系统灵敏、稳定，能够实现对松散层深部注水的过程实时监测，试验为进一步实施松散层地区沉降治理提供了重要的依据。     

Process mineralogy studies of Corrego do Garimpo REE ore, catalao-I alkaline complex, Goias, Brazil

Corrego do Garimpo is described as a lateritic rare earths (REE) deposit related to hydrothermal alteration of dolomitic carbonatitic rocks. Although the deposit has been known since the sixties, all the previous mineral dressing attempts to concentrate the REE bearing minerals resulted in unsatisfactory outcomes. Process mineralogy studies of bulk and borehole samples were fundamental to understanding the ore's behavior and to the development of an unusual physical concentration process.The ore comprises a medium to very fine-grained soil material with large amounts of secondary (autigenous) minerals. Monazite, the essential REE bearing mineral, occurs as microcrystalline aggregates, sometimes presenting colloidal textures, which are frequently associated with iron oxide—hydroxides and quartz. Since these aggregates are extremely friable, the monazite crystallites are mainly associated with the −20 μm size fraction.These particular characteristics supported the development of an unconventional mineral processing method for monazite based on disaggregation, followed by scrubbing and hydrocyclone classification operations. Three volumetric samples and 27 borehole samples, comprising four ore types, have been studied. The attained final products, −10 μm, were further submitted to leaching tests, simulating chemical processing for the REE sulphuric extraction at low temperature.     

煤矿采空区放射法二次探水技术研究

为解决薄煤层开采中的采空区探水钻孔布置数量过多、钻孔施工常受已施工钻孔的影响而导致钻孔偏向、串孔、塌孔等问题,研究了分2次从掘进工作面不同阶段进行钻探的方法,以减少掘进工作面探水施工钻孔数量。第1次探水作业在掘进工作面布置9个钻孔,其钻孔密度能满足小于10 m掘进距的安全需要,第2次探水在新掘进工作面施工6个钻孔。结果表明：通过分二次探水作业可以达到《煤矿防治水规定》的探水要求,减少探水钻进进尺60 m,也减少了钻进过程中钻孔间的相互影响,提高了探放效果。     

基于不同钻孔间距的瓦斯抽采效果实验研究

为了研究钻孔布置对瓦斯抽采效率的影响,采用自主研发的多场耦合煤层气开采物理模拟实验系统,开展了不同钻孔间距条件下瓦斯抽采物理模拟实验研究,探讨了钻孔间距对瓦斯抽采效果的影响。结果表明：在抽采初期,各测点瓦斯压力下降速率和下降量主要受到离钻孔中心距离的影响,与测点距钻孔出口距离基本无关,在瓦斯抽采过程中,靠近钻孔中心位置的瓦斯压力梯度大,瓦斯流速也较大,断面瓦斯压力场中等压线以钻孔为中心呈圆环形分布|相邻钻孔之间产生的抽采叠加效应会影响有效抽采范围,钻孔间距越近,有效抽采范围越大,同时其有效抽采范围也随抽采时间呈指数型增长。     

井下大直径钻孔瓦斯抽采技术研究

为研究面间煤柱内的大直径钻孔抽采采空区瓦斯效果,基于某矿实际生产条件及COMSOL数值模拟软件,依据上覆岩层运移理论、采空区顶板岩性、顶板垮落破坏特征对采空区孔隙率进行了分块赋值,COMSOL数值模拟研究结果表明:钻孔布置的最佳距离为8～10 m。考虑经济因素及顶板垮落步距的影响,钻孔布置的最佳距离应为10 m;靠近工作面上隅角处,采空区内瓦斯浓度呈中心高、四周低的圆环状分布,该低瓦斯浓度圆环的出现与大直径钻孔对采空区内瓦斯的抽采作用密切相关。ORIGIN数据拟合及计算表明:10 m钻孔间距条件下,控制上隅角瓦斯浓度不超限的钻孔最小瓦斯抽放量为5.4 m³/min。该理论成果的成功运用,指导了该矿的生产安全。     

基于COMSOL Multiphysics模拟的瓦斯抽采钻孔合理间距研究

为考察坪上煤业主采3号煤层的合理抽采钻孔间距,利用瓦斯在煤层中的运移和渗流规律,结合实测煤的参数条件,在相同的抽放负压、抽放时间等影响条件下,运用COMSOL Multiphysics有限元软件模拟了不同钻孔间距时所抽煤层在抽采时间为400 d时钻孔影响范围内煤体瓦斯含量变化规律,得出了满足抽采时间条件下的合理钻孔间距为5 m。结合矿井2305（上）回采面巷道内开展了不同钻孔间距实测,在相同的瓦斯地质参数及抽采系统条件下,连续抽采且观测时间达到400 d时各钻孔的瓦斯抽采纯量和钻孔浓度变化。确定了在抽采时间达到400 d时,抽采钻孔间距为5 m时的钻孔瓦斯浓度为35%、流量为0.04 m3/min,受抽采系统影响明显;而间距在6 m的钻孔的流量和浓度仍保持自然衰减特征。模拟和现场实测均验证了该矿瓦斯抽采钻孔间距布置以5 m最佳,该研究为实际生产过程中确定合理的钻孔间距提供理论依据,为矿井瓦斯抽采布局及瓦斯治理提供了技术保障。     

基于COMSOL钻孔有效抽采半径测定的数值模拟研究

为了准确测定霍尔辛赫煤矿3308工作面煤层钻孔有效抽采半径,合理布置钻孔间距,结合现场实测的煤层瓦斯压力和渗透率等参数,运用COMSOL-Multiphysics仿真软件对3308工作面钻孔的瓦斯涌出规律和有效抽采半径进行了模拟分析,并进行了现场实测验证。结果表明:有效抽采半径随着抽采时间的推进不断增大并最终趋于恒定值,整体呈正指数函数关系;瓦斯预抽率随着与钻孔距离的增加而不断减小并最终趋于恒定值,整体呈负指数函数关系;数值模拟和现场实测结果较为一致,钻孔有效抽采半径略大于1.5 m,现场每间隔3.0 m布置1个钻孔可大大提高煤层瓦斯抽采效果。     

Upgrading titanium bearing Na-feldspar by flotation using sulphonates, succinamate and soaps of vegetable oils

Large reserves of feldspar ores exist in the Aegean region of Turkey. Unlike conventional ores, the main impurity in some of these deposits is titanium. In this study, the results of testwork carried out to determine flotation conditions for efficient separation of titatium bearing minerals from two different feldspar ores from the area are presented. The study commenced with mineralogical examination which indicated that the main titanium bearing mineral in the ore was rutile. Another titanium mineral, sphene, was also present in relatively small quantities. In the tests, the effects of particle size, pH, collector types and their amount were tested.The results showed that efficient separation of titanium bearing minerals could be achieved by oleate flotation at around pH 5, after grinding the ore down to 100% −180μm. Oleate provided results superior to sulphonates and succinamate. Equivalent success was obtained by the use of collectors prepared from locally available vegetable oils. Of the five oils tested, sunflower and cotton seed oils produced the most efficient separation.     

Oriented hydraulic fracturing of a mass of rocks enclosing the "international" diamond pipe

Conclusions  1. Whereas in previous works oriented hydraulic fracturing was carried out at a maximum depth of 450 m, in the present work the depth was 780 m. 2. Oriented hydraulic fracturing was effected in two types of sedimentary rocks. The maximum water pressure confined to the instant of shifting and passing of the initiating slit into an extended slit was 24 MPa for rock salt and 26 MPa for dolomite anhydrites. 3. The calculated and experimental maximum pressure data were in good agreement. Divergences for rock salt and dolomite anhydrites were 9.5 and 11%, respectively. 4. The technology and technical facilities developed by the Institute of Mining, Siberian Branch, Russian Academy of Sciences for creating oriented hydraulic fracture were proved to be efficient in new, more complicated situations. 5. Creation of extended slits through boreholes made it possible to achieve the set goal, i.e., to detect oil and gas shows in rock masses enclosing diamond-bearing kimberlite pipe. It is recommended that underground mining operations be carried out by using borehole-slit technique as a method for prospecting these hazardous sites. Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, Vol. 33, No. 6, pp. 105–109, November–December, 1997.     

定向长钻孔整体水力压裂增透技术在赵固二矿的应用

针对赵固二矿煤层透气性低、钻孔有效影响半径小,实施定向长钻孔代替底板岩巷进行区域瓦斯治理期间钻孔工程量大、瓦斯抽采效果不理想的问题。结合煤层赋存特征及钻孔施工情况,采用定向长钻孔整体水力压裂增透技术,理论分析了合理坐封位置、压裂参数,完成200 m煤巷条带一次整体压裂,最大泵注压力24.3 MPa、累计注水量1 613 m³。并基于煤层全水分变化,考察确定了单个钻孔压裂影响范围达到巷道两帮30 m,有效改善了煤体储层特性,提高了煤层瓦斯抽采效率。在实现定向钻孔对预抽煤巷条带可靠控制的同时,最大程度降低了钻孔工程量、缩短了瓦斯治理周期,为实现矿区“以孔代巷”及高效安全开采提供了技术支撑。     

Electric field during seepage of grout

Conclusions 1. The value of the potential occurring as a result of sorption of ions of the mineralized solution by the filtering medium in the form of a fractured rock mass is tens of mV and depends more on the structure of the rock and less on the concentration and composition of the solution.2. In the case of plane-radial flow of the solution the distribution of the potentials and seepage field strength in the injection zone depends on the pressure distribution along the length of the flow from the injection borehole (for grouts — with consideration of sedimentation of the solid particles and filtering the liquid phase) as well as on the permeability of the medium.3. The seepage zone represents a space-charged body whose potential in the external medium depends on the effective seepage radius.Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 4, pp. 52–56, July–August, 1995.     

Control of longitudinal hydraulic fracturing of wells

An analytical solution is presented for the problem of the hydraulic fracturing of a rock mass by radial cracks. The possibility of controlling longitudinal hydraulic fracturing by creating an initiating slit and uniaxial loading of the walls of a borehole is analyzed. An example is described for the synchronous hydraulic fracturing of a system of parallel boreholes to form a horizontal cavity for an electrohydraulic source of vibration. Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 5, pp. 3–12, September–October, 1999.     

三软不稳定煤层深孔注水防尘与注浆防片帮技术

为降低综放工作面煤尘浓度及控制煤壁片帮,针对白坪煤矿三软煤层情况,对工作面煤层进行了深孔注水防尘与注浆加固煤壁。首先采用ZDY-3200钻机施工60～80 m深的注水孔;然后在注水孔周围6 m内使用ZBQ-6/2.5型钻机施工深9 m、间距0.6～1.2 m、排距0.8～1.0 m的煤壁注浆孔;选用MRB125/31.5型注水泵用12～14 MPa压力对煤层注水压裂,再用5～8 MPa压力反复间歇式注水。现场应用效果表明,采用该技术能够使煤层水分由4%增至5%～6%,回风巷煤尘平均质量浓度269 mg/m3降至108 mg/m3;工作面煤壁片帮范围由占煤壁总长的50%～70%减少到10%～30%,有效地解决了煤壁片帮问题。     

深井无煤柱煤与瓦斯共采的技术挑战与对策

深井留巷钻孔法煤与瓦斯共采中留巷围岩变形大,留巷钻孔易破坏、抽采效果差。结合淮南矿区煤与瓦斯共采实践,通过力学分析构建了钻孔在采动作用下的破坏模型,对各参数的影响规律进行了分析,通过套管-水泥环-围岩三维数值模拟计算,探讨了水泥环与围岩性质对钻孔稳定性的影响,得出:采动应力集中易导致钻孔发生挤压型失稳,而岩层层间滑移易导致钻孔发生剪切型失稳,采用厚壁套管、柔性充填、危险层位扩孔让压等措施可以有效提高钻孔稳定性。进而提出了深井超前留巷强化钻孔与高位回风巷强化钻孔的瓦斯抽采技术,并在朱集矿1111(1)工作面与1112(1)工作面进行了试验。试验结果表明:强化钻孔的抽采效果及钻孔稳定性显著优于普通抽采钻孔,单孔最大瓦斯抽采流量达8.1 m3/min,有效抽采距离达150 m以上,实现了深井无煤柱煤与瓦斯的高效共采。     

RFPA~(2D)数值模拟在高位钻孔参数优化中的应用

基于准确划分煤层上覆岩层"竖三带"的煤层法向分布范围,以及有效提高高位钻孔瓦斯抽采效果的重要性,应用RFPA2D软件数值模拟祁南煤矿714工作面顶板垮落情况,初步分析了"竖三带"的煤层法向分布范围,并结合经验公式的计算结果,综合判定距71煤层顶板上方18.4～49.0m的岩层区域为裂隙带,高位钻孔法距参数的取值范围优化选择为18.0～34.0m。现场应用表明,高位钻孔的法距参数施工控制在20.0～35.0m时,钻孔抽采瓦斯体积分数均在30%以上,最大为53.2%。同时,高位钻孔的平均瓦斯抽采量为7.32m3/min,占工作面总瓦斯涌出量的60.6%,远高于采空区埋管技术的瓦斯抽采量,并且工作面的平均瓦斯抽采率提高到60.0%。     

保德煤矿81306综放工作面高位钻孔最优参数研究

为了确定工作面采空区高位钻孔施工的合理工艺参数,以81306综放工作面为研究对象,结合上覆岩层运移规律,推算出高位钻孔的终孔位置在18.04~52.21 m。以此为基础,在81306一号回风道布置4个高位钻场,共计15个高位钻孔,研究不同钻孔类型、终孔位置、钻孔长度和距巷帮距离对钻孔抽采浓度和纯瓦斯流量的影响。研究结果表明,定向长钻孔优于常规钻孔,高位钻孔距底板30 m时效果最好,20 m时次之。综合现场测试和Fluent 软件模拟结果,制定了保德煤矿高位钻孔布孔设计方案,为工作面采空区瓦斯治理提供了借鉴。     

基于抽采半径考察的回采工作面瓦斯预抽钻孔优化设计

为了解决高瓦斯长推进距离回采工作面各区域瓦斯预抽时间极不均衡的问题,提出了基于抽采半径考察的回采工作面瓦斯预抽钻孔优化设计方案：采用瓦斯储量法对回采工作面瓦斯预抽钻孔有效抽采半径进行考察,得出工作面瓦斯预抽钻孔不同预抽时间的有效抽采半径,将高瓦斯长推进距离回采工作面按瓦斯预抽时间长短的不同划分为若干个区块,每个区块瓦斯预抽钻孔根据其有效抽采半径设计钻孔间距,预抽时间长的区块钻孔间距较大,预抽时间短的区块钻孔间距较小,实现工作面瓦斯抽采达标的同时最大限度的减少钻孔工程量。现场应用结果表明,2311回采工作面采用优化的瓦斯预抽钻孔设计方案,钻孔工程量减少约7万m,节约工作面瓦斯预抽时间约15d,并且在开采期间实现了瓦斯抽采达标和安全回采,高瓦斯长推进距离回采工作面采用基于抽采半径考察的回采工作面瓦斯预抽钻孔优化设计方案,取得了良好的技术经济效益。