Processing of measurement while drilling data for rock mass characterization

The information extracted from monitoring of rotary blasthole drills helps to optimize the overall mining operation. Rock hardness, drillability, blastability and specific energy of drilling are examples of parameters that have been estimated in the past using measurement while drilling techniques. In order to be able to properly utilize measurement while drilling techniques, it is important to properly collect, analyze and interpret extracted data. This paper deals with processing of measurement while drilling data such as rate of penetration, rotary speed, rotary torque and pulldown force collected from rotary blasthole drills.Different methods are discussed to calculate a true rate of penetration which is the most important monitored drill variable for use in rock mass characterization. Then specific energy of drilling is defined and calculated based on electrical and mechanical inputs and the results are compared. The results show that specific energy of drilling can be estimated using the drill's primary drive systems' electrical responses with good accuracy when compared to values based on mechanical inputs.     

晋宁磷矿东采区分区爆破研究及应用

晋宁磷矿东采区进入深部开采后,岩体构造复杂,加之坑底积水影响,导致该作业区域局部地段的岩石可钻性、可爆性发生了变化,现有穿孔爆破方式已满足不了生产需要。晋宁磷矿为改善该区域的成孔及破碎效果,根据区域内岩性特征并结合现场实际情况,将作业区域划分成不同试验单元,并依此进行单孔爆破试验,同时对试验的爆破漏斗及块度进行测定分析,最终确定出不同爆破性指数并进行不同爆区划分及作业优化, 满足了采矿和剥离的需要,并节约了穿孔爆破费用。     

Drillability prediction in some metamorphic rocks using composite penetration rate index(CPRI)——An approach

Assessment of drillability of rocks is vital in the selection, operation, and performance evaluation of cutting tools used in various excavation machinery deployed in mining and tunneling. The commonly used rock drillability prediction methods, namely, drilling rate index(DRI) and Cerchar hardness index(CHI)have limitations in predicting the penetration rate due to differential wear of the cutting tool in rocks with varied hardness and abrasivity. Since cutting tools get blunt differently in different rocks, the stress beneath the tip of the bit decreases until it reaches a threshold value beyond which the penetration rate becomes constant. In this research, a new composite penetration rate index(CPRI) is suggested based on the investigations on four metamorphic rocks viz. quartzite, gneiss, schist and phyllite with varied hardness-abrasivity values. The penetration-time behavior was classified into active, moderate, passive,and dormant phases based on the reduction in penetration rate at different stages of drilling. A comparison of predicted penetration rate values using DRI and CPRI with actual penetration rate values clearly establishes the supremacy of CPRI. Micro-structure and hardness-based index was also developed and correlated with CPRI. The new indices can help predict cutting tool penetration and its consumption more accurately.     

A review of light amplification by stimulated emission of radiation in oil and gas well drilling

The prospect of employing Light Amplification by Stimulated Emission of Radiation(LASER)for well drilling in oil and gas industry was examined.In this work,the experimental works carded out on various oil well drilling operations was dis-cussed.The results show that,LASER or LASER-aided oil and gas well drilling has many potential advantages over conventional rotary drilling,including high penetration rate,reduction or elimination of tripping,casing,bit costs,enhanced well control,as well as perforating and side-tracking capabilities.The investigation also reveals that modern infrared LASERs have a higher rate of rock cuttings removal than that of conventional rotary drilling and flame-jet spallation.It also reveals that LASER can destroy rock without damaging formation permeability but rather,it enhances or improves permeability and that permeability and porosity increases in all rock types.The paper has therefore provided more knowledge on the potential value to drilling operations and techniques using LASER.     

Use of drilling performance to improve rock-breakage efficiencies: A part of mine-to-mill optimization studies in a hard-rock mine

In a hard-rock mine, blasting is an important rock-breakage process that impacts energy consumption both in downstream comminution processes and mine productivity. Optimizing the blast fragmentation to improve rock-breakage efficiencies during crushing and grinding is key to mine-to-mill(MTM) optimization. This study explores the use of monitoring while drilling(MWD) data to achieve this goal.Representative penetration rates(PRs) were extracted from blastholes to estimate intact rock properties and predict the breakage efficiencies that directly affect comminution energy consumption. Two intact rock properties, tensile strength(TS) and Bond work index(BWI), were correlated with the PR data to predict these efficiencies in crushing and grinding, respectively. Because of the complexity of the raw MWD data and effects of various disturbances, the MWD data was preprocessed and normalized to achieve a representative PR value at each blasthole. This preprocessing entailed defining valid PR ranges from the MWD data that could eliminate the noise related to discontinuity features in the rock mass structure as well as errors in operator behaviors. The PR data was also normalized using the adjusted penetration rate(APR) to minimize the effects of mechanical factors such as drill feed force, torque, and rotational speed. To correlate the representative APR value with intact rock properties, TS and BWI, various laboratory experiments were conducted: drilling tests using a high-precision coring machine, Brazilian disc tests, and Bond grindability tests. Based on the results of these experiments, models were developed to predict rock-breakage efficiencies during crushing and grinding based on APR. The result of this study can be used to obtain blast energy designs that consider comminution energy consumption and efficiency in the downstream rock-breakage processes.     

geoNEXT录井系统中钻井效率监测软件现场应用分析

通过钻井效率分析软件对机械比能值进行监测,综合判定钻头磨损程度、钻井参数选用的合理性,计算地层岩性的强度.根据监测和判定分析结果提出合理参数.     

Selected elements of rock burst state assessment in case studies from the Silesian hard coal mines

Exploitation of coal seams in the Upper Silesian Coal Basin is conducted in complex and difficult conditions. These difficulties are connected with the occurrence of many natural mining hazards and limitations resulting from the existing in this area surface infrastructure. One of the most important problems of Polish mining is the rock burst hazard and reliable evaluation of its condition. During long-years' mining practice in Poland a comprehensive system of evaluation and control of this hazard was de-veloped. In the paper the main aspects of rock burst hazard state evaluation will be presented, comprising: 1) rock mass inclination for rock bursts, I.e., rock strength properties investigation, comprehensive parametric evaluation of rock mass inclination for rock bursts, prognosis of seismic events induced by mining operations, methods of computer-aided modelling of stress and rock mass deformation parameters distribution, strategic rock mass classification under rock burst degrees; 2) immediate seismic and rock burst hazard state evaluation, I.e., low diameter test drilling method, seismologic and seismoacoustic method, comprehensive method of rock burst hazard state evaluation, non-standard methods of evaluation; 3) legal aspects of rock burst hazard state evaluation. Selected elements of the hazard state evaluation system are illustrated with specific practical examples of their applica-tion.     

Numerical simulations of failure behavior around a circular opening in a non-persistently jointed rock mass under biaxial compression

Pre-existing discontinuities change the mechanical properties of rock masses,and further influence failure behavior around an underground opening.In present study,the failure behavior in both Inner and Outer zones around a circular opening in a non-persistently jointed rock mass under biaxial compression was investigated through numerical simulations.First,the micro parameters of the PFC^3D model were carefully calibrated using the macro mechanical properties determined in physical experiments implemented on jointed rock models.Then,a parametrical study was undertaken of the effect of stress condition,joint dip angle and joint persistency.Under low initial stress,the confining stress improves the mechanical behavior of the surrounding rock masses;while under high initial stress,the surrounding rock mass failed immediately following excavation.At small dip angles the cracks around the circular opening developed generally outwards in a step-path failure pattern;whereas,at high dip angles the surrounding rock mass failed in an instantaneous intact rock failure pattern.Moreover,the stability of the rock mass around the circular opening deteriorated significantly with increasing joint persistency.     

岩石矿物成分与可钻性关系研究

钻井地层岩石的物理力学性质和矿物成分性质是实现科学快速钻井的基础数据．但是矿物成分对可钻性的影响一直没有得到重视。取一研究油区以录井资料的地层岩屑为研究对象．对塑性泥岩、细砂岩和砾岩三种岩屑进行了较全面的矿物成分鉴定分析：研究结果表明，研究油田区块岩石的矿物成分主要以石英、粘土、斜长石、方解石和正长石五种矿物成分为主。矿物成分中含量较高的粘土和斜长石含量随井深增加而降低；石英含量随井深增加而增大。泥岩的可钻性级值随粘土的增加有增加趋势，随石英含量的增加而增大．砂岩的可钻性级值随粘土含量的增加有降低趋势．而随石英含量的增加而增大。砾岩的可钻性级值随粘土和石英含量的增加而下降。     

钻头瞬时三维力方向岩石可钻性的确定

由于地层的各向异性，在钻定向井时，沿钻头瞬时作用力方向的岩石可钻性是变化的。为了确定沿钻头瞬时作用力方向的岩石可钻性，作者将钻头的瞬时合力分解成钻压、变井斜力和变方位力３个分力。通过地层与钻头三维力的空间几何关系，推导出了任意井斜角和方位角时钻压、变井斜力和变方位力方向与地层内法线的夹角公式。在假设均匀层状地层内岩石可钻性级值呈椭球型分布的基础上，通过求解岩石可钻性级值椭球方程与三维力方向之一的直     

利用声波测井资料预测地层可钻性及钻速的试验研究

扼要叙述了室内试验的方法,介绍了用声波测井数据预测地层可钻性及钻速的试验研究概况．在详述对试验数据分析处理过程的基础上,给出了室内声波速度与岩石可钻性级值之关系式以及室内声速与测井地下声速之关系式,并首次提出了应用现场声波测井资料预测钻速的数学模型．     

利用声波测井资料预测地层可钻性及钻速的试验研究

扼要叙述了室内试验的方法,介绍了用声波测井数据预测地层可钻性及钻速的试验研究概况.在详述对试验数据分析处理过程的基础上,给出了室内声波速度与岩石可钻性级值之关系式以及室内声速与测井地下声速之关系式,并首次提出了应用现场声波测井资料预测钻速的数学模型.     

岩质高边坡岩体力学参数确定及稳定性研究

以云南某露天矿采场岩质高边坡工程为研究对象,阐述了岩体力学参数在边坡稳定性分析中的重要性,因原位试验对于坚硬岩体或极软岩体的不适用性,对坚硬岩体,以室内试验得出的岩石物理力学参数和岩体质量评价RMR评分值为依据,并综合考虑岩体中节理裂隙、岩体结构、地下水的影响,运用霍克-布朗(Hoek-Brown)强度准则将岩石力学参数进行折减修正后换算成岩体力学参数,并与现场原位试验所得软弱岩体力学参数结果相结合得到最终岩体力学参数.在上述调查、研究基础上,采用有限差分法(FLAC数值分析软件)对现状边坡进行静态的稳定性分析,提出合理的最终边坡角及总台阶高度,保证矿山正常生产和经济效益的提高.     

Variation of vertical and horizontal drilling rates depending on some rock properties in the marble quarries简

The main objective of this study is to determine the rates of vertically and horizontally oriented drilling processes in marble quarries and to observe the factors affecting the drilling rates in terms of physical and mechanical properties of the rocks. In situ drilling tests were performed in different marble quarries with different marble types and drilling times and penetration rates for a series of successive depth-increments were trying to be determined under vertically and horizontally oriented conditions. In order to understand the relation between the parameters that are investigated within the scope of this research, uniaxial compressive strength, Brazilian tensile strength, impact strength, Bohme abrasion strength, P-wave velocity, porosity, unit volume weight, Schmidt hardness index and brittleness index values were correlated with the drilling rates. It was noticed that the porosity and unit volume weight could be taken as the key parameters among them for obtaining meaningful correlation with drilling performance. It was also observed that the physical and mechanical rock properties are more relevant in vertical drilling than horizontal drilling.     

某小区项目岩土工程勘察与评价

本文首先从拟建工程概况确定岩土勘察等级、钻孔布置。再根据地形地貌特征、岩土层结构以及物理力学性质和水文地质条件等工程地质条件进行场地稳定性、适宜性评价。勘察采用过取样（原状土式样、岩样、水样）、室内试验和室外原位测试试验（标准贯入试验）。根据工程勘察结果,进行地基土层评价和地基基础选型分析。     

冻融荷载下节理岩体的复合损伤模型

针对工程实际中的冻融受荷岩体,以岩石初始损伤状态为参考状态,将冻融与荷载作用引起的损伤视为细观损伤,节理引起的损伤视为宏观损伤,根据Lemaitre应变等效性假设,推导建立考虑宏细观缺陷的节理岩体复合损伤模型.应用该模型分析贯通率和冻融次数分别对岩体力学性质劣化的影响,结果表明:在贯通率一定时,损伤演化曲线随冻融次数的增加而增加,试验与理论峰值强度(或弹性模量)曲线随冻融循环次数增加而降低;在冻融次数一定时,损伤演化曲线与贯通率呈正相关关系,试验与理论峰值强度(或弹性模量)与贯通率呈负相关关系.说明贯通率与冻融次数对岩体的劣化产生一定影响,且饱和试验组受冻融效应较天然试验组力学性能劣化严重.将所建模型计算结果与试验值进行比较,理论曲线与试验曲线吻合良好,验证了所建模型的合理性与有效性.     

Prediction of Rock Burst with Deep Mining Excavation in Linglong Gold Mine

To predict rock burst in deep mining excavation in Linglong gold mine, systematical laboratory tests of mechanical properties of rock, in situ stress measurement and 3-D FEM analysis on energy distribution in rock mass surrounding deep mining rooms were carried out. According to various prediction criteria of rock burst, it is concluded that rock burst is liable to occur during deep mining excavation in the mine.     

Evaluation of boring machine performance with special reference to geomechanical characteristics

The duration of tunneling projects mostly depends on the performance of boring machines. The performance of boring machines is a function of advance rate, which depends on the machine characterizations and geomechanical properties of rock mass. There were various theoretical and empirical models for estimating the advance rate. In this paper, after determining the geome-chanical properties of rock mass encountered in the Isfahan metro tunnel, the performance of the roadheader and tunnel boring ma-chine (TBM...     

井工开采对边坡稳定性影响的有限元分析

边坡下方井工开采是一个露天煤矿普遍存在的问题。本文采用有限元方法针对某一具体实例进行了数值模拟。模拟考虑了岩体力学特性及岩体结构特征,并模拟了井采过程。通过井采前后边坡岩体应力分析、位移分析,对边坡下方井工开采对边坡稳定性影响获得了一些认识。