Prediction of rotary drilling penetration rate in iron ore oxides using rock engineering system

Prediction of the drilling penetration rate is one of the important parameters in mining operations. This parameter has a direct impact on the mine planning and cost of mining operations, Generally, effective parameters on the penetration rate is divided into two classes： rock mass properties and specifications of the machine, The chemical components of intact rock have a direct effect in determining rock mechan- ical properties, Theses parameters usually have not been investigated in any research on the rock drill- ability, In this study, physical and mechanical properties of iron ore were studied based on the amount of magnetite percent, According to the results of the tests, the effective parameters on the pen- etration rate of the rotary drilling machines were divided into three classes： specifications of the machi- nes, rock mass properties and chemical component of intact rock, Then, the rock drillahility was studied using rock engineering systems, The results showed that feed, rotation, rock mass index and iron oxide percent have important effect on penetration rate, Then a quadratic equation with 0,896 determination coefficient has been obtained, Also, the results showed that chemical components can he described as new parameters in rotary drill penetration rate,

Integrated design and control technology of liner completion and drilling for horizontal wells

Aiming at the problems of large load of rotation drive system,low efficiency of torque transmission and high cost for operation and maintenance of liner steering drilling system for the horizontal well,a new method of liner differential rotary drilling with double tubular strings in the horizontal well is proposed.The technical principle of this method is revealed,supporting tools such as the differential rotation transducer,composite rotary steering system and the hanger are designed,and technological process is optimized.A tool face control technique of steering drilling assembly is proposed and the calculation model of extension limit of liner differential rotary drilling with double tubular strings in horizontal well is established.These results show that the liner differential rotary drilling with double tubular strings is equipped with measurement while drilling(MWD)and positive displacement motor(PDM),and directional drilling of horizontal well is realized by adjusting rotary speed of drill pipe to control the tool face of PDM.Based on the engineering case of deep coalbed methane horizontal well in the eastern margin of Ordos Basin,the extension limit of horizontal drilling with double tubular strings is calculated.Compared with the conventional liner drilling method,the liner differential rotary drilling with double tubular strings increases the extension limit value of horizontal well significantly.The research findings provide useful reference for the integrated design and control of liner completion and drilling of horizontal wells.

Evaluation of the energy efficiency of rotary percussive drilling using dimensionless energy index

This paper sets forth a geomechanics framework for assessing the energy efficiency of rotary percussive drilling using the energy criterion, which has been proposed by Victor Oparin for volumetric destruction of high-stress rocks having nonuniform physico-mechanical properties. We review the long-term research and development in the specified area of science and technology, including research and development projects implemented at the Institute of Mining, Siberian Branch of the Russian Academy of Sciences. A new modified expression of Oparin’s dimensionless energy criterion of volumetric rock destruction k is introduced. The range of in situ values is determined for the energy criterion of volumetric rock destruction at the optimized energy efficiency of rotary percussive drilling. The temporospatial intervals of geotechnical monitoring are found to control pneumatic drilling energy efficiency at subsoil use objects in Russia. The integrated experimental, theoretical and geotechnical approach to the comprehensive investigation of real-time processes of rock fracture in rotary percussive drilling using the energy concept possesses the necessary geomechanical performance-and-technology potential to create the next level geotechnical monitoring of drilling systems for various purposes, including determination of physico-mechanical properties and the stress-strain analysis of rock mass in full-scale drilling.

In situ digital testing method for quality assessment of soft soil improvement with polyurethane

This study purposes an in situ testing method on quality assessment of soil improvement.Factual drilling data includes the spatial distribution and in situ strength of untreated and treated soil along three different drillholes measured by on-site drilling monitoring method.These factual drilling data can characterize the degree of soil improvement by penetration injection with permeable polyurethane.Result from on-site drilling monitoring shows that the linear zones represent constant drilling speeds shown in the plot of drill bit advancement vs.net drilling time,which indicates the spatial distributions of soil profile.The soil profile at the study site is composed of four layers,which includes fill,untreated silty clay,treated silty clay,and mucky soil.The results of soil profile are verified by the parallel site loggings.The constant drilling speeds profile the coring-resistant strength of drilled soils.By comparing with the untreated silty clay,the constant drilling speeds of the treated silty clay have been decreased by 13.0-62.8%.Two drilling-speed-based indices of 61.2%and 65.6%are proposed to assess the decreased average drilling speed and the increased in situ strength of treated silty clay.Laboratory tests,i.e.uniaxial compressive strength(UCS)test,have been performed with core sample to investigate and characterize in situ strength by comparing that with drilling speeds.Results show that the average predicted strengths of treated silty clay are 2.4-6.9 times higher than the average measured strength of untreated silty clay.The UCS-based indices of 374.5%and 344.2%verified the quality assessment(QA)results by this new in situ method.This method provides a cost-effective tool for quality assessment of soil improvement by utilizing the digital drilling data.

Enhancing diamond drilling performance by the addition of non-ionic polymer to the flushing media

Drilling is a most important and crucial operation in the excavation industries.With the objective of looking into the enhancement of diamond drilling performance detailed laboratory investigations were carried out on phosphate rock.The effect of Poly（Ethylene Oxide）（PEO） added to the drilling water was studied by varying machine parameters and PEO concentration.The responses were rate of penetration and torque at the bit rock interface.Slake durability tests were also performed to understand the slaking behavior of phosphate rock in PEO solutions.

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.

Application of Frequency Control Technique to a Rotary Drill

The scheme of a frequency control system in a rotary drill is established by integrating a converter and a programmable logic controller （ PLC ）. The principle of speed regulation, characters of speed-up and speed-down, and the mechanical running performance are also analyzed. The result of application indicates that the frequency control system excellently solves the problems of start, stop, and speed regulation of the drill. The equipment maintenance workload and cost are thus reduced.

Hole surface strengthening mechanism and riveting fatigue life of CFRP/aluminum stacks in robotic rotary ultrasonic drilling

Carbon fiber reinforced plastic(CFRP)and aluminum stacks are widely used in aviation industry due to light weight and high performance.Millions of rivet holes need to be drilled on body materials,and more than 80%of fatigue cracks occur at the connection holes,so the damage and residual stress of hole surface have crucial effect on the riveting fatigue life of CFRP/aluminum stacks and the flight performance.Recently,robotic rotary ultrasonic drilling(RRUD)technology is a promising method to machine the stacks.However,the hole surface strengthening mechanism in RRUD and the service performance of the riveting joint are not verified.Thus,in this paper,the hole surface strengthening mechanism of RRUD for CFRP/aluminum stacks is investigated,a theoretical residual stress model is established,and the fatigue life experiment of riveted joints is conducted.Firstly,analysis on residual stress in RRUD is carried out with consideration of strengthening force and cutting temperature.Residual stress model is established based on the calculation of elastic stress,plastic stress and stress release.Validation experiment results show that ultrasonic vibration changes residual stress from tensile stress to compressive stress.At the same time,comparative damage analysis of CFRP hole exit and hole surface in robotic conventional drilling(RCD)and RRUD is presented.Finally,fatigue strength experiments of riveted joints are conducted for performance verification.Experimental results indicate that fatigue life of single-hole riveted joints is increased by 68%with ultrasonic vibration,and four-hole riveted joint arranged according to aerospace design standards is increased by more than 86%.

Analysis on Pore-Forming Pouring Pile Construction Technology of House Building Project

Compared with the in-place pile, the pore-forming pouring pile is more simple and convenient, with a wider range of construction. In the actual construction process, it is able to pass through complex bottom layer and water layer underground without very high requirements in equipment. The actual bearing capacity of single pile is very strong, so that it can be better to adapt to the actual needs of different scales or the different geological conditions in building. And it has been promoted and used greatly in building construction work [1]. This paper introduces the concept of the pore-forming pouring pile technology, analyzes the pore-forming construction technology and the pile construction technology, then talks about prevention problems of the pore-forming pouring pile construction in House Building Project, at last draws a conclusion that the pore-forming pouring pile technology is the most basic construction technology and is the most effective and convenient way of construction.

Application and reliability analysis of DPM system in site investigation of HK weathered granite

A drilling process monitor （DPM） for ground characterization of weathered granite is presented. The monitor is portable and can be mounted on a hydraulic rotary drilling rig to record various drilling parameters in real time during normal subsurface investigation. The identification method for dominative and subsidiary interfaces has been established. The study reveals that the monitored drilling parameters are dependent on geotechnical materials and can be further applied to characterize ground interfaces. The t-test between manual logging and DPM logging has been carried out. The results show that the DPM has high accuracy in interfaces detection and well agreement with the manual logging. The findings show that the device and data analysis method are of potential application in subsurface drilling exploration in weathered granites. It also seems to have prospective uses in the determination of orebody boundary as well as in the detection of geohazards.

Cutting force and specific energy for rotary ultrasonic drilling based on kinematics analysis of vibration effectiveness

Rotary ultrasonic drilling(RUD)has become an effective approach for machining advanced composites which are widely using in the field of aeronautics.The cutting kinematics and the corresponding material removal mechanisms are distinct in different drilling areas during RUD.However,these fundamentals have not been fully considered in the existing studies.In this research,two distinct forms of interaction induced by ultrasonic vibration were considered as impact-separation and vibratory lapping between the abrasives and workpiece.And the conditions to guarantee the effectiveness of these interactions were obtained to eliminate diminishing effects of ultrasonic vibration.Based on indentation fracture theory,the penetration depth of abrasives and the axial drilling force model was derived for RUD.The verification tests of C/SiC composites resulted in a prediction error within 15%.Due to the minimal volume of material removed during each vibration cycle,the drilling force was more stable in vibration assisted mode.The specific drilling energy of RUD was firstly calculated based on the measured drilling load.It was found the drilling parameters should be matched with vibration frequency and amplitude to make better usage of the advantages of ultrasonic vibration,which is critical in the vibration assisted processing of advanced materials.