RQD predictions based on drill performance parameters

Schunnesson, Håkan

doi:10.1016/0886-7798(96)00024-7

Cited by 73 publications

(38 citation statements)

References 2 publications

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“…• Variability parameters: The penetration rate variability and rotation pressure variability have been used in field tests, with both parameters found to be sensitive to rock fracturing [21]. As shown in Equations (1) and (2), variability is calculated as the sum of residuals over a defined interval along the borehole:…”

Section: Calculated Parametersmentioning

confidence: 99%

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Monitoring of Drill System Behavior for Water-Powered In-The-Hole (ITH) Drilling

2017

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A detailed understanding of the drilling system and the drilling control is required to correctly interpret rock mass conditions based on monitored drilling data. This paper analyses data from hydraulic in-the-hole (ITH) drills used in LKAB's Malmberget mine in Sweden. Drill parameters, including penetration rate, percussive pressure, feed pressure, and rotation pressure, are monitored in underground production holes. Calculated parameters, penetration rate variability, rotation pressure variability, and fracturing are included in the analysis to improve the opportunity to predict rock mass conditions. Principal component analysis (PCA) is used to address non-linearity and variable interactions. The results show that the data contain pronounced hole length-dependent trends, both linear and step-wise linear, for most parameters. It is also suggested that monitoring can be an efficient way to optimize target values for drill parameters, as demonstrated for feed force. Finally, principal component analysis can be used to transfer a number of drill parameters into single components with a more straightforward geomechanical meaning.

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Section: Calculated Parametersmentioning

confidence: 99%

“…A parameter called fracturing has been suggested by [21] as an indicator of rock mass inhomogeneity; the parameter can be calculated by combining the variability of the penetration rate and the variability of the rotation pressure. This has been improved more recently by [22].…”

Section: Introductionmentioning

confidence: 99%

Monitoring of Drill System Behavior for Water-Powered In-The-Hole (ITH) Drilling

2017

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“…15,18 Measured variations in the value of the index can be helpful in identifying the boundaries between different rock formations. It also can be indicative of a rock mass with a high degree of geological alteration, something that often occurs in mineral deposits.…”

Section: Formulation Of the Specific Rock Energy Index Using Dth Drilmentioning

confidence: 99%

A methodology for estimation of the specific rock energy index using corrected down-the-hole drill monitoring data

Izquierdo

Chiang

2004

Mining Technology

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A methodology developed to estimate with accuracy the instantaneous specific rock energy using corrected downthe-hole (DTH) drill monitoring data is presented. A specific rock energy profile can be generated for every hole, and thus a drilling site can be mapped for this index. A special data acquisition system was developed to measure and register the following operational variables: penetration rate, torque, hole depth, pull-down force, air pressure, revolutions per minute (rpm) and the hammer percussion frequency, the latter obtained by sound recording and signal processing. The measured data are fed into two simulation models that estimate the power absorbed by the rock through impact, and then the specific rock energy index. The first of these models simulates the thermodynamic cycle of the DTH hammer, rendering the piston kinetic energy at impact, impact velocity as well as impact frequency. The second model is used for stress wave propagation analysis to estimate the effective energy delivered to the rock. Correlations were found between the specific rock energy and penetration rate, and between the specific rock energy and impact frequency, as well as between the penetration rate and applied torque, and between the penetration rate and impact frequency.Nomenclature: A, hole area (m 2 ); E Impact , impact energy (piston contribution) (J); E Torque , torque energy (J); E Thrust , thrust energy (J); e, piston impact restitution coefficient; F, percussion frequency; F Pull-down , applied pull-down force (weight on bit) (N); F Thrust , thrust force (N); m Piston , piston mass (kg); SRE, specific rock energy (J cm -3 ); Pow Hammer , hammer power (W); V Impact , piston impact velocity (m s -1 ); V Penetration , penetration rate (m s -1 ); Torque, torque applied to the hammer (N m); W Rods-hammer , rods and hammer weight (N); ω, hammer angular velocity (rad s -1 ); ∆t, time increment; ∆θ, hammer spin angle increment; ∆x, hammer displacement increment; ∆Vo, rock volume increment INTRODUCTIONThe operation of rock drilling systems is an important issue in many industries such as mining, construction, petroleum and water well drilling. Due to its economic importance, it has motivated many research studies; recently, monitoring systems have been used to understand rock drilling better. In such systems, the variables most commonly measured are: penetration rate, penetration depth, torque, rotation speed (RPM), pull-down (feed force) and the air pressure. The analysis of these data has provided important information about the drilled rock mass such as hardness, fracturing and weathering. 15 It has permitted the location of rock boundaries, rock-type boundaries to name the most important, and it has helped in blast hole array design. 15,18,20 One advantage of drill monitoring is the possibility to extract valuable information without causing disturbances in the drilling process. Monitoring is considered an important necessary step prior to the automation of the entire drilling process 2 because it helps to understand bet...

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“…In recent decades, advanced measure-while-drilling (MWD) technology has been rapidly developed to create the opportunities to assess the geological conditions ahead of a tunnel face in broad tunneling projects [24][25][26][27]. The MWD technology can therefore be considered a robust technique for detailed characterization of large rock masses, provided that the raw data are treated properly and effective analysis is applied.…”

Section: Introductionmentioning

confidence: 99%

Application of Specific Energy in Evaluation of Geological Conditions Ahead of Tunnel Face

Liu

Sakaguchi²,

Ishizu

et al. 2020

Energies

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In underground construction, especially tunnel building, a detailed knowledge of the geological conditions ahead of the tunnel face is essential for both safety and efficiency of work. Many tunnel collapses have been reported to occur because of a lack of accurate evaluation of the geological conditions. While conventional horizontal boring conducted from a tunnel face provides good accuracy, it is infrequently conducted due to its high cost and time-consuming nature. In addition, the tunnel seismic reflection method has limited practicality owing to the complexity of data processing. This paper presents a new approach based on the specific energy of the mechanical drilling rig to evaluate the geological conditions ahead of the tunnel face. In order to assess the geological conditions, rock mass quality index, buried depth of the tunnel and tunnel deformation investigation were undertaken, and the obtained data were compared to the specific energy. Results from the comparison reveal the evaluation criterion that if the distribution of specific energy in some areas deviates from the distribution of buried depth, it is considered that abnormal geological conditions exist in this area. This work can greatly contribute to the accurate and effective evaluation of the geological conditions ahead of the tunnel face.

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RQD predictions based on drill performance parameters

Cited by 73 publications

References 2 publications

Monitoring of Drill System Behavior for Water-Powered In-The-Hole (ITH) Drilling

Monitoring of Drill System Behavior for Water-Powered In-The-Hole (ITH) Drilling

A methodology for estimation of the specific rock energy index using corrected down-the-hole drill monitoring data

Application of Specific Energy in Evaluation of Geological Conditions Ahead of Tunnel Face

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