Spatial modeling of discontinuity intensity from borehole observations at El Teniente mine, Chile

Hekmatnejad, Amin; Emery, Xavier; Brzovic, Andrés; Schachter, Paulina; Vallejos, Javier

doi:10.1016/j.enggeo.2017.07.012

Cited by 17 publications

(3 citation statements)

References 9 publications

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“…Esmeralda, Pacifico Superior, and Reservas Norte sectors have samples located in red and light blue rock type units, while Dacita sector samples are from the blue unit. These units were classified in the base of the P32, number (Dershowitz & Herda 1992;Hekmatnejad et al 2017) classification that has been used in El Teniente mine to asses rock mass stability (Brzovic & Villaescusa 2007;Brzovic et al 2015). The calculations of P32 includes the effect of soft veins in the rock mass classification.…”

Section: Measurementmentioning

confidence: 99%

Analysis of drillhole deviation during drawbell construction in block caving

Bustos¹,

Villaescusa²,

Onederra³

2020

MassMin 2020: Proceedings of the Eighth International Conference &Amp; Exhibition on Mass Mining

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In Block Caving drawbells allow for flow of broken rock. The drawbell construction starts with a drawbell design, which is constrained by the extraction layout shape and development drives sizes. The resulting shape of the drawbell is highly influenced by drilling performance, particularly drillhole deviation. This paper presents the results of a comprehensive analysis of drillhole deviation data undertaken from more than 2,000 holes of 76 mm diameter, having an average length of 12 m and drilled in more than 500 ring positions. In terms of drawbell design, the analysis indicates that the holes less affected by drillhole deviation are those with plunge angle ranging between 65° to 90°. Those holes are located near the centre of the drawbell. The holes less inclined show more deviation. They correspond to those forming the edge of the drawbell shape. Therefore, these areas can be exposed to possible blast damage due to confined charges. The analysis also indicated that 59% of the measured points have a drillhole deviation percentage (DD%) greater than 2%, while 2% of the points present a DD% over 10%. An industry standard for drawbell drill deviation along drilled depth was developed as a tool to check the effectiveness of a blast design, in terms of drill patterns that are likely to appear due to drillhole deviation.

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Section: Measurementmentioning

confidence: 99%

Analysis of drillhole deviation during drawbell construction in block caving

Bustos¹,

Villaescusa²,

Onederra³

2020

MassMin 2020: Proceedings of the Eighth International Conference &Amp; Exhibition on Mass Mining

View full text Add to dashboard Cite

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“…Grossmann [13] proposed mathematical calculation method on volumetric intensity. Hekmatnejad et al [14] addressed the problem of predicting the volumetric intensity in space and of quantifying the uncertainty in the true values, using information from observed discontinuities intersecting boreholes. Sanderson and Nixon [15] introduced some simple techniques to characterize the topology of a fracture network, which extended concepts of topological to 3 dimensions.…”

Section: Introductionmentioning

confidence: 99%

A New Approach for Estimating Rock Discontinuity Trace Intensity Based on Rectangular Sampling Windows

Huo

Tang

et al. 2020

Advances in Civil Engineering

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Trace intensity is defined as mean total trace length of discontinuities per unit area, which is an important geometric parameter to describe fracture networks. The probability of each trace appearing in the sampling surface is different since discontinuity orientation has a scatter and is probabilistically distributed, so this factor should be taken into account in trace intensity estimation. This paper presents an approach to estimate the two-dimensional trace intensity by considering unequal appearing probability for discontinuities sampled by rectangular windows. The estimation method requires the number of discontinuities intersecting the window, the appearing probability of discontinuities with both ends observed, one end observed, and both ends censored, and the mean trace length of discontinuities intersecting the window. The new estimator is validated by using discontinuity data from an outcrop in Wenchuan area in China. Similarly, circular windows are used along with Mauldon’s equation to calculate trace intensity using discontinuity trace data of the same outcrop as a contrast. Results indicate that the proposed new method based on rectangular windows shows close accuracy and less variability than that of the method based on circular windows due to the influence of finite sample size and the variability of location of the window and has advantage in application to sampling surfaces longer in one direction than in the other such as tunnel cross sections and curved sampling surfaces such as outcrops that show some curvature.

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“…To get a more detailed spatial modeling, geostatistical tools and methods can be used. In the past two decades, kriging and conditional simulation have been applied to the prediction of RQD (Ozturk and Nasuf, 2002;Madani and Asghari, 2013;Ozturk and Simdi, 2014;Séguret and Guajardo, 2015), UCS (Abdideh et al, 2014;Doostmohammadi et al, 2015), RMR (Choi and Park, 2002;Oh et al, 2004;Stavropoulou et al, 2007;Choi et al, 2009;Jeon et al, 2009;Egaña and Ortiz, 2013;Ferrari et al, 2014;Pinheiro et al, 2016aPinheiro et al, , 2016bSantos et al, 2018), GSI (Deisman et al, 2013;Ozturk and Simdi, 2014), Q (Exadaktylos and Stavropoulou, 2008), P10 (Ellefmo and Eidsvik, 2009;Séguret et al, 2014) and P32 (Hekmatnejad et al, 2017).…”

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confidence: 99%