Abstract:At present there is a lack of an instrument to measure the trajectory of up-holes in a safe and efficient way with minor disruption of underground production. To overcome this, a mechanically operated probe equipped with Inertial Measurement Units (IMU) and centralisers is integrated in an explosive charge-up unit, which allows the operator to start and stop the measurements from a safe area, while he views the records in real time in a handheld PC. The system incorporates a real-time quality indicator based in the 95% confidence standard deviational ellipse (SDE) of the toe’s positions that clearly indicates whether the survey should be repeated before moving to the next blasthole to ensure measurements with limited uncertainty. In-field data shows an accuracy and repeatability between measurements below 1.3 cm/m, which ensures detecting drilling errors in production rings, often of amount to several tens of centimetres, that may compromise blast results.
On the Influence of Sampling Scale on the In Situ Block Size Distribution
Abstract:The modelling of discontinuities in rock mass is undertaken with different measurement techniques and used to determine the in situ block size distribution (IBSD). Two monitoring techniques are employed: televiewer logging of boreholes and photogrammetry of highwall faces in a quarry bench; televiewer performs at the borehole diameter scale, while photogrammetry surveys at the entire bench scale. Ground sampling distances were, respectively, about 1 and 8.5 mm. The discontinuities are modelled as a stochastic discrete fracture network (DFN), with the number of discontinuities used in the simulation calibrated by the intensity per unit length (P10) on the televiewer data, or by the fracture density (P21) on the photogrammetry data, leading to different fracture networks. From the discontinuity network models, the IBSDs are calculated and discussed as function of the sampling scale (i.e. televiewer or photogrammetry data source) and of the fracture density. The goal is to compare the results from both techniques for rock mass structural characterization, to assess their limitations and shortcomings, and to show their potential complementarity at different sampling scales. The televiewer data provides smaller block sizes than the photogrammetry, following the higher number of fractures observed in the former. All volumetric distributions obtained are extremely well represented by Gamma with a power law tail distribution. Despite different location parameters, it is particularly remarkable that all distributions present very similar Gamma shape parameters. The constant log–log slopes of the tails provide evidence of multi-scale validity and a scaling invariant structure (more than two orders of magnitude) of discontinuities of the rock mass. The IBSDs and the scale effect are discussed in the light of the fragment size distributions from blasts carried out in the area characterized.
Design and Usage Example of a Data Warehouse in the Context of the DigiEcoQuarry Project
Abstract:It is not always obvious the role that a data warehouses plays in many projects. It often seems that it solves the same problem as an operational database. In the context of the DigiEcoQuarry project, is not obvious how to implement a data warehouse and the role it plays to answer the business questions used to run a quarry. In this document, we provide an example use-case that aims to illustrate how a data warehouse fits in the project and how it is designed. As a result, we show how a simple data warehouse is designed and how to write an SQL query to answer a hypothetical business question. This document justifies why the data warehouse is needed in the DigiEcoQuarry project and illustrates how it is intended to be used in the context of the project.
Sandstone: is detrital (clastic) sedimentary rock made of sand-sized grains (0.062 to 2 mm). Sandstones can be composed of grains with diverse origin: quartz, feldspar, calcite are typical constituents. They are mostly lithifified by the cementation (calcium carbonate, silica, iron oxide) of sands.
Conglomerate: is detrital (clastic) sedimentary rock made of rounded gravel-sized clasts (> 2 mm). The rock containing angular-shaped gravels, is called breccia. They are mostly cemented and contain a matrix (finer grained sediments), such as sand, silt or clay, which fills the pores between the clasts.
Limestone: is a chemical sedimentary rock made of the mineral calcite (CaCO3). It is formed by the direct precipitation of calcite from water containing dissolved calcium. This can take place through both biological and nonbiological processes.
Dolostone: is a chemical sedimentaty rock that contains the mineral dolomite (CaMg(CO3)2). Most of them are formed as a magnesium replacement of calcium in limestones before lithification, a process called dolomitization.
Granite: intrusive igneous rock with a phaneritic texture (coarse-grained: visibles crystals) which consists mainly of quartz, feldspar (and plagioclase) and mica (felsic composition). It is formed underground (some km below surface) by the slowly cooling of magma.
Diorite: intrusive igneous rock with a phaneritic texture (coarse-grained: visibles crystals) which consists mainly of amphibole and plagioclase (intermediate composition). It is formed underground (some km below surface) by the slowly cooling of magma.
Andesite: extrusive (volcanic) igneous rock with an aphanitic texture (fine-grained: small crystals non visible to the naked eye), although a porphyritic texture (large crystals known as phenocrysts surrounded by a fine-grained matrix or groundmass of microscopic crystals, indicating two phases of crystallization) is also common. It is constitued mainly of amphibole and plagioclase minerals (intermediate composition). It is formed during volcanic eruptions or near the surface by the rapid cooling of magma.
Basalt: extrusive (volcanic) igneous rock with an aphanitic texture (fine-grained: small crystals non visible to the naked eye) which consists mainly of pyroxene, plagioclase and olivine (mafic composition). It is formed during volcanic eruptions or near the surface by the rapid cooling of magma.
Gabbro: intrusive igneous rock with a phaneritic texture (coarse-grained: visibles crystals) which consists mainly of pyroxene plagioclase and olivine (mafic composition). It is formed underground (some km below surface) by the slowly cooling of magma.
Gneiss: is a foliated metamorphic rock which shows a banded texture characterized by alternating darker and lighter colored bands made of felsic (such as feldspar or quartz) and mafic minerals (ferromagnesian), respectively. This metamorphic rock is formed under high-temperature and high-pressure.
Quartzite is a non-foliated metamorphic rock which was originally a sandstone made mainly of quartz. This metamorphic rock is formed through increasing pressure and heating usually related to compresive stresses.
Marble: is a non-foliated metamorphic rock which was originally a limestone (or dolostone). This metamorphic rock is formed through increasing pressure and temperatura (regional) and heating (thermal).
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