Terrestrial Laser Scanning on Rock Mass Stability Analysis - Ejge.com

<strong>Terrestrial</strong> <strong>Laser</strong> <strong>Scanning</strong> on Rock
Mass Stability Analysis
André Nagalli
Professor, Civil Construction Department,
The Federal University of Technology – Paraná, Curitiba, Brazil.
e-mail: nagalli@utfpr.edu.br
Alberto Pio Fiori
Professor, Geology Department,
The Federal University of Paraná, Curitiba, Brazil.
e-mail: fiori@ufpr.br
Bruno Nagalli
University Student, Geology Department,
The Federal University of Paraná, Curitiba, Brazil.
e-mail: brunonagalli@hotmail.com
Ronaldo Luis dos Santos Izzo
Professor, Civil Construction Department,
The Federal University of Technology – Paraná, Curitiba, Brazil.
e-mail: izzo@utfpr.edu.br
ABSTRACT
The use of terrestrial laser scanning is getting better for geotechnical purposes. Instead of
monitoring slopes and evaluating trends it is desirable to improve this technique, obtaining
objective data from the geological structures. A terrestrial laser scanning equipment was used
to image a meta-calcareous mine intending to investigate if it is possible, in a 2cm grid image,
to recognize fracture planes. To prove its applicability, the point cloud obtained, as result of
imaging, was used to evaluate slope stability in terms of planar failure. The results show the
advantages of using terrestrial laser scanning to geotechnical purposes, because it permits to
work with large data amount simultaneously with the same precision.
KEYWORDS: Slope stability; Rock masses; <strong>Terrestrial</strong> laser scanning.
INTRODUCTION
The application of geological knowledge has provided many benefits to both humans and the
environment. One such example of the beneficial application of geotechnical activities in the
daily life of humans is the study of slope stability.
Among its many benefits, the assessment of slope stability enables the optimization of mining
areas, as well as the safety of road slopes, tunnels, natural and artificial slopes. The instability of a
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rock slope is generally defined by the observation of several factors that attest to the probability
of structure collapse and include such aspects as the stresses (earthquakes, power surges, thermal
gradients, etc.), the geological and geotechnical characteristics of the rock mass (origin,
constitution, history of tension, etc.), its geometric characteristics (shape, slope of the strands,
spatial distribution of discontinuities, etc.) and fluids migration.
The advance of science, in particular the use of computers, has allowed the collection and
simultaneous treatment of an increasing amount of data, which in turn enables more accurate
statistical analysis and, consequently, better results.
Ensuring slope stability becomes even more important when it concerns the safety and
security of people, property or mine workers. In addition, the use of new technology creates
opportunities for streamlining the mining process which in turn may generate more economic
benefits through improved productivity.
Considerable progress has been achieved in the study of failure mechanisms and modeling,
especially with regard to the field of slip on three-dimensional universe and its monitoring. Most
of these studies employ digital topographic maps and digital elevation models (DEM) derived
from airborne sensors, ie, aerial photography and airborne equipment such as LIDAR (Light
Detection and Ranging) (Abellán et al., 2006; Pesci et al., 2007, Laefer et al., 2010).
The drawback in the use of air technology stems from the fact that these sensors achieve
maximum densities of information when its incidence is perpendicular to the topography,
typically sub-horizontal surfaces. On the other hand, the instabilities due to fracturing of rocks
and their movements usually occur on the second vertical planes or sub-vertical, right where the
results obtained using ground sensors are the best (Abellán et al., 2006; Armesto et al., 2009).
The terrestrial laser scanner (TLS) is a device capable of capturing images and threedimensional
coordinates of the points that make up the surface of objects in a reference system,
with high speed and accuracy (Laefer et al., 2010). Staiger (2003) evaluated the performance of
different TLS’s available today (Manufacturers: Cyra, Mensi, Optech, Riegl and Z & F), and
concluded that the equipment performance analysis is impressive, especially the easy and fast
data, data acquisition, and good precision (according to the terms of the manufacturers). The
processing stage was seen as limiting because it takes up too much time, so requires more
automation and agility.
Compared with other measurement techniques such as terrestrial total station, the TLS has the
advantage of automatically obtaining large amounts of data quickly and accurately (Pesci et al.,
2007) while a total station, for example, is dependent on operator skills to obtain an amount of
points that may well represent an outcrop, and this turns out to be exceedingly slow (Armesto et
al., 2009). Another point in favor of TLS is that it allows data acquisition in the uppermost parts
of the outcrop, allowing a more accurate characterization, for example, including better data
persistence, orientation and curvature discontinuities, which enables a database for more reliable
analysis (Sturzenegger and Stead, 2009).
There have been attempts to make the scanner more mobile by putting it on a moveable base.
Barber et al. (2008) set the scanner on a van and executed mobile scanning in the streets, with
a view to identifying geometric problems associated with this method. The main objective of the

Vol. 17 [2012], Bund. M 1819
study was the registration of urban facilities, essentially not needed. Surveys, compared to
associated theoretical errors were considered acceptable, although with some limitations of the
method. The average absolute errors for planimetric surveys were of the order of 0.10 m and
altimetric surveys of about 0.03 m.
The applications of laser technologies have been quickly expanding, with reduced costs and
increased accuracy (Yoon et al., 2009).
Possibilities; using imagery to study sculpture and its preservation; analysis of civil structures
and urban infrastructure; testing, digital modeling and reconstruction of tree architecture for
evaluation of wood and leaf development; preservation of artistic heritage; archaeological and
historical tool robot vision; medical applications and industrial uses, among others (Nagalli,
2010).
Limited use with applications in the field of geology, the use of TLS appears still restricted,
with applications in the field of photogrammetry (Pesci et al., 2007, Mezzomo, 2007), in
recognition of stratigraphic and structural features compared with other airborne technologies, for
example, the study of surface roughness on multiscale (Fardin et al., 2001, Fardin et al., 2004)
and recognition / differentiation of rocks (marble and clay) using intensity data from a scanner
(Franceschi et al., 2009).
As part of the geotechnical and geomorphology analyses, the main application of the TLS is
the monitoring of landslides in soil slopes and back-analysis (Dunning et al., 2009; Paronuzzi and
Serafini, 2009), obtaining digital terrain models (Pesci et al., 2007) and subordinate place studies
for the recognition of shapes (Armesto et al., 2009) and structural features (Lato et. al., 2009) for
geomechanical purposes.
The study aims to evaluate the applicability of terrestrial laser scanning for the analysis of
rock mass stability and slope stability. The research also investigates the accuracy and the
limitations of using this method.
MATERIALS AND METHODS
The study focus
As the focus of this study was chosen the Saiva mine, located in Rio Branco do Sul, Paraná,
Brazil, a metacalcareous rock used for cement manufacture. The outcropping rocks in the Saivá
mine belong to the Açungui Group, specifically the Votuverava Formation, dating from the
Paraná Precambrian. The Açungui Group can be subdivided into several lithologic assemblages,
separated by thrust faults and / or transcurrent.
The lithological sequence described by Fiori (1990), called Saivá, has three main rock types.
At the base, there is a layer of dark brown phyllite, with possible graphitic levels, followed by a
bank of dark gray marble, relatively homogeneous and this, in turn, finds itself followed by a
pack of red mudstones. Among the marble and the latter package, there is a body of metabasite.
On portion of the mine, it can be recognized a gray marble, with a banding primary structures of
sedimentary origin. The depositional environment identified for these rocks (Scholl, 1981), is the
calm water with carbonates indicating a closed environment, passing to euxinic.

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Metamorphism identified by Figueira (1999) for the sequence of carbonate rocks, intercalated
by metamarls, which in turn find themselves bounded by siltstones and phyllites and forming the
block Saivá and low grade attained greenschist facies zone chlorite, allowing the preservation of
textural and structural characteristics, such that the most appropriate designation for these rocks is
of metamarble.
It is noteworthy that in macroscopic terms, especially in rock quarries and disassembled, it is
not possible to distinguish the various types of metamarble in relation to the contents of lithic
dolomite aggregates and thereby its MgO content.
According to Figueira (1999), the dolomites and limestones of this region show a complex
structural pattern. The calcareous rock band most favorable to the manufacture of cement has an
average thickness of 600m and includes two large interlayered lenses: one NW, consists
predominantly of semi-pure dolomitic limestone, with an average thickness of 400m and another
to SE, with a thickness average of 200 m, consists predominantly of semi-pure magnesian
limestones.
The Applied Method
The main equipment used in research is the terrestrial laser scanner Leica Cyrax HDS 3000
model. This shows well the main characteristics of its versatility and high efficiency coupled with
high accuracy, the ability to incorporate a 360° (horizontal) and 270º (vertical) scanning through a
fast georeferencing. The interface between user and equipment is the Cyclone software, which
allows the capture of cloud data point, processing and integration with conventional CAD-type
software.
Although this equipment has already been used in the field of geotechnical engineering for
purposes of monitoring of slopes, the parametric study / geometry of geological structures for
geotechnical (stability), this technology has not been evidenced in the literature. The use of this
equipment is new and innovative in the field of geology (Nagalli, 2010; Mezzomo, 2007;
Dalmolin and Dos Santos, 2004).
The fact is that the different approach requires technique, interpretation and recognition of a
certain portion of the cloud of points as being geological-structural, inferring that preferential
directions of discontinuities, taking into account their size, frequency, persistence, penetrate, and
so on. All these factors can directly influence the calculation of slope stability.
In general, the studies that have been developed sought to validate the application of laser
scanner technology to geotechnical slope stability, definition of parameters to be used in such
analysis, in addition to applying the method to the case study with analysis of slope stability and
removability of blocks according to the structures identified. In addition, conditions were
evaluated for mechanical strength of the rock from the mine, its mass was classified geotechnical
and their results are presented in Nagalli (2010). The method used on this research is summarized
in Figure 1.

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Figure 1: Workflow of research
Technique Validation
The initial stage of work was to verify
the applicability of the proposed tool, defining the
guidelines and limitations of the equipment. To this end, a small area was selected
in the eastern
portion of the mine; a bench of
about 200m
long and 18m high was imaged, which represented
about
three hours of data acquisition. It is noteworthy that the use of imaging equipment for
outdoor areas (mining or road blocks, for example) requires good weather conditions (sunny or at
least cloudy). Raindrops stand as shields to the beams of light, impairing data acquisition.
Having defined the area to
be imaged, the process of scanning is accomplished in stages,
separating the dataa acquisition boards in the Cyclone software. An important consideration, which
facilitates the georeferencing of the data and
minimizes the effects off image distortion, refers to

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the placement and routing equipment to the object being imaged and the imaging horizon
(Sturzenegger and Stead, 2009; Pierin et al., 2007). Regarding the positioning of equipment, this
should not be at a distance greater than 100m from the bench (object) to be imaged (limited range
of the device). The equipment was positioned at a distance of about 80m from the bench, never
more than 100m (this is because the bench is not circular and thus the distance between the object
and the scanner is variable).
Regarding the direction of the equipment, it must be directed / pointed to true north, by
compass. This avoids the need for a pre-processing of data, the rotation of coordinates to a new
axis system, and associated errors. The device, attached to a tripod is fixed to the ground and
calibrated by the leveling bubble. Power cables are connected to the batteries and connect the
network cable to the computer equipment that handles the storage of data. The procedure in detail
was described in Mezzomo (2007).
Regarding the resolution of the image, even before the commencement of the surveys, it is
necessary to parameterize the laser scanner with the mesh data acquisition (distance between
points). This was defined as a function of time constraints for information acquisition and battery
unit such as a mesh that varied from 1.7 x 1.7 cm to 2.0 x 2.0 cm. The mesh resolution influences
directly the data acquisition time and the image quality. For purposes of a preliminary
assessment, it was deemed useful, depending on the size of the mine and limitations of the
method, an image resolution covering large area (of the order of hundreds of meters for the
representativeness of structures), without significant loss for hypothesis, data quality. Meshes
100cm spacing no longer represent important structures in the DEM of centimetric or
decacentimetric, for example.
In parallel, some measures were obtained and checked in the field. These representative
structures subsequently served as a basis for comparison between digital and real structures. For
example, the planes oriented in the west face N76E/33W, N52E/88SE, N40W/88NE,
N58E/20SE, N88E/65NW, N50E/42NW.
The steps of the field showed the main results referenced point cloud which is assumed to
enable the acquisition of structural data for geotechnical purposes. However, the clouds of points
obtained in the field by the equipment are not yet ready for application, requiring pre-processing
of data. The first step of this treatment is the removal of imaged points that do not belong to the
object of interest (in this case, the benches of the mine). Thus, the points are not excluded from
the figure object of research, such as tailings piles, benches outside the boundary of the study,
vegetation, etc..
This issue is positive, because it prevents an eventual non visualization of the points that
constitute the virtual geological object and its structures. Additionally, the cloud post-treatment,
being composed of fewer points, it becomes lighter when it comes to computer processing (rotate
images, zoom, choose attributes, etc).
Recognition of digital geological structures
After the point clouds was generated and processed, began the work on the identification of
structures, whose primary results are on the spatial position of structures and corresponding
analysis, and as an indirect result, there are the parameters necessary for use with the method to
this purpose. In order to investigate the accuracy of the method, in some more pronounced

Vol. 17 [2012], Bund. M 1823
fracture planes, the markup of planes through three points referenced, the short (of the order of
cm) and medium distances (the order of meters).
The recognition of planes in digital media is visual. A technique that helps on this recognition
is rotating the point cloud because it permits to visualize the plane on a different way. We
considered planes succession of points aligned in a certain perspective, so that from another
perspective these points form an approximately regular quadrangular mesh.
Each of the planes identified, represented from the coordinates of three of his referenced
points, was subjected to a calculation to determine their spatial position using analytic geometry.
The planes were put into a Schmidt-Lambert diagram and grouped into families, aiming to define
the structural patterns of the area. After the geotechnical analysis by means of structural
diagrams, these measures allow set in the mine which faces are subject to block removals (slip).
Its also possible determine forms and volumes of these blocks, allowing them to take preventive
or mitigating issue.
Methods of analysis of slopes
The stability of the mine tailings Saiva was investigated through a geometric analysis of the
structures highlighted in the digital model and field. It is, therefore, an analysis of level I, which
are the conventional application of kinematical analyses and limit equilibrium analyses and their
modifications, as specified by Stead and Coggan (2006). Stereographic structures projections and
geo-mechanical properties of the massive landslide were used in the evaluation of the second
planar structures, landslides wedge, using the Markland test (1972), and the toppling of blocks. In
general, the methods apply to the construction of overlays, which are superimposed on
stereographic projections jigs or polar structures of interest, constructed from the geometry of the
slope and angle of internal friction of the rock. The construction of overlays and projections came
through the program AutoCAD.
The measures of the average structures were obtained after the delimitation of isocurves
poles, when they determined the major concentrations of data centers being expressed by these
concentrations. The basic condition for application of stereographic projection to study the
stability of slopes in rock is the recognition that the angle of friction between surfaces can be
represented by a small circle in the stereographic projection. According to the definition of angle
of friction or friction (φ) that a block will remain at rest on a planar surface is the result of all
forces acting on the block to depart from the normal to the surface with an angle less than φ (Fiori
and Carmignani, 2009).
RESULTS AND DISCUSSION
Field Results and Method Limitations
The field experiments shows that some things could interfere in the results, like positioning
and number of stations (places where the equipment is installed), the presence of baffles and areas
of shading, resolution mesh points and the reference system adopted.
Placement of the stations must take into consideration some technical specifications of
equipment, such as distance from the equipment to the object being imaged, the incidence of light

Vol. 17 [2012], Bund. M
1824
on the
object, time
availability and range of
equipment, the mesh resolution, among others. The
number of stationss should be enough that there are no significant flaws in the image obtained so
as not to prejudice future analysis. Armesto et al. (2009) recommend using only two distinct
placements of equipment (stations) as necessary and sufficient for technology applications in
geomorphology.
Once the equipment promotes acquiring data through emanation and reflection of light
beams, these are only observed
and data obtained on thee object’s surface. Thus, the presence of
baffles (trees, people or other) between the scanner and the object prevents the attainment of the
object
data. This is consideredd by many authors (Sturzenegger and Stead, 2009; Barber et al.,
2008;
Dalmolin and Dos Santos, 2004) as an
important phenomenon to
be observed
in conducting
the tests. Similarly, areas of shading caused by the object itself, hinder the achievement of a
continuous grid of
points, providing loopholes in this. This effect can
be minimized / solved by
using more than one season (positioning device). The incidence of light on the equipment can be
adjusted internally in the software (Cyclone, for example) ) parameterizing the image
contrast.
The grid resolution must be obtained according to the characteristics of each scanner. In
general, most commercial equipment for external use permits millimetrical accuracy, depending
on the
distance-scanner object.
However, the higher thee resolution of the mesh, the longer the
acquisition of thesee will take So, for practical reasons, scanning is usually shown with resolutions
of the
order of centimeters (2
to 5cm), as shown inn Figure 2. The TLS can’t distinguish
automatically textures or filling of structures. Even visually on the digital model with this
resolution it’s not easy to be identified. For this reason, flat structures identified in
field mapping
have been ignored in the analysis.
Pesci et al. (2007), aiming
to get a digital topographic model, performed the comparison
between results obtained from terrestrial laser scanning equipment with aerial photogrammetry
and concluded that the two tools are complementary andd allow the obtaining of a quite accurate
model, at different scales (the scanner, in detail scale).
Figure 2: Example of pointt cloud view
Through identified and measured structures in the digital model, one can infer a structural
pattern of the imaged area. 112 planes were registered onn the east face
and 76 planes on the west
face of the mine, totaling 188 planes, consisting of three points referenced (564
coordinates).

Vol. 17 [2012], Bund. M 1825
There were identified planar structures in the dike of diabase image (DEM), which was excluded
from analysis.
These results are compatible with those reported by Figueira (1999), by Fiori (1993) and the
knowledge of the technicians of the mine. It’s possible to identify five groups (families) of major
structures, oriented in: N60E/75SE, N15W/60NE, N30E/75SE, and EW/65SW N40E/63NW.
These families of structures were employed to analyze the slope stability and removability of
blocks.
As done to the fracture planes, the TLS can be used to measure the spacing between fractures
as complementary geometrical parameters (besides their orientation and size and shape), for
determining the block geometry. It was done and its results are shown in Nagalli (2010). For
simplicity, a kinematic analysis of slopes is shown as an example of geotechnical use of the cloud
point from TLS.
Kinematic Analysis of Slopes
Kinematic analysis of rock slopes in the Saiva mine starts with the representation by means of
polar and cyclographic projection, of families identified as penetrative planes (188 planes) in
geological and structural surveys digital. These were represented by their poles. During the
surveys of the cloud of points, these 188 were grouped into six families together, which later
revealed five families together, represented by their median planes. We identified five families of
joints are used in the kinematic analysis of the mine tailings.
As determining measures of geological structures, measuring the slope of the sides of the
benches of the Saiva mine happened by coordinates referenced by three points. Three
measurements were taken and an average value adopted . The values obtained for these slopes
ranged from 64.1 to 75.1 degrees. Thus, for calculation purposes, we adopted an inclination of
70° to the strands and away from the slip direction in relation to dip direction of the slope face
value limit 20º. Regarding the friction angle of rock, for the purpose of generating diagrams, it
was observed an angle of internal friction, determined experimentally (Nagalli, 2010), equal to
30º. The acquisition of critical structures is obtained by rotating the overlay around the center of
the circle and observing which poles are overlapped by the zone of instability plotted.
The application for the overlay analysis of landslides in the second planar structures through
their overlapping and guidance under the dip direction of the four strands that currently exist in
the study area, ie strands N40E/70NW, N50W/70NE, N50W/70SW and N30E/70SE (slope of the
mine). The results are shown in Figure 3.

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1826
Figure 3: Results of kinematic analysis of landslides by structural planes for existing
sheds in
mine, represented in direction of diving

Vol. 17 [2012], Bund. M 1827
Applying the Markland test (1972), the analysis of sliding wedge proceeded, considering that
the mine develops excavations whose directions of the slopes (slopes of the mining front) are
N40E/70NW, N50W/70NE, and N50W/70SW N30E/70SE and slopes averaging 70 degrees.
Table 1 summarizes the results; pointing to miners the structures that associated to another
one can represent risk of disruption in the wedge. It means that miners must pay attention each
time during exploiting one of these structures (primary risk). Not included in table structures
whose ψ stood just next to the overlay (subsidiary risk), which are presented in Table 2.
Table 1: Summary table of landslides in wedge primary risks
STRUCTURES ORIENTATION
N30E/75SE N15W/60NE N60E/75SE EW/65S N40E/63NW
N40E/70NW x x x x
SLOPE
N50W/70NE
N50W/70SW x x x x x
N30E/70SE x x
Table 2: Summary table of risks side of landslides in wedge
STRUCTURES ORIENTATION
N30E/75SE N15W/60NE N60E/75SE EW/65S N40E/63NW
N40E/70NW x x x
SLOPE
N50W/70NE
N50W/70SW x x
N30E/70SE x x x x
The toppling of blocks was analyzed by an overlay. The analysis showed that there is no
possibility of overturning by block structures (joints) analyzed. This situation occurs because
minimum conditions are not met (Markland, 1972; Hoek and Bray, 1981; Walton, 1985).
Potential Uses of TLS
References were made, supplemented by experimental and field studies conducted, inferring
some potential uses for the application of a laser scanner tool in geological and geotechnical area.
They constitute, therefore, potential uses of the laser scanner in the area of geotechnical
engineering:

Vol. 17 [2012], Bund. M 1828
(a) Imaging of slopes in mines, aiming at the investigation of structures which could
destabilize the rock mass;
(b) Rockmass classification as shown by Nagalli (2010)
(c) Remote monitoring of slopes (or any slip back analysis) or buildings (differential
settlements);
(d) Definition of geometric properties (surface area, volume, center of gravity, etc..) and the
relation to the geological surface exposed (boulders, for example) and its commercialindustrial-scientific;
(e) Recognition of stratigraphic and structural features;
(f) Evaluating the surface roughness of breaking rock or concrete;
(g) Recognition of rock types, among others.
Greater process and recognition automation, and the use of the identified structures in slope
atability analysis, would allow, for example, the application of the technique in registration and
monitoring sections of roads or tunnels which are subject to falling rock blocks. Which means
that, the use of the scanner would allow a safer user operation, perhaps saving lives, and enable a
planning and prioritization of actions in areas of risk, including the acquisition of geological and
structural data in areas of difficult access.
CONCLUSIONS
The geotechnical study of rock slopes allows evaluation of its stability, increasing the
excavation safety and optimizing the economics and technical aspects. The laser scanner use
revealed a broad potential application in the study of slope stability. In addition some other
potential uses of the tool were investigated.
The goal of validating the application of this new imaging method was achieved by inferring
that mesh resolutions lifting the order of centimeters (2 to 5cm) are sufficient for geotechnical
applications. Thus, this new tool provides the possibility of immediate use in excavation of
tunnels, highway cuts, slopes monitoring, geotechnical and other activities.
The discrepancies between the measures of structures in the field and the measures obtained
from the digital model proved to be very small, ie a maximum of 3º more or less, as in the
direction as on the dip direction. This difference is attributed to the better or worse choice of the
three points which represents the plane.
Standing out as key advantages of this new method are the possibility of surveying the
geology and structure from a distance, especially in areas where access is difficult and / or
dangerous; the backup of field information which permits resolve, a posteriori, some doubts or to
complement data in mathematical and computational models, etc.

Vol. 17 [2012], Bund. M 1829
The numerous structural data which can be obtained through the laser scanning and processed
simultaneously increases the reliability of interpretations.
We recommend the use of histograms for tracking errors in transcribing data, whenever they
are done manually, as in the case study.
It must be emphasized that the limitations of applying this technique are that the surveys for
data acquisition must take place in good weather conditions, ie, no rain and that the equipment
examined Cyrax HDS-3000 should not be positioned at distances beyond 100 m from the object
be imaged. It is also evident that there can be no barriers (trees, people, other objects) arranged
between the scanner and the object, otherwise the image acquired failure. For this reason it is
recommended to use at least two scanning stations, not necessarily simultaneously, for analysis,
although in the case study the use of a single station has proved sufficient. Another point is that
this technique does not take the place of the field surveys, for example in identifying the complete
structure, condition of fluid percolation, etc..
The results show that the tool appears to giving accurate measurement of planes of rupture.
The range of variation of measures taken digitally was compatible with the observed field and the
ability simultaneously to work with large amount of data proves to be a differential. The preferred
directions of the field measurements are consistent with the results of digital analysis.
The digital model of the mine, geological and structural data could be brought up that
supported the analysis of slope slides along planar or wedge structures, depending on the spatial
layout of the recognized families together in the point cloud generated by the scanner. This
finding opens the way for the application of new methods of stability analysis and studies on
structural geology.
To the actual mine layout, the digital model obtained shows that the slip process could occurs
only trough the N40E/70NW mine face, considering the N60E/75SE, N30E/70SE and
N40E/63NW. However, analysis performed also recommends attention to the structure family
called number 5 (N40E/63NW) and number 2 and 3 (N15W/60NE and N30E/75SE,
respectively), which under certain conditions may facilitate planar slip.
Considering the sliding wedge, the N40E/70NW mine face is potentially instable. The sliding
structures associations are the N15W/60NE and N60E/75SE and the EW/65S and N40E/63NW.
Next to shed N50W/70SW, all structures analyzed (N30E/75SE, N15W/60NE, N60E/75SE, and
EW/65S N40E/63NW) are associated with slip wedge.
The analysis performed showed that there is no risk of tumbling blocks, considering
structures analyzed.
It is suggested for future work to automate the process of viewing, logging, coordinating,
measuring the planes and its integration among the various computational tools used, including
outputs for compatible programs capable of generating, for example, diagrams or others like the
Lambert-Schmidt type, that directly affect the geometrical analysis of rock slope stability.

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